Effective photocatalytic degradation of malachite green dye by Fe(III)-Cross-linked Alginate-Carboxymethyl cellulose composites
Graphical abstract
Introduction
Pollution of water with toxic industrial wastes is the most critical environmental problem. Many techniques and materials are being developed to clean the waters [1], [2], [3]. Many thousands of synthetic dyes are the leading water-polluting materials. Since most of these dyes are not biodegradable, they remain in the water for a long time. Besides their toxic properties, even minimal concentrations threaten aquatic life by preventing sunlight. Malachite green (MG) (N-methylated diaminotriphenylmethane) is one of the industrial dyes which shows a toxic effect on mammalian cells. MG is used as a dye for cotton, paper, jute, silk, wool, leather products, and acrylic industries and is also used as an antiseptic and fungicidal product [4]. Tewari et al. reviewed adsorption techniques to remove MG from waters [5]. Although the most widely used methods for dye removal are adsorption methods as efficient and inexpensive methods, a secondary pollutant problem arises since the pollutants are converted from one phase to another in these applications. Therefore, there are intensive studies on the removal of pollutants by photodegradation [6], [7], [8], [9], [10], [11], [12].
Advanced oxidation technologies (AOTs) are wastewater treatment methods that have been used effectively in the decomposition of toxic compounds in recent years [13], [14]. The basis of AOTs is to break down toxic pollutants through reactive free radicals. The hydroxyl radical (·OH) is the most important one [15]. Fenton and photo Fenton reactions, which are based on the generation of hydroxyl radicals from H2O2 with iron (II) salts, are the most used AOTs technologies for wastewater purifications [16], [17]. The disadvantage of homogeneous Fenton reactions is the requirement to remove the formed iron sludge and the necessity of working around pH = 2 with strict pH control [18]. The sludge problem is eliminated in the heterogeneous Fenton catalysis prepared by immobilizing the iron ions or iron oxide nanoparticles to the solid phase such as clay, zeolite, activated carbon, alumina, or natural polymers [19], [20], [21], [22], [23], [24]. Moreover, the working pH range can be extended with heterogeneous Fenton catalysis. However, the use of H2O2 in both homogeneous and heterogeneous Fenton processes increases the cost of this process.
Furthermore, low-molecular-weight Fe(III)-hydroxyl complexes in an aqueous solution have photochemical properties. When irradiated with UV light, these species can produce hydroxyl radicals and Fe(II) ions. In the hydrolysis of Fe(III) salts in an aqueous solution, different iron-hydroxyl species are formed, and between pH 2.5–5, the dominant species is Fe(OH)2+. The yield of ·OH radicals formed by photolysis of Fe(OH)2+ is much higher than other hydroxy species [25]. After UV irradiation the formed Fe(II) ions are reoxidized by dissolved oxygen to Fe(III). While the redox circle of Fe(III)/Fe(II) is completed, hydroxyl radical is produced from several circle reactions. Wu and Deng reviewed the possible mechanism of photolysis of Fe(III)-hydroxy complexes and the feasibility of the photochemical methods using Fe(III) salts in wastewater treatments [25]. In addition, Fe(III)-polycarboxylate complexes have been shown to be more efficient than Fe(III)-hydroxy complexes in accelerating the photodegradation of the dyes [26], [27], [28]. Recently, Nawar et al. showed efficient Fe(III) - aqua complex-mediated photodegradation of methylene blue dye in homogenous solution [29]. Li et al. reported high photocatalytic efficiency of Fe-alginate gel against MG dye with the incorporation of citric acid [30]. Effective dye removal was achieved with the contribution of citric acid to radical formation under UV light.
Alginate is one of the most widely used polysaccharides. Alginate hydrogels cross-linked with metal ions are frequently used as adsorbents and drug encapsulation [31], [32]. However, since alginate gels have low durability in an aqueous solution, it is preferred to use it in composite form with other biopolymers. Alginate and CMC can form compatible composites [33], [34], [35].
The present study aims to propose a simple and efficient photocatalytic degradation of MG dye in an aqueous solution under UV light with alginate-CMC composites cross-linked with Fe(III) ions without the addition of H2O2. As far as we know, the Fe@Alg-CMC composite material is being tested for the first time in dye photocatalytic degradation. In this study, the optimal conditions for maximum photodegradation of MG in an aqueous solution are reported.
Section snippets
Materials
Sodium alginate (Medium viscosity, Product number: A2033), sodium carboxymethyl cellulose (Low viscosity, Product number: C5678), and malachite green oxalate salt (Product number: M9015), and ferric chloride hexahydrate (FeCl3·6H2O) were obtained from Sigma-Aldrich (St. Louis, MO). Calcium chloride dihydrate (CaCl2·2H2O) was obtained from J.T. Baker (Deventer, The Netherlands). All chemical reagents were analytical grade and were used without further purification. Distilled water from Elga
Size, SEM Morphology, FTIR and XRD analysis
From digital photographs given in Fig. 1, it is seen that Fe@(Alg-CMC) beads are in their wet (Fig. 1a) and dry state (Fig. 1b). After completely drying, the beads have lost their light orange color and turned to orange-brown color. The dimensions of the beads were measured in width and length as 2.41 ± 0.20 mm and 3.45 ± 0.31 mm in their wet state and as 1.21 ± 0.05 mm and 1.60 ± 0.04 mm in their dry state, respectively.
Fig. 2 introduces SEM images of Fe@(Alg-CMC) beads. In Fig. 2a and Fig. 2
Discussion
With the prepared Fe@(Alg-CMC) composite gels, a very high percentage of dye degradation was achieved in a very short time. Although the degradation mechanism of Fenton-type applications is not completely clear, it is predicted that the •OH radicals formed due to UV irradiation of the hydroxyl complexes of Fe(III) ions are the active species. In the pH range of 2.5 to 5, [Fe(OH)(H2O)5]2+ is the predominant monomeric Fe(III) hydroxyl complex [29]. Maintaining the pH in this range, reduction of
Conclusion
Alginate-carboxymethyl cellulose composite material was prepared by a simple, fast, and inexpensive method. The composite material cross-linked with Fe(III) ions removed the malachite green dye from water under UV light with an excellent degradation percentage and time. The radicals formed by the iron ions of the composite material with UV light served as photocatalysis. The photocatalysis task of the composite material prepared in this study without using hydrogen peroxide could well be used
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 did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The research was done at Istanbul Technical University, Capillary Electrophoresis, and Biopolymer Applications Research Laboratory. The research facilities of the laboratory are covered by the Research Foundation of Istanbul Technical University.
References (35)
- et al.
Low-cost adsorbents for waste and wastewater treatment - a review
Sci. Total Environ.
(1992) - et al.
In-situ formation and entrapment of Ag/AgCl photocatalyst inside cross-linked carboxymethyl cellulose beads: a novel photoactive hydrogel for visible-light-induced photocatalysis
J. Photochem. Photobiol. A: Chem.
(2020) - et al.
A novel heterogeneous photo-Fenton Fe/Al2O3 catalyst for dye degradation
J. Photochem. Photobiol. A: Chem.
(2021) - et al.
Visible light-driven photocatalyst: an iron (III) coordination compound in rhodamine B degradation
J. Photochem. Photobiol. A: Chem.
(2022) - et al.
Photodegradation of cresol red by a non-iron Fenton process under UV and sunlight irradiation: effect of the copper (II)-organic acid complex activated by H2O2
J. Photochem. Photobiol. A: Chem.
(2021) - et al.
Fe-doped Al2O3 nanoplatforms as efficient and recyclable photocatalyst for the dyes remediation
J. Photochem. Photobiol. A: Chem.
(2022) - et al.
Color, TOC and AOX removals from pulp mill effluent by advanced oxidation processes: a comparative study
J. Hazard. Mater.
(2007) - et al.
Homogeneous photocatalytic processes for degradation of some endocrine disturbing chemicals under UV irradiation
J. Water Process. Eng.
(2017) - et al.
A review of classic Fenton's peroxidation as an advanced oxidation technique
J. Hazard. Mater.
(2003) - et al.
Heterogeneous catalytic treatment of synthetic dyes in aqueous media using Fenton and photo-assisted Fenton process
Desalination
(2011)
Preparation and catalytic activity of Fe alginate gel beads for oxidative degradation of azo dyes under visible light irradiation
Catal. Today
Enhanced degradation of Acid Red 73 by using cellulose-based hydrogel coated Fe3O4 nanocomposite as a Fenton-like catalyst
International Journal of Biological Macromolecules
Carboxylcellulose hydrogel confined-Fe3O4 nanoparticles catalyst for Fenton-like degradation of Rhodamine B
Int. J. Biol. Macromol.
Fe/polymer-based photocatalyst synthesized by sono-sorption method applied to wastewater treatment
J. Photochem. Photobiol. A: Chem.
Neutral solar photo-Fenton degradation of 4-nitrophenol on iron-enriched hybrid montmorillonite-alginate beads (Fe-MABs)
J. Photochem. Photobiol. A: Chem.
Photochemistry of hydrolytic iron (III) species and photoinduced degradation of organic compounds
A minireview, Chemosphere.
Photodegradation of dyes in aqueous solutions containing Fe(III)-oxalato complexes
Chemosphere.
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