Removal of 4-chlorophenol, bisphenol A and nonylphenol mixtures by aqueous chlorination and formation of coupling products
Graphical abstract
Introduction
With the development of industrialization in recent years, large amounts of endocrine disrupting chemicals (EDCs) were discharged into the environment, which has received extensive attention. Among these contaminants, 4-chlorophenol (4-CP), bisphenol A (BPA) and nonylphenol (NP) are typical phenolic environmental hormones that have been widely used in chemical synthesis [1], [2], [3], [4]. 4-CP is commonly found in industrial wastewater effluents from the production of pesticides, paper and pulp, and petrochemical products [5], [6]. BPA is mainly incorporated into polycarbonate, epoxy resin, polysulfone resin and many other polymer materials, with an annual production volume of more than six billion pounds before prohibition [7]. NP is widely used as a raw material for the manufacture of nonionic surfactants and lubricant additives, and its major source in aquatic environment includes the oxidation of nonylphenol ethoxylates (NPE) which have widespread applications in the textile industry for printing, dyeing and cleaning [3], [8]. These compounds are persistent, bioaccumulative and can mimic the effects of estrogen, thus causing female precocity, decreased sperm count and prostate growth even at extremely low concentrations [9]. Currently, the environmental presence of these chemicals is even more concerning, because they mostly appear as a complex mixture, which usually lead to synergistic toxic effects [10].
Chlorine is the most commonly used reagent in drinking water disinfection and municipal wastewater treatment. A wide range of organic chemicals including phenolic compounds could be degraded by free chlorine [11]. For instance, Zheng et al. [12] have found that bisphenol F (BPF) could react with chlorine at a pseudo-first-order rate constant (kobs) of 0.2162 min−1 under pH 8.0 and 25 °C and the chlorination reaction is dependent on free available chlorine. The apparent second-order rate constants (kapp) for chlorination between phenol and aqueous chlorine vary between 0.02 and 0.52 M−1·s−1, for the reaction phenolate and HOCl between 8.46 × 101 and 2.71 × 10 4 M−1·s−1 [13]. Compared with traditional disinfectants such as chlorine gas and chlorine dioxide, sodium hypochlorite has gradually caused global attention as it is more efficient and generates less toxic by-products in the process. To date, large efforts have been devoted to the chlorination of single pollutants during water and wastewater treatment, leaving the simultaneous transformation of multi-component pollutants less studied [14]. In fact, the phenolic substances do coexist in aquatic environments. It was reported that the average concentration of NP and BPA in the Tuojiang River of China is 33.1 ng/L and 47.2 ng/L, respectively [15]. Thus, it is of great significance to investigate the reaction behaviors of phenolic mixtures with free chlorine.
The primary objective of this research was to investigate the chlorination process of 4-CP, BPA and NP mixture during water treatment, with special emphasis on the cross-coupling reaction mechanisms. First, the reaction kinetics of single compound were studied over a pH range of 5.0–11.0 with different concentrations of free chlorine (10.0–60.0 μM) to determine the species-specific second-order rate constants. Second, the transformation of three phenols in mixture solutions was evaluated to explore the effect of co-existing pollutants, and the reaction rate constants in presence of dissolved organic matter (DOM) were also compared. Third, the transformation products generated during the reaction were determined by high-resolution mass spectrometry, and the reaction pathways were then tentatively proposed. Finally, the reaction mechanisms were elucidated by quantum chemical computations (atom partial charges, spin densities, Gibbs free energy change, transition states, and activation energies). This work would shed light on the behaviors of multi-component phenolic pollutants during aqueous chlorination process.
Section snippets
Materials
4-CP, BPA and NP were supplied by Sinopharm Chemical Reagent Co., ltd. (Shanghai, China). Sodium hypochlorite was acquired from Xiqiao Chemical Co., ltd. (Shanghai, China). Disodium hydrogen phosphate and sodium dihydrogen phosphate were purchased from Ning Test Chemical Reagent Co., ltd. (Nanjing, China). HPLC-grade formic acid and methanol were supplied by Merck (Darmstadt, Germany). Humic acid (HA) and sodium thiosulfate were obtained from Aladdin (Shanghai, China). All the compounds were
Exploration of proper experiment conditions for single reactant
The concentrations of the oxidants and the speciation of chlorine and phenolic compounds may greatly influence the rate of oxidative degradation. We chose 4-CP as the target compound to examine the effect of aqueous chlorine concentration on reaction rates. Fig. S1 shows that the reaction is accelerated with increasing concentration of free available chlorine. After 20 min of reaction, the removal efficiency of 4-CP (1.0 µM) reaches 34.2%, 79.8%, 95.5% and 100% at 10.0, 15.0, 30.0 and 60.0 μM
Conslusions
Our work has demonstrated that chlorine can effectively degrade the ubiquitous phenolic pollutants (4-CP, BPA, and NP) over a wide pH range of 5.0–11.0 via two parallel pathways. Chlorine electrophile substitution leads to the formation of chlorine-substituted products (i.e., mono/di/tri/tetra- chlorinated phenolic compounds), and electron transfer pathways involves the generation of phenoxy species and subsequent self-coupling reactions. In the mixture solutions of the three phenols, a greatly
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This research was financially supported by the National Natural Science Foundation of China (No. 21806073), and the Fundamental Research Funds for the Central Universities (No. 021114380137, 021114380128). The authors extend their appreciation to the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding Program.
References (56)
- et al.
A review of the environmental fate, effects, and exposures of bisphenol A
Chemosphere.
(1998) - et al.
Degradation of 4-chlorophenol using catalyzed peroxymonosulfate with nano-MnO2/UV irradiation: Toxicity assessment and evaluation for industrial wastewater treatment
J. Clean. Prod.
(2018) - et al.
Mechanistic insight into degradation of endocrine disrupting chemical by hydroxyl radical: An experimental and theoretical approach
Environ. Pollut.
(2017) - et al.
4-Chlorophenol degradation using ultrasound/peroxymonosulfate/nanoscale zero valent iron: Reusability, identification of degradation intermediates and potential application for real wastewater
Chemosphere.
(2018) - et al.
Capability of novel ZnFe2O4 nanotube arrays for visible-light induced degradation of 4-chlorophenol
Chemosphere.
(2011) - et al.
Human exposure to bisphenol A (BPA)
Reprod. Toxicol.
(2007) - et al.
Nonylphenol in the environment: A critical review on occurrence, fate, toxicity and treatment in wastewaters
Environ. Int.
(2008) - et al.
The separation of catechol and phenol with each other by two-stage batch foam fractionation
Chem. Eng. J.
(2017) - et al.
A review on emerging contaminants in wastewaters and the environment: current knowledge, understudied areas and recommendations for future monitoring
Water Res.
(2015) - et al.
Chlorination of bisphenol S: Kinetics, products, and effect of humic acid
Water Res.
(2018)
Chlorination of bisphenol F and the estrogenic and peroxisome proliferator-activated receptor gamma effects of its disinfection byproducts
Water Res.
Reaction of fleroxacin with chlorine and chlorine dioxide in drinking water distribution systems: Kinetics, transformation mechanisms and toxicity evaluations
Chem. Eng. J.
Oxidative degradation of triclosan by potassium permanganate: Kinetics, degradation products, reaction mechanism, and toxicity evaluation
Water Res.
Effective degradation of fenitrothion by zero-valent iron powder (Fe0) activated persulfate in aqueous solution: Kinetic study and product identification
Chem. Eng. J.
Quantitative structure-activity relationships for reactivities of sulfate and hydroxyl radicals with aromatic contaminants through single-electron transfer pathway
J. Hazard. Mater.
Ab initio study of solvated molecules: A new implementation of the polarizable continuum model
Chem. Phys. Lett.
QSPR study for estimation of acidity constants of some aromatic acids derivatives using multiple linear regression (MLR) analysis
J. Mol, Struct. Theochem.
Polyaniline-coated chitosan-functionalized magnetic nanoparticles: Preparation for the extraction and analysis of endocrine-disrupting phenols in environmental water and juice samples
Talanta.
Chlorination of bisphenol A: Kinetics and by-products formation
Chemosphere.
Ferrate(VI) oxidation of tetrabromobisphenol A in comparison with bisphenol A
Water Res.
Solid surface-mediated photochemical transformation of decabromodiphenyl ether (BDE-209) in aqueous solution
Water Res.
UV-activated persulfate oxidation of sulfamethoxypyridazine: Kinetics, degradation pathways and impact on DBP formation during subsequent chlorination
Chem. Eng. J.
Chlorination and chloramination of bisphenol A, bisphenol F, and bisphenol A diglycidyl ether in drinking water
Water Res.
Chlorination of bisphenol A in aqueous media: formation of chlorinated bisphenol A congeners and degradation to chlorinated phenolic compounds
Chemosphere.
Products of methotrexate during chlorination
J. Environ. Sci.-China.
Reactions of chlorine with inorganic and organic compounds during water treatment—Kinetics and mechanisms: A critical review
Water Res.
Simultaneous aqueous chlorination of amine-containing pharmaceuticals
Water Res.
Mechanistic insight into degradation of endocrine disrupting chemical by hydroxyl radical: An experimental and theoretical approach
Environ. Pollut.
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