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  • d -Glucosamine contributes to cell membrane stability and regenerative medicine
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-31
    Yoshihiko Hayashi

    d-glucosamine contributes to cell membrane stability. d-Glucosamine controls biological responses and protect both cells and tissues. This review focuses the mechanisms of stability in biomedical situations. Positively charged amino groups of d-glucosamine can bind the cell membrane electrically to protect against tissue damage. Wound healing can be accelerated by the application of a d-glucosamine dressing, which promotes cell proliferation and differentiation. d-Glucosamine has superoxide/hydroxyl radical scavenging activities, a strong chelating effect on ferrous ions, and enhances the reduced glutathione level to promote activity against intracellular oxidative stress. The prompt repair of microleakage through electropores on the cell membrane occurs after electroporation using d-glucosamine. The effects of this stability can also explain the pain relief as d-glucosamine binds to sodium channel to result in a longer open time. Furthermore, specific applications of d-glucosamine are proposed for the regenerative medicine.

  • Environmental-friendly one-pot cascade synthesis of 3-cyanopiperidin-2,6-diones
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-10-05
    Daniel Paprocki, Stanisław Berłożecki, Ryszard Ostaszewski

    Abstract 3-Cyanopiperidin-2,6-diones are key intermediates in the synthesis of several drugs and natural products. We developed one-pot synthesis of 3-cyanopiperidin-2,6-diones by Knoevenagel condensation of cyanoacetic acid and aldehydes, followed by addition of cyanoacetic acid, Achmatowicz reaction and decarboxylation. We tested a wide range of aliphatic and aromatic aldehydes. Products were obtained under simple, environmentally friendly conditions and in yields up to 99%. Substrates were stirred in toluene at reflux, and filtered through short pad of silica gel, and the product was purified by recrystallization.

  • Agricultural uses of chitin polymers
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-09-19
    Julia L. Shamshina, Adrian Kelly, Tetyana Oldham, Robin D. Rogers

    Abstract Due to strict legislation which governs the use of pesticides, fertilizers and plant growth regulators, there is a demand for organic alternatives. Potential risks for people, possible long-term health effects, and pesticide environmental fate resulted in a widespread societal issue. Because sustainable agriculture interconnects the economically and socially, the use of environmentally sound compounds has become popular. Improving plant growth using natural compounds such as chitin, a carbohydrate chain polymer, and its derivatives is a promising sustainable agriculture strategy. Chitin and its derivatives exhibit a unique mode of action being at the same time safe and non-toxic by nature. They are recognized as promising soil amendments for improving soil quality, induce abiotic and biotic plant stress tolerance, boost defense mechanism of plants against invading microorganisms, elicit the production of secondary metabolites, and protect the safety of edible products. Here, we review beneficial effects of chitin as a fertilizer, soil conditioning agent, plant disease control agent, antitranspirant, ripening retardant, and seed and fruit coating.

  • An efficient plant–microbe phytoremediation method to remove formaldehyde from air
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-22
    Yuxia Yang, Yuhong Su, Suya Zhao

    Abstract In 2012, 7 million premature deaths were attributed to air pollution, of which 4.3 million to indoor air pollution inducing the “sick building syndrome.” In particular, formaldehyde, a toxic and highly reactive chemical, has been linked to cancer. The use of soil microbial biomass and plants to remove formaldehyde from polluted air by plants has been proposed, but there are so far few quantitative reports. Here, we developed an efficient plant–microbe technology to remove formaldehyde by adding cultured microorganism into the rhizosphere of three plant species, Tradescantia zebrina Bosse (T. zebrina), Aloe vera (Haw.) Ber (A. vera) and Vigna radiata (Linn.) Wilczek (V. radiata). Shoots were exposed to 0.72 mg of formaldehyde per m3 of air for 24 h. Results show that formaldehyde removal rates were 23.1 ± 0.1 μg/h/g fresh weight with microbes versus 18.5 ± 0.21 μg/h/g without microbes for A. vera, 86.4 ± 0.7 versus 59.3 ± 0.2 μg/h/g for T. zebrine and 97.6 ± 0.9 versus 25.1 ± 4.2 μg/h/g for V. radiata. Overall, formaldehyde removal was increased by 6.7–90.5% using microbes. Formaldehyde removal was influenced by light intensity, with this effect more pronounced in plant–microbe systems.

  • Dish handwashing: an overlooked source of contamination
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-31
    Mojca Bavcon Kralj, Anja Fortuna, Anže Abram, Polonca Trebše

    Abstract Daily dishwashing is a common household activity. Washing dishes in a sink is considered safe for the environment because it requires few water and human energy. There are concerns, however, that residues from the detergent used may impact health and the environment. Here, we studied the adsorption and toxicity of two detergent ingredients, the biocide 1,2-benzisothiazol-3(2H)-one and the surfactant sodium dodecyl sulphate, left on tableware, cups and plates, made of glass, stainless steel, ceramic, plastic and wood. Results show that levels of biocide and surfactant residues were much higher on wooden plates, of 8.4 ng biocide cm−2 and 226.4 ng surfactant cm−2, than on glass, of 0.9 ng biocide cm−2 and 55.9 ng surfactant cm−2. Residues levels increase with material roughness. Toxicity analysis of compounds in water using the luminiscence of Vibrio fischeri revealed that toxic inhibition was much higher (20%) when the biocide and the surfactant were together than when the surfactant occurred alone (1.9%) or the biocide occurred alone (11.5%). Overall, our findings imply that, depending on the dish material and roughness, contaminants will be transferred either to humans through eating using contaminated dishes, or to wastewater and then to humans indirectly through contamination of natural waters.

  • Fate and risk of metal sulfide nanoparticles in the environment
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-03
    Khan Ashfeen Ubaid, Xiaoxia Zhang, Virender K. Sharma, Lingxiangyu Li

    Abstract With the rapid development of nanotechnology, metal sulfide nanoparticles have been widely detected in the environment including water, soils and sediments. Metal sulfides are considered as stable species in the environment, while transformation and risk of nanoparticles have attracted increasing attention due to their specific physicochemical properties compared to bulk materials. Here we review aggregation, sedimentation, chemical and biological transformations, and potential risk of silver sulfide (Ag2S), zinc sulfide (ZnS), copper sulfide (CuS), cadmium sulfide (CdS) and lead sulfide nanoparticles, and quantum dots such as ZnS and CdS. The review shows that both stability and risk of metal sulfide nanoparticles are highly dependent on environmental factors such as pH, inorganic salts and natural organic matter.

  • Sorbents for hydrogen sulfide capture from biogas at low temperature: a review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-19
    Dongjing Liu, Bin Li, Jiang Wu, Yangxian Liu

    Biogas, e.g., biomethane, is produced by fermentation of organic matter and can be used as an alternative fuel or as a raw material for the production of hydrogen and syngas. However, biogas includes hydrogen sulfide (H2S) as a byproduct of fermentation. Hydrogen sulfide is toxic, has a foul odor, corrodes equipments, and deactivates catalysts. Thus, hydrogen sulfide has to be removed before biogas combustion or conversion. Compared with classical wet desulfurization, low-temperature dry desulfurization is of interest due to higher desulfurization, simpler operation, less pollution, and less energy consumption. Here, we review solid sorbents for low-temperature biogas desulfurization, such as activated carbon, metal-exchanged zeolites, single metal oxides, composite metal oxides, ordered mesoporous silica, and metal–organic frameworks.

  • Dual-network design to enhance the properties of agar aerogel adsorbent by incorporating in situ ion cross-linked alginate
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-09-25
    Dajian Huang, Qiling Quan, Yuting Zheng, Wenjie Tang, Zhuo Zhang, Xiaohu Qiang

    Natural and synthetic adsorbents are used to remove contaminants from polluted waters. In particular, polymer-based aerogels are promising but their adsorption capacity and dimensional stability should be improved. Here we propose a new design strategy to prepare a dual-network aerogel, consisting of physical cross-linked agar and Ca2+ cross-linked sodium alginate as the first and second networks, respectively. After introducing cross-linked sodium alginate into the agar matrix, the morphology of the agar aerogel transformed from a distinct layered structure to a co-continuous network. The swelling degree ratio of the agar aerogel is reduced, and the dimensional stability was improved by introducing ion cross-linked sodium alginate into the agar matrix. The aerogels were used as adsorbents to remove methylene blue from aqueous solutions. The adsorption capacity of the agar aerogel was remarkably improved by adding sodium alginate due to the increase in electrostatic attraction and adsorption site.

  • Enhanced abatement of organic contaminants by zero-valent copper and sulfite
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-24
    Xiaodan Zhao, Ying Wu, Danying Xing, Zhaojin Ren, Lingfeng Ye

    Sulfate radicals (SO4·−) are highly efficient for the degradation organic pollutants. SO4·− can be produced by activation of sulfites, yet actual heterogeneous activators exhibit a lower reactivity for activation of sulfite to SO4·− at pH 7.0–8.0. Here we hypothesized that zero-valent copper can activate sulfite under mild conditions. We tested the reaction with iohexol, diatrizoate, atrazine, benzoic acid, and p-chlorobenzoic acid contaminants. Reactive radicals were identified by electron paramagnetic resonance, fluorescence spectrometry, and radical scavenging experiments. Results show up to 90% abatement of contaminants by combining sulfite with zero-valent copper at pH 8.0. Moreover, zero-valent copper maintains a crystalline stability and satisfactory reusability with iohexol abatement efficiency up to 80% after five runs.

  • Chitosan role for shelf-life extension of seafood
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-10-05
    Piotr Kulawik, Ewelina Jamróz, Fatih Özogul

    Chitosan, a deacetylated derivative of chitin, has many functional properties that can be used for processing, preservation and as food additive. Chitosan application can be done by edible coatings, direct addition to the batter, and tumbling in the chitosan solution. Chitosan exhibits antioxidant and antimicrobial properties. Here we review applications of chitosan in seafood products and effects on the shelf life of the stored product. Chitosan treatment is effective against two main spoilage factors of seafood: increased oxidation and microbiological spoilage. Chitosan treatment avoids the decrease of sensory scores during storage, and prolongs shelf life of chitosan-treated seafood products.

  • Fenton oxidation for effective removal of color and organic matter from denim cotton wastewater without biological treatment
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-10
    Seval Sözen, Tugba Olmez-Hanci, Masoomeh Hooshmand, Derin Orhon

    Denim is a cotton fabric specifically used to manufacture jeans. Denim processing generates complex effluents with high levels of pumice stone, color and chemical oxygen demand (COD). There is therefore a need for advanced treatment methods to limit pollution of natural waters. Here, we hypothesized that Fenton oxidation, a method using Fe2+ and H2O2, could replace the traditional step of activated sludge treatment. We studied a daily composite sample at laboratory scale for preliminary settling, chemical settling and Fenton oxidation. We found that pumice stone can be effectively controlled by preliminary settling with partial COD removal and limited color removal. Chemical treatment improved COD removal, but color reduction still remained partial. Fenton oxidation decreased color below visual detection after 5 min and COD decreased to 110 mg/L after 30 min. These findings surpassed the performances of activated sludge treatment.

  • CO 2 capture from coalbed methane using membranes: a review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-05
    Na Zhang, Zhen Pan, Zhien Zhang, Wenxiang Zhang, Li Zhang, Francisco M. Baena-Moreno, Eric Lichtfouse

    Coalbed methane is an abundant form of natural gas extracted from coal beds. Coalbed methane is viewed as a cleaner energy source versus petroleum and coal combustion because methane extraction, transport and use are more efficient and less polluting. However, coalbed methane contains high amounts of CO2 that induce solidification during liquefaction. Therefore, CO2 has to be reduced below 2% to meet the pipeline transportation standards. In addition, CO2 capture would reduce the amount of gas emissions to the atmosphere, thus mitigating global warming. Here, we review membrane absorption, which is an advanced method for CO2 capture from coalbed methane, by controlling the gas and liquid phases separately during the operation process. We compare CO2 removal methods for various coalbed methane sources. Parameters influencing CO2 removal by membrane absorption are discussed to conclude that CO2 capture efficiency is improved by increasing the flow rate, temperature, and absorbent concentration, reducing the gas flow rate, and selecting a mixed absorbent. We also explain the principles, processes and applications of CO2 membrane absorption.

  • Water monitoring using polymer inclusion membranes: a review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-09-18
    Bambang Kuswandi, Fidelis Nitti, M. Inês G. S. Almeida, Spas D. Kolev

    Water monitoring by conventional analytical methods is often complicated, time-consuming and laborious, requiring highly skilled personnel, thus calling for simpler, rapid and cost-effective methods. Polymer inclusion membranes (PIM) are of interest in environmental analysis due to their selectivity and sensitivity for the detection of a wide range of analytes such as metals. PIM have been used in the development of passive sampling, analyte separation and preconcentration, and sensing. PIM are also suitable for the automation of chemical analysis. Here we review PIM applications in environmental water monitoring.

  • Determination of Cr(III) and Cr(VI) in water by dual-gel electromembrane extraction and a microfluidic paper-based device
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-09
    Hadi Tabani, Farzaneh Dorabadi Zare, Waleed Alahmad, Pakorn Varanusupakul

    Abstract A major goal of green chemistry is to avoid the use of toxic organic solvents. In particular, there are few green methods allowing extraction and quantification of chromium species in environmental samples. Here, we developed home-made, dual-gel electromembrane extraction combined with a microfluidic paper-based analytical device for the simultaneous determination of Cr(III) and Cr(VI) in water, without using any organic solvent. The positively charged Cr(III) and negatively charged Cr(VI) migrated selectively into the cathodic (pH 2.0) and anodic (pH 3.0) aqueous acceptor phases, respectively. After extraction, the anodic acceptor phase containing Cr(VI) was analyzed directly by a microfluidic paper-based analytical device, after the addition of the diphenylcarbazide colorimetric reagent. The cathodic acceptor phase containing Cr(III) was mixed with Ce(IV) to oxidize Cr(III) to Cr(VI), and then, Cr(VI) ions were detected on the microfluidic paper-based analytical device after adding diphenylcarbazide. Under the optimized conditions, limits of detection of 2.0 and 3.0 ng/mL and extraction recoveries of 58.8% and 83.3% were achieved for Cr(VI) and Cr(III), respectively.

  • How to distinguish natural versus engineered nanomaterials: insights from the analysis of TiO 2 and CeO 2 in soils
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-26
    Zebang Yi, Frédéric Loosli, Jingjing Wang, Debora Berti, Mohammed Baalousha

    Abstract Increasing amounts of engineered nanomaterials such as TiO2 and CeO2 are released into air, waters, soils, and sediments. However, assessing the human-made origin of those nanomaterials is rather difficult because Ti- and Ce-rich particles are naturally present in soils and sediments at concentrations typically much higher than estimated concentrations of engineered nanomaterials. In addition, analysis is complicated by the interactions and aggregation of nanoparticles with environmental particles. Therefore, more knowledge on the properties of natural nanomaterials is needed to distinguish engineered nanomaterials in natural systems. Here, we extracted soil nanomaterials with six extractants and compared recovery and disaggregation to primary particles. Nanomaterials were characterized for hydrodynamic diameter and zeta potential by dynamic light scattering, size-based elemental distribution by field-flow fractionation coupled with inductively coupled plasma-mass spectroscopy, and morphology by transmission electron microscopy. Results show that nanomaterial concentrations increased from CH3COOH–NaCl–water (lowest), to water or NaCl–water, Na2CO3, Na4P2O7, and NaCl–Na4P2O7 (highest). Na4P2O7 was the most efficient extractant that induced the release of primary nanomaterials from microaggregates. Although sodium carbonate extracted relatively high concentrations of nanomaterials, the extracted nanomaterials occurred mainly as aggregates of primary nanomaterials. Ultrapure water, sodium chloride and acetic acid resulted in poor nanomaterial extraction and broad size distributions. Elemental ratios illustrate that Ti is associated with Nb, Ta, and V, and that Ce is associated with rare earth elements such as La, Eu, Y, Ho, Er, Tm, and Yb. Our findings indicate that size, size distribution, and elemental ratios can be used as fingerprints to differentiate engineered nanomaterials such as TiO2 and CeO2 from natural nanomaterials in complex media.

  • Methods for preparation and activation of activated carbon: a review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2020-01-04
    Zoha Heidarinejad, Mohammad Hadi Dehghani, Mohsen Heidari, Gholamali Javedan, Imran Ali, Mika Sillanpää

    Activated carbon refers to a wide range of carbonised materials of high degree of porosity and high surface area. Activated carbon has many applications in the environment and industry for the removal, retrieval, separation and modification of various compounds in liquid and gas phases. Selection of the chemical activator agent is a major step controlling the performance and applicability of activated carbon. Here, we review chemical activators used to produce activated carbon. We compare the impregnation method with the physical mixing method used in activating with alkali hydroxides. We selected 81 articles from Google Scholar, PubMed, Scopus, Science Direct, Embase and Medlin databases. Eighteen articles report the activation with potassium hydroxide, 17 with phosphoric acid, 15 with zinc chloride, 11 with potassium carbonate, nine with sodium hydroxide, and 11 with new activating agents. Activation with phosphoric acid is commonly used for lignocellulosic material and at lower temperatures. Zinc chloride generates more surface area than phosphoric acid but is used less due to environmental concerns. Potassium carbonate, in comparison with potassium hydroxide, produces higher yields and a higher surface area for the adsorption of large pollutant molecules such as dyes. Activating with potassium hydroxide in terms of surface area and efficiency shows better results than sodium hydroxide for various applications. Also, the comparison of the physical mixing method and the impregnation method in activation with alkali metals indicates that the activated carbon obtained through physical mixing had a higher porosity than the activated carbon produced by the impregnation method.

  • Cleaning chromium pollution in aquatic environments by bioremediation, photocatalytic remediation, electrochemical remediation and coupled remediation systems
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2020-01-04
    Caiwen He, Lipeng Gu, Zhixiang Xu, Huan He, Gen Fu, Fengxia Han, Bin Huang, Xuejun Pan

    Abstract Industrialization such as metallurgy, papermaking, chemicals, electroplating and tanning is contributing to the pollution of ecosystems by chromium (Cr). Cr pollution has many sources and high toxicity. Indeed, Cr(VI) is a strong oxidizing agent and, as a consequence, Cr(VI) bioaccumulation may induce acute, subacute or chronic poisoning, mutagenesis, carcinogenesis and teratogenesis. Cr(VI) is usually very mobile and highly soluble in aqueous solutions, but Cr(III) is not. Cr(III) is relatively stable and less toxic than Cr(VI). Thus, some remediation techniques aim to reduce Cr(VI) to Cr(III). Herein, we review bioremediation, photocatalytic remediation, electrochemical remediation and coupled remediation systems. We found that Cr(VI) remediation using coupled systems is relatively easier and more efficient, compared with other treatment systems. This review provides a basis for the development of high-efficiency Cr(VI) removal systems suitable for industrial applications.

  • Advanced methods to analyze steroid estrogens in environmental samples
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2020-01-03
    Congwen Li, Yunlin Wei, Shenting Zhang, Wenli Tan

    Contamination of waters, soils, sediments and other environmental media by steroid estrogens is an emerging health issue because estrogens exhibit toxic effects on fishes and animals. Levels of steroid estrogens vary widely, ranging from below the detection limit to hundreds of nanograms per liter. Estrogens alter hormone levels and the homeostasis system of living organisms, they increase the risk of cardiovascular diseases, prostate cancer and breast cancer in humans and they may induce reproductive disorders, fetal malformations and feminization of males. Here, we review detection methods of steroid estrogens in water samples. Methods mainly include chemical analysis, immunoassays and bioassays. Advanced sensors increase the selectivity and sensitivity of electrochemical assays. For instance, graphene-based sensors can decrease the detection limit to 50 fM, though estrogen analogues may interfere. Immunoassays such as ELISA have the advantages of high sensitivity, fast analysis speed and wide applicability from 2 to 4000 ng/L, though it is susceptible to cross-reactivity.

  • Plasmonic nanoparticles for environmental analysis
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2020-01-03
    Karol Kołątaj, Jan Krajczewski, Andrzej Kudelski

    Gold and silver nanoparticles have unique optical properties. For instance, the intense colour of nanoparticle suspensions results from the excitation of a collective oscillation of surface conduction electrons, named surface plasmons. This excitation is done using an electromagnetic radiation that interacts with nanoparticles having a negative real and small positive imaginary dielectric constant, such as nanoparticles of gold or silver. The plasmonic optical properties of metal nanostructures are dependent on their shape and size, the dielectric properties of the metal and the surroundings and on the possible electromagnetic coupling with the localized surface plasmons in nearby other plasmonic objects. The other important consequence of the excitation of surface plasmons is a local significant enhancement of the electromagnetic field at some places of the illuminated nanoparticles. Specific plasmonic properties of gold and silver nanoparticles have allowed the development of many sensors for chemical analysis, including sensors dedicated for environmental analysis. Some of these sensors are so sensitive that recording of the reliable analytical signal of a single molecule is possible. Here, we review analytical techniques based on plasmonic properties of metallic nanoparticles for environmental analysis. We present the theory and mechanism of interaction of the electromagnetic radiation with the plasmonic nanoparticles. We detail analytical techniques including methods utilizing local enhancement of the intensity of the electromagnetic field induced by plasmons, and hence increase in the efficiency of some optical processes in the proximity of the plasmonic nanoparticles. Those techniques are surface-enhanced Raman scattering, surface-enhanced infrared absorption and metal-enhanced fluorescence and methods based on the change in the optical properties of plasmonic nanoparticles caused by the analyte-induced aggregation or by analyte-influenced growth or etching of plasmonic nanostructures. Environmental compounds include heavy metal cations, metallo-organic compounds, polycyclic aromatic hydrocarbons, pesticides, nitrite ions, bacterial cells and bacterial pathogens.

  • Photocatalytic oxidation removal of elemental mercury from flue gas. A review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-19
    Dongjing Liu, Bin Li, Jiang Wu, Yangxian Liu

    Air pollution caused by mercury emissions from combustion and pyrolysis of fossil fuels, biomass, and solid wastes is a major health issue. Elemental mercury (Hg0), the dominant species in flue gas, is poorly captured by actual control equipments because Hg0 has a high volatility and is insoluble in water. Alternatively, photocatalytic processes can oxidize Hg0 into Hg compounds that are easier to remove. Here we review the recent research on oxidative removal of Hg0 by photocatalysts, with focus on titanium dioxide, bismuthides, silver compounds and hybrid photocatalysts. We discuss the Hg0 removal performances and mechanisms of catalytic oxidation. The TiO2 photocatalyst often suffers from low absorption of solar energy and easy recombination of photoinduced electron–hole couples. BiOIO3 appears as a promising photocatalyst due to its high Hg0 oxidation activity under visible light irradiation. Silver carbonates and silver halides are newly developed visible-light-responsive photocatalysts for Hg0 removal. Fast separation and transformation of photogenerated electrons and holes control the performance of Hg0 removal by photocatalysts.

  • Enhanced Cr reduction and bioelectricity production in microbial fuel cells using polypyrrole-coated MnO 2 on carbon cloth
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-18
    Xiang Liu, Weifen Yin, Xin Liu, Xiaohua Zhao

    Hexavalent chromium (Cr(VI)) is a carcinogenic pollutant that can be transformed into less toxic trivalent chromium (III). Microbial fuel cells can be used simultaneously to reduce wastewater Cr(VI) and to generate bioelectricity, yet actual cell cathodes are not well-optimized for high performance. Here, we tested the reduction of Cr(VI) using an abiotic cathode made of carbon cloth coated by polypyrrole-coated turf-like manganese dioxide in a two-chamber cell. Results show a 100% Cr(VI) removal within 32 h using an initial catholyte at pH 2 and 50 mg L−1 Cr(VI). The reduction rate of 1.56 mg L−3 h−1 is 175% higher than for the bare carbon cloth cathode, of 0.89 mg L−3 h−1. The maximum power density of 1429 mW m−2 was higher than that for the polypyrrole cathode, of 1017 ± 65 mW m−2, the MnO2 cathode, of 648 mW m−2, and the carbon cloth cathode, of 595 mW m−2. Noteworthy, Cr reduction was efficient without the use of electron transfer mediators such as anthraquinone-2,6-disulfonate. Moreover, polypyrrole allowed an excellent stability of the electrode under acidic conditions.

  • Reduced smoke and nitrogen oxide emissions during low-temperature combustion of ethanol and waste cooking oil
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-18
    Avinash Alagumalai

    Air pollution is a major issue affecting the health of millions of citizens, notably in cities where pollutants are concentrated. Low-temperature combustion is a promising route to reduce nitrogen oxides and smoke emissions from compression ignition engines. Reduction in emissions during low-temperature combustion is known, yet emissions using oxygenated biofuels are poorly known. Therefore, I tested the potential reduction in emissions using oxygenated biofuels during low-temperature combustion, in the reactivity-controlled compression ignition mode. Ethanol, a low-reactivity fuel, was inducted in the intake manifold at 10% and 20% levels on energy basis, whereas waste cooking oil biodiesel, a high-reactivity fuel, was injected directly inside the cylinder. Results show a reduction in emission of nitrogen oxides up to 60%, and of smoke up to 29%. Nonetheless, unburned hydrocarbons and carbon monoxide emissions increased up to 2% at full load for biodiesel with 20% ethanol induction, compared to neat diesel and biodiesel.

  • Sustainable wool fibers dyeing using henna extract in non-aqueous medium
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-14
    Omer Kamal Alebeid, Liujun Pei, Wenlong Zhou, Jiping Wang

    Dyeing processes usually consume a large amount of water and toxic chemicals, thus inducing environmental pollution. Therefore, we have designed here an eco-friendly process of dyeing wool fibers using natural dyes extracted from henna leaves in decamethyl cyclopentasiloxane. In this process, traditional hazardous metallic mordants and heavy metal salts were substituted by safe chitosan to pretreat wool fibers. Decamethyl cyclopentasiloxane was used to reduce the consumption of the high amount of water needed in traditional dyeing. Chitosan-treated and untreated samples were dyed with different henna extract/decamethyl cyclopentasiloxane suspensions at 40 °C, 60 °C, 80 °C and 90 °C. Results showed that dye uptake, fixation rate and apparent color depth of the samples dyed in henna extract/decamethyl cyclopentasiloxane suspensions were higher than water-based dyed samples. The dye uptake of samples dyed using our system reached 80–98%, as compared with 70–75% for water-based dyed samples; accordingly, the color strength and fixation rate were increased.

  • Eco-friendly preparation of superhydrophobic copper surfaces for oil/water separation
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-10
    Ravi Kant Upadhyay, Prashant R. Waghmare

    Copper surfaces decorated with micro- and nanostructures can be applied to self-cleaning superhydrophobic surfaces, energy devices and pollution remediation. Wet chemical etching is the classical strategy to grow micro- and nanostructures on copper surfaces. However, such processes usually produce hazardous chemical waste. Here, we present a one-step, eco-friendly and solvent-less alternative to conventional wet chemical methods. Our method involves the use of volatile compounds released from yolk and egg white of boiled chicken eggs as green oxidants for the growth of micro- and nanostructures on the copper surface. After treatment with egg components, copper substrates were modified with stearic acid to make them superhydrophobic. Stearic acid-coated substrates had a contact angle of about 150°, thus confirming their superhydrophobicity. Similar to copper sheets, superhydrophobic copper meshes were also prepared and used for the selective removal of oil from oil/water mixture. Results show that our method produces a wide range of shapes including hollow and solid spheres, nanoflakes, nanoneedles and dome shapes. We found that H2S, the major volatile compound emitted by eggs, is mainly responsible for the growth of microstructures. Therefore, our method can be used both to capture H2S and to design specific surfaces. The mesh exhibited excellent separation efficiency, more than 95% for the organic solvents. A key advantage of our method is that it can be performed also using waste and expired eggs.

  • Removal of phenolic substances from wastewater by algae. A review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-12-04
    Caisong Zhang, Xiuju Wang, Zhun Ma, Zhen Luan, Yingying Wang, Zhongpeng Wang, Liguo Wang


  • Recovery of vanadium with urea in acidic medium
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-12
    Hao Peng, Liu Yang, Lilian Wang, Jing Guo, Bing Li

    Classical hydrometallurgy methods such as chemical precipitation, ion exchange, solvent extraction and adsorption have been used to recover vanadium from aqueous solutions, but the last step of these methods involves precipitation with ammonium salts, which are harmful to the environment at high concentration. Therefore, here we tested urea as a new precipitant to replace ammonium salts. We studied the effect of various parameters on the precipitation efficiency of vanadium. Results showed that urea is hydrolyzed to form NH4+ in acidic medium at 90 °C. Then, NH4+ reacts with V6O162− and precipitates as (NH4)2V6O16. Nearly 95% of the vanadium was precipitated within 120 min in the system containing 2.8 g/L vanadium and n(CON2H4)/n(V) of 0.6. The Avrami model was used to describe crystallization kinetics and analysis of the dimensions of crystal growth. Model results show that the crystalline growth was one-dimensional and that the crystals were shaped in columns. Overall, this study introduced a new way for urea utilization as a new precipitant to recover vanadium.

  • Palladium nanoparticles supported on silica, alumina or titania: greener alternatives for Suzuki–Miyaura and other C–C coupling reactions
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-04
    Miguel Díaz-Sánchez, Diana Díaz-García, Sanjiv Prashar, Santiago Gómez-Ruiz

    Most of the catalytic systems for C–C coupling reactions are based on homogeneous catalysts which are normally used only once and do not have a sustainable molecular economy, as they cannot be easily separated from the reaction products to be subsequently recycled and used in other catalytic cycles. The alternative use of heterogeneous catalytic systems, which follow better the principles of green chemistry, is of current environmental and industrial interest for C–C coupling reactions. In this context, although heterogeneous C–C coupling catalysis research has a long history focused on the development of palladium nanoparticles, this field still has several drawbacks to overcome and is an area in continuous evolution, which has developed novel systems based on reusable supported palladium nanoparticles or supported palladium complexes with improved catalytic properties. In this review, the recent research developments of novel hybrid nanostructured materials based on silica, titania and alumina as efficient supports for palladium complexes or palladium nanoparticles are revisited, with special regards to synthetic methodology, characterization methods and catalytic performance. The most relevant results concerning the improvement in the environmental impact of the use of palladium complexes or palladium nanoparticles supported onto silica, titania and alumina reported in the last 10 years on Suzuki–Miyaura and other C–C coupling reactions of interest are also described.

  • Advances in the antimicrobial and therapeutic potential of siderophores
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-04
    Marta Ribeiro, Manuel Simões

    The increasing bacterial resistance from antibiotic overuse has fostered the search for novel antimicrobial strategies. In particular, bacterial systems involving iron (Fe) uptake are studied to develop new therapeutics against infectious diseases, because iron is crucial for bacterial growth and is a main virulence factor for infection. Iron assimilation is commonly based on the production of siderophores, which are iron chelators produced to facilitate iron uptake. Siderophores are thus crucial for bacterial pathogenicity. Here we review the antimicrobial and therapeutic potential of siderophores. There are three main approaches for siderophore application in antimicrobial therapy: siderophore-mediated drug delivery, inhibition of siderophores biosynthesis and iron starvation by competitive chelation. Major advances on the use of siderophores as therapeutic agents for disease treatment are also presented.

  • Textiles for health: a review of textile fabrics treated with chitosan microcapsules
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-08-21
    Daniele Massella, Stéphane Giraud, Jinping Guan, Ada Ferri, Fabien Salaün

    The textile industry has recently been developing innovative products that integrate functional properties within commodity textiles. In particular, research has focussed on the concept of biofunctional textiles, i.e., textile materials possessing beneficial properties for human health. Biofunctional textiles are synthesised by functionalization of fabric surfaces with biopolymers. As an example, the chitosan biopolymer is promising for textile functionalization due to chitosan availability, low cost, safety and unique properties. Yet several challenges have to be overcome. Firstly, the morphology of chitosan must be optimized prior chitosan application to the textile surface. Secondly, the last treatment must be carefully designed in order to achieve an effective and durable functionalization. Lastly, the overall production process must comply with environmental rules concerning pollution emission and utilization of harmful substances. This review describes microencapsulation as a strategy to overcome limitations and to confer better properties to the textile material. The properties of chitosan and the concept of microencapsulation are presented. Then we present the main techniques of chitosan encapsulation. Furthermore, we detail the textile finishing processes and the textile products. Last, the perspectives are discussed in the context of green chemistry and compliance with an environmentally friendly approach.

  • Biochar-derived heterogeneous catalysts for biodiesel production
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-28
    Muthusamy Balajii, Subramaniapillai Niju

    Population increase, urbanization and industrialization induce a drastic need for energy. Actually, fossil fuel resources are heavily exploited to meet the energy demand and result in the emission of greenhouse gases. Alternatively, biodiesel is a renewable fuel produced by transesterification of biomass lipidic feedstocks. Biodiesel is a renewable fuel that can replace fossil diesel. Short-chain alcohols and efficient catalysts are required for biodiesel production. For instance, biochar can be used as a heterogeneous catalyst for biodiesel production owing to its high surface area and porosity. Biochar is a low-cost, carbon-rich material produced by pyrolysis of plant biomass. Here, we review the production, activation, and application of biochar, with focus on characteristics of biochar-derived catalysts, such as surface chemistry, thermal stability, total acidity or basicity, structural morphology, and elemental composition. We also present the developments of biochar-based catalysts from various biomass sources for biodiesel production.

  • Treatment of fluoride-contaminated water. A review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-19
    P. Senthil Kumar, S. Suganya, S. Srinivas, S. Priyadharshini, M. Karthika, R. Karishma Sri, V. Swetha, Mu. Naushad, Eric Lichtfouse

    Delivering the right amount of fluoride to drinking water protects the teeth from decay and reduces the risk of cavities. Nonetheless, fluorosis has been diagnosed as the result of excessive exposure of fluoride, which induces brain impairment, muscle disorders and hyperactivity. Fluoride ingestion during the formation of the tooth enamel is the main reason for fluorosis, which is characterized by hypomineralization. Dissolution of fluoride-containing rock minerals contributes to naturally occurring fluoride contamination in water. The intentional addition of fluoride to water in dental care is alarming in growing countries such as India. This article reviews the origin of fluoride, the analysis of fluoride derivatives and the technologies to remove fluoride from water. The manuscript presents adsorption techniques for fluoride removal, using different types of adsorbents. The adsorption capacities of adsorbents under various conditions, such as contaminant concentration, adsorbent dosage, time, pH and temperature, are presented. Adsorbent types include alumina, zeolites, organic waste, shell-based and carbon-based including graphite and carbon nanotubes. Defluoridation of water using clays and muds, modified activated alumina, chitosan derivatives and composites are also discussed.

  • Organic ligands unexpectedly increase the toxicity of chromium(III) for luminescent bacteria
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-22
    Weijie Zhou, Wenjun Long, Teng Xu, Liangqiong Peng, Wenhua Zhang

    Organic ligands are commonly believed to decrease the toxicity of metal ions, but there is few experimental evidence, especially for chromium (Cr(III)), which often coexists with organic compounds in industrial effluents. Here, the complexation of Cr(III) with acetate, lactate, l-tartrate, biphthalate and oxalate was tested under the conditions of a toxicity test, with high ion strength, by spectroscopic techniques. The stability constants of the complexes were found to follow the order Cr(III) oxalate > Cr(III) lactate > Cr(III) biphthalate > Cr(III) L-tartrate > Cr(III) acetate. Then, aquatic toxicity of Cr(III) to Photobacterium phosphoreum for a 15-min exposure period was tested in the absence and presence of organic ligands. Results unexpectedly show that the complexation of Cr(III) with acetic, lactate, l-tartrate and biphthalate resulted in enhanced toxicity to luminescent bacteria, whereas the coordination of Cr(III) with oxalate sharply alleviated the toxicity of individual oxalate and inorganic Cr(III), which was further confirmed by the scanning electron microscopy (SEM). Our findings show thus that organics do not always mitigate the toxicity of Cr(III) in acidic water.

  • Nanocarrier-mediated co-delivery systems for lung cancer therapy: recent developments and prospects
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-06-12
    Muhammad Asim Farooq, Md Aquib, Daulat Haleem Khan, Sana Ghayas, Anam Ahsan, Muhammad Ijaz, Parikshit Banerjee, Maqsood Ahmed Khan, Muhammad Masood Ahmad, Bo Wang

    Research has recently focused on combinational therapy using nanocarriers to overcome the obstacles associated with conventional therapy of lung cancer. The classical therapeutic approach is indeed insufficient for suppressing tumor growth. Simultaneous delivery improves therapeutic outcomes, synergistic effects, and targeting moiety. Besides, multidrug-loaded nanocarriers allows the consecutive release of two or more drugs and genes. A such nanodrug delivery system reduces drug–drug interactions and improves the pharmacokinetics profile of loaded drugs. Currently, nanotechnology-based co-delivery system is the only suitable option for lung cancer therapy. Combinational delivery systems show promising results for the treatment of lung cancer. Here we review the design and development of co-delivery systems based on nanocarriers for effective cancer treatment.

  • Applications of chitosan in food, pharmaceuticals, medicine, cosmetics, agriculture, textiles, pulp and paper, biotechnology, and environmental chemistry
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-13
    Nadia Morin-Crini, Eric Lichtfouse, Giangiacomo Torri, Grégorio Crini

    Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the exoskeletons of arthropods such as crustaceans, e.g., crabs, lobsters and shrimps, and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians. The discovery of chitin in 1811 is attributed to Henri Braconnot while the history of chitosan dates back to 1859 with the work of Charles Rouget. The name of chitosan was, however, introduced in 1894 by Felix Hoppe-Seyler. Chitosan has attracted major scientific and industrial interests from the late 1970s due to its particular macromolecular structure, biocompatibility, biodegradability and other intrinsic functional properties. Chitosan and derivatives have practical applications in the food industry, agriculture, pharmacy, medicine, cosmetology, textile and paper industries, and in chemistry. In recent years, chitosan has also received much attention in dentistry, ophthalmology, biomedicine and bioimaging, hygiene and personal care, veterinary medicine, packaging industry, agrochemistry, aquaculture, functional textiles and cosmetotextiles, catalysis, chromatography, beverage industry, photography, wastewater treatment and sludge dewatering, and biotechnology. Nutraceuticals and cosmeceuticals are actually growing markets, and therapeutic and biomedical products should be the next markets in the development of chitosan. Chitosan is also the object of numerous fundamental studies. In this review, we highlight a selection of works on chitosan applications published over the past two decades.

  • Will nano-biosorbents break the Achilles’ heel of biosorption technology?
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-23
    Courtie Mahamadi

    Release of toxic substances into public waterways continues unabated, despite concerted efforts to minimize environmental pollution. In particular, heavy metals and dyes are problematic due to their toxicity and persistence in the environment. As a consequence, remediation technologies such as biosorption have been designed, but biosorption applications have rarely been used at industrial levels. More recently, research has sought to harness the unique properties of nanotechnology by developing biosorbents at nanoscale, e.g. nano-biosorbents. Here I review principles and applications of nano-biosorbents. The major points are the following: (1) nano-biosorbents offer unique properties such as high surface area, which boosts the chemical activity and adsorption capacity, increase surface binding energy, and reduce internal diffusion resistance; (2) performances of nano-biosorbents are improved by encapsulation of nano-biosorbents in materials such as alginate polymers, chemical and biological modification of the raw biomass, and magnetic modification by incorporating materials such as magnetite; (3) use of nanoparticles with magnetic properties allows for rapid and efficient separation by using an external magnetic field, thus presenting a possibility for online separation and point-of-use water purification as well as sorbate and biosorbent recovery; (4) green engineered nanoscale zero-valent metals such as zero-valent iron and zero-valent silver have shown greater potential due to their high reducibility and large specific surface area; and (5) nano-biosorbents have shown great potential for the removal of dyes and heavy metals, and for the recovery of precious metals.

  • Evidence for regional heterogeneous atmospheric particulate matter distribution in China: implications for air pollution control
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-10
    Rui Feng, Hui-jun Zheng

    China has suffered from severe nationwide air quality degradation for decades. PM2.5, the atmospheric particulate matter with an aerodynamic equivalent diameter of less than 2.5 μm, is the most concerning atmospheric pollutant for heath. Pollution control policies are commonly applied nationwide, but atmospheric pollution may vary from one area to another, thus suggesting the need for different, adapted policies. However, there is little knowledge on pollution distribution in China. Therefore, here we used recurrent neural network and random forest models to analyze the wintertime regional PM2.5 patterns in four most polluted cities of China, which are Beijing, Shanghai, Guangzhou and Chengdu, from December 2014 to February 2019. We find that different megacities in China have completely different PM2.5 patterns, which remained unchanged during the past 6 years. CO plays a predominant role in shaping PM2.5 nationwide, and the importance of CO varies from region to region. Therefore, different regional PM2.5 control policies should be carried out for better regulation. Furthermore, we demonstrate that PM2.5 is not strongly linked with time series, inferring that PM2.5 concentrations at a given date are not linked with previous PM2.5 concentrations. This finding suggests that the chemical reaction equilibrium may get reversed and that the rate of chemical reactions of PM2.5 is faster than we normally think.

  • Enhanced bioleaching of copper from circuit boards of computer waste by Acidithiobacillus ferrooxidans
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-20
    Mohan Annamalai, Kalaichelvan Gurumurthy

    Computer circuit boards are a major electronic waste containing higher concentrations of copper, gold and silver. These metals may be recovered by bioleaching, an eco-friendly process to recover metals from natural ores. However, the application of the bioleaching to electronic waste is still in the infancy stage. Here, the bioleaching capability of Acidithiobacillus ferrooxidans to extract copper from printed circuit boards was investigated at laboratory scale using shake flasks. The effect of initial pH, amount and size of printed circuit boards, and volume of inoculum on copper dissolution rates were evaluated. Results show that the highest dissolution rate of 32.44% was achieved after 7 days of leaching at initial pH 2.0, 10 g/L of waste printed circuit board, 40% v/v of inoculum for 1 mm size of circuit board. The smallest size of 1 mm induces the higher dissolution rates, which is explained by higher surface area and thus better bacterial adhesion. Also, the copper dissolution rates increase with the inoculum volume. Overall, bioleaching of copper from waste printed circuit boards using Acidithiobacillus ferrooxidans is achievable.

  • Microplastic contamination in freshwater: first observation in Lake Ulansuhai, Yellow River Basin, China
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-11
    Zhichao Wang, Yiming Qin, Weiping Li, Wenhuan Yang, Qing Meng, Jianlin Yang

    Microplastic pollution has been widely studied in the marine environment, but is much less explored in terrestrial waters, notably in China. Therefore, we studied the degree of microplastic pollution in surface waters of Lake Ulansuhai, a major freshwater lake in the Yellow River basin of northern China. Results show microplastic concentrations ranging from 1760 ± 710 to 10,120 ± 4090 n/m3. The microplastic spatial distribution is heterogeneous, with higher levels near the drainage canal entrance of Lake Ulansuhai, and a downward trend from north to south in the lake. The main type of microplastics is colored particles, including fibers as the most abundant. More than 80% of microplastics were smaller than 2 mm. FTIR analysis results show that the main plastics were polyethylene, polystyrene and polybutylene terephthalate. There were also some metallic elements adsorbed on the surface of microplastics, such as Fe, Ca and Zn, detected by energy-dispersive spectrometry. The presence of metallic elements may worsen water pollution.

  • Polymeric nanocomposite membranes for water treatment: a review
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-28
    Yinghao Wen, Jieming Yuan, Xingmao Ma, Shiren Wang, Yuchen Liu

    Water scarcity is a pressing global challenge. Filtration with actual polymeric membranes shows good capability for pollutant separation, but broad applications of polymeric membranes are limited. Filtration can be improved using nanocomposite membranes, which are formed by incorporating nanofillers into polymeric membrane matrixes. The most extensively investigated nanofillers are carbon-based nanoparticles and metal/metal oxide nanoparticles. Here, we review the performance of nanocomposite membranes in antifouling and permeability, their physical and chemical properties and we compare nanocomposite membranes with bare membranes. Nanocomposite membranes generally display better antifouling properties due to the antimicrobial properties of nanoparticles and the reduced roughness of membrane. They also demonstrate higher permeability because of the higher porosity and narrower pore size distribution created by nanofillers. The concentration of nanofillers changes membrane performance, and the optimal concentration depends on both the properties of nanoparticles and the membrane composition. Higher concentrations of nanofillers above the optimal value result in poor performance due to nanoparticle aggregation. Despite intensive research in the synthesis of nanocomposite membranes, most previous efforts are limited to laboratory scale, and the long-term membrane stability following nanofiller leakage has not been extensively investigated.

  • Methods for nanoemulsion and nanoencapsulation of food bioactives
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-06-01
    Niharika Walia, Nandita Dasgupta, Shivendu Ranjan, Chidambaram Ramalingam, Mansi Gandhi

    Nanoencapsulation is a promising technology allowing miniaturized dosage and administration of valuable volatiles, degradable bioactives and biologicals. The produced nanoparticles display qualities such as a sustained availability of active constituents, targeted delivery and enhanced shelf stability. This review presents methods of nanoencapsulation and nanoemulsion, such as solvent evaporation–emulsification, coacervation, nanoprecipitation, inclusion complexation, electrospraying, electrospinning, freeze drying and spray drying. Those methods are particularly relevant for the pharmaceutical, food and agricultural industries.

  • Trace elements in commercial marine organisms from the Russian part of the Northwest Pacific (2010–2018)
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-15
    Maksim M. Donets, Vasiliy Yu. Tsygankov

    We report levels of trace elements in commercially harvested species from the Far Eastern seas of Russia from 2010 to 2018. The best studied organisms in this region are algae and fish, and the least studied are crustaceans. The trace element content in target species of marine fisheries generally meets the standards of sanitary rules and norms established by the Russian Federation. However, in some cases, the maximum permissible levels (MPL) are exceeded for lead in algae and fish, cadmium in fish, and arsenic in crustaceans, which indicates the necessity to continue monitoring the commercial marine organisms. The requirements for seafood quality in Russia and the European Union (EU) are compared. European MPL limits are stricter for cadmium and lead concentrations. Also, the EU regulations do not have MPLs of arsenic (As) for all marine organisms, which is explained by the predominance of the low-toxic organic form of As in them. Thus, the regulatory documentation in Russia needs to be updated; also, a nationally standardized method of separate determination of organic and inorganic As forms should be created.

  • Engineered nanostructured materials: benefits and risks
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-05-27
    Vinod Kumar Yata

    Engineered nanostructured materials have widespread applications in multiple fields ranging from diagnosis to treatment of diseases. These materials are used in bioimaging, drug delivery and beauty care products. The preparation of nanostructured materials does not involve specific methods but different types of materials are synthesized by various strategies to reach a nanoscale dimension, so their range of effect will also vary depending upon the material and strategy involved. In recent years, nanostructured materials and their effect on human health has become a debatable issue. The conclusion is that most nanostructured materials have toxicity issues with one or more cell lines or organisms, though very few are lethal at very low concentration. This review updates the information on a wide range of nanostructured materials and studies showing associated health benefits and risks.

  • Chitosan for direct bioflocculation of wastewater
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2019-07-19
    Eric Lichtfouse, Nadia Morin-Crini, Marc Fourmentin, Hassiba Zemmouri, Inara Oliveira do Carmo Nascimento, Luciano Matos Queiroz, Mohd Yuhyi Mohd Tadza, Lorenzo A. Picos-Corrales, Haiyan Pei, Lee D. Wilson, Grégorio Crini

    Coagulation/flocculation is a major phenomenon occurring during industrial and municipal water treatment to remove suspended particles. Common coagulants are metal salts, whereas flocculants are synthetic organic polymers. Those materials are appreciated for their high performance, low cost, ease of use, availability and efficiency. Nonetheless, their use has induced environmental health issues such as water pollution by metals and production of large amounts of sludges. As a consequence, alternative coagulants and flocculants, named biocoagulants and bioflocculants due to their biological origin and biodegradability, have been recently developed for water and wastewater treatment. In particular, chitosan and chitosan-based products have found applications as bioflocculants for the removal of particulate and dissolved pollutants by direct bioflocculation. Direct flocculation is done with water-soluble, ionic organic polymers without classical metal-based coagulants, thus limiting water pollution. Chitosan is a partially deacetylated polysaccharide obtained from chitin, a biopolymer extracted from shellfish sources. This polysaccharide exhibits a variety of physicochemical and functional properties resulting in numerous practical applications. Key findings show that chitosan removed more than 90% of solids and more than 95% of residual oil from palm oil mill effluents. Chitosan reduced efficiently the turbidity of agricultural wastewater and of seawater, below 0.4 NTU for the latter. 99% turbidity removal and 97% phosphate removal were observed over a wide pH range using 3-chloro-2-hydroxypropyl trimethylammonium chloride grafted onto carboxymethyl chitosan. Chitosan also removed 99% Microcystis aeruginosa cells and more than 50% of microcystins. Here, we review advantages and drawbacks of chitosan as bioflocculant. Then, we present examples in water and wastewater treatment, sludge dewatering and post-treatment of sanitary landfill leachate.

  • High reduction of ozone and particulate matter during the 2016 G-20 summit in Hangzhou by forced emission controls of industry and traffic.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2018-05-02
    Pengfei Li,Liqiang Wang,Ping Guo,Shaocai Yu,Khalid Mehmood,Si Wang,Weiping Liu,John H Seinfeld,Yang Zhang,David C Wong,Kiran Alapaty,Jon Pleim,Rohit Mathur

    Many regions in China experience air pollution episodes because of the rapid urbanization and industrialization over the past decades. Here we analyzed the effect of emission controls implemented during the G-20 2016 Hangzhou summit on air quality. Emission controls included a forced closure of highly polluting industries, and limiting traffic and construction emissions in the cities and surroundings. Particles with aerodynamic diameter lower than 2.5 µm (PM2.5) and ozone (O3) were measured. We also simulated air quality using a forecast system consisting of the two-way coupled Weather Research and Forecast and Community Multi-scale Air Quality (WRF-CMAQ) model. Results show PM2.5 and ozone levels in Hangzhou during the G-20 Summit were considerably lower than previous to the G-20 Summit. The predicted concentrations of ozone were reduced by 25.4%, whereas the predicted concentrations of PM2.5 were reduced by 56%.

  • Soil C and N models that integrate microbial diversity.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2016-09-20
    Benjamin P Louis,Pierre-Alain Maron,Valérie Viaud,Philippe Leterme,Safya Menasseri-Aubry

    Industrial agriculture is yearly responsible for the loss of 55-100 Pg of historical soil carbon and 9.9 Tg of reactive nitrogen worldwide. Therefore, management practices should be adapted to preserve ecological processes and reduce inputs and environmental impacts. In particular, the management of soil organic matter (SOM) is a key factor influencing C and N cycles. Soil microorganisms play a central role in SOM dynamics. For instance, microbial diversity may explain up to 77 % of carbon mineralisation activities. However, soil microbial diversity is actually rarely taken into account in models of C and N dynamics. Here, we review the influence of microbial diversity on C and N dynamics, and the integration of microbial diversity in soil C and N models. We found that a gain of microbial richness and evenness enhances soil C and N dynamics on the average, though the improvement of C and N dynamics depends on the composition of microbial community. We reviewed 50 models integrating soil microbial diversity. More than 90 % of models integrate microbial diversity with discrete compartments representing conceptual functional groups (64 %) or identified taxonomic groups interacting in a food web (28 %). Half of the models have not been tested against an empirical dataset while the other half mainly consider fixed parameters. This is due to the difficulty to link taxonomic and functional diversity.

  • Radiocarbon in food: a non-problem of health effects.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2011-07-19
    J van der Plicht,J P M Beijers

    Recently it has come to our attention that a paper was published in this journal entitled "recycling greenhouse gas fossil fuel emissions into low radiocarbon food products to reduce human genetic damage" (Williams in Environ Chem Lett 5:197-202, 2007). In this article, it is argued that food grown in a greenhouse is healthier for people, when the greenhouse is fertilised with CO(2) prepared from fossil fuels. In this comment, however, we argue that the effect on human health is completely negligible.

    Environ. Chem. Lett. (IF 4.617) Pub Date : 2010-12-21
    Gernerique Stewart,Keonia Smith,Ashley Chornes,Tracy Harris,Tiffany Honeysucker,Suman Raj Dasary,Hongtao Yu

    Photochemical degradation of 1-nitropyrene, 2-nitrofluorene, 2,7-dinitrofluorene, 6-nitrochrysene, 3-nitrofluoranthene, 5-nitroacenaphthene, and 9-nitroanthracene were examined in CHCl(3), CH(2)Cl(2), DMF, DMF/H(2)O (80/20), CH(3)CN, or CH(3)CN/H(2)O (80/20). The degradation follows mostly the 1(st) order kinetics; but a few follow 2(nd) order kinetics or undergo self-catalysis. The photodegradation rates follow the order: CHCl(3) > CH(2)Cl(2) > DMF > DMF/H(2)O > CH(3)CN > CH(3)CN/H(2)O. DMF is an exceptional solvent because 3 of the 7 compounds undergo self-catalytic reaction. 9-Nitroanthracene, which has a perpendicular nitro group, is the fastest, while the more compact 1-nitropyrene and 3-nitrofluoranthene, are the slowest degrading compounds.

  • Isotopic evidences for microbiologically mediated and direct C input to soil compounds from three different leaf litters during their decomposition.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2010-03-18
    M Rubino,C Lubritto,A D'Onofrio,F Terrasi,C Kramer,G Gleixner,M F Cotrufo

    We show the potentiality of coupling together different compound-specific isotopic analyses in a laboratory experiment, where (13)C-depleted leaf litter was incubated on a (13)C-enriched soil. The aim of our study was to identify the soil compounds where the C derived from three different litter species is retained. Three (13)C-depleted leaf litter (Liquidambar styraciflua L., Cercis canadensis L. and Pinus taeda L., delta(13)C(vsPDB) approximately -43 per thousand), differing in their degradability, were incubated on a C4 soil (delta(13)C(vsPDB) approximately -18 per thousand) under laboratory-controlled conditions for 8 months. At harvest, compound-specific isotope analyses were performed on different classes of soil compounds [i.e. phospholipids fatty acids (PLFAs), n-alkanes and soil pyrolysis products]. Linoleic acid (PLFA 18:2omega6,9) was found to be very depleted in (13)C (delta(13)C(vsPDB) approximately from -38 to -42 per thousand) compared to all other PLFAs (delta(13)C(vsPDB) approximately from -14 to -35 per thousand). Because of this, fungi were identified as the first among microbes to use the litter as source of C. Among n-alkanes, long-chain (C27-C31) n-alkanes were the only to have a depleted delta(13)C. This is an indication that not all of the C derived from litter in the soil was transformed by microbes. The depletion in (13)C was also found in different classes of pyrolysis products, suggesting that the litter-derived C is incorporated in less or more chemically stable compounds, even only after 8 months decomposition.

  • Efficient uranium immobilization on red clay with phosphates.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2014-05-13
    Ewelina Grabias,Agnieszka Gładysz-Płaska,Anna Książek,Marek Majdan

    Uranium is a very toxic and radioactive element. Removal of uranium from wastewaters requires remediation technologies. Actual methods are costly and ineffective when uranium concentration is very low. Little is known about the enhancement of sorption of uranyl ions by phosphate ions on aluminosilicates. Here, we studied sorption of uranyl acetate on red clay in the presence of phosphates. The concentration of U(VI) ranged 0.0001-0.001 mol/L, whereas the concentration of PO43- was constant at 0.0001 mol/L. We designed a new method for the analysis of ternary surface complexes. We observed for the first time a remarkable improvement of U(VI) sorption on red clay under the influence of phosphates. We also found that at least two different ternary surface complexes U(VI)-phosphate-clay are formed in the sorbent phase. The complexation of UO22+ cations by phosphate ligands in the sorbent phase was confirmed by the X-ray photoelectron spectra of U 4f electrons.

  • Antiaflatoxigenic activity of Carum copticum essential oil.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2014-02-25
    Mohammad Reza Rezaei Kahkha,Saeed Amanloo,Massoud Kaykhaii

    Plants are unique sources of useful metabolites. Plant essential oils display a wide range of antimicrobial effects against various pathogens. Here, we studied the essential oil from the seeds of Carum copticum. We monitored aflatoxin by high-performance liquid chromatography. Results show that Carum copticum essential oil inhibits Asergillus parasiticus growth and prevents aflatoxin production. The half-maximal inhibitory concentration (IC50) is 127.5 μg mL-1 for aflatoxin B1 and 23.22 μg mL-1 for aflatoxin G1. Our findings show that Carum copticum essential oil is a potential candidate for the protection of foodstuff and feeds from toxigenic fungus growth and their subsequent aflatoxin contamination.

  • Improved soil carbonate determination by FT-IR and X-ray analysis.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2013-03-06
    Viktor J Bruckman,Karin Wriessnig

    In forest soils on calcareous parent material, carbonate is a key component that influences both chemical and physical soil properties and thus fertility and productivity. At low organic carbon contents, it is difficult to distinguish between organic and inorganic carbon, e.g. carbonates, in soils. The common gas-volumetric method to determine carbonate has a number of disadvantages. We hypothesize that a combination of two spectroscopic methods, which account for different forms of carbonate, can be used to model soil carbonate in our region. Fourier transform mid-infrared spectroscopy was combined with X-ray diffraction to develop a model based on partial least squares regression. Results of the gas-volumetric Scheibler method were corrected for the calcite/dolomite ratio. The best model performance was achieved when we combined the two analytical methods using four principal components. The root mean squared error of prediction decreased from 13.07 to 11.57, while full cross-validation explained 94.5 % of the variance of the carbonate content. This is the first time that a combination of the proposed methods has been used to predict carbonate in forest soils, offering a simple method to precisely estimate soil carbonate contents while increasing accuracy in comparison with spectroscopic approaches proposed earlier. This approach has the potential to complement or substitute gas-volumetric methods, specifically in study areas with low soil heterogeneity and similar parent material or in long-term monitoring by consecutive sampling.

  • Monitoring of environmental exposure to polycyclic aromatic hydrocarbons: a review.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2007-01-01
    K Srogi

    Polycyclic aromatic hydrocarbons (PAHs) are a large group of organic compounds with two or more fused aromatic rings. They have a relatively low solubility in water, but are highly lipophilic. Most of the PAHs with low vapour pressure in the air are adsorbed on particles. When dissolved in water or adsorbed on particulate matter, PAHs can undergo photodecomposition when exposed to ultraviolet light from solar radiation. In the atmosphere, PAHs can react with pollutants such as ozone, nitrogen oxides and sulfur dioxide, yielding diones, nitro- and dinitro-PAHs, and sulfonic acids, respectively. PAHs may also be degraded by some microorganisms in the soil. PAHs are widespread environmental contaminants resulting from incomplete combustion of organic materials. The occurrence is largely a result of anthropogenic emissions such as fossil fuel-burning, motor vehicle, waste incinerator, oil refining, coke and asphalt production, and aluminum production, etc. PAHs have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic. Eight PAHs (Car-PAHs) typically considered as possible carcinogens are: benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene (B(a)P), dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene. In particular, benzo(a)pyrene has been identified as being highly carcinogenic. The US Environmental Protection Agency (EPA) has promulgated 16 unsubstituted PAHs (EPA-PAH) as priority pollutants. Thus, exposure assessments of PAHs in the developing world are important. The scope of this review will be to give an overview of PAH concentrations in various environmental samples and to discuss the advantages and limitations of applying these parameters in the assessment of environmental risks in ecosystems and human health. As it well known, there is an increasing trend to use the behavior of pollutants (i.e. bioaccumulation) as well as pollution-induced biological and biochemical effects on human organisms to evaluate or predict the impact of chemicals on ecosystems. Emphasis in this review will, therefore, be placed on the use of bioaccumulation and biomarker responses in air, soil, water and food, as monitoring tools for the assessment of the risks and hazards of PAH concentrations for the ecosystem, as well as on its limitations.

  • Recycling greenhouse gas fossil fuel emissions into low radiocarbon food products to reduce human genetic damage.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2007-01-01
    Christopher P Williams

    Radiocarbon from nuclear fallout is a known health risk. However, corresponding risks from natural background radiocarbon incorporated directly into human genetic material have not been fully appreciated. Here we show that the average person will experience between 3.4 × 1010 and 3.4 × 1011 lifetime chromosomal damage events from natural background radiocarbon incorporated into DNA and histones, potentially leading to cancer, birth defects, or accelerated aging. This human genetic damage can be significantly reduced using low radiocarbon foods produced by growing plants in CO2 recycled from ordinary industrial greenhouse gas fossil fuel emissions, providing additional incentive for the carbon sequestration.

  • Pharmaceuticals and personal care products in waters: occurrence, toxicity, and risk.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2015-12-01
    Leslie Cizmas,Virender K Sharma,Cole M Gray,Thomas J McDonald

    Pharmaceuticals and personal care products (PPCP) are compounds with special physical and chemical properties that address the care of animal and human health. PPCP have been detected in surface water and wastewater in the ng/L to µg/L concentration range worldwide. PPCP ecotoxicity has been studied in a variety of organisms, and multiple methods have been used to assess the risk of PPCP in the environment to ecological health. Here we review the occurrence, effects, and risk assessment of PPCP in aquatic systems, as well as the sustainability of current methods for managing PPCP contamination in aquatic systems. The major points are the following: (1) a number of PPCP present potential concerns at environmentally relevant concentrations. PPCP mixtures may produce synergistic toxicity. (2) Various methods have been used for the ecological risk assessment of PPCP in aquatic systems. There are similarities in these methods, but no consensus has emerged regarding best practices for the ecological risk assessment of these compounds. (3) Human health risk assessments of PPCP contamination in aquatic systems have generally indicated little cause for concern. However, there is a lack of information regarding whether antibiotic contamination in wastewater and aquatic systems could lead to an increase in clinically relevant antibiotic-resistant bacteria and antibiotic-resistant genes. (4) Over the next century, the combination of increasing global population size and potential droughts may result in reduced water availability, increased need for water reuse, and increasing concentrations of PPCP in wastewaters. The current wastewater treatment methods do not remove all PPCP effectively. This, coupled with the possibility that antibiotics may promote the development of antibiotic-resistant bacteria and antibiotic-resistant genes, leads to concerns about the sustainability of global water supplies.

  • Mobility of toxic elements in carbonate sediments from a mining area in Poland.
    Environ. Chem. Lett. (IF 4.617) Pub Date : 2014-08-29
    Natalia Ospina-Alvarez,Lukasz Głaz,Krzysztof Dmowski,Beata Krasnodębska-Ostręga

    The Bolesław-Bukowno mining area in Poland is highly polluted by elements such as Zn, Pb, Cd and As. The reactivity and mobility of toxic elements such as Tl are poorly known. Here, we studied by sequential extraction the mobility of As, Cd, Co, Cr, Cu, Mn, Mo, Pb, Tl and Zn in sediments from two water reservoirs near Bukowno. Results show that available As, Co, Mn, Pb and Zn are found in carbonate minerals. Available Cd, Cu and Tl are found in sulphides and organic matter. The extractability of As, Cr, Mo and Tl was rather poor. By contrast, 85 % of total Cd, Pb and Zn was mobile. We discuss Tl and Mo association in carbonate sediments from ore deposits.

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上海纽约大学William Glover