Decolorization Of Dye Wastewater Research Articles

Synthesis, magnetic properties, biotoxicity and potential mechanism of modified nano zero-valent iron for decolorization of dye wastewater

ABSTRACT SiO2-coated nano zero-valent iron (nZVI) has emerged as a fine material for the treatment of dye wastewater due to its large specific surface area, high surface activity, and strong reducibility. However, the magnetic properties based on which SiO2-coated nZVI (SiO2-nZVI) could effectively separate and recover from treated wastewater, and the biotoxicity analysis of degradation products of the dye wastewater treated by SiO2-nZVI remain unclear. In this study, SiO2-nZVI was synthesized using a modified one-step synthesis method. The SiO2-nZVI nanoparticles were characterized using Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Fully automatic specific surface and porosity analyzer, Vibrating sample magnetometer, and Zeta potential analyzer. The removal rate of methyl orange (MO) by SiO2-nZVI composite reached 98.35% when the degradation performance of SiO2-nZVI treating MO was optimized. Since SiO2-nZVI analysed by magnetic hysteresis loops had large saturation magnetization and strong magnetic properties, SiO2-nZVI exhibited excellent ferromagnetic behaviour. The analysis of the degradation products showed that the MO treated by SiO2-nZVI was converted into a series of intermediates, resulting in reducing the toxicity of MO. The potential mechanism of MO degradated by SiO2-nZVI was speculated through degradation process and degradation kinetics analysis. Overall, the SiO2-nZVI composite may be regarded as a promising catalyst for decolorization of dye wastewater.

Encapsulated laccase in bimetallic Cu/Zn ZIFs as stable and reusable biocatalyst for decolorization of dye wastewater

Laccase have received extensive attention in pollutant degradation, but its practical viability is largely affected by the poor stability, easy inactivation and difficulty in recycling for the present. Enzyme immobilization offers enhanced enzyme stability and constructs a synergistic system for the efficient adsorption and degradation of pollutants. In this study, bimetallic Cu/Zn ZIFs were synthesized by co-precipitation method as the protective carrier for laccase. Lac@Cu-ZIF-90 exhibited a good protective effect on laccase and showed a high operational stability in various interfering environments. Free laccase was completely inactivated at pH 7.0 but Lac@Cu-ZIF-90 could maintain 50.0 % activity. Benefiting from the encapsulation of laccase and porous structure of Cu-ZIF-90, the Lac@Cu-ZIF-90 exhibited decolorization efficiency for dye wastewater. More importantly, the Lac@Cu-ZIF-90 could be recovered from the dye solution and re-used to adsorb and degrade the synthetic dye for multiple times, its removal rate for reactive deep green was only decreased about 10.8 % after five cycles. This work reveals that the Cu-ZIF-90 provides a favorable environment for laccase and as a protective layer to relieve the conformation change, which provides an efficient strategy to decolorize dye wastewater. Therefore, Cu-ZIF-90 promises applications as enzymes encapsulation has great potential in water remediation.

Wastewater treatment: A universal, scalable and recyclable catalyst with adjustable activity for diverse dyes degradation

The growing concern over water shortage and pollution is propelling and accelerating the development of sewage treatment technologies. Among them, the catalytic hydrogenation method is highly recommended from a sustainable perspective, because it can turn toxic pollutants into valuable raw materials. The catalyst with excellent activity and stability plays a critical role in this “trash to treasure” approach. Herein, we proposed a novel economical, scalable and recyclable candidate catalyst, i.e., the copper nanoparticles supported on zinc oxide nanowire array (Cu–ZnO NWA), for realizing efficient and stable dye wastewater treatment. The salix argyracea-shaped Cu–ZnO NWA displays very outstanding universality and controllability towards the catalytic hydrogenation reactions of diverse dyes, owing to the fact that ZnO nanowire array not only offers a platform to realize stable and homogeneous dispersion of Cu nanoparticles, but also provides a large quantity of catalytically active sites. More attractively, its synthetic method can be facilely extended to various conductive substrates through combined electrodeposition and hydrothermal technique, showing its general applicability for the surface assembly of sewage treatment facilities. Benefiting from above advantages, this proposal offers an attractive approach for large-scale and continuous decolorization of dye wastewater, and presents a broad application prospect in the textile printing industry.

Decolorization of Dye Wastewater by Activated Carbons Produced from Peanut Shell using ZnCl2 Impregnation Method

This study assessed the adsorption capacity of different activated carbons produced from peanut shell for S3B dye (Sunfix Red 150%) present in dye wastewater under different contact conditions. The pre-impregnation of input material by ZnCl2 (weight ratio 1:1) increased surface charge of produced activated carbon to positive value; While activated carbons produced from non-impregnation and post-impregnation procedures had negative charge. The optimal adsorption conditions were at pH 5 with 10 g/L activated carbon in original dye wastewater , for 180 minute contacting time. Under the optimal conditions, pre-impregnated activated carbon had highest adsorption capacity, corresponding to80.2% S3B dye removal; while the two other types of activated carbons obtainedabout 40% dye removal. The adsorption process suited to Freundlich isotherm model (multilayer adsorption) with KF adsorption constants being 0.0377, 0.3314 and 0.0523 for non-, pre- and post-impregnated activated carbons, respectively.

Enhancing dye wastewater treatment efficiency in ozonation membrane contactors by chloro– and fluoro–organosilanes’ functionality on hydrophobic PVDF membrane modification

This work investigated the decolorization of dye wastewater using an ozonation membrane contactor. The hydrophobicity of a PVDF membrane was developed by applying novel plasma activation followed by grafting with methyltrichloroalkylsilane (PVDF–MTCS) and 1H, 1H, 2H, 2H–perfluorodecyltriethoxysilane (PVDF–FAS–C8) at different grafting times and grafting agent concentrations. After hydrophobic membrane modifications, the ozonation membrane performances were improved. The ozone flux of PVDF–FAS–C8 was higher and more stable, maintaining 88% of the initial flux after 20 h, compared to 79% and 53% for the PVDF − MTCS and original membranes, respectively. After 90 mins, COD removals of Direct Blue 71 (DB 71) and Reactive Red 239 (RR 239) by the ozonation membrane contactor using PVDF–FAS–C8 were 62.5% and 67.5%, and TOC removals were 20% and 23%, respectively, with almost complete decolorization. The releases of sulfate and nitrate ions confirmed the dye mineralization. By applying a PVDF − FAS − C8 membrane, energy consumption was 33.2% lower than when using the original membrane. The findings exhibited that the performance of ozonation membrane contactor improved was due to the role of the functionality on modified PVDF membranes. The PVDF − MTCS membrane had a higher silicon composition and better surface roughness than the PVDF − FAS − C8 membrane. The water contact angle (WCA) of the PVDF − MTCS membrane was higher than that of the PVDF − FAS − C8 membrane, increasing from 74.7°(original) to 126.0° and 112.7°, respectively, after 6 h of grafting, leading to reduced membrane wetting.

Studies on decolorization of dye wastewater in down flow jet loop sparged reactor using response surface methodology

Studies on decolorization of dye wastewater in down flow jet loop sparged reactor using response surface methodology

Bibliometric analysis of global research on white rot fungi biotechnology for environmental application.

In recent years, white rot fungi (WRFs) have received tremendous attention as a biotechnological tool for environmental pollution control. In order to systematically and comprehensively describe the progress, trends, and hotspots of WRF biotechnology in the field of environmental pollution control, the 3967 related publications from 2003 to 2020 were collected from Web of Science Core Collection database, and the bibliometric characteristics including publication output, country, institution, journal, author, citation frequency, h-index, and research focus were evaluated by using Excel 2007, CiteSpace V, and VOSviewer. The results indicated that the number of research publications increased rapidly before 2009, but after that, the number of publications fluctuated in a certain range. China and USA were the most productive countries and the most active country in international cooperation. In this field, most authors tend to cooperate within a small group. The journal and subject category with the largest number of publications are “International Biodeterioration & Biodegradation” and “Biotechnology Applied Microbiology”, respectively. The analysis of high-frequency keywords revealed that “laccase”, “biodegradation”, “decolorization”, and “Phanerochaete chrysosporium” were the most cited terms among all publications. The pretreatment of biomass waste, decolorization of dye wastewater, and bioremediation of polluted environment are the key research directions of WRF biotechnology. Finally, the frontier topics and active authors in this research field were identified using burst detection. We believe that this bibliometric study provides a comprehensive and systematic overview and promoted the future cooperative research and knowledge exchange in this field of WRF biotechnology for environmental applications.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-15787-1.

Boosting piezocatalytic performance of Ag decorated ZnO by piezo-electrochemical synergistic coupling strategy

The highly efficient piezocatalysts of Ag decorated ZnO nanocrystals (Ag-ZnO) have been designed and synthesized. Remarkably, piezocatalytic activity of Ag-ZnO depends on Ag concentrations. The piezocatalyst with suitable amount of 15% Ag-ZnO presents excellent piezocatalytic activity towards methylene orange (MO) organic dye degradation under ultrasonic vibration. The reaction rate constant of 15% Ag-ZnO is up to 19.58 × 10−3 min−1, which is 4.2 times in contrast with pure ZnO. Piezocatalytic efficiency of 15% Ag-ZnO reaches to ~ 90.5% after 120 min via combining piezoelectric effect with electrochemical synergistic coupling strategy. It also demonstrates that Ag decorated and piezo-electrochemical synergistic coupling effects can induce large amount polarization electric charges to form active superoxide radicals (·O2−) and hydroxyl radical (·OH), further greatly facilitate the carriers transport and accelerate the electric charges carrier separation of the reaction kinetics process resulting in promoting the piezocatalytic degradation activity. Furthermore, a novel piezocatalytic mechanism has been put forward to elucidate the relationship between piezocatalytic decomposition performance and contribution in Ag decorated, and piezo-electrochemical synergistic coupling effects. The promising strategy provides an innovative guidance and idea for designing excellent performance piezocatalyst in dye wastewater decolorization treatment application.

Textile Dye Biodecolorization by Manganese Peroxidase: A Review.

Wastewater emissions from textile factories cause serious environmental problems. Manganese peroxidase (MnP) is an oxidoreductase with ligninolytic activity and is a promising biocatalyst for the biodegradation of hazardous environmental contaminants, and especially for dye wastewater decolorization. This article first summarizes the origin, crystal structure, and catalytic cycle of MnP, and then reviews the recent literature on its application to dye wastewater decolorization. In addition, the application of new technologies such as enzyme immobilization and genetic engineering that could improve the stability, durability, adaptability, and operating costs of the enzyme are highlighted. Finally, we discuss and propose future strategies to improve the performance of MnP-assisted dye decolorization in industrial applications.

Decoloration behavior of hydrolyze sediment of ferric salt doped with magnetite on dye wastewater

Based on the strong adsorption capacity of colloidal precipitate formed by hydrolysis of iron salts (FHCP), a kind of composite material of FHCP/Fe3O4 was prepared and used in the decoloration of dye wastewater. The results showed that FHCP/Fe3O4 had high decolorization efficiency for anionic dyes. FHCP/Fe3O4 was more suitable for the decolorization of anionic dyes in acidic environment. The impact order of foreign ions on the decolorization performance of FHCP/Fe3O4 was as follows, that is HCO3 - >SO4 2- >Cl-. The fitting of adsorption kinetic of anionic dyes on FHCP/Fe3O4 matched with the pseudo-second-order kinetic equation.

Preparation of Quinone Mediator / Polyvinylidene Fluoride Functionalized Membrane

In this study, the redox mediator accelerated the degradation of dyes and improved the efficiency of dye wastewater treatment by immobilizing quinone mediators on the membrane. Specifically, polyvinylidene fluoride, quinone, and lithium chloride were used as the membrane substrate, redox mediator modifier, and porogen, respectively. By changing the type of quinone, the concentration of quinone, and the concentration of crossing-linker, the effect of quinone mediator-functionalized polyvinylidene fluoride membrane on the decolorization of dye wastewater was investigated. This study has shown that the cross-linking agent could effectively improve the compatibility of the quinone mediator casting solution system, and the increase in the addition amount of quinone mediator increased the decolorization rate of the membrane. The increase of the quinone content could also improve the decolorization effect of the dye. The decolorization rate of the original membrane without adding quinone was only 36%, whereas the decolorization rate of the blend membrane reached 75%, which shows the PVDF film with immobilized quinone mediator exhibited a significant dye degradation effect.

Improved decolorization of dye wastewater and enhanced power output in the electrically stacked microbial fuel cells with H2O2 modified corncob anodes

AbstractThe key operational constraints of the microbial fuel cell (MFC) technology in achieving its due potential are the high cost of electrodes and the difficulties in scaling up. To address these issues, carbonized corncob anodes were prepared and modified with the hydrogen peroxide (H2O2) to increase the oxygenated functional groups favoring the extracellular electron transfer between the microbes and electrodes. Compared to the MFC with anode without any modification, that is, bare anode, the single chambered MFC with 20% H2O2 modified anode exhibited excellent electro‐catalytic activity and a 91% decrease in the internal resistance (decreased from 35 ± 0.5 to 3.0 ± 0.6 kΩ) along with 89% increase in the maximum power density (increased from 8.8 ± 0.7 to 89.7 ± 0.6 mW/m2). MFCs with 20% H2O2 modified anode resulted in high decolorization efficiency of real dye wastewater (RDW) up to 92% which is 18% higher than that of the MFC with the bare anode. In order to boost the power output, the system was designed and studied by electrically stacking the 24 individual units of the MFC with the modified anode into parallel and series configurations. In parallel stacking and series stacking, the power output was 18.9 and 13.5 times higher than the single MFC unit, respectively. The RDW degradation rate was in the order of parallel stack > series stack > single MFC unit.

Effective promoting piezocatalytic property of zinc oxide for degradation of organic pollutants and insight into piezocatalytic mechanism

The piezoelectric zinc oxides with different morphology (ZnO nanoparticles and nanorods, hereafter abbreviated as ZnO NPs and NRs) are successfully synthesized using facile, green and harmless solid-state chemistry method at room temperature. The piezocatalytic activity of zinc oxide towards methylene blue (MB) of organic pollutants degradation has been explored under ultrasonic vibration. The ZnO NRs exhibit effectively enhanced piezocatalytic performance towards degradation dye compared with the ZnO NPs. In particular, the piezocatalytic decolorization ratio of MB solution is up to ~38% in ZnO NRs under 120 min, ~ 99% under 5.5 h and show good recycling utilization characteristics, indicating great potential for dye wastewater decolorization treatment. The main oxidizing hydroxyl radical (OH) and superoxide radicals (O2−) of the piezocatalytic reactions are confirmed and the production of piezocatalytic degradation process induced polarization electric charges. Moreover, we investigate the relationship between morphology and piezoelectric potential based on the finite element method for ZnO NPs and NRs, which further clarify the enhanced piezocatalytic activity and insight into piezocatalytic mechanism. This work offers a novel strategy towards wastewater decontamination applications and further understanding the relationship between piezocatalysis, morphology, and piezocatalytic mechanism in piezoelectric materials.

Melt-spun modified poly (styrene-co-butyl acrylate) fiber as a carrier to support manganese oxide and its application in dye wastewater decolorization.

Polymer fiber, a kind of versatile material, has been widely used in many fields. However, emerging applications still urge us to develop some new kinds of fibers. Advanced oxidation processes (AOPs) have created a promising prospect for organic wastewater decontamination; thus, it is of important significance to design a kind of special fiber that can be applied in AOPs. In this work, a viable route is proposed to fabricate manganese oxide-supporting melt-spun modified poly (styrene-co-butyl acrylate) fiber, and the prepared fiber has an excellent activity to catalyze H2O2 and O3 to decolorize dye-containing water. The results show that the decolorization of a cationic blue solution can be completely accomplished within 10 min with the prepared fiber as a catalyst, and its decolorization efficiency can reach up to 96.2% within 40 min. The concentration of total organic carbon can decrease from 20.3 to 12.3 mg/L. The prepared fiber can be reused five times without any loss in decolorization efficiency. Compared with other manganese oxide-based catalysts reported in the literature, the prepared fiber also shows many advantages in decolorizing methylene blue such as easy separation, mild reaction condition, and high decolorization efficiency. Therefore, we are confident that the fiber introduced in this study will exhibit a great application potential in the field of dye wastewater treatment.

The favourable synergistic operation of photocatalysis and catalytic oxygen reduction reaction by a novel heterogeneous CoFe2O4-TiO2 nanocomposite

The improved photocatalytic activity of TiO2 with the addition of spinel CoFe2O4 as an effective catalyst for O2 reduction reaction (ORR) is studied and proved in this study. CoFe2O4-TiO2 heterostructure nanoparticles are prepared by a reflux condensation and two-step hydrolysis-hydrothermal method. The addition of trace CoFe2O4 onto TiO2 can improve its affinity to O2, generate a faster transportation of photo-induced carriers, but hardly affect band structure. With an appropriate amount of CoFe2O4 to TiO2, a remarkable acceleration occurs in photocatalytic decolorization of dye wastewater, and the calculated apparent kinetic constant (kapp) of the composite (0.020 min−1) is 2.4 and 5.6 times of pure TiO2 (0.0085 min−1) and CoFe2O4 (0.0036 min−1), respectively. Quenching experiments with different radical scavengers show that O2–∙ is the key oxidative radical in all photocatalytical reactions. Meanwhile, the rapid growth of O2–∙ production by CoFe2O4-TiO2 is proved to be a major cause for photocatalytic performance improvement. Furthermore, an improved electrochemical ORR catalytic ability by CoFe2O4-TiO2 is verified and the 2-plus-2 electron route generates the same product (H2O2) as the photocatalytic process. Therefore, the synergistic operation of photocatalytic and catalytic ORR process by CoFe2O4-TiO2 resulted in a rapid degradation of dye wastewater.

Insight into performance and mechanism of tea polyphenols and ferric ions on reductive decolorization of malachite green cationic dye under moderate conditions

Dye decolorization is of crucial concern for effectively treating dye wastewater. In this study, rapid and effective decolorization of malachite green cationic dye was achieved by tea polyphenols and ferric ions under moderate conditions. Approximately 96.2% of decolorization efficiency could be obtained within the first 10 min at the initial dye concentration of 50 mg/L. The proposed method can perform excellently in a wide pH range of 5–9 and decolorization kinetics of malachite green under different solution pH were well fitted by the pseudo-second-order model. After the decolorization, only a slight reduction of tea polyphenols was observed, while the strength of peaks assigned to nitrogen-containing groups was significantly weakened, indicating that the N-demethylation reaction might occur during the decolorization process. The nucleophilic attack of deprotonated hydroxyl groups of tea polyphenols was proposed as the decolorization mechanism. The presence of ferric ions at an appropriate dosage could promote the deprotonation process and therefore enhance decolorization efficiency, while excess ferric ions in solution might compete with malachite green dye towards reductive sites on tea polyphenols. The findings from this study provided an economical and environmentally friendly technique for the effective decolorization of dye wastewater.

Rice Husk Biochars Modified with Magnetized Iron Oxides and Nano Zero Valent Iron for Decolorization of Dyeing Wastewater

This study investigated if biochar, a low-cost carbon-rich material, can be modified with reactive materials for decolorization of dyeing wastewater. Two types of rice husk biochars were produced by using different processes of gasification and pyrolysis in limited air condition. The biochars were first magnetized and then modified with nano-scale zero-valent iron (nZVI) to achieve the final products of magnetic-nZVI biochars. Batch experiments were conducted to investigate the efficiency of the modified biochars for reducing color of the reactive dyes yellow (RY145), red (RR195), and blue (RB19) from dyeing solutions. Results showed that color removal efficiency of the modified biochars was significantly enhanced, achieving the values of 100% for RY145 and RR195 and ≥65% for RB19, while the effectiveness of the original biochar was significantly lower. In addition, with increasing dose of the modified biochars, the color removal efficiency increased accordingly. In contrast, when the dose of nZVI was increased beyond a certain value then its color removal efficiency decreased accordingly. It is reported that the magnetic-nZVI rice husk biochars effectively removed the reactive dyes. The impregnation of nZVI particles on the biochar surface spatially separates the nZVI particles, prevents its aggregation and therefore enhances the decolorization efficiency.

Switch Effect, Water‐Like State, and New Interaction Mechanism of an H‐Bonded Polycation–Polyacrylamide System to Realize Instant Decolorization of Dyeing Wastewater

AbstractA switch for controlling hydrogen bonds is incorporated into a polymer‐based system of polyamine polycation and polyacrylamide, with an ultrahigh molecular weight of 18 million; a surprising process results whereby the apparent viscosity of the whole system suddenly plunges from 321 cps to below 6.5 cps, forming a new water‐like phase state (WLPS) of an H‐bonded polymer‐based system. When WLPS products are used as decolorant materials to purify dyeing wastewater, they can flow similar to water during mass transfer and be quickly dissolved, immediately interacting with the anionic dyes in water. This observation is the first of a sudden change in apparent viscosity and the formation of a water‐like state in a polymer‐based system. Moreover, due to the switch effect to control hydrogen bonds, WLPS decolorants can change from water‐like states to strong hydrogen bonding states after interacting with anionic dyes, thus increasing the attractive forces of formed flocs to realize the instantaneous and highly adaptable decolorization of dyeing wastewater. It only took 10 s for the WLPS decolorants to remove more than 95% of various dyes in dyeing wastewater. Subsequently, a series of new cohesive floc structure–forms are first discovered by a computer imaging optical microscope.

Preparation and performance characterization of solid polyferric sulfate(SPFS) water purifier from sintering dust

The mother solution of high purity ferric sulfate can be extracted by water washing, acid leaching, high-temperature aging, water leaching and removing K, Ca and Si elements with high content in sintering dust with sintering dust as raw material. Under the optimal acid leaching scheme, the leaching rate of Fe element can reach 99.8%. Subsequently, the mother solution of high purity ferric sulfate was configured to 100 ml 3 mol L−1 Fe2(SO4)3, and then add 0.1 mol FeSO4.7H2O, mixing reaction 1 h at room temperature, the liquid polyferric sulfate product can be just made. Then the liquid polyferric sulfate can be dried to SPFS product with the 17.4% base degrees at 50 °C. Through the comparison and analysis of TG, DTG and IR test results of purchased SPFS and self-made SPFS, it can be concluded that the self-made SPFS has the similar hydroxyl bridged frame structure with that of purchased SPFS. The experiment of purifying different kinds of simulated dye wastewater with self-made SPFS shows that the optimal pH range of these three dyes is 5–9 in the dye wastewater decolorization experiment and all their chrominance removal rates can reach above 96% at pH = 7.0. In addition, the adsorption isotherm of orange GGL solution is well represented by the Langmuir isotherm model in this experiment.

Performance of Freshly Generated Magnesium Hydroxide (FGMH) for Reactive Dye Removal

Coagulation-flocculation (CF) is an essential process for water and wastewater treatment plants. Whilst compared with the conventional coagulants, the freshly generated magnesium hydroxide (FGMH) is environmental friendly within its coagulative and adsorptive jellied sediment. However, decoloration of dye wastewater using FGMH has not been well understood yet. In this paper, operating variables such as initial pH, coagulant dosage, agitation speed and duration were examined for efficient reactive dye removal. The flocs breakage and regrowth capacity after slow agitation of original CF phase were monitored for mechanism analysis. The mechanism analysis showed that the charge neutralization was the predominance during coagulation, and the precipitate enmeshment and adsorption bridging dominated the flocculation stage. In comparison with the initially formed flocs, though the regenerated flocs were considerably smaller after the second rapid agitation, the bridging interaction of loose flocs could absorb the small residual particles during the slow agitation stage.