Color Removal Research Articles

Magnetic coagulant derived from Cassia fistula seed for real textile wastewater treatment: A pilot-scale study

Cassia fistula (C. fistula) seed-derived coagulants have demonstrated substantial potential for treating dye-based wastewater. Such coagulants exhibit notable coagulating-flocculating activity and are environmentally friendly. However, recovering these natural coagulants from aqueous media poses challenges. In this study, we introduce a novel plant-derived magnetic coagulant that is a combination of C. fistula seed gum with magnetic spinel ferrite. This research includes a pilot-scale study to simulate full-scale textile wastewater treatment using this composite. Material characterisations revealed that spherical CoFe2O4 particles could be effectively coated with the active coagulant, C. fistula gum. The saturation magnetisation of the composite, measured at 54.11 emu/g, facilitates its convenient separation from aqueous solutions using an external magnetic field. Bench-scale studies showed that initial pH and coagulant dosage substantially affect the removal efficiency of colour and chemical oxygen demand (COD). In the pilot-scale study, the C. fistula–CoFe2O4 composite demonstrated promising coagulant properties. It achieved a colour removal percentage of 94.0 % with a volume of 30 L and a coagulant dosage of 12.3 g L− 1. Using this coagulation–flocculation process as a primary treatment step, possibly followed by biological or membrane methods, can help meet Vietnamese environmental standards.

Improved photocatalytic properties of WO3 nanoparticles for Malachite green dye degradation under visible light irradiation: An effect of La doping

Abstract Doped materials have received substantial attention due to their increased usefulness in photocatalytic applications. Within this context, the present study was dedicated to investigating the potential of the precipitation technique for producing La-doped tungsten oxide (WO3). To comprehensively characterize the synthesized La-doped WO3, scanning electron microscopy and X-ray diffraction were judiciously employed. The focal point of the investigation encompassed an examination of the impact of varying La concentrations on multiple fronts: the photocatalytic activities (PCAs), as well as any associated structural and morphological modifications. This holistic approach aimed to uncover the intricate relationship between La incorporation and the resulting properties of the WO3 matrix. Through the degradation of Malachite green dye within an aqueous medium, PCA of the La-doped WO3 samples was quantitatively evaluated. Remarkably, over 180 min under irradiation of visible light irradiation, the achieved levels of dye degradation were remarkable, amounting to 81.165, 83.11, and 83.85% for the respective samples. These findings firmly underscore the potential of La-doped WO3 as a proficient photocatalyst, particularly in color removal from wastewater. This study paves the way for enhanced wastewater treatment approaches by utilizing doped WO3 materials.

Removal of COD, BOD and color of different industrial effluents using activated neem char

Characterization of industrial effluent i.e. sugar, dye, paper and pulp; and combined effluent is performed using the standard method, which indicates higher amount of pollutants exist in all the effluents. Adsorptive batch treatment is conducted using activated neem leaf powder (a-NLP), in which adsorbent dose, temperature and contact duration are the factors selected for this study to reduction of COD, BOD and color from individual and combined wastewater. Maximum elimination of COD, BOD and color is attained upto 93.4-82.4, 82.6-75.9 and 93.4-86.1 % respectively from sugar, dye, paper-pulp and combined effluent respectively at dosage of 23 gm/L a-NLP, temperature of 300 K and contact duration of 60 min. Adsorption isotherms such as Freundlich, Langmuir, Dubinin-Raduskevich, Flory-Huggins and Temkin Isotherm are examined in order to explore the adsorption mechanism. The reaction rate is estimated by different kinetic models (Pseudo First-, Pseudo Second-order, Intra-particle and Elovic equation). From correction coefficient value, Freundlich isotherm and Pseudo First-order govern adsorption process. Different thermodynamic parameters such as free energy of adsorption (∆G°), enthalpy change (∆H°) and entropy change (∆S°) are also accessed, which indicates that adsorption is thermodynamically feasible. Solvent desorption is carried out to regenerate this adsorbent for three consecutive cycles.

Valorization of agitated thin film dryer (ATFD)-mixed-salt from textile wastewater for its application in leather manufacturing – a sustainable approach

ABSTRACT The textile industry uses sodium chloride and sodium sulphate during the dyeing process to improve the fixation of dyes on fabrics. After wastewater treatment, the reject stream is dried resulting in mixed salts as solid wastes that are not reused. The leather industry also uses a vast quantity of salt for temporary preservation of skins/hides and as swelling-suppressing agent during the pickling (acidification) process. Thus, an attempt was made to utilize the mixed salt obtained from the textile industry to replace sodium chloride in leather processing. It was found that a 40% w/w offer of ATFD salt was able to preserve the skins for 3 months, which was on par with the preservation carried out using a similar quantity of sodium chloride in conventional preservation process. Likewise, for the pickling process, an offer of 10% w/w ATFD salt provided sufficient deswelling action when compared to conventionally used sodium chloride. However, the residual colour of the mixed salts affected the quality of the leather obtained. To overcome this, an electro-oxidation treatment was carried out to obtain decolourized salts. The COD measurements showed that the 1% solution of ATFD-3 salt reduced from 471 ± 25 to 88 ± 16 ppm. A similar trend was also seen in BOD reduction from 80 ± 12 to 18 ± 10 ppm. These results confirmed that the colour removal could be due to the degradation of the organic contaminants present in the ATFD salt. Thus, the treated ATFD salt can be reused for leather processing without affecting leather quality, thus promoting the concept of circular economy.

Purifying surface water contaminated with azo dyes using nanofiltration: Interactions between dyes and dissolved organic matter

In this research, the interactions of two azo dyes, Methyl Orange (MO) and Eriochrome Black T (EBT), with dissolved organic matter (DOM) in surface water were studied, emphasizing their removal using nano-filtration membranes (NF-270 and NF-90). High-Performance Size Exclusion Chromatography (HPSEC) findings indicated that the dyes' molecular weight in deionized (DI) water ranged from 500 to 15k Dalton (Da), adjusting peak intensities with Jingmi River (JM) water Beijing. Notably, when dyes were diluted in JM water, ultraviolet (UV533 &466, and UV254), together with total organic carbon (TOC) parameters, revealed color removal rates of 99.49% (EBT), 94.2% (MO), 87.6% DOM removal, and 86% TOC removal for NF-90. The NF-90 membrane demonstrated a 75% flux decline for 50 mL permeate volume due to its finer pore structure and higher rejection effectiveness. In contrast, the NF-270 membrane showed a 60% decline in flux under the same conditions. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) analysis of dye-treated membranes in JM water revealed that the NF-270 showed a CC bond peak at 1660 cm−1 across various samples, while analyzing NF-90, the peaks at 1400 cm−1, 1040 cm−1, 750 cm−1, and 620 cm−1 disappeared for composite sample removal. The hydrophobicity of each membrane is measured by the contact angle (CA), which identified that initial CAs for NF-270 and NF-90 were 460 and 700, respectively, that were rapidly declined but stabilized after a few seconds of processing. Overall, this investigation shows that azo dyes interact with DOM in surface waters and enhance the removal efficiency of NF membranes.

Evaluation of vat blue removal by Aspergillus niger using scanning electron microscopy and glucose oxidase enzyme activity

AbstractThe use of fungi to reduce dye removal in water from diverse industries can be an efficient option for solving environmental problems. However, the mycoremediation processes involved in color removal are unknown. In this article, Aspergillus niger CDBB‐H‐175 was applied for vat blue discoloration (DC). Hence, inactive biomass by two methods (metabolic inhibitor and heat) and active biomass were studied by scanning electron microscopy and enzyme activities to determine the vat blue DC. When using active biomass, 62% of DC, glucose oxidase (GOX) enzyme activity, 1.19 U/mL and 1.43 mg/L of H2O2 were obtained. It was observed that 68% of DC was due to the degradation process and 32% was due to biomass sorption. When the biomass was inactivated with sodium azide, DC increased by 90% (1.45‐fold), low GOX activity (0.138 U/mL), and H2O2 (0.25 mg/L) were detected. High DC might be due to a high dye sorption in hyphae, since an increase in the thickness and morphology of the hyphae were observed by SEM. Inactivated biomass through heating, showed a 69.5% of DC, where 0.01 U/mL GOX and 0.25 mg/L H2O2 were reached, demonstrating that inactivation of A. niger biomass by sodium azide can be considered as an alternative treatment for colored wastewater.

Comparing efficacy of anodic and cathodic chambers in a low-cost algae-assisted microbial fuel cell for textile wastewater remediation

Remediation of industrial textile effluent using both the anodic and cathodic chambers of an algae-assisted microbial fuel cell (AMFC) is demonstrated and evaluated in this study. A low-cost AMFC is developed using clayware as the anode compartment housed inside a plastic bucket which acts as the cathode chamber. A comparative analysis of textile wastewater (TWW) treatment in both chambers is presented. Four treatment configurations were considered, namely T1 (only cathode supplied with TWW), T2 (both cathode and anode supplied with TWW), T3 (only anode supplied with TWW) and the control AMFC (no TWW was added in any compartment). It was observed that the bacterial populations in the anodic compartment were more adapted towards TWW than the microalgae in the cathodic chamber. The color removal efficiency by the anode and cathode chamber was respectively 89.55% and 40.53%. The COD removal was 94% and 48% from the anodic and cathodic chambers respectively. The T3 AMFC with effluent being supplied only to the anode chamber exhibited the highest power and current density of 2.1 W/m3 and 8 A/m3. The proposed system was able to degrade dyes from real textile wastewater and simultaneously generate bioelectricity and algal biomass.

Semiconductor Catalyst: Investigation for the Degradation of BB9 Azo Dye by Sonophotocatalytic Process

AbstractThe degradability of an azo dye, Basic Blue 9 (BB9), by heterogeneous sonocatalytic, photocatalytic, and sonophotocatalytic oxidation process was examined using simultaneous irradiation of UV‐C at 254 nm and power ultrasound at 20 kHz accompanied with a heterogeneous catalyst zinc oxide (ZnO) in the study. The effect of ZnO dose and initial dye concentration was investigated on the dye degradation in sonocatalytic, photocatalytic, and sonophotocatalytic processes at pH 5.5 (natural pH). The results obtained from the experimental studies were evaluated with the parameters of color removal, pseudo‐first‐order rate constant, and half‐life time. It was observed that the degradation of BB9 dye by the sonophotocatalytic process was higher compared to both sonocatalytic and photocatalytic degradation. as follows: 97.46, 48.64 and 56.88 %. The combination of sono and photocatalytic showed a remarkable synergistic effect in BB9 degradation. The kinetics of sonophotocatalytic oxidations, depending on the initial BB9 dye concentration, were found to follow the Langmuir‐Hinshelwood model. In addition, the effect of ZnO on the sonophotocatalytic oxidation process was higher compared to titanium dioxide and zero‐valent iron as follows: 97.47, 80.77 and 80.62 %.

A Comprehensive Approach to Azo Dichlorotriazine Dye Treatment: Assessing the Impact of Physical, Chemical, and Biological Treatment Methods through Statistical Analysis of Experimental Data

This exploration investigates integrated treatment systems combining advanced oxidation processes (Fenton and photo-Fenton) with biological methods for the effective elimination of stubborn organic compounds in simulated textile wastewater composed of azo Dichlorotriazine dye. A comprehensive optimization of key process factors including catalyst dosage, hydrogen peroxide quantity, irradiation duration, etc. was systematically conducted for both Fenton and photo-Fenton processes to realize maximum COD and color removal. Under ideal conditions (0.4 g/L photocatalyst, 1 mL/L H2O2, and 75-Watt UV intensity for 60 min), the photo-Fenton process realized 80% COD elimination and complete decolorization, meeting industrial discharge limits without needing extra biological treatment. Statistical models correlating process parameters to treatment efficiency were developed, giving important design insights. For Fenton, effluent COD exceeded discharge thresholds, so a post-biological treatment using activated sludge was essential to comply with regulations. This integrated Fenton–biological scheme utilizes synergism between chemical and biological processes for enhanced overall treatment. Notable economic benefits were achieved by photo-Fenton over conventional UV-only and UV/H2O2 methods regarding energy consumption and operating costs. Overall, this pioneering work successfully proves integrated advanced oxidation–biological systems as a superior, sustainable alternative to traditional techniques for economically removing obstinate pollutants, such as azo Dichlorotriazine dye, as it is a simulated textile wastewater treatment used to satisfy environmental standards.

Aluminum Waste as Electrode for Home Textile Industry Wastewater Treatment using Batch Electrocoagulation Process: Studies on Operating Parameters

The manufacture of the Sasirangan home textile industry involves coloring and dyeing processes using synthetic dyes in large quantities. These contaminants of dyes and organic materials would cause high color and chemical oxygen demand (COD) contaminants values. This study aims to characterize the wastewater of batik-modified Sasirangan and determine the effect of current density and length of operating time on color removal and reduction of COD in Sasirangan home textile industry wastewater through the batch electrocoagulation process. The method used in this research is an electric current flowing in the same direction to the Sasirangan home textile industry wastewater in a reactor with dimensions of 310 180 240 mm3. The electrode used is aluminum alloy type 1100. The aluminum/aluminum (Al/Al) electrode is used in this electrocoagulation (EC) process, then connected to a direct current (DC) power supply. The experiment was carried out at room temperature using an electrode distance of 2 cm with variations in the time of the electrocoagulation process for 15–120 minutes. The experiment was repeated for variations in pH (4–9) with a current density of 3.5–5.5 mA/cm2. Furthermore, an analysis of the color removal and the decrease in the concentration of COD was carried out. The results showed that the contaminant content in Sasirangan home textile industry wastewater decreased significantly, whereas the optimal conditions for the EC reaction were determined using color and COD removal efficiency parameters. The decrease in color and COD concentrations occurred at a current density of 5.5 mA/cm2 with a pH of 4 for 120 minutes, around 1110 PtCo and 90.4 mg/L of COD, respectively

Study on COD and color removal efficiency in textile dyeing wastewater by iron electro-coagulation technology combined with persulfate

Electrocoagulation (EC) is an attractive method for treating many types of wastewater due to its advantages. The purpose of this study is to investigate the effect of persulfate addition on the efficiency of textile wastewater treatment through the removal percentage of COD and color parameters. Persulfate is proven to significantly enhance the rate and efficiency of pollutant removal in textile wastewater. The removal percentage of COD could reach 91.33 ± 1.23% and 97.99% ± 0.52% was the highest removal percentage of the color parameter at the optimal reaction parameters. The effluent concentration meets the standards according to Vietnam national technical regulation on textile industry wastewater. By using persulfate, the COD and color removal efficiency increased by 17.53 ± 2.69% and 8.81 ± 0.91%, respectively, compared to the single electrocoagulation process. The amount of sludge generated in the system is 0.542 ± 0.0357 kg/m3, significantly reduced compared to the flocculation process of 0.875 ± 0.0295 kg/m3.

Investigation of the performance of the combined moving bed bioreactor-membrane bioreactor (MBBR-MBR) for textile wastewater treatment

The present study focused on the investigation of the performance of a Moving Bed Bioreactor coupled with a Membrane Bioreactor (MBBR-MBR) on a small scale for textile wastewater treatment. The parameters examined in this study included the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), turbidity, color, and heavy metals (HM). The two reactors were operated consecutively and maintained aerobic conditions. The idea is to reduce the pollutant load significantly through the activity of microorganism attached to the biofilm covered carriers in MBBR and successive membrane filtration. The system demonstrated a favorable outcome even in a smaller hydraulic retention time (HRT) of 1 day, which presents a significant advantage in terms of cost and space saving. The removal effectiveness of COD attained a maximum of 92 %, BOD reached a maximum of 95 %, and the color removal performance obtained a removal efficiency of 87 %. Furthermore, the treatment showed remarkable efficiency in removing up to 100 % of TSS and 96 % of turbidity. Additionally, an evaluation was conducted on the elimination of heavy metals, including Zinc (Zn), Lead (Pb), Chromium (Cr), and Iron (Fe). The efficacy of removing these HMs was found to exceed 85 %. All these favorable outcomes contribute to the improvement of effluent quality, mitigation of contamination hazards, and fouling reduction.

Immobilized enzymatic membrane surfaces for biocatalytic organics removal and fouling resistance

This research reported on the immobilization of environmentally friendly enzymes, such as horseradish peroxidase (HRP) and laccase (L), along with the hydrophilic zwitterionic compound l-DOPA on nano-filtration (NF) membranes. This approach introduced biocatalytic membranes, leveraging combined effects between membranes and enzymes. The aim was to systematically assess the efficacy of the enzymatic modified membrane (HRP-NF) in degrading colors in the wastewater, as well as enhancing the membrane resistance toward organic fouling. The enzymatic immobilized membrane demonstrated 96.3 ± 1.8% to 96.6 ± 1.9% removal of colors, and 65.2 ± 1.3% to 67.2 ± 1.3% removal of TOC. This result was underpinned by the insights obtained from the radical scavenger coumarin, which was employed to trap and confirm the formation of PRs through the reaction of enzymes and H2O2. Furthermore, membranes modified with enzymes exhibited significantly improved antifouling properties. The HRP-NF membrane experienced an 8% decline in flux, while the co-immobilized HRP-L-NF membrane demonstrated as low as 6% flux decline, contributed by the synergistic effect of increased hydrophilicity and biocatalytic effects. These findings confirmed that the immobilized enzymatic surface has added function of degrading contaminants in addition to separation function of nanofiltration membrane. These l-DOPA-immobilized enzymatic membranes offered a promising hybrid biocatalytic membrane to eliminate dyes and mitigate membrane fouling, which can be applied in many industrial and domestic water and wastewater treatment.

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.

Comprehensive study of Fenton reaction efficiency on textile wastewater treatment from dye solution to real effluent with emphasis on Fukui function analysis

This study investigated the continuous degradation monitoring of three reactive dyes, reactive yellow 176 (RY), reactive Blue 4 (RB) and reactive red 293 (RR), both in separate solutions and in a mixture, along with their corresponding dye bath and industrial dyeing effluent, using Fenton reaction. A kinetic study was conducted to compare the degradation efficiency of the studied solutions. This work provides important yield of dye degradation, where the results showed that RB, RY, and RR had 96.64 %, 92.47 %, and 73.27 % color removal, respectively, within a two-hour reaction time. The pseudo-second-order model fit well to describe the degradation of RR and RY, while the zero-pseudo-order model provided a better fit for RB. The dye mixture exhibited 57 % color removal, whereas the dyeing bath and real effluent showed 41 % and 36 % removal, respectively, over a two-hour reaction time. Moreover, significant reductions in chemical oxygen demand (COD) and biological oxygen demand over 5 days (BOD5) were observed, with the real effluent demonstrating a 73.91 % COD reduction and an 86.66 % reduction in BOD5. The COD and BOD5 reductions for the dye bath were 67.53 % and 95 %, respectively. Additionally, COD and BOD5 reductions of 72.96 % and 96.66 %, respectively, were observed for the dye bath. DFT calculations were employed to elucidate the regioselectivity of radical oxidation of the three reactive dyes by Fenton's reagent, providing insights into global and local reactivity descriptors. Toxicity studies further underscored the efficacy of the Fenton reaction in wastewater treatment. Additionally, UV–visible spectral analysis before and after 12 h of Fenton reaction revealed total discolouration and a reduction in UV and visible peaks across all reactions, indicating comprehensive dye degradation and reduction.

Electrooxidation pretreatment prevents membrane fouling and improve treatment efficiency of a membrane bioreactor treating reject water and condensate generated during sludge dewatering

This study explored electrooxidation pretreatment of reject water and condensate generated using sludge dewatering with goal of improving its treatment using a membrane bioreactor (MBR) and also prevent membrane fouling. Initially the important parameters for electrooxidation process were optimized. The results showed that a total current of 4.03 A/L, current density of 60 mA/cm2, pH 7, and 1500 mg/L of Cl- ion concentration were best in terms of solubilization and removal of fouling-causing substances from wastewater. The colour removal from the wastewater could be as high as 92.4% (7 colour unit (CU) of treated effluent) under optimum operating condition. For biological treatment, a four-tank biological system consisting of consequently placed anoxic and aerobic compartments with final tank containing a MBR was used. When compared with untreated wastewater, the MBR treating EO pretreated wastewater showed significant improvement in terms of membrane fouling measured as transmembrane pressure (TMP). Further improvement in the nitrogen and TOC removal could be achieved by extending the EO treatment duration and subsequent HRT of MBR treatment. The findings from the study clearly demonstrates the potential for integrating a combined electrooxidation and MBR treatment in the conventional wastewater treatment plant for reducing its influent pollutant load.

In-situ anion-exchange construction of Z-scheme Ag3PO4/AgI, derived AgCl/Ag3PO4/AgI and Ag2CO3/Ag3PO4/AgI composites with multiple redox energy bands and charge transfer pathways for efficient absorption and sonocatalytic properties

Z-scheme Ag3PO4/AgI composites were synthesized by facile in-situ anion-exchange method at room temperature (RT). All the catalysts have excellent affinity to dyes and adsorb larger than 70 % of Methyl blue. The fastest adsorption equilibrium of Ag3PO4 (qe: 25.9278 mg/g) with low specific surface area (SSA: 4.6624 m2/g) can be rapidly attained for 6 min. The best color removal efficiency (RE) for Methyl blue over all the composites can rapidly increase to 100 % within 45 min. Meanwhile, the highest RE for RhB over S3 is 98.9 % for 60 min, and corresponding rate constant (k) is 0.07018 min−1. After adding NaCl or Na2CO3 into sonocatalysis, because of the formation of novel ternary AgCl/Ag3PO4/AgI and Ag2CO3/Ag3PO4/AgI during sonocatalytic process, the best REs for RhB over S3 composite increase from 89.8 % (no scavenger) to 98.2 % (1.2 mM NaCl), or to 97.6 % (1.8 mM Na2CO3) for 30 min, respectively, and the REs for Methyl blue over S3 are about 100 % for 10 min. From single Ag3PO4 to binary Ag3PO4/AgI, and to ternary Ag2CO3/Ag3PO4/AgI or AgCl/Ag3PO4/AgI, REs are significantly enhanced. New redox energy bands and charge transfer channels lead to efficiently spatial charge separation and further activation of hole (h+), superoxide anions (·O2−), hydroxyl radicals (·OH). Additionally, the relation among oxygen vacancies (Ov), Zeta potential and RE was discussed in detail. Density functional theory (DFT) calculations were used to make clear charge transfer and sonocatalytic mechanism. The evaluation of used samples, adsorption kinetics and modes, diverse degradation pathways and sonocatalytic mechanisms were also discussed in detail. The work provides a novel in-situ strategy for real-time control of catalytic performance by rapidly forming new phase during catalysis at RT. Furthermore, the strategy obviously facilitates real-time development of rare more than ternary composites for enhanced catalytic performance.

Removal of melanoidin from baker yeast plant wastewater: A comparative study on chemical and biological processes

Dark brown color and large quantities of chemical oxygen demand (COD) are challenging for the successful treatment of molasses-based baker's yeast (BY) wastewater. In this study, the sequential biological and chemical coagulation processes were compared in terms of their ability to remove color and COD from industrial molasses-based BY wastewater. In the sequential chemical-biological processes, using the desired dosages of ferric chloride (FeCl3, 4 g/L) and calcium oxide (CaO, 2 % (w/v)) as coagulating agents, the color and COD removal were 90.6 % and 57 %, respectively. The COD removal of the samples from chemical pre-treated wastewater in an aerated biological reactor (reactor A) was improved to 78 %. In sequential biological-chemical processes with extended aeration (bioreactor A), the COD and color removal were 89.1 % and 93.7 %, respectively. The chemical post-treating of the effluent of the combined anaerobic-aerobic system (reactor C) led to COD and color removal of 80.8 % and 94.65 %, respectively. According to experimental findings, the chemical post-treatment was more efficient than the chemical pre-treatment process. This study offers new insights into the utilization of combined systems for the efficient removal of color and COD from industrial wastewater.

Binary color adsorption by zinc@magnetite nanocomposites: Robust parametric optimization using Taguchi method

AbstractThe goal of the current study was to determine the optimal level (value) of adsorption process variables for the adsorption of color from binary aqueous solution. The impact of key adsorption factors, including adsorbent dose, initial color concentration, and contact time, on the color removal effectiveness of Zinc@magnetite nanocomposites (Zin@Fe3O4(ME) produced from bacterial extracts and Zin@Fe3O4(M) produced from bacterial cell mass), has been examined. Utilizing an L9 orthogonal array (OA), average values and the SN ratio for each variable at three diverse points are calculated. ANOVA has determined the most advantageous optimum conditions for raw and SN data. According to the study, the adsorbent dose is shown to be the most important parameter for color adsorption, while contact duration is determined to be the least important factor based on Pareto chart analysis. The percentage of color removal at optimal values for Zin@Fe3O4(M) and Zin@Fe3O4(ME) nanocomposites, respectively, was found to be 81% and 73%. The optimal parameters were found to be 12.5 mg of adsorbent, 125 mg/L initial dye concentration, and 90 min of contact time at pH 7, room temperature. The confirmatory experiments conducted under optimized conditions revealed a higher percentage of color eliminated than was optimized in each test run of the Taguchi design, proving the credibility of the process variables optimized within the designated experiments.

Integration of sequential electrocoagulation and adsorption for effective removal of colour and total organic carbon in textile effluents and its utilization for seed germination and irrigation.

Textile effluent discharge can negatively impact the environment and living organisms due to its potential toxicity, higher percentages of total organic carbon (TOC) contents, and so on. The study investigates the extraordinary performance of the electrocoagulation process (ECP) combined with powdered activated carbon (PAC) as a highly effective and environmental friendly method of treating textile effluents. This scientific work mainly includes the focus on removing toxic components in textile effluents, such as high concentrations of colour and TOC using synthesized PAC derived from coconut shells coupled with the ECP (ECP-PAC). Initially, PAC was characterized by using XRD, Raman, BET, FTIR, and TGA studies. Subsequently, the pilot-scale ECP-PAC batch reactor was constructed with iron (Fe) as an anode and copper (Cu) as a cathode. The pilot-scale ECP-PAC batch reactor has achieved higher treatment efficiency in a shorter reaction time with low energy consumption compared to a stand-alone ECP. Further, the optimum conditions for effective ECP-PAC have been optimized, such as pH 7.5, applied current density (0-50mA/cm2), reaction time (0-30min), electrode combinations (Fe-Cu) with electrode distances of 5cm apart, and an optimum dose of 5g/L of PAC. Specifically, 98% of the colour and 96% of the TOC contents present in the industrial textile effluent were treated in 15 and 30min, respectively. In quantitative perspectives, the developed batch reactor has sharply decreased TOC (324.1mg/L), IC (1410mg/L) and TC (1019mg/L) to 13.55mg/L (96%), 31.49mg/L (97%), and 48.05mg/L (95%), respectively, in 30min demonstrating its sensitivity and selectivity with the utmost care. Moreover, the physicochemical properties of the treated water were convincingly assessed. That is, it remains suitable for the seed germination of mung bean and chlorophyll content study. Thus, the developed methodology could effectively reduce freshwater consumption in the agricultural sector, increase freshwater availability in water-scarce regions, and facilitate the increase of the recharging capacity of groundwater tables.