Dye Reactive Black Research Articles

Effect of Beech Sawdust Conditions Modification on the Efficiency of the Sorption of Anionic and Cationic Dyes

The article presents studies on the effect of the modification method of beech sawdust on the sorption capacity of the anionic dye Reactive Black 5 (RB5) as well as the cationic dye Basic Violet 10 (BV10). In the studies, the pH value, the dose of sawdust activated with epichlorohydrin and the dose of ammonia were determined for the efficiency of the removal of anionic and cationic dyes. In the next phase of the study, the pH and the dose of epichlorohydrin activator on the previously activated sorbent were determined. The modification proposed in the work, which consists in the amination of sawdust in direct reaction with ammonia, increased the efficiency of the sorption of anionic dyes. This reaction increased the positive charge on the surface of the sorbent by introducing -NH2 groups, which led to an increase in the electrostatic attraction between the sorbent and the anionic dye, but to a decrease in the interaction between the sorbent and the cationic dye.

Catalytic degradation of Reactive Black 5 through peroxymonosulfate activation with Co organic frameworks combined with graphite oxide

The development of high-efficiency catalysts for peroxymonosulfate (PMS) activation is critical for pollutant treatment in environmental applications. In this research, a Co organic framework (CoHHTP) combined with graphene oxide (GO) (CoHHTP/GO) with a 2D structure was prepared for PMS activation to treat the azo dye Reactive Black 5 (RBK5). The combination of CoHHTP and GO via oxygen groups resulted in the high activity of CoHHTP/GO, and almost 100 % performance was achieved within 30 min under various pH, temperature, PMS loading, and catalyst loading conditions. The maximum RBK5 removal efficiency was obtained with a catalyst loading of 3.0 g L−1, PMS loading of 0.5 mM, temperature of 25 °C, and pH of 6 with a pseudo-first-order kinetics k value of 0.1903 min−1. The activation energy of the CoHHTP/GO/PMS/RBK5 system was calculated to be 14.34 kJ mol−1. Meanwhile, radicals and nonradicals, including SO4·−, ·OH, ·O2−, and 1O2, were proven to be generated and involved in RBK5 degradation. Moreover, RBK5 degradation pathways were identified through experimental research and density functional theory calculation.

Photodegradation of RB5 dye with modified zeolites: influence of temperature and UV irradiation

Abstract This study explores the photocatalytic degradation of Reactive Black 5 (RB5) dye using thermally modified natural zeolites, aiming to improve water purification methods. Zeolites were calcined at 250 °C, 350 °C, and 500 °C, and characterized through x–ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) to analyze their structural and morphological transformations. The results reveal that calcination significantly enhances the photocatalytic performance, particularly for ZNM500, which exhibited the highest efficiency, reaching a 60% removal rate of RB5. The degradation process follows a pseudo-first-order kinetic model at lower dye concentrations but adheres more closely to the Langmuir–Hinshelwood equation at higher concentrations, emphasizing the role of surface adsorption in catalysis. UV irradiation was a key factor in boosting reaction rates, with shorter wavelengths (254 nm) providing greater energy, leading to more effective dye breakdown by facilitating the generation of reactive hydroxyl radicals (·OH). These findings suggest that thermally modified zeolites, especially ZNM500, represent a promising solution for wastewater treatment, offering an efficient, cost–effective, and environmentally friendly approach to removing synthetic dyes from contaminated water sources.

Role of surfactants in the degradation and sustainable dyeing for reactive dyeing wastewater

To enhance the decolorization rate of thermally activated sodium persulfate in dye wastewater, C.I. Reactive Black 5 (RB5) was investigated in this study, which was evaluated by the decolorization of the dye solution. The effect of surfactant concentration (including anionic surfactant sodium dodecyl sulfate (SDS), nonionic surfactant Tween 80 (TW-80) and amphoteric surfactant (BS-12)), SPS concentration, and reaction temperature on the degradation of RB5 was studied. Furthermore, the relationship between free radicals and RB5 degradation was investigated. The results showed that the addition of SDS and TW-80 would inhibit the decolorization of RB5. Correspondingly, the effect would enlarge as the surfactant concentration increased. Nevertheless, the addition of BS-12 wouldn’t affect the final decolorization of RB5 dye solution, despite it could increase the decolorization rate in the initial stage. After 10 min of decolorization, compared to the dye liquor without BS-12, the decolorization could increase by 9.07 % and 0.69 %, respectively, after adding 0.5 and 1.0 CMC of BS-12. Besides, when reactive dyes were degraded by thermally activated sodium persulfate, the SO4-· and ·OH would work together, and SO4-· played a major role while ·OH played an auxiliary part. When the treated wastewater was used for dyeing, the addition of BS-12 could effectively regulate the dyeing rate. The fixation and K/S value were increased by 1.1 % and 0.20, respectively. Furthermore, the dyed fabrics also exhibited improved uniformity, with negligible differences in color fastness. The effects of adding SDS were similar to BS-12, while it decreased the exhaustion and fixation rate of RB5. In addition, non-ionic TW-80 was unfavorable to dyeing. This work provides a new way for efficient treatment of dyeing wastewater as well as reuse, opening an environmentally friendly treatment concept.

Enhancing Biodegradation Efficiency of Reactive Black-5 Dye using Bacillus wiedmannii strain NAF4: Optimization of Degradation Parameters via Response Surface Methodology (RSM)

Reactive Black 5 (RB-5) dye is extensively used in industries such as textile, paper, and leather, raising environmental concerns due to its persistence and adverse effects. This study aimed to develop efficient and eco-friendly strategies for RB-5 dye removal from industrial wastewater. RB-5 dye-degrading bacteria, namely NAF1, NAF2, NAF3, and NAF4, were isolated from soil contaminated with textile effluents. Evaluation of their decolorization potential revealed NAF4 as the most effective, achieving a decolorization percentage of 89%, followed by NAF3 and the co-culture at 75% and 73%, respectively. NAF2 exhibited the lowest decolorization potential. The isolate NAF4 showed significant production of tyrosinase and laccase enzymes, with lower quantities of lignin peroxidase and azoreductase. Phylogenetic analysis confirmed the identities of the isolates as Bacillus, Pseudomonas, Escherichia, and Citrobacter. The decolorization potential exhibited by Bacillus wiedmannii NAF4 has instigated the investigation of its capacity to secrete degradative enzymes implicated in the breakdown of azo dyes. Substantial enzyme production was observed over a duration of 192 hours. The biodegradation potential of B. wiedmannii strain NAF4 for RB-5 dye was assessed using Surface Response Optimization (SRO) modeling. The optimized conditions for RB-5 degradation were determined to be an agitation speed of 115.777 rpm, pH of 7.449, inoculum size of 12.255, and temperature of 29.74°C. The SRO model exhibited high statistical significance with an F-value of 53.30 and low p-values (<0.0001), as well as a correlation coefficient (R2) value of 0.9813. Validation studies confirmed the adequacy and precision of the model. The maximum RB-5 degradation achieved was 90.2291%. Three-dimensional plots visually represented the validated optimum conditions of variables and responses. The successful application of Response Surface Methodology (RSM) as an optimization tool highlights its effectiveness in enhancing degradation processes. This study provides insights into the potential applicability of RSM for optimizing degradation processes in various contexts. The developed eco-friendly strategies offer promising solutions for RB-5 dye removal from industrial wastewater, mitigating its environmental impact.In conclusion, the application of Response Surface Methodology (RSM) as an optimization tool proved effective in maximizing the degradation process by optimizing the degradation parameters. The success of this approach suggests its potential applicability in other contexts to enhance degradation processes.

Valorization of agricultural by-product Moringa stenopetala seed husks into activated carbon for Reactive Black and Basic Blue dye removal from textile wastewater

Valorization of agricultural by-product Moringa stenopetala seed husks into activated carbon for Reactive Black and Basic Blue dye removal from textile wastewater

Removal of reactive black 5 in water using adsorption and electrochemical oxidation technology: kinetics, isotherms and mechanisms

AbstractIn this work, a novel graphite intercalation compound (GIC) particle electrode was used to investigate the adsorption of Reactive Black 5 (RB5) and the electrochemical regeneration in a three-dimensional (3D) electrochemical reactor to recover its adsorptive capacity. Various adsorption kinetics and isotherm models were used to characterise the adsorption behaviour of GIC. Several adsorption kinetics were modelled using linearised and non-linearised rate laws to evaluate the viability of the sorption process. Studies on the selective removal of RB5 dyes from binary mixture in solution were evaluated. RSM optimisation studies were integrated with ANOVA analysis to provide insight into the significance of selectivity reversal from the salting effect of textile dye solution on GIC adsorbent. A unique range of adsorption kinetics and isotherms were used to evaluate the adsorption process. Non-linear models best simulated the kinetic data in the order: Elovich > Bangham > Pseudo-second-order > Pseudo-first-order. The Redlich–Peterson isotherm was calculated to have a dye loading capacity of 0.7316 mg/g by non-linear regression analysis. An error function analysis with ERRSQ/SSE of 0.1390 confirmed the accuracy of dye loading capacity predicted by Redlich–Peterson isotherm using non-linear regression analysis. The results showed that Redlich–Peterson and SIPS isotherm models yielded better fitness to experimental data than the Langmuir type. The best dye removal efficiency achieved was ~ 93% using a current density of 45.14 mA/cm2, whereas the highest TOC removal efficiency achieved was 67%.

Accessing the Potential of Bismuth Oxide Nanosheets for an incredible revelation in the removal of contamination in water bodies

<p>Water contamination is a pressing global issue with far-reaching environmental, health, and socio-economic consequences. As the demand for clean water intensifies, researchers are exploring innovative nanomaterials to develop efficient and sustainable water treatment technologies. The Bismuth oxide (Bi2O3) nanosheets were synthesized using a sustainable approach comprising Moringa oleifera seed extract as a biological capping and reducing agent. Analytical techniques were utilized to inspect the prepared nanosheets' crystalline, morphological, and optical characteristics. The optical properties, including light absorption and bandgap width, were investigated using UV-visible spectroscopy using a bandgap energy of 4.65 eV. In addition, the nanosheet's ability to degrade cationic malachite green and Rhodamine 6G dye and anionic eosin yellow and reactive black dyes by photocatalysis was evaluated. The degradation of cationic and anionic dyes was characterized by nanocatalysis using UV-visible spectroscopy and a pseudo-first-order kinetics model. The pseudo-first-order degradation kinetic rate of malachite green and Rhodamine 6G was determined to be 3.46 and 3.20 X 10-2 min-1, indicating that the prepared nanosheets effectively initiate this dye's degradation. The results showed dye degradation was more effective at cationic dyes than anionic dyes.</p>

One-step fabrication of millimeter-scale hollow vesicles with chitosan /DADMAC/ sodium alginate graft copolymer for enhanced anionic dye adsorption

Hollow vesicles are promising in water treatment due to their unique structure of the membrane and inner cavity. However, the adsorption capacity needs to be improved for targeted pollutants. Herein, millimeter-scale hollow vesicles were prepared with a one-step process of sequential stirring and grafting using chitosan, diallyldimethylammonium chloride, and sodium alginate as raw materials with the purpose of efficient removal of anionic dyes from wastewater. The composite vesicles were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The hollow vesicles showed the structure of the cationic membrane and the inner cavity, facilitating the dye adsorption. The adsorption capacity for the anionic dye Reactive Black 5 reached 698.1 mg/g, more than twice that of the binary composite vesicles without graft. The adsorption kinetics and isotherm data coincided with the pseudo-second-order and Langmuir models, respectively, and the adsorption mechanism was monolayer chemisorption. Moreover, the vesicles worked well in wide ranges of environment pH, temperature, and co-existing pollutants. They also possessed excellent cyclic regeneration performance, in which 93 % of the initial adsorption capacity was maintained after four cycles. These results indicate that the millimeter-scale hollow vesicles exhibit broad application prospects for wastewater purification.

Superior decomposition of xenobiotic RB5 dye using three-dimensional electrochemical treatment: Response surface methodology modelling, artificial intelligence, and machine learning-based optimisation approaches

The highly efficient electrochemical treatment technology for dye-polluted wastewater is one of hot research topics in industrial wastewater treatment. This study reported a three-dimensional electrochemical treatment process integrating graphite intercalation compound (GIC) adsorption, direct anodic oxidation, and ·OH oxidation for decolourising Reactive Black 5 (RB5) from aqueous solutions. The electrochemical process was optimised using the novel progressive central composite design–response surface methodology (CCD–NPRSM), hybrid artificial neural network–extreme gradient boosting (hybrid ANN–XGBoost), and classification and regression trees (CART). CCD–NPRSM and hybrid ANN–XGBoost were employed to minimise errors in evaluating the electrochemical process involving three manipulated operational parameters: current density, electrolysis (treatment) time, and initial dye concentration. The optimised decolourisation efficiencies were 99.30%, 96.63%, and 99.14% for CCD–NPRSM, hybrid ANN–XGBoost, and CART, respectively, compared to the 98.46% RB5 removal rate observed experimentally under optimum conditions: approximately 20 mA/cm2 of current density, 20 min of electrolysis time, and 65 mg/L of RB5. The optimised mineralisation efficiencies ranged between 89% and 92% for different models based on total organic carbon (TOC). Experimental studies confirmed that the predictive efficiency of optimised models ranked in the descending order of hybrid ANN–XGBoost, CCD–NPRSM, and CART. Model validation using analysis of variance (ANOVA) revealed that hybrid ANN–XGBoost had a mean squared error (MSE) and a coefficient of determination (R2) of approximately 0.014 and 0.998, respectively, for the RB5 removal efficiency, outperforming CCD–NPRSM with MSE and R2 of 0.518 and 0.998, respectively. Overall, the hybrid ANN–XGBoost approach is the most feasible technique for assessing the electrochemical treatment efficiency in RB5 dye wastewater decolourisation.

Removal of reactive black dye color in textile effluent using Palmyra sprout and Moringa oleifera waste bio char

In this study treatment of the textile wastewater by color removal using adsorbent (Palmyra sprout peel and Moringa oleifera peel) is done. This study collects information to discharge color using adsorbent (Palmyra sprout peel and Moringa oleifera peel) which acts as an effective adsorbent. Both the adsorbent Palmyra sprout peel and Moringa oleifera peel are low-cost adsorbent. Moringa oleifera peel is readily available for use, Palmyra sprout peel has seasonal availability. A series of batch experiment was carried out to determine the optimum dosage for color removal using various adsorbent dosage (4 - 12g/lit), and optimum contact time 120 minutes. The efficiency of the color removal was calculated by subtracting initial concentration and final concentration. The pH was varied from 10 to 2 and the color removal rates was found to be from 25% to 93%. Lower pH conditions have increased color removal rate for textile wastewater. Key Words: adsorption, Palmyra sprout peel, Moringa oleifera peel, Reactive black dye (RB5), and dye removal.

One-Step Synthesis of Polyethyleneimine-Grafted Styrene-Maleic Anhydride Copolymer Adsorbents for Effective Adsorption of Anionic Dyes.

Wastewater containing organic dyes has become one of the important challenges in water treatment due to its high salt content and resistance to natural degradation. In this work, a novelty adsorbent, PEI-SMA, was prepared by grafting polyethyleneimine (PEI) onto styrene-maleic anhydride copolymer (SMA) through an amidation reaction. The various factors, such as pH, adsorbent dosage, contact time, dye concentration, and temperature, which may affect the adsorption of PEI-SMA for Reactive Black 5 (RB5), were systematically investigated by static adsorption experiments. The adsorption process of PEI-SMA for RB5 was more consistent with the Langmuir isotherm model and the pseudo-second-order model, suggesting a single-layer chemisorption. PEI-SMA exhibits excellent adsorption performance for RB5 dye, with a maximum adsorption capacity of 1749.19 mg g-1 at pH = 2. Additionally, PEI-SMA exhibited highly efficient RB5 competitive adsorption against coexisting Cl- and SO42- ions and cationic dyes. The adsorption mechanism was explored, and it can be explained as the synergistic effect of electrostatic interaction, hydrogen bonding and π-π interaction. This study demonstrates that PEI-SMA could act as a high performance and promising candidate for the effective adsorption of anionic dyes from aqueous solutions.

Bioremediation of reactive black 5 textile dye wastewater using bacterial exopolysaccharides

Purpose The purpose of this paper is to investigate the efficacy of bacterial exopolysaccharides (Eps) in reactive black 5 (RB5) textile dye wastewater bioremediation. Design/methodology/approach The Eps were produced by bacteria isolated from cotton gin trash soils collected from different cotton-growing regions in Kenya for comparison purposes. A broth medium reconstituted using molasses was assessed for its capacity to produce the Eps. RB5 textile dye wastewater was optimized for dye removal under different temperatures, times and molasses concentrations. Dye removal was studied by Lovibond-Day Light Comparator, UV–Vis spectrophotometer and FTIR. Findings It was found that cotton gin trash soils contained Eps-producing bacteria. Three of the Eps studied were found to have the capacity to remove at least 80% of the dye from the wastewater. Research limitations/implications This research did not assess the efficacy of the RB5 dye removal from the wastewater by mixtures of the Eps. Practical implications Bioremediation of textile dye wastewater with Eps produced by bacteria cultured from cotton gin trash soil is significant because it will offer an effective and cleaner alternative to the chemical coagulants. Social implications Alternative treatment of textile wastewater with the Eps would result in safer water being released into the water bodies as opposed to the chemically treated wastewater that contains remnant chemicals. Originality/value Research on the use of Eps produced by bacteria isolated from cotton gin trash soils for removal of RB5 dye from textile wastewater has not been done before.

Accessible Eco-Friendly Method for Wastewater Removal of the Azo Dye Reactive Black 5 by Reusable Protonated Chitosan-Deep Eutectic Solvent Beads.

A novel approach to enhance the utilization of low-cost and sustainable chitosan for wastewater remediation is presented in this investigation. The study centers around the modification of chitosan beads using a deep eutectic solvent composed of choline chloride and urea at a molar ratio of 1:2, followed by treatment with sulfuric acid using an impregnation accessible methodology. The effectiveness of the modified chitosan beads as an adsorbent was evaluated by studying the removal of the azo dye Reactive Black 5 (RB5) from aqueous solutions. Remarkably, the modified chitosan beads demonstrated a substantial increase in adsorption efficiency, achieving excellent removal of RB5 within the concentration range of 25-250 mg/L, ultimately leading to complete elimination. Several key parameters influencing the adsorption process were investigated, including initial RB5 concentration, adsorbent dosage, contact time, temperature, and pH. Quantitative analysis revealed that the pseudo-second-order kinetic model provided the best fit for the experimental data at lower dye concentrations, while the intraparticle diffusion model showed superior performance at higher RB5 concentration ranges (150-250 mg/L). The experimental data were successfully explained by the Langmuir isotherm model, and the maximum adsorption capacities were found to be 116.78 mg/g at 298 K and 379.90 mg/g at 318 K. Desorption studies demonstrated that approximately 41.7% of the dye could be successfully desorbed in a single cycle. Moreover, the regenerated adsorbent exhibited highly efficient RB5 removal (80.0-87.6%) for at least five consecutive uses. The outstanding adsorption properties of the modified chitosan beads can be attributed to the increased porosity, surface area, and swelling behavior resulting from the acidic treatment in combination with the DES modification. These findings establish the modified chitosan beads as a stable, versatile, and reusable eco-friendly adsorbent with high potential for industrial implementation.

Synergistic RB5 dye degradation and oxygen evolution reaction (OER) catalysis by WO3 nano-pellets: mechanistic insights and water remediation applications

Transition metal oxides (TMO), a non-noble element based oxides, establish remarkable potential in the realm of textile wastewater remediation and water splitting due to their sustainable catalytic performance. Highly functional TMO materials, in form of nanostrcutures, are of great interest owing to their robust photo and electro-catalytic activities for instituting sustainable development for the water and energy resource management framework. In the present article, we have reported catalytically active WO3 nano-pellets (NP) synthesized using microwave-assisted for photocatalytic wastewater remediation and electrocatalytic oxygen evolution reaction (OER). Promisingly, WO3 NP abetted degradation of the reactive black 5 (RB5) dye by almost 95 % in short time interval of 60 min in exposer of sun light. Present work includes the strategies to remove and observe the progression of reaction kinetics of dye degradation in neutral and alkaline media. By varying concentration of the catalyst (ranging from 250 mg/L to 1000 mg/L, in the step of 250 mg/L), we have prolifically verified that 750 mg/L turn out optimal dosage for 100% degradation in time interval of 120 min. Besides, WO3 NP has shown highest photocatalytic behaviour at 9 pH. The WO3 NP shows the electrocatalytic OER performance in an alkaline condition (1M KOH) with an overpotential of 418 mV to generate the geometric current density of 10 mA/cm² and Tafel slope of 178 mV dec⁻¹. Owing to robust nature, WO3 NP shows the almost similar photocatalytic response for ten cycles dye degradation and demonstrates the stable electrochemical charge transport for OER at 10 mA/cm2 for 50 hours.

Synergistic effects of micronanobubbles and AC/Ag–TiO2 nanocomposites in photocatalytic process

The AC/Ag–TiO2 nanocomposites were prepared by sol-gel method using different concentrations of Ag. Comprehensive characterization of the crystalline structure, surface morphology, elemental composition, and optical properties of the AC/Ag–TiO2 photocatalysts was carried out using XRD, FTIR, SEM, EDX, TEM, and UV–vis DRS techniques. Consequently, a detailed investigation into the photocatalytic degradation of Indigo Carmine (IC) and Reactive Black 5 (RB5) dyes was conducted, thoroughly examining the involved photocatalytic mechanisms. The study revealed promising outcomes, particularly with the hybrid photocatalyst AC/0.5%Ag–TiO2, showcasing enhanced characteristics in both photooxidation and absorption processes, thereby boosting overall efficacy for IC (70.15%) and RB5 (69.9%). Remarkably, the introduction of small air bubbles significantly improved the removal efficiency of IC and RB5 dyes, achieving removal levels of 93.66% and 88.66%, respectively. The utilization of these micro-nanobubble systems (MNBs) resulted in notably higher first-order reaction constants compared to scenarios without MNBs, indicating the pivotal role of the photocatalyst in dye removal processes. Additionally, the photocatalyst showed unmatched efficacy in eliminating the pesticide carbaryl, attaining 100% removal with and without the presence of MNBs. Moreover, the AC/Ag–TiO2 photocatalyst exhibited significant inhibition of both gram-positive and gram-negative pathogenic bacteria, showcasing its capability to curb their growth even without MNB aeration. This underscores its potential for applications in environmental remediation and microbial control.

Nitrogen and sulfur-doped biochar supported magnetic CuZnFe2O4 as a sustainable adsorbent for efficient reactive black dye 5 removal from industrial wastewater

AbstractThe shortage of clean and safe water resources, due to the growing pollution and the high cost of water treatment techniques, has become a real threat. Herein, CuZnFe2O4@N,S-doped biochar (CZF@N,S-BC), a novel magnetic, cleaner, and completely green-based composite, was fabricated using the aqueous extract of Beta vulgaris (sugar beet) leaves for the efficient removal of reactive black dye 5 (RB5) from industrial wastewater discharge. With the aid of numerous techniques, including Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Spectroscopy (SEM), Vibrating Sample Magnetometer (VSM), and zeta potential analyses, CZF@N,S-BC was well-characterized. The results revealed the successful fabrication of CZF@N,S-BC with good magnetic saturation of 12 emu/g and a highly positively charged surface of 32 mV at pH 2. The removal efficiency of RB5 was reached 96.5% at equilibrium time 60 min, and adsorbent dose of 80 mg. The equilibrium data fitted well with the Freundlich isotherm model, while the adsorption kinetics followed a pseudo-second-order model (PSO), with a maximum adsorption capacity of 276.57 mg/g. The thermodynamics results confirmed the physical interaction between the composite and RB5. Additionally, the composite also demonstrated exceptional reusability, maintaining a removal efficiency of 57.27% even after six consecutive cycles. To evaluate the performance of CZF@N,S-BC composite in a real water matrix, the composite was subjected to remove RB5 from a real wastewater sample obtained from an industrial discharge of a textile dyeing industry. Also, a plausible mechanism of RB5 removal by the composite was intensively discussed using XPS before and after adsorption.

Facile preparation of Fe2O3 catalyst and assessment of its photodegradation performance for industrial effluent purification

This study focuses on synthesizing nano-scaled Fe2O3 particles using Araucaria columnaris (Cook's pine) leaf extract under atmosphere circumstances. These extracts serve as both a reductant and a stabilizer. Fe2O3 nanoparticle synthesis was confirmed through a comprehensive characterization process using many analytical techniques. The analysis of XRD patterns indicated that the examined samples consisted of nanoparticles of γ-Fe2O3, exhibiting a cubic crystal structure with a high degree of crystallization. Furthermore, the calculated crystallite size was resolute to be 24.5 nm. The scanning electron microscopy pictures revealed that the created samplesexhibited a combination of spherical and polyhedral morphologies. The investigation of optical characteristics, such as light absorption and bandgap width, was conducted usingUV–visible spectroscopy, employing a bandgap energy value of 3.78 eV. The study aimed to assess the removal effectiveness of Eosin yellow, Malachite green, Reactive black, and Rhodamine 6G dyes using Fe2O3 nanoparticles synthesized as a photocatalyst which exhibited remarkable photocatalytic efficacy in the breakdown of dyes when exposed to sunlight, and the reaction period of 90 min resulted in a maximum degradation rate of 97.4 %. Considering the promising results, utilizing Fe2O3 nanoparticles as a photocatalyst for degrading dyes in wastewater is feasible. Additionally, Araucaria columnaris leaf extract can be an environmentally friendly and economically viable method for synthesizing Fe2O3 nanoparticles.

Preparation of a CPVC composite loose nanofiltration membrane based on plant polyphenols for effective dye wastewater treatment.

The textile industry's high-salinity wastewater presents a significant difficulty for fractioning salts and dyes. To fractionate the dyes and salts, a high-performance CPVC composite loose nanofiltration membrane (LNM) was fabricated by interfacial polymerization. The organic phase was obtained by crosslinking polyethylenimine (PEI) with tannic acid (TA) and gallic acid (GA) using TMC. The resultant composite LNM performance was enhanced by adjusting the coating parameters, which included TA and GA concentrations as well as coating time. The study examined the effects of the total content of TA/PEI and GA/PEI concentrations on the chemical structure, surface roughness, and microstructure of the selective layer of LNM using SEM, AFM, FTIR, and water contact angle measurements. It also investigated the filtration performance of the membrane's selective layer, including pure water flux, PEG800 rejection rate, and membrane fouling analysis. However, the resultant membrane treated simulated reactive black 5 (RB5) dye wastewater. When the total content of TA/PEI is 4 kg L-1, the permeability of pure water flux is high at 7.5 L per m2 per h per bar when the total content of GA/PEI is 14 kg L-1 and the pure water flux is high at 8.8 L per m2 per h per bar. The overall PEG800 rejection rates were 97-98.98%. The optimal TA : PEI ratios reached a good pure water permeability up to 6.4 L per (m2 per h per bar) with a high rejection rate of 99.69% for a ratio 1/3 to dye, and GA : PEI ratios reached a good water permeability at 5.5 and 6.5 L per (m2 per h per bar) with rejection rates of 99.21% and 98.88% for ratio 1/3 and 3.5/10.5 for simulated RB5 dye, and the NaCl retention rate gradually decreased from 4% to 3%. The resultant LNM demonstrated promising applications in dye and salt fractionation.

Reduction in phytotoxicity of a textile wastewater against Vigna radiata using Citrobacter sp. M41 in a bioaugmented packed bed column bioreactor

The current research was carried out to devise a biological strategy to remediate dyes and metal ions from textile wastewater. For this purpose, Citrobacter sp. M41 was isolated from a textile wastewater sample. This strain efficiently decolorized > 90 % of the added reactive black-5 (RB5) dye using yeast extract as a C source at 8.5 pH and 30 °C in mineral salt medium containing a mixture of metals (Pb2+, Ni2+ and Cd2+). Moreover, M41 showed > 90 % decolorization of RB5 beside > 80 % concurrent removal of hexavalent Chromium [Cr(VI)]. Furthermore, the granulated corncob and its biochar bioaugmented with M41 and filled within packed bed column based bioreactors efficiently (>90 %) removed the RB5 and Cr(VI) from a textile wastewater. The M41 bioaugmented corncob biochar resulted into a 60.8 %, 57.8 % and 68.7 % decrease in chemical oxygen demand (COD), electrical conductivity (EC) and total dissolved solids (TDS) of the wastewater, respectively. A phytotoxicity study conducted by using mung bean (Vigna radiata) as a test crop indicated that the treated synthetic wastewater was relatively less toxic as compared with the untreated wastewater. Therefore, it can be concluded that Citrobater sp. M41 is an important bio-resource for treatment of textile effluent polluted with azo dyes and Cr(VI).