Color Removal Efficiency Research Articles

Enhancing biodecolorization of Malachite Green by Flavobacterium sp. through monothetic analysis

Malachite Green (MG) is a prevalent dye in the textile industry, known for its harmful environmental impacts. Addressing the urgent need for environmentally friendly and cost-effective methods to remove MG from wastewater, this study investigated the efficacy of Flavobacterium sp., isolated from Malaysian batik wastewater, in decolorizing MG. Under shaking conditions at 160 rpm, Flavobacterium sp. exhibited a notable decolorization efficiency, with 91 % removal of MG after a 3-day incubation time, surpassing the static mode efficiency of 39 %. Further optimization using a one-factor-at-a-time (OFAT) methodology at 37 °C, pH 10, 6 % (v/v) inoculum, banana peel as the carbon source and 250 mg/L MG resulted in a remarkable enhancement, achieving 95 % decolorization within a reduced incubation time of 12 h. Moreover, repeated addition of 250 mg/L MG showed consistent and complete decolorization after 6 h by Flavobacterium sp. for four successive cycles, suggesting its economic viability for treating actual Malaysian batik wastewater. Ultraviolet–visible (UV) analysis confirmed the biodegradation of MG, evidenced by the disappearance of characteristic peaks at 618 nm and the appearance of new peaks, indicating the formation of metabolites. Flavobacterium sp. reduced pH, temperature, color, TDS, TSS, BOD and COD in batik wastewater, showing 99 % color removal efficiency. This research highlights its potential as an eco-friendly, cost-effective treatment for batik wastewater. The capacity of Flavobacterium sp. to decolorize MG in an immobilized state will be the subject of future research endeavors, aimed at elucidating the adaptability and usefulness of the biocatalyst.

Decolorization of Acid Red 337 dye with hydroxyl and sulfate radical based advanced oxidation processes using different iron Catalyst: An experimental and statistical Investigation

The removal efficiencies of Acid Red 337 dye were investigated by combining advanced oxidation processes based on OH and SO4− radicals. The photocatalytic oxidation processes were carried out at the natural pH (5.4) and acidic pH (3.0) values of the dye solution. In the experiments, iron (II) sulfate (Fe2+) and potassium ferrioxalate (FeOx) were used as catalysts, hydrogen peroxide (H2O2) and peroxymonosulfate (PMS) were used as oxidants to compare dye removal efficiency and to determine the optimum doses. This comparison provided the opportunity to identify suitable catalysts and oxidants for dye removal. Furthermore, time-based comparisons were conducted from 2 to 10 min using the optimum catalyst doses. It was obtained that PMS was more effective as an oxidant in the presence of both iron catalysts for colour removal. The colour removal efficiency of 98.2 % was achieved in the PMS/Fe2+/UV process with doses of 1 mM PMS and 0.1 mM Fe2+ at pH 5.4 and an irradiation time of 10 min. In experiments using light-sensitive ferrioxalate (FeOx), colour removal was achieved in the PMS/FeOx/UV process with an efficiency of 97.8 %. Additionally, an artificial neural networks (ANNs) model effectively optimized the oxidation parameters, with predicted values closely matching the experimental data. The ANNs model yielded excellent statistical performance, with a root mean square error (RMSE) of 0.0317, 0.0223 and coefficient of determination (R2) of 0.9690 and 0.9854 for UV/Fe2+/H2O2-UV/FeOx/H2O2 and UV/Fe2+/PMS-UV/FeOx/PMS oxidation systems respectively.

Optimization of Dissolved Air Flotation (DAF) process for the treatment of oily water from biodiesel production

Biodiesel production has become one of the most efficient ways of diversifying the energy matrix. However, the increase in biodiesel production increases the generation of wastewater. Therefore, this study aimed to characterize the wastewater generated in the biodiesel washing process, obtained by the alkaline transesterification of sunflower oil, and to evaluate its treatment by the dissolved air flotation (DAF) system, using a Central Composite Rotational Design (CCRD). The first DCCR was carried out with 4 independent variables: pH, Coagulant Dose (CD), Polymer Dose (PD), and Recirculation Rate (RR), with the response variables being apparent color removal and turbidity removal. Based on the results of the first DCCR, optimization tests were designed with DC and DP as independent variables and apparent color, turbidity, COD, and oil and grease (OG) as response variables. The process showed high apparent color and turbidity removal efficiency. The best results were obtained in tests 10 (DC = 1545 mg.L-1 and DP = 1050 mg.L-1) and 3 (DC = 700 mg.L-1 and DP = 8.8 mg.L-1), with the removal of 99.88% and 99.22%, respectively. For the COD and OG parameters, the best results were observed in tests 8 (DC= 555 mg.L-1 and DP= 6 mg.L-1) and 5 (DC= 1050 mg.L-1 and DP= 6 mg.L-1), with 98% and 99.42% removal, respectively. FAD treatment using the combination of coagulant and cationic polymer proved to be highly efficient in treating wastewater from biodiesel production.

Preparation and Characterization of Acid and Base Modified Fish Scales of Labeo Rohita and Their Application as an Adsorbent

The study is carried out to investigate the removal efficiency of the textile dye Congo Red (CR) on fish scales (FS) of Labeo rohita. Huge fish scales are dumped as waste from the fish markets and are not converted into valuable products. That is why a fish scale of widespread fish in Bangladesh Labeo rohita has been selected as an adsorbent in removing Congo red from an aqueous solution. In the present study, the effect of different parameters such as adsorption dosage, contact time, concentration of dye, and pH on the removal of CR were investigated. The maximum dye removal efficiency (88.53 %) was observed for 3g/100 mL of adsorbent at an initial concentration of 1×10-4 M and pH 8.80 after 60 minutes. Modification of the surface of the fish scales was carried out by using HCl and KOH. The surface of the adsorbents was characterized by FTIR spectroscopy. After 60 minutes of contact time, the percentage of adsorption for the acid and base-modified FS was 54.81% and 90.51% respectively. The higher intense FTIR spectra of the base-modified FS denoted the better efficiency of the adsorbent at the basic medium. The adsorption kinetics of CR on FS is studied by following the pseudo-first-order and pseudo-second-order kinetic model. Experimental results showed that fish scales of Labeo rohita have satisfying color removal efficiency and might be a better alternative to other adsorbents to detoxify industrial wastewater. A mechanism of adsorption of CR on FS has been proposed.

Dual approach in textile wastewater treatment: optimisation and comparison of fluidised-bed and conventional Fenton processes

ABSTRACT This study optimises secondary textile dyeing wastewater removal using fluidised-bed Fenton (FBR-Fenton) and standard Fenton processes for chemical oxygen demand (COD) and colour removal efficiency. The Box–Behnken response surface approach optimised pH, iron ion concentration, and hydrogen peroxide concentration. At pH 3.3, [Fe2+] = 2.6 mm, [H2O2] = 6.4 mm in the fluidised bed reactor with 67 g/L quartz sand, with a 50% bed expansion after 40 min, the FBR-Fenton process removed 75.8% COD and 98.0% colour. The standard Fenton method was tuned to pH 3.2, [Fe2+] = 3.1 mm, [H2O2] = 6.6 mm, and COD and colour removal effectiveness of 69.7% and 97.5%, respectively. FBR-Fenton enhanced COD and total iron removal efficiency, reduced chemicals, and reduced sludge by 28.0% compared to conventional Fenton. This study also showed quartz sand reusability in FBR-Fenton treatment cycles. Experimental results matched response surface model predictions, proving regression equation correctness.

Performance of a novel Built-in Static Magnetic Field – Biological Aerated Filter (BSMF–BAF) for treating high-salt textile dyeing wastewater

High-salt textile dyeing wastewater is difficult to treat. Magnetic fields can enhance the biodegradation capacity and extreme environmental adaptabilities of microorganisms. Thus, magnetically enhanced bioreactors are expected to improve the treatment efficiency and stability of high-salt textile dyeing wastewater. Accordingly, a novel Built-in Static Magnetic Field – Biological Aerated Filter (BSMF–BAF) was constructed and investigated for treating actual high-salt textile dyeing wastewater in this study. Two other BAFs packed with traditional and magnetic ceramsite carriers, respectively, were simultaneously operated for comparison. The removal of color, chemical oxygen demand (COD), suspended solid (SS) and acute toxicity were monitored. The activities of key enzymes and microbial community structure were analyzed to reveal possible mechanisms for improving the treatment efficiency of traditional BAF using the BSMF. The results showed that the BSMF–BAF possessed the highest removal efficiencies of color, COD, SS and acute toxicity among the three BAFs. The BSMF induced significant increases in the activities of azoreductase and lignin peroxidase, which were responsible for the degradation of azo compounds in the wastewater and the detoxification of toxic intermediates, respectively. Additionally, the BSMF induced the relative enrichment of potentially effective bacteria and fungi, and it maintained a relatively high abundance of fungi in the microbial community, resulting in a high treatment efficiency.

Eco-benevolent synthesis of ZnO-NPs and ZnO-MFs from Inula oculus-christi L. (Asteraceae) with effective antioxidant, antimicrobial, DNA cleavage, and decolorization efficiencies.

As a result of the changes occurring globally in recent years, millions of people are facing challenging and even life-threatening diseases such as cancer and the COVID-19 pandemic, among others. This phenomenon has spurred researchers towards developing and implementing innovative and environmentally friendly scientific methods, merging disciplines with significant technological potential, such as nanotechnology with medicinal plants. Therefore, the focus of this research is to synthesize zinc nanoparticles (ZnO-NPs) and microflowers (ZnO-MFs) using extracts of the medicinal plant I. oculus christi prepared in n-hexane and methanol as new bioreduction and capping agents through a simple and environmentally friendly chemical approach. Optical, thermal, and morphological structural analyses of ZnO-NPs and ZnO-MFs were conducted using Ultraviolet-Visible (UV-Vis) spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, Thermogravimetric Analysis (TGA), and Field Emission Scanning Electron Microscopy (FE-SEM). Metabolic profiles of extracts from different plant parts were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) and supported by visualization of contents through Principal Component Analysis (PCA), hierarchical cluster analysis heatmaps, and Pearson correlation graphs. Interestingly, ZnO-NPs and ZnO-MFs exhibited strong antioxidant properties and demonstrated particularly potent antimicrobial activity against Micrococcus luteus NRRL B-4375, Escherichia coli ATCC 25922, and Candida albicans ATCC 10231 strains compared to standard antibiotics. Furthermore, ZnO-NPs and ZnO-MFs showed excellent plasmid DNA-cleavage activity of pBR322 with increasing doses. The photocatalytic performance of the synthesized ZnO-NPs and ZnO-MFs was evaluated for methylene blue (MB), congo red (CR), and safranin-O(SO) dyes, demonstrating remarkable color removal efficiency. Overall, the results provide a promising avenue for the green synthesis of ZnO-NPs and ZnO-MFs using I. oculus-christi L. inflorescence and pappus extracts, potentially revolutionizing biopharmaceutical and catalytic applications in these fields.

Effect of chromophore type on efficiency of reactive dye removal using polyamidoamine dendrimer

AbstractIn this study, by selecting a sample of dyes from a wide variety of chromophores used in the production of reactive dyes (monoazo, bisazo, metal azo, phthalocyanine, anthraquinone, copper formazan and triphendioxazine), the colour removal performance of polyamidoamine (PAMAM) dendrimer in reactive dyes was statistically evaluated depending on the dye chromophore groups (and accordingly molecular weight and number of sulfo groups of the dye), dendrimer concentration and centrifugation time. When all the results were examined, it was observed that the colour removal efficiency was significantly lower in metalazo and copper formazan‐based reactive dyes, whereas colour removals ranging from 93% to 98% could be obtained in bisazo, triphendioxazine, monoazo, anthraquinone and phthalocyanine dyes. With the use of dendrimer, the best colour removal efficiencies occurred at pH 3. However, it was found that the centrifugation time of 15 min is sufficient for all dyes, and a longer centrifugation does not provide any additional benefit in terms of colour removal.

Reuse and Recovery of Water from Industrial Textile Dyeing Effluent Using High-Performance Electrodes Continuous Flow Electrocoagulation Reactor

The dye effluents released from the textile and printing industries contain strong colorants, inorganic salts, and other toxic compounds. The conventional coagulation technique of dye effluent treatment is plagued with issues of low removal rate of color, generation of large quantities of sludge, and toxic end-products. Recently electrocoagulation technique gained immense attention due to its high efficiency. This technique involves the dissolution of the sacrificial anodes to provide an active metal hydroxide as a strong coagulant that destabilizes the pollutants and removes them by precipitation or flocculation. This study is about the efficiency of the electrocoagulation process using titanium coated - aluminum and mild steel electrodes to treat industrial dye wastewater. Effects of parameters such as current density & initial dye concentration were investigated. It was observed that, for the same current density, electrode consumption was higher with TiO2/Al electrode than with mild steel electrode, resulting in more color removal efficiency (CRE) using TiO2/Al electrode. The settling rate of the flocs was higher in the rector having TiO2/Al electrode at the 100 mL with current density (2.5 mL.min-1 to 5.3 mL.min-1), while in the reactor with mild steel electrode, the settling rate was very less. The results showed that dye removal was 95.11% and 92.1% for mild steel and titanium-coated electrodes, respectively. It was observed that 50 % of Aluminum was removed from the treated effluent after the final stage of filtration. Based on the multicriteria analysis to identify the optimum operational parameters to be applied at the field level, it was observed that maximum CRE may be obtained with TiO2/Al electrode and the applied current of 1 Amps with a flow rate of 100 mL.min-1. It can be concluded that electrocoagulation is a highly efficient and the fastest method to treat dye effluents from industries.

Fabrication and performance evaluation of polyethersulfone membranes with varying compositions of polyvinylpyrrolidone and polyethylene glycol for textile wastewater treatment using MBR

Various industries polluting the water bodies by discharging untreated wastewater directly into the environment and conventional wastewater treatments are often insufficient for effectively treating the pollutants. However, membrane bioreactors (MBRs) offer a promising solution for wastewater treatment where membrane serving as the heart of the system. In this study, polyethersulfone (PES) was used as the membrane material and hydrophilicity of the membranes were tuned up by mixing with hydrophilic additives such as polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) and the membranes have shown promising results in treating wastewater, particularly in terms of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and color removal. For example, PES-PEG membrane demonstrated COD, BOD, and color removal of 96 %, 94 %, and 92 %, respectively while those were 95 %, 94 %, and 92 %, respectively for PES-based commercial membrane. Although the performances of fabricated membranes were comparable to that of commercial membrane in COD, BOD, and color removal efficiencies, there is room for improvement in permeate yields. Notably, the average permeate efficiency for MBR modules produced with PES-3PEG and PES-5PVP membranes was recorded as 47 % (18 L/m2h) and 13 % (5 L/m2h) respectively of the commercial membrane (38 L/m2h). Despite the variance in permeate yields, the fabricated membranes also showcased significant efficacy in removing microorganisms, a crucial aspect of wastewater treatment. Their performance in this regard proved highly comparable to that of the commercial membrane, emphasizing the potential of these fabricated membranes in enhancing the wastewater treatment.

Comparative Evaluation of Fenton and Persulfate Processes with UV/H2O2 for Batik Wastewater Treatment: Optimizing Fe2+ and S2O8 2- Ratio by H2O2 for Enhanced Pollutant Degradation

Wastewater generated from industrial processes including the batik industry in Indonesia contains high organic pollutants and dyes. In this study, the advanced oxidation process that will produce hydroxyl radicals was used to degrade pollutants in this batik industry wastewater. This study aims to compare the Fenton and Persulfate processes with the influence of variations in the concentration of Fe2+ and S2O8 2- added. This method is carried out by adding H2O2 as an oxidant which is added to each catalyst, namely Fe2+ and S2O8 2- in the presence of a combination of UV light. Fenton process was carried out in 60 minutes and Persulfate process was carried out in 45 minutes. In this study, there was a tendency to increase the efficiency of COD and color removal along with the increasing concentration of each catalyst added. The highest COD and color removal efficiency occurred at a ratio of H2O2:Fe2+ and H2O2: S2O8 2- of 1: 0.08.

Refractory organic matter removal from mature leachate by bipolar electrocoagulation-electrooxidation reactor configurations

In this study, mature leachate treatment with combined electrochemical processes was investigated to benefit from the advantages of electrocoagulation (EC) and electrooxidation (EO) simultaneously. First, control experiments were conducted, the most effective anode-cathode combination for EO was selected as Ti/IrO2-Gr, the number of Al electrodes for EC was determined as 3 and the number of Fe electrodes was determined as 5. Optimization of process parameters of the combined system with Al and Fe electrodes was conducted with Box-Behnken design (BBD). With BBD, the effect of the process parameters (initial pH, current density, and reaction time) on the system responses (COD, UV254, and color removal efficiencies) was determined. The suitability of the created model in the study was analyzed statistically and the results of quadratic models were found compatible with experimental studies. The model's capacity for prediction was also confirmed by validation experiments under optimum conditions. By implementing the optimum conditions, COD, UV254, and color removal efficiencies were determined as 71.5 %, 60.2 %, and 93.2 %, respectively for the combined process with Al electrodes and 79.5 %, 68.0 %, and 97.7 %, respectively for the combined process with Fe electrodes. Correlation of actual and predicted data showed that BBD is reliable for optimizing process parameters of combined processes with Al and Fe electrodes. The obtained results showed that combined processes are more effective than hybrid processes, based on both pollutant removal efficiencies and energy consumption.

Investigating the efficiency of electrocoagulation using similar/dissimilar electrodes for the detoxification of Coralene Rubine dye: a cost effective approach.

Efficient treatment of textile dyeing wastewater can be achieved through electrocoagulation (EC) with minimal sludge production; however, the selection of the appropriate electrode is essential in lowering overall costs. Also, the reuse of the treated aqueous azo dye solution from this process has not been explored in detail. With these objectives, this study aims to treat synthetic azo dye solutions and achieve high colour removal efficiency (CRE%) using similar (Ti-Ti) and dissimilar (Ti-Cu) metal electrodes through EC with an attempt to reduce the cost. The aqueous Coralene Rubine GFL azo dye was used to examine the efficiency and cost of the EC process. X-Ray Photoelectron Spectroscopy was used to study the EC mechanism, while High Performance Liquid Chromatography was used to analyse the degradation of the dye and the formation of intermediate compounds. The concentration of metal ions in the treated dye solution was quantified using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), with Ti-Ti treated solution having 14.20mg/L concentration of Ti and Ti-Cu treated solution having 0.078mg/L of Ti and 0.001mg/L of Cu, respectively. Colour removal efficiency of 99.49% was obtained for both electrode sets, with a lower operating time and voltage for dissimilar metal combination. Ecotoxicity studies showed negligible toxicity of Ti-Cu treated dye samples compared to untreated solutions. Survival rate, protein estimation, and catalase activity was used to validate the treatment method's efficacy. The study found that the dissimilar electrode material exhibited reduced toxicity due to the presence of heavy metals below the permissible limit.

Evaluation of Artocarpus heterophyllus seed performance and kinetics in the coagulation–flocculation process for the purification of paint industrial wastewater

The Artocarpus heterophyllus (AH) seed was used as a coagulant in this study to explore the effects of pH, settling time, and coagulant doses on the removal of colour, turbidity, and heavy metals from paint industrial wastewater. The AH coagulant was instrumentally characterized by SEM, FTIR, and XRD. The maximum colour and turbidity removal efficiencies were 94.33% and 99.94% at the dosage of 0.2 g/L, pH 2. The mercury removal efficiency of 99.29% was achieved at the optimal conditions of 0.8 g/L coagulant dosage and pH 8. At a dose of 1.0 g/L and a pH of 10, the highest lead removal efficiency was 99.76%. The best removal efficiency for arsenic was 75.24% at a 0.8 g/L coagulant dosage and pH of 8. All at a time of 50 and 40 min, respectively. XRD diffraction results before treatment depict that the AH coagulant was crystalline and changed to amorphous after treatment. The SEM and FTIR results of the coagulant revealed changes in the surface morphology and functional groups before and after treatment. The reaction kinetics were best modelled in second order.

Comparative Investigation of the Color Removal Efficiency of Different Mosses Species from Dye Solutions

In this study, Acid Red 88 (Sodium 4-(2-hydroxy-1-naphthalenylazo)-naphthalenesulfonate) dye solution, which is used extensively in textile industry, was used. Dye removal efficiency determination studies were firstly performed by using three moss species, Chiloscyphus polyanthus, Cinclidotus pachylomoides and Palustriella Falcata (Hedw). In the case of comparison of color removal efficiency of Chiloscyphus polyanthus, Cinclidotus Pachylomoides and Palustriella Falcata (Hedw), it was seen that the species with the highest color removal efficiency with increasing dye concentration was determined for Palustriella Falcata (Hedw). Furthermore, the effect on color removal efficiency was determined at specific concentration, pH and under UVA (Ultraviolet-A) lamp light by using a photo reactor with these mosses species. It has also been detected that these three mosses can be used in photocatalytic studies. Thus, these three mosses species can be employed as color removing material both separately and with UVA light.

Removal of a model reactive azo dye from aqueous solution by a bioadsorbent in batch and fixed-bed column modes: Application of the developed technology to a textile wastewater

Sugarcane bagasse (SB) was used to produce a new bioadsorbent (STEA), drawing on circular economy concepts. STEA was synthesized using a two-step one-pot reaction, employing epichlorohydrin and triethylamine in the presence of N,N-dimethylformamide, without the use of a petroleum-based catalyst. The structure and surface of STEA were characterized by elemental C, H, N, and Cl analysis, X-ray diffraction, infrared spectroscopy, 13C solid-state nuclear magnetic resonance spectroscopy, thermogravimetric analysis, specific surface area and pore size distribution determination, and point of zero charge measurement. Batch adsorption and desorption tests were performed with the model dye Remazol Golden Yellow (RGY) RNL, a reactive anionic azo dye widely used in textile industry, to evaluate the potential reuse and application of STEA in a fixed-bed column for wastewater treatment. For batch adsorption, the best dose and agitation speed were 0.2 g L−1 and 50 rpm, respectively. STEA effectively removed RGY over a wide range of pH (2.00–10.00). The equilibrium time, maximum adsorption capacity (Qmax), and desorption efficiency (Edes) were 720 min, 369 mg g−1 (0.71 mmol g−1), and 49.5 %, respectively. The fixed-bed column fed with a spiked aqueous RGY solution could be operated for 415 min, with Qmax of 422 mg g−1 (0.81 mmol g−1) and Edes of 58.9 %. Batch and continuous experiments using real textile industry wastewater containing reactive azo dyes showed high color removal efficiency by STEA, with no interference of other compounds present in wastewater on adsorption of the reactive azo dyes (overshooting effect). The technology was validated in a relevant environment and achieved technology readiness level 5, showing potential to be upscaled. Therefore, STEA proved to be an efficient bio-based technology for application in tertiary treatment of real textile plant wastewater to remove reactive anionic azo dyes.

Differences in anodizing of two copper-containing coordination compounds by different degradation factors: Experiments and DFT calculations

Copper phthalocyanine (CuPc) and copper formazan (CuFz) are typical coordination compounds widely utilized due to their physicochemical properties and biochemical behavior. The production and application of CuPc and CuFz have produced large amounts of copper-containing wastewater and aromatic organics, posing great risks to human health and the environment. This research introduced a feasible and efficient treatment method based on BDD anodic oxidation for CuPc and CuFz wastewater and provided a novel perspective on the degradation differences of the two pollutants through DFT calculation. Firstly, the color removal efficiency and chemical oxygen demand (COD) during the anodic oxidation of the two molecules were compared. Secondly, the effect of pH, inorganic anions type, and current density on the oxidative degradation of CuPc and CuFz was discussed. Thirdly, cyclic voltammetry (CV) was carried out to evaluate the direct anodic oxidation speed of CuPc and CuFz. Then, the principal reactive oxygen species (ROS) of CuPc and CuFz in the indirect oxidation process were investigated through free radical quenching and Electron paramagnetic resonance (EPR) spectroscopy. The functional group changes in degradation, the degradation products, and the shed copper ions were also analyzed. Finally, the global, local, and condensed properties and CuPc and CuFz reaction sites to be attacked by ROS were theoretically analyzed using density functional theory (DFT) calculation. Altogether, this study can help broaden the discussion and further the understanding of the links between the electrochemical oxidation pathway and decolorization of coordination compounds.

Removal of methylene blue and Congo red from the wastewater in a jet loop reactor using ozone and activated carbon

The textile industry consumes a large amount of fresh water, resulting in colored effluent due to the incomplete fixation of certain dyes. Traditional textile wastewater treatment such as coagulation-flocculation, membrane filtration, thermal separation and electrochemical processes are expensive and pose significant environmental challenges. To address these issues an alternative technique for decolorizing textile effluent using a modified sparged loop reactor was proposed in this study. The jet loop reactor basically a multiphase reactor was utilized to treat textile wastewater with ozone. In this study, the textile wastewater containing water-soluble basic dyes such as Methylene blue and Congo red was simulated at a concentration of 50 ppm and the color removal efficiency of the reactor was analyzed. The effect of process parameters such as effluent flow rate (0.2– 0.4 Liter/min), sparger openings (2−4), adsorbent weight (0.5 – 1.5 g) and ozone dosage time (10–30 min) on the decolorization efficiency of the reactor were examined and optimized using Response Surface Methodology. In this study, a maximum color removal of 93 % and 85 % for Congo red dye and Methylene blue dye simulated wastewater was achieved. A correlation was developed using Response Surface Methodology-Box Behnken Design and the developed model was successfully interpreted with experimental values. Based on our results, we believe that it is possible to replace the energy-intensive thermal separation process with jet loop sparged reactor to treat the textile effluent. As a sustainable process, loop reactor may result in a huge reduction of freshwater consumption.

Application of photocatalytic and fenton processes for the degradation of toxic pollutants from pulp and paper industry effluents

Pulp and paper mill effluents represent a significant environmental concern due to the presence of various toxic organic and inorganic pollutants, posing risks even at low concentrations. With the paper production process consuming approximately 200 tons of water per ton of paper and generating effluents containing over 250 different chemicals, effective treatment methods are essential to mitigate the environmental impact of the pulp and paper (PP) industry. This study presents a comprehensive evaluation of the efficacy of heterogeneous and homogeneous photocatalytic treatments for PP industry-derived effluents, targeting reductions in major pollutant concentrations below environmental standards. A thorough review of the literature on pollutant removal from PP effluents using photocatalytic treatment, particularly employing UV/TiO2 and UV/ZnO photocatalysts, reveals significant removal rates. Doped photocatalysts have shown enhanced performance, achieving removal percentages of 98 % for BOD and COD, and 99 % for color and lignin. Additionally, Fenton and photo-Fenton treatment techniques have demonstrated high removal efficiencies for BOD, COD, color, and lignin.

Experimental approach and analysis of the effectiveness of a tubular helical flow flocculator for water supply in developing communities

The main objective of this study was to evaluate the impact of the length and retention time of a tubular helical flow flocculator (THFF) on the elimination of turbidity and color from raw water, to obtain quality treated water for consumption in areas rural. For this, a large-scale field experimental system was used, the THFF was built with 4-inch diameter polyethylene hose and coupled to a sedimentation and filtration process. For the different experimental tests, aluminum sulfate was chosen as the coagulant. To find the optimal dose of coagulant, jar tests were previously carried out. For the tests the length of the THFF was varied (50 m and 75 m), flow rates of 0.25, 0.5, 0.75, 1 and 2 L/s and turbidity ranges of <10, 10–20, 21–50, 51–100 and > 100 NTU of raw water were tested. An evaluation of the hydraulic behavior of the THFF was carried out through an analysis of the temporal distribution curve of the concentration of a tracer, applying the Wolf-Resnick model. The average results revealed a haze and color removal efficiency of 98.07 % and 98.50 %, respectively. The residence time and velocity gradient exhibited variations in a range of 2.25–35.0 min and 3.64 to 56.94 s−1, respectively. It was evident that the operation and effectiveness of THFF are directly influenced by the turbidity of the raw water, the residence time and the velocity gradient. These findings indicate that THFF could play a valuable role as a flocculation unit in a purification system, mainly the existence of a plug-type flow was observed. The findings indicate that THFF, complemented by settling and filtration processes, could be a valuable tool for implementation in rural areas.