Treatment Of Dye-contaminated Wastewater Research Articles

Surfactant-modified coconut coir powder (SMCCP) as a low-cost adsorbent for the treatment of dye-contaminated wastewater: parameters and adsorption mechanism.

The dye-contaminated wastewater discharged from various industries such as dye manufacturing, paint, textile, paper, and cosmetic is a prime source of surface water pollution having serious detrimental effects on both the environment and human beings. These hazardous dyes when exposed to water obstruct the penetration of sunlight into the water and thus restrain aquatic plants from generating photosynthetic compounds. Moreover, some dyes are potential cancer-causing and also negatively impact the human nervous and respiratory systems. In this current study, modification of coconut coir powder (CCP) was carried out through cationic surfactant treatment and was successively utilized as the adsorbent for decoloring anionic dye (acid blue 185 (AB 185)) containing waste stream. Further, a comparative investigation of the dye removal efficiency of raw CCP and surfactant-modified coconut coir powder (SMCCP) as the adsorbent was studied. On surfactant treatment, using a very minimal SMCCP dosage of 8.3g/L, a very high percentage dye removal of 98.4% is possible, whereas with raw CCP, even after using a higher dosage of 14g/L, only 70.1% dye removal can be achieved. Characterization of SMCCP adsorbent was done by Fourier transform infrared, thermogravimetric, X-ray, and scanning electron microscope analyses. Furthermore, the optimization of critical operating parameters was investigated for the effective adsorption of AB 185 dye in batch mode. The adsorption of AB 185 onto SMCCP was a thermodynamically spontaneous endothermic process, following the Langmuir isotherm and pseudo-second-order kinetic model. Moreover, regeneration of exhausted SMCCP by 0.1 (M) NaOH was achieved with a satisfactorily high recovery of 97% in the first cycle. Subsequently, SMCCP can be successfully reutilized for five consecutive cycles with a loss of 17.6% in the total adsorption capacity. With all such advantages, the present study delivers a new paradigm to utilize the novel adsorbent SMCCP as a promising eco-friendly adsorbent aided by its advantage of regeneration and reusability for the treatment of dye-contaminated wastewater.

Surface engineered recombinant Escherichia coli for the potential application of the cobalt contaminated wastewater treatment and the photocatalytic dye degradation

The novel recombinant Escherichia coli strain was construct through cell surface display for the treatment of cobalt contaminated wastewater and dye contaminated wastewater. First, structural analysis of known cobalt binding peptide was conducted and core binding sites were figured out which showing better cobalt binding ability. The cobalt peptides were attached to OmpC to construct cobalt adsorbing recombinant Escherichia coli. The recombinant strain efficiently absorbed and retrieved cobalt from cobalt wastewater by adsorbing 1895 µmol/g DCW of cobalt. Following adsorption, cobalt nanoparticles were synthesized through thermal decomposition of cobalt adsorbed recombinant strain at 500˚C. The nanoparticles exhibited noteworthy photocatalytic properties, demonstrating a substantial capacity for degrading dyes when used as a catalyst at a concentration of 10 mg/dl. These results presenting potential solutions for effective and environmentally friendly approaches to address cobalt and dye contaminated wastewater treatment process.

Penggunaan Katalis SiO2/ZnO untuk Menghilangkan Pewarna Rhodamin B Secara Efisien melalui Impregnasi Basah

This study explores the removal of Rhodamine B dye from wastewater using SiO2/ZnO catalysts synthesized by wet impregnation with varying zinc nitrate loadings (0.25–1.25 g). The catalyst prepared with 1 g of Zn(NO₃)₂ exhibited the highest activity, achieving a remarkable 95% degradation of Rhodamine B under UV irradiation. This enhanced performance is attributed to optimized active site availability on the catalyst surface. FTIR characterization confirmed the presence of both SiO₂and ZnO, with characteristic vibrational modes observed at 1067.44 cm⁻¹ and 428.72 cm⁻¹, respectively. These findings highlight the promising potential of tailored SiO₂/ZnO catalysts for efficient and environmentally friendly treatment of dye-contaminated wastewater.

RSM approach for process optimization of the photodegradation of congo red by a novel NiCo2S4/chitosan photocatalyst

The current study reported a facile co-precipitation technique for synthesizing novel NiCo2S4/chitosan nanocomposite. The photocatalytic activity of the prepared nanocomposite was evaluated using congo red (CR) dye as a target pollutant. The central composite design was employed to examine the impact of different reaction conditions on CR dye degradation. This study selected the pH, photocatalyst loading, initial CR concentration and reaction time as reaction parameters, while the degradation efficiency (%) was selected as the response. A desirability factor of 1 suggested the adequacy of the model. Maximum degradation of 93.46% of 35 ppm dye solution was observed after 60 min of visible light irradiation. The response to surface methodology (RSM) is a helpful technique to predict the optimum reaction conditions of the photodegradation of CR dye. Moreover, NiCo2S4/Ch displayed high recyclability and reusability up to four consecutive cycles. The present study suggests that the prepared NiCo2S4/chitosan nanocomposite could prove to be a viable photocatalyst for the treatment of dye-contaminated wastewater.

Coupled adsorption-phytoremediation treatment of cellulose-reactive blue dye in a sustainable multi-step pilot-scale process.

A single-step dye removal strategy from wastewater is inadequate for concentrations above 100mg/L. In order to address this limitation, the adsorption of high dye concentrations followed by phytoremediation is a potential approach for the treatment of dye-contaminated wastewater. This combined method utilizes physical adsorption and biological processes to remove dyes from wastewater. Herein, we investigated a pilot-scale multi-step cascaded process where batch adsorption and fixed-bed column adsorption were combined with phytoremediation to remove cellulose-reactive blue dye at 200 to 500mg/L concentrations. The batch adsorption utilized low-cost water hyacinth root powder (WHRP) bioadsorbent having 670 m2/g surface area, whereas the fixed-bed column adsorption used sand having a surface area of 75 m2/g. The phytoremediation process utilized water hyacinth plants in a series of ponds. The effluent from one unit is fed to the next until the dye is removed to more than 98% for all concentrations considered in this study. Pilot-scale experimental data fitting to adsorption isotherms and kinetics were performed to gain insight into the pilot-scale adsorption mechanism. The fixed-bed sand column adsorption was conducted at different inlet dye concentrations, flow rates, and bed heights. The breakthrough curves were fit to the Thomas, Yoon-Nelson, and Bohart-Adams models. The effluent from the fixed-bed column was transferred to phytoremediation ponds, where complete dye removal was achieved. Overall, data collectively presented in this study demonstrated that the combined adsorption and phytoremediation approach offers a potential solution for the remediation of high dye concentration in wastewater, providing an effective and sustainable treatment option.

Insights into the visible light induced photocatalytic degradation of Acid Violet dye using carbon functionalized Ag2WO4 nanoparticles

The study investigates the photodegradation of Acid Violet 7, a commonly used azo dye in textile industries, using carbon functionalized Ag2WO4 nanostructures as a photocatalyst. The materials were characterised by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectra and UV-Vis diffuse reflectance spectra. In this research work, carbon functionalized Ag2WO4 nanostructures is synthesized and evaluated for its effectiveness in degrading Acid Violet 7 under visible light irradiation. The degradation process is explored by investigating various parameters such as catalyst loading and initial dye concentration. It is worth mentioning that the 75 % degradation is achieved in 30 minutes. The results demonstrate the photocatalytic activity of carbon functionalized Ag2WO4 nanostructures in degrading Acid Violet 7, highlighting its potential for efficient treatment of dye-contaminated wastewater. The primary active species involved in the degradation process is identified to be the hydroxyl radical. The modification of Ag2WO4 nanostructures with carbonaceous material enhances its photocatalytic performance by improving the light absorption and preserves the structural integrity of the nanostructures. The carbon functionalized nanostructures investigated in this research holds great promise towards the development of sustainable and effective photocatalytic system for environmental remediation.

Use of biochar and a post-coagulation effluent as an adsorbent of malachite green, beneficial bacteria carrier, and seedling substrate for plants belonging to the poaceae family

Wastewater treatment plants produce solid and semi-solid sludge, which treatment minimises secondary environmental pollution because of wastewater treatment and obtaining new bioproducts. For this reason, in this paper, the co-pyrolysis of biogenic biomasses recovered from a biological reactor with immobilised fungal and bacterial biomass and a tertiary reactor with Chlorella sp. used for dye-contaminated wastewater treatment was carried out. Biogenic biomasses mixed with pine bark allowed the production and characterisation of two types of biochar. The raw material and biochar were on the “in vitro” germination of Lolium sp. seeds, followed by adsorption studies for malachite green (MG) dye using the raw material and the biochar. Results showed that using 60 mg L−1 of a cationic coagulant at pH 6.5 allowed for the recovery of more than 90% of the microalgae after 50 min of processing. Two biochar resulted: BC300, at pH 5.08 ± 0.08 and BC500, at pH 6.78 ± 0.01. The raw material and both biochars were co-inoculated with growth-promoting bacteria; their viabilities ranged from 1.7 × 106 ± 1.0 × 101 to 7.5 × 108 ± 6.0 × 102 CFU g−1 for total heterotrophic, nitrogen-fixing and phosphate-solubilising bacteria. Re-use tests on Lolium sp. seed germination showed that with the post-coagulation effluent, the germination was 100%, while with the biochar, with and without beneficial bacteria, the germination was 98 and 99%, respectively. Finally, BC500 adsorbed the highest percentage of malachite green at pH 4.0, obtaining qecal values of 0.5249 mg g−1 (R2: 0.9875) with the pseudo-second-order model.

ZnO-based heterojunction catalysts for the photocatalytic degradation of methyl orange dye

In this study, a variety of ZnO-based heterojunctions with disparate wt.% doping of WO3 and BiOI have been prepared for the photodestruction of methyl orange (MO) dye in aqueous solution. The composites were analysed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, optical studies, and nitrogen adsorption-desorption isotherms. The SEM images revealed non-uniform surfaces of the ZnO–BiOI based composites while mostly nodular morphology was observed for all three samples of ZnO-WO3. As the WO3 loading increased, more clustering was detected. The analysed samples exhibited characteristic peaks representative of the triclinic phase of WO3 and the hexagonal wurtzite structure of ZnO, while the diffractogram observed from the materials displayed distinct peaks corresponding to the crystalline phases of both BiOI and ZnO in their pure forms. Further evidence of the samples' characteristics includes the presence of distinct crystalline patterns without any impurity peaks, a red shift in the absorption spectra of the heterostructure, the detection of only the reference elements, and mostly Type IV isotherm adsorption. This study identified the ZnO-[10%]BiOI and ZnO-[10%]WO3 heterojunctions as the best performing photocatalysts, as MO was completely destroyed in 120 and 90 min, respectively. Thus, confirming 10% wt. as the optimal doping concentration for the best photo-activity in this study. The impact of varying process parameters demonstrates that at an elevated photocatalyst mass of 40 mg, both heterojunctions effectively degraded MO. The photodegradation efficiency of MO was more pronounced in strong acidic conditions (pH 2) when compared to high alkaline conditions (pH 11) for the ZnO-[10%]BiOI heterostructure. However, a decrease in performance was observed for both strong acidic and high alkaline pH values when the ZnO-[10%]WO3 heterostructure was applied. The kinetic analysis of the photodegradation study reveals that all the photodegradation experiments can be represented by the pseudo-first-order kinetic model. The findings from this investigation propose that the ZnO-[10%]BiOI heterojunction photocatalyst holds significant potential for the effective treatment of dye-contaminated wastewater.

Surface activity, kinetics, thermodynamics and comparative study of adsorption of selected cationic and anionic dyes onto H3PO4-functionalized bagasse from aqueous stream.

The discharge of dyes into the water body creates toxicity to aquatic organisms because of their aromatic structure and difficult degradation. So, the treatment of dye-contaminated wastewater is required before releasing it. In the present study, thermally treated (600 °C) and H3PO4 (55%)-functionalized bagasse, henceforth called thermochemically activated bagasse (TCAB), was synthesized as potential adsorbent for the effective removal of selected cationic and anionic dyes from their aqueous stream. TCAB characterization was done employing FT-IR, SEM, XRD, zeta potential, BET, and PZC techniques. The comparative study shows that the relative adsorption on TCAB followed the sequence, methyl red (185 mg/g) > safranin (178 mg/g) > congo red (146 mg/g) > brilliant green (139 mg/g) > malachite green (130 mg/g) > bromocresol green (94 mg/g). The adsorption efficiency was investigated concerning the effect of change in TCAB dose (0.05-0.3 g/100 mL), initial dye concentration (20-200 mg/L), pH (4.0-10.0), ionic strength (0.1-0.5 M KCl), urea concentration (0.1-0.5 M) and temperature (25-45 °C). The representative adsorption isotherms belong to typical L-type. The time-dependent dye removal was best explained by the pseudo-second-order (PSO) kinetic model (R2 = 0.9859-0.9991), while equilibrium data were best explained by the Freundlich model (R2 = 0.9881-0.9961). Thermodynamic study showed the spontaneous (ΔG0 <0) and exothermic nature (ΔH0 <0) of the adsorption of different cationic and anionic dyes. The cyclic adsorption ability of TCAB for different dyes was checked up to three cycles (185 to 168 mg/L for MR, 178 to 165 mg/L for SF, 146 to 130 mg/L for CR, 139 to 127 mg/L for BG, 130 to 114 mg/L for MG and 94 to 80 mg/L for BCG), and no significant decrease in the adsorption capacity was noticed. So, the present study provides valuable insights into the adsorption of cationic and anionic dyes onto H3PO4-functionalized bagasse. Addressing the adsorptive aspects enhances the clarity, reliability and applicability of the study's findings and contributes to its overall scientific impact.

Synergy of cold plasma and sulfate radicals in the treatment of dye-contaminated wastewater; mechanistic study of the degradation mechanism using DFT

Organic dyes including azo and xanthene dyes are used widely, and ultimately discharged into wastewaters. Owing to the drawbacks of conventional water treatment, different advanced oxidation processes (AOPs) have been combined with nonthermal atmospheric pressure plasma (NTAPP) as sustainable alternatives for reclaiming dye-polluted wastewater. Herein, the synergy of NTAPP and sulfate radicals were utilized for treating real colored wastewater. Individual and combined systems of NTAPP and UV-C activated sulfate and hydroxyl radicals were evaluated based on their removal efficiencies for two model dyes: Rhodamine B (Rh.B) and Congo red (CR). The combined system of NTAPP and UV-C activated persulfate (PSUVP) was the most efficient with >80 % degradation of both dyes in 10 min and showed synergy factors of 2.55 and 5.71 for Rh.B and CR degradation, respectively. Moreover, PSUVP was highly efficient in TOC removal from Rh.B (90 %) and CR (67 %) solutions. The determining oxidants in Rh.B and CR degradation were the singlet oxygen and sulfate radical, respectively. The DFT analysis revealed that higher number of acidic hydrogens were available in CR compared to Rh.B and this might be one reason for observing the influential role of SO4∙- in CR degradation. Although the background constituents had negligible effects on Rh.B degradation, the degradation efficiency of the PSUVP system decreased by 30 % in real wastewater containing 50 ppm CR. The treatment of real colored wastewater using PSUVP resulted in 94 % TOC removal. Despite the toxicity of the PSUVP (toxicity unit ≥1), which can be mitigated by diluting the treated wastewater before discharge, this system exhibited high efficiency in decolorization and degradation of organic components. Thus, the proposed system has promising potential for the treatment of industrial effluents with high TOC.

G-C3N4-Co3O4 Z-Scheme Junction with Green-Synthesized ZnO Photocatalyst for Efficient Degradation of Methylene Blue in Aqueous Solution.

A simple wet chemical ultrasonic-assisted synthesis method was employed to prepare visible light-driven g-C3N4-ZnO-Co3O4 (GZC) heterojunction photocatalysts. X-ray diffraction (XRD), scanning electromicroscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), ultraviolet (UV), and electrochemical impedance spectroscopy (EIS) are used to characterize the prepared catalysts. XRD confirms the homogenous phase formation of g-C3N4, ZnO, and Co3O4, and the heterogeneous phase for the composites. The synthesized ZnO and Co3O4 by using cellulose as a template show a rod-like morphology. The specific surface area of the catalytic samples increases due to the cellulose template. The measurements of the energy band gap of a g-C3N4-ZnO-Co3O4 composite showed red-shifted optical absorption to the visible range. The photoluminescence (PL) intensity decreases due to the formation of heterojunction. The PL quenching and EIS result shows that the reduction of the recombination rate and interfacial resistance result in charge carrier kinetic improvement in the catalyst. The photocatalytic performance in the degradation of MB dye of the GZC-3 composite was about 8.2-, 3.3-, and 2.5-fold more than that of the g-C3N4, g-C3N4-ZnO, and g-C3N4-Co3O4 samples. The Mott-Schottky plots of the flat band edge position of g-C3N4, ZnO, Co3O4, and Z-scheme g-C3N4-ZnO-Co3O4 photocatalysts may be created. Based on the stability experiment, GZC-3 shows greater photocatalytic activity after four recycling cycles. As a result, the GZC composite is environmentally friendly and efficient photocatalyst and has the potential to consider in the treatment of dye-contaminated wastewater.

Optimization of dye-contaminated wastewater treatment by fungal Mycelial-light expanded clay aggregate composite

Dye-contaminated wastewaters from the printing batik industry are hazardous if discharged into the environment without any treatment. Finding an optimization and reusability assessment of a new fungal-material composite for dye-contaminated wastewater treatment is important for efficiency. The study purposes to optimize fungal mycelia Trametes hirsuta EDN 082 – light expanded clay aggregate (myco-LECA) composite for real priting batik dye wastewater treatment by using Response Surface Methodology with Central Composite Design (RSM-CCD). The factors included myco-LECA weight (2–6 g), wastewater volume (20–80 mL), and glucose concentration (0–10%) were applied for 144 h of incubation time. The result showed that the optimum condition was achieved at 5.1 g myco-LECA, at 20 mL wastewater, and at 9.1% glucose, respectively. In this condition, the decolorization values with an incubation time of 144 h were 90, 93, and 95%, at wavelengths 570, 620, and 670 nm, respectively. A reusability assessment was conducted for 19 cycles and the result showed that decolorization effectiveness was still above 96%. GCMS analysis showed the degradation of most compounds in the wastewater and the degradation products of the wastewater demonstrated detoxification against Vigna radiata and Artemia salina. The study suggests that myco-LECA composite has a good performance and therefore is a promising method for the treatment of printing batik wastewater.

Synchronous pyrolysis and activation of poly (ethylene terephthalate) for the generation of activated carbon for dye contaminated wastewater treatment

To address the increasing accumulation of water bottle waste and lack of effective recycling processes, water bottle waste was upcycled into a high value activated carbon product. This growing waste feedstock has proved to be a promising precursor for activated carbon, but it has not been investigated for use in the treatment of dye-contaminated effluent which is a very high-volume source of waste from textile industries. In this work, the production of activated carbon from water bottle waste by chemical activation using KOH was optimized and validated for the application as an adsorbent of textile dyes. The activation conditions of 800 °C for 1 h proved to be most optimal based on conversion efficiency, surface area, surface charge, and yield measurement. It was found that the product’s negative zeta potential (−40 mV) and high surface area (1124 m2/g), provided excellent adsorption capacity for the cationic methylene blue dye (335 mg/g). The adsorption of this representative dye was studied in detail and compared with cationic brilliant green dye and a mixture containing anionic methyl orange dye. Although the adsorption was found to depend on dye charge characteristics, there is potential for adsorption enhancement through pH adjustments. Additionally, the AC demonstrated the ability to treat mixed dye wastes containing anionic dyes despite its selective adsorption towards cationic dyes of over twice the amount. Overall, the product showed potential to be extended to a variety of textile dyes to provide excellent value for the textile industry while also helping to divert a significant amount of waste from landfills.

Biodegradation of Congo Red Using Co-Culture Anode Inoculum in a Microbial Fuel Cell

Congo red is an azo dye widely used as a colouring agent in textile industries. It is a serious threat due to its carcinogenic effects. Its degradation has been challenging due to its complex yet stable structure. The present study was aimed to investigate the effective degradation of Congo red by bioremediating bacteria isolated from different environments. To investigate predominant microorganisms that degrade Congo red and its functions in microbial fuel cells (MFCs), strains isolated from cow dung (Enterococcus faecalis SUCR1) and soil (Pseudomonas aeruginosa PA1_NCHU) were used as a co-culture inocula. The remarkable results establish that E. faecalis as an excellent microbial source for the biological degradation of dye-contaminated wastewater treatment alongside bioactive treating wastewater with varied concentrations of congo red dye. The highest efficiency percentage of dye degradation was 98% after 3 days of incubation at pH 7 and 37 °C, whereas findings have shown that the decolorization at pH 5 and 6 was lower at 66% and 83.3%, respectively, under the same incubation conditions. Furthermore, the co-culture of E. faecalis SUCR1 and P. aeruginosa at a 1:1 ratio demonstrated improved power generation in MFCs. The maximum power density of 7.4 W/m3 was recorded at a 150 mg L−1 concentration of Congo red, indicating that the symbiotic relation between these bacterium resulted in improved MFCs performance simultaneous to dye degradation.

Novel Amapá latex-mediated synthesis of defective α-Fe2O3 nanoparticles with enhanced ferromagnetism and sunlight photocatalytic activity

Iron oxide (α-Fe2O3) nanoparticles were synthesized using the latex of the Parahancornia amapa tree (Amapá latex) as an ecofriendly chelating agent. Raman, XRD, and Rietveld refinements analysis confirmed that all samples are single-phase with crystallite size in the range of 64–93 nm. SEM images showed that the volume of Amapá-latex used for synthesis plays an important role in forming nanoparticles with different morphologies and particle sizes of about 65–110 nm. PL spectra revealed the presence of ligand-to-metal charge-transfer transition (wide emission band positioned at ∼ 400 nm) and coexistence of both Oi and VO defects in the α-Fe2O3 nanoparticles. The highest remanent magnetization (∼0.09 μB/f.u.) and decolorization (94%) of MB dye were majority driven by the Oi and VO structural defects. A 33% TOC removal around 1h of the degradation process, which further increased to 70% after 6h, confirmed that MB molecules were cleaved and broken. These findings reveal that α-Fe2O3 nanoparticles synthesized by our Amapá latex-mediated route proved to be efficient for the obtention of α-Fe2O3 nanostructures with the potential to be used for the affordable treatment of dye-contaminated wastewater.

Bimetallic zeolitic imidazolate framework-derived nitrogen-doped porous carbon-coated CoFe2O4 core–shell composite with high catalytic performance for peroxymonosulfate activation in Rhodamine B degradation

The rational design and development of a highly efficient and sustainable heterogeneous catalyst has become a limiting factor for the practical application of persulfate-based advanced oxidation processes in organic dye degradation. Herein, a nitrogen-doped porous carbon-coated CoFe 2 O 4 core – shell composite (CoFe 2 O 4 @NPC) was synthesized by in-situ growth of cobalt/iron bimetallic zeolitic imidazolate framework-9 (Co/Fe-ZIF-9) on graphene oxide (GO) nanosheets followed by one-step calcination of the bimetallic ZIF-GO composite in nitrogen. The textural, chemical, and magnetic properties of the composites were comprehensively characterized using various analytical techniques. The catalytic performances of the as-prepared CoFe 2 O 4 @NPC in activating PMS to decompose Rhodamine B (RhB) were then systematically evaluated. The composite calcined at 600 °C exhibited the highest catalytic activity. The maximum RhB degradation efficiency of 99.05% and pseudo-second-order kinetic constant of 0.0766 L/(mg·min) were achieved after 20 min at 25 °C. Moreover, CoFe 2 O 4 @NPC displayed excellent recyclability and stability with negligible leaching of Co and Fe ions into the solution. Subsequently, electron spin resonance, reactive oxygen species quenching, and X-ray photoelectron spectroscopy were conducted to clarify the PMS activation mechanisms. Results suggested that SO 4 •− and •OH were generated during PMS activation and that SO 4 •− was the predominant radical involved in RhB degradation. In addition, Co(II), Fe(III), and structured nitrogen, especially pyridinic and graphitic N groups, participated in the PMS activation. Some insights into possible mechanisms of RhB degradation were also attained from spectral analyses. All these results suggested that CoFe 2 O 4 @NPC had excellent potential as a PMS activator for application in dye-contaminated wastewater treatment. • Nitrogen-doped porous carbon shell-coated CoFe 2 O 4 core – shell composites (CoFe 2 O 4 @NPC) prepared. • Multiple parameters influenced the catalytic performance of CoFe 2 O 4 @NPC. • CoFe 2 O 4 @NPC recyclable, stable, and resists the leaching of Co and Fe ions. • SO 4 •− is the principle radicals involved in the degradation of RhB. • Co(II), Fe(III) and structured nitrogen participated in the PMS activation process.

Biodegradation of Methylene Blue Using a Novel Lignin Peroxidase Enzyme Producing Bacteria, Named Bacillus sp. React3, as a Promising Candidate for Dye-Contaminated Wastewater Treatment

The emission of methylene blue (MB) from common industries causes risks to human health by making clean drinking water unavailable and hampering environmental safety. A biological approach offering a more cost-efficient and sustainable alternative solution has been studied and demonstrated to be significantly effective for the removal of MB using promising microbial isolates. Therefore, this study targeted bacterial candidates, namely Bacillus sp. React3, isolated from soil with the potential to decolorize MB. The phenogenic identification of strain React3 was performed by 16S rRNA sequencing, showing a similarity of 98.86% to Bacillus velezensis CR-502T. The ability of this bacterial strain to decolorize MB was proven through both the lignin peroxidase efficiency and accumulation in the biomass of the living cells. MB removal was determined by the reduction in the maximum absorption at a wavelength of 665 nm, which was observed to be up to 99.5% after 48 h of incubation. The optimal conditions for the MB degradation of strain React3 were pH 7, 35 °C, static, 4% inoculum, and 1000 mg/L of MB, with tryptone as a carbon source and yeast extract as a nitrogen source.

Dye contaminated wastewater treatment through metal–organic framework (MOF) based materials

A complete discussion of MOFs and MOF composites such as MOF-based membranes, magnetic MOFs, and metal–organic gels (MOGs) used for dye removal along with their adsorption efficiency has been done.

Synchronous Pyrolysis and Activation of Poly (Ethylene Terephthalate) for the Generation of Activated Carbon for Dye Contaminated Wastewater Treatment

Synchronous Pyrolysis and Activation of Poly (Ethylene Terephthalate) for the Generation of Activated Carbon for Dye Contaminated Wastewater Treatment

Photocatalysis: an effective tool for photodegradation of dyes-a review.

The disposal of dye-contaminated wastewater is a major concern around the world for which a variety of techniques are used for its treatment. The photocatalytic treatment of dye-contaminated wastewater is one of the treatment methods. Semiconductor-assisted photocatalytic treatment of dye-contaminated wastewater has gained pronounced attention recently. This review outlines the recent advancements in the photocatalytic treatment of dye-contaminated wastewater. The photocatalytic degradation of dyes follows three types of mechanisms: (1) dye sensitization through charge injection, (2) indirect dye degradation through oxidation/reduction, and (3) direct photolysis of dye. Several experimental parameters like initial concentration of dyes, pH, and catalyst dosage significantly affect the photocatalytic degradation of dyes. The photocatalytic materials can be categorized into three generations. The single-component (e.g., ZnO, TiO2) and multiple component semiconductor metal oxides (e.g., ZnO-TiO2, Bi2O3-ZnO) are categorized as first-generation and second-generation photocatalysts, respectively. The photocatalysts dispersed on an inert solid substrate (e.g., Ag-Al2O3, ZnO-C) are classified as third-generation photocatalysts. Finally, we reviewed the challenges that affect the photocatalytic degradation of dyes.