Design of mesoporous ZnO @ silica fume-derived SiO2 nanocomposite as photocatalyst for efficient crystal violet removal: Effective route to recycle industrial waste

https://doi.org/10.1016/j.jclepro.2021.129416Get rights and content

Highlights

  • A novel mesoporous ZnO@silica fume-derived SiO2 was synthesized.

  • ZnO@SF-derived SiO2 nanocomposite was used for CV-photodegradation.

  • The energy bandgap of prepared nanocomposite and ZnO was determined.

  • The spent photocatalyst was successfully recycled several times.

  • Removal of CV from real wastewater was achieved.

Abstract

Recycling sustainable industrial solid waste, such as silica fume, has recently become an important issue. Due to its large amounts, the exploitation of industrial solid waste is a great urgent issue and optimal solution for environmental and water resources protection. Consequently, this manuscript aims to synthesis a novel, low-cost, and efficient photocatalyst to degrade crystal violet and produce crystal violet-free water. The proposed photocatalyst was prepared by combining ZnO nanosheets with silica fume-derived SiO2 to get a novel, mesoporous ZnO@silica fume-derived SiO2 photocatalyst. The influence of pH, time, dose, temperature and initial CV concentration were systematically investigated. The results showed that ZnO@silica fume-derived SiO2 actively removed >98% of the crystal violet dye from synthetic wastewater of 10 ppm concentration within 1 h, at pH 9.0 with a first-order kinetic model. The reaction mechanism between photocatalysts and crystal violet was also discussed. The prepared photocatalyst displayed high stability after five reuse cycles, leading to a decrease in the overall cost of the wastewater remediation process. The as-synthesized ZnO@silica fume-derived SiO2 nanocomposite shows promising potential for ecological safety, demonstrating that ZnO@silica fume-derived SiO2 has a large removal performance.

Introduction

Since antiquity, water has always been a great resource for human civilization and is an essential substance for all modes of living on earth (Sayed et al., 2021; Zhang et al., 2021). Today, the rapid speed of civilization and manufacturing, which have had significant adverse environmental and human health consequences, has made water pollution a critical problem (Gomaa et al., 2021b; Sarabadan et al., 2019). Water purification has become a critical humanitarian objective and has recently received a great deal of research attentiveness (Gopakumar et al., 2017; Saya et al., 2020). Industrial-waste water became one of the most significant environmental issues, with various organically toxic compounds and substances (Pan et al., 2018). The key source of organic water contamination is releasing organic contaminants through leather, paper, plastics, printing, electroplating, and cosmetics industries. Most waste from dye manufacture consists of heteropolyaromatic, anthraquinonic, and xanthenic dyes (Natarajan et al., 2018; Wen et al., 2020). A massive quantity of toxic dyes within industrial-waste water is discharged into the surrounding environment. Due to the high molecular weight, most of these dyes are not easy to eliminate from polluted water (Hu et al., 2013; Zhou et al., 2014). In general, these pollutants pose a potential danger to humans, as they may lead to severe diseases such as cancer. So, toxic dyes must be effectively separated from industrial influent water before disposal in the surrounding environment (Mohanty et al., 2006). One of the most common basic cationic dyes is crystal violet (CV, named in IUPAC as Tris(4-(dimethylamino)phenyl)methylium chloride), which can be used vastly in the textile, cosmetic, paper, printing, and leather made-up. So, CV is a common existing artificial type of dye in released wastewater (Loqman et al., 2017).

Recently, many efforts were made for water decontamination, including filtration (Zhou et al., 2021), electrochemical methods (Li et al., 2017), precipitation (Liu et al., 2021), coagulation (Li et al., 2016), and adsorption (Mohammadi et al., 2019), all of which are widely used water treatment techniques. The advanced oxidant process (i.e., photocatalysis), which has emerged in the last few years, forms part of these techniques due to the high efficiency and low cost. The photocatalysis process is used extensively to treat contaminated water using UV or sunlight in the existence of a suitable catalyst without creating any secondary toxic contaminants (Samsami et al., 2020). The photocatalysis process is dependent on the generation of electrons and holes after UV-light irradiates the catalyst. These fragments can cause oxidation-reduction reactions to degrade organic compounds on the surface of the semiconducting-catalyst (Sajid et al., 2018). Photocatalytic degradation has recently become an innovative economic and promising technology to treat wastewater due to eco-friendly and cost-effective methods, so it has been widely used to remove CV-dyes from polluted water (Vanthana Sree et al., 2020).

Metal oxides as photocatalysts have an outstanding performance in environmental pollution control due to the unique pore structure, high surface area, large photocatalytic action, photostability, cost-effectiveness, and non-toxicity (Katouah, 2021; Gomaa et al., 2021a). The increased surface area of photocatalyst helps to collect many contaminants and minimize the cost of used materials. Moreover, the vast bandgap semiconductors (e.g., ZnO, TiO2, ZnS, BiTiO3, etc.) use sunlight or UV-light to remove organic pollutants and are used as promising sustainable materials water-purging applications (Jinrun Liu et al., 2020). Zinc oxide as a semiconductor feature with several favorable characteristics, such as a significant energy gap (3.37 eV), high photosensitivity, low synthesis costs, enormous binding energy reaches to 60 MeV, non-toxic nature, chemical stability, and using on an industrial scale (Nemiwal et al., 2021). These features made ZnO an excellent promising desirable photocatalyst and are becoming a subject of growing interest. It can be used for photocatalytic degradation of a wide variety of organic-dyes contaminants (Goktas and Goktas, 2021). Moreover, the particle size of ZnO plays a significant role in the photocatalytic process. Nano-scaled size of ZnO-particles leads to an increase in the specific surface area, leading to create more quantities of active surface sites and generate surface charge (i.e., O2−• and OH), that facilitate adsorption, react and degradation of organic-dyes pollutants (Chen et al., 2020; Gautam et al., 2020).

Industrial solid waste is considered a severe menace to ecosystems due to its large quantity and inorganic toxins. Therefore, recently, recycling industrial solid waste is becoming a significant issue (Seaf El-Nasr et al., 2021; Ali et al., 2021). One of the most common industrial solid wastes is silica fume (SF, micro-silica). SF as amorphous solid fine-powder is generated from raised smoke from metallic silicon or ferrosilicon industries operations (Wang et al., 2018). Due to the high specific surface area, SF would be a viable alternative precursor for porous nano-silica synthesis (Wang et al., 2020). Due to its high activity, cost-effectiveness, and rich SiO2 content, SF is a strong candidate for synthesizing porous nano-SiO2. Due to the economic benefits, the use of porous and nano-scale material from solid waste also has become an attractive process (Wang et al., 2018). Herein, we used SF-derived nano-SiO2 as a platform or scaffold to increase the exposed area of ZnO-photocatalyst nanosheets. However, few reports are available to use solid industrial waste to photocatalytic degradation of crystal violet from wastewater.

This manuscript describes the low-cost and eco-friendly synthesis of a novel, mesoporous ZnO@SF-derived SiO2 nanocomposite. The mesoporous ZnO@SF-derived SiO2 was used to remove CV-dye from wastewater through a photocatalytic degradation approach. The as-synthesized ZnO@SF-derived SiO2 nanocomposite was characterized using SEM, TEM, XRD, FTIR, TG/DTA, and N2 adsorption-desorption isotherm. Several parameters, such as pH, contact time, catalyst-dose, etc., were methodically examined to estimate the optimum conditions of the photocatalytic process. The spent ZnO@SF-derived SiO2 can be employed numerous times, reducing the cost of toxic-dyes removal from wastewater. The photodegradation mechanism of CV using ZnO@SF-derived SiO2 was proposed as well.

Section snippets

Chemicals

The applied chemicals were a high purity grade, so it was used without more purification. Zinc sulfate heptahydrate (ZnSO4. 7H2O), polyvinylpyrrolidone (PVP, average Mol. Wt. 40,000 g/mol), crystal violet (C25H30N3Cl, Mol Wt. 407.98 g/mol), and ethylene glycol (anhydrous, 99.8%) were bought from Sigma–Aldrich Company, Ltd., USA. Urea, ammonium hydroxide, sodium hydroxide, sulfuric acid, hydrochloric acid, and ethanol absolute were gained from Merck Chemicals Company, Germany.

Characterization

The calorimetric

Characterization of mesoporous ZnO@SF-derived SiO2 nanocomposite

In the present manuscript, the mesoporous ZnO@SF-derived SiO2 nanocomposite was obtained through three main steps of synthesis. In the first step, ZnO was prepared within nanosheets-like morphology. In the second step, industrial waste such as silica fume, as a secondary source of silica, was contacted with a strong alkaline solvent like NaOH to obtain sodium silicate solution. ZnO was added to get ZnO@Na2SiO3 suspended solution-like milky. Finally, the mesoporous ZnO@SF-derived SiO2

Conclusion

Our proposed work highlighted that we could exploit the accumulated silica fume in wastewater treatment applications, reducing the risks of industrial solid waste and thence environmental protection. According to the previous literature, there are no publications about using silica fume-derived silica grafted with ZnO-sheets for crystal violet removal through a photocatalytic degradation approach. Herein, we have developed a novel mesoporous ZnO@SF-derived SiO2 nanocomposite through a low-cost

CRediT authorship contribution statement

Kh.O. Kassem: Writing – original draft. Mohamed A.T. Hussein: Methodology, Software, Investigation. Mohamed M. Motawea: Methodology, Software, Investigation. H. Gomaa: Supervision, Conceptualization, Methodology, Software. Z.A. Alrowaili: Writing – original draft. Mohammed Ezzeldien: Methodology, material preparation, Reviewing and Editing, Funding acquisition.

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.

Acknowledgment

The authors extend their appreciation to the Deanship of Scientific Research at Jouf University for funding this work through research grant No (DSR2020-02-512).

References (56)

  • H. Gomaa et al.

    Mesoscopic engineering materials for visual detection and selective removal of copper ions from drinking and waste water sources

    J. Hazard Mater.

    (2021)
  • Y. Hu et al.

    Dye adsorption by resins: effect of ionic strength on hydrophobic and electrostatic interactions

    Chem. Eng. J.

    (2013)
  • Y.R. Huang et al.

    Removal of crystal violet by ultraviolet/persulfate: effects, kinetics and degradation pathways

    Environ. Technol. Innov.

    (2020)
  • H.A. Katouah

    Facile synthesis of Co3O4 and ZnO nanoparticles by thermal decomposition of novel Co(II) and Zn(II) Schiff base complexes for studying their biological properties and photocatalytic degradation of crystal violet dye

    J. Mol. Struct.

    (2021)
  • H. Li et al.

    Removal of reactive dyes from wastewater assisted with kaolin clay by magnesium hydroxide coagulation process

    Colloids Surfaces A Physicochem. Eng. Asp.

    (2016)
  • X.-Y. Li et al.

    TiO2-SiO2/GAC particles for enhanced electrocatalytic removal of acid orange 7 (AO7) dyeing wastewater in a three-dimensional electrochemical reactor

    Separ. Purif. Technol.

    (2017)
  • Junfei Liu et al.

    Novel CoS2/MoS2@Zeolite with excellent adsorption and photocatalytic performance for tetracycline removal in simulated wastewater

    J. Clean. Prod.

    (2020)
  • M. Liu et al.

    High-efficient removal of organic dyes from model wastewater using Mg(OH)2-MnO2 nanocomposite: synergistic effects of adsorption, precipitation, and photodegradation

    Separ. Purif. Technol.

    (2021)
  • F. Mohammadi et al.

    Application of amino modified mesostructured cellular foam as an efficient mesoporous sorbent for dispersive solid-phase extraction of atrazine from environmental water samples

    Microchem. J.

    (2019)
  • M. Nemiwal et al.

    Recent progress in g-C3N4, TiO2 and ZnO based photocatalysts for dye degradation: strategies to improve photocatalytic activity

    Sci. Total Environ.

    (2021)
  • V.D. Potle et al.

    Sonochemical preparation of ternary rGO-ZnO-TiO2 nanocomposite photocatalyst for efficient degradation of crystal violet dye

    Optik

    (2020)
  • A.V. Samrot et al.

    Adsorption efficiency of chemically synthesized Superparamagnetic Iron Oxide Nanoparticles (SPIONs) on crystal violet dye

    Curr. Res. Green Sustain. Chem.

    (2021)
  • S. Samsami et al.

    Recent advances in the treatment of dye-containing wastewater from textile industries: overview and perspectives

    Process Saf. Environ. Protect.

    (2020)
  • R.S. Saravan et al.

    Evaluation of the photocatalytic efficiency of cobalt oxide nanoparticles towards the degradation of crystal violet and methylene violet dyes

    Optik

    (2020)
  • A. Sayed et al.

    A novel fluorescent sensor for fast and highly selective turn-off detection of Fe3+ in water and pharmaceutical samples using synthesized azopyrazole-benzenesulfonamide derivative

    J. Mol. Struct.

    (2021)
  • A. Serrà et al.

    Simple and scalable fabrication of hairy ZnO@ZnS core@shell Cu cables for continuous sunlight-driven photocatalytic water remediation

    Chem. Eng. J.

    (2020)
  • T. Tavakoli-Azar et al.

    Improving the photocatalytic performance of a perovskite ZnTiO3 through ZnTiO3@S nanocomposites for degradation of Crystal violet and Rhodamine B pollutants under sunlight

    Inorg. Chem. Commun.

    (2020)
  • G. Vanthana Sree et al.

    Calcium oxide a sustainable photocatalyst derived from eggshell for efficient photodegradation of organic pollutants

    J. Clean. Prod.

    (2020)
  • Cited by (0)

    1

    Both authors contributed equally to this work.

    View full text