Dyeing Research Articles

Synthesis of Nanoparticle ZnO via Chemical Reduction Using Singkil (<i>Premna serratifolia linn</i>) Leaf Extract as Photocatalytic

Nanoparticles are one of the widely studied research topics. ZnO nanoparticles have numerous benefits, such as photocatalysts and antibacterial applications. Methylene blue, which a highly dangerous and pollutes the environment and human health, is mostly used as a coloring dye in the textile industry. The use of biodegradation to treat textile waste is time-consuming and less effective. Applying photocatalysts using semiconductor materials is a more efficient method than conventional approaches for decomposing organic waste. One environmentally friendly method is green synthesis, which involves the use of microorganisms, enzymes, and plant extracts in the fabrication process. In this study, the green synthesis using chemical reduction of Premna serratifolia linn leaf extract was used to produce ZnO nanoparticles. The objective of this study is to investigate the effect of temperature on the fabrication of ZnO nanoparticles and their photocatalytic performance. Zinc nitrate tetrahydrate was used as a precursor, and the furnace temperature was varied at 400, 500, and 600 °C. The obtained ZnO was then tested using scanning electron microscopy (SEM), X-ray diffractometry (XRD), and Fourier transforms infrared spectrophotometry (FTIR). Moreover, the photocatalytic test was evaluated by examining the degradation efficiency of methylene blue using UV light. The XRD analysis indicated that the ZnO nanoparticles had crystallite sizes ranging between 44-60 nm. The SEM morphological test showed that the ZnO particles had a nano-sized spherical shape. The FTIR test results demonstrated the presence of ZnO peaks around 520 cm‑1. The performance of photocatalytic activity under UV light irradiation was significantly affected by tuning the temperatures. It was observed that the photocatalytic activity increased with increasing temperature, and methylene blue degradation efficiency reached 50% at a temperature of 600 °C. The ability of ZnO as a photocatalyst material was also evaluated by recycling the used material two times, where there was no significant change in photocatalytic performance.

Physico-Chemical Analysis of Textile Effluents from Bagru, Jaipur (Rajasthan, India): Implications for Environmental Impact and Treatment Needs

The textile industry is one of the largest water polluters worldwide. The coloured and bad odour effluent discharged from such industries pollutes not only the water bodies but also affects groundwater quality. In the present study, thirty-five water samples were collected from different dyeing units of the Bagru textile area (Rajasthan, India) famous for using natural dyes for textile processing. The physico-chemical analysis of these water samples shows that all parameters exceeded the permitted range recommended by the Central Pollution Control Board (CPCB) and World Health Organization (WHO). The analysis revealed the use of synthetic dyes in Bagru's textile industry for dyeing and printing. Based on the estimated characteristics, these textile effluents must be properly treated before releasing into the environment as the discharge of untreated effluents into local water bodies leads to significant water pollution, adversely affecting aquatic ecosystems and biodiversity. Additionally, contaminants can permeate the soil, compromising agricultural productivity and food safety. The air quality is also compromised due to the release of volatile organic compounds (VOCs) during the dyeing process, posing respiratory risks to nearby communities. This research underscores the urgent need for improved waste management practices and regulatory measures to mitigate the adverse environmental effects associated with synthetic dyes in Bagru's textile industry.

Optimization of biosorption of industrial dyes into Luffa cylindrica functionalized with quaternary ammonium salts

Optimization of biosorption of industrial dyes into Luffa cylindrica functionalized with quaternary ammonium salts

Hydrocarbonization of the pigeon pea husk as an alternative to increase the biosorption of the industrial dye yellow tartrazine from aqueous solutions

Tartrazine Yellow is a synthetic dye that is part of industrial effluents and can harm the environment when disposed of incorrectly. Biosorbents are alternatives to reduce the cost of the adsorption technique and add value to agricultural wastes. This work reports an investigation regarding the hydrocarbonization process effect on the adsorption capacity of Pigeon Pea Husk, for the removal of the dye from aqueous solutions. The adsorbents were treated chemically and were characterized. The kinetics and adsorption isotherms were investigated and the results showed that the pseudo second-order and Langmuir were the best models, respectively. The hydrocarbonization process increase the adsorption of the adsorbent from 1.54 mg g-1 to 3.60 mg g-1. The increase was even greater in the basic medium, reaching the highest adsorption capacity of 4.78 mg g-1. The hydrocarbonization process was demonstrated to be a sustainable and feasible path to increase the adsorption capacity.

Breaking New Grounds: solid-state synthesis of TiO2 – La2O3 – CuO Nanocomposites for degrading Brilliant Green dye under Visible Light

Environmental pollution, particularly from industrial dyes and chemicals, poses a significant threat to ecosystems and human health. Traditional pollution mitigation methods are often inefficient and costly. Photocatalysis has emerged as a promising solution for degrading pollutants using light energy. Titanium dioxide (TiO2) is a widely studied photocatalyst due to its stability, non-toxicity, and strong oxidative power. However, its efficiency is limited by a wide bandgap, restricting absorption to the UV region, and rapid electron-hole recombination. To address these limitations, doping TiO2 with materials like La2O3 and CuO has been explored to enhance its photocatalytic activity under visible light. This study investigates the enhancement of TiO2 nanocomposites by incorporating La2O3 and CuO. X-ray diffraction (XRD) revealed that the nanocomposites retained TiO2's anatase and rutile phases with improved crystallinity. Scanning electron microscopy (SEM) displayed spherical nanoparticles forming agglomerates, typically due to high surface energy. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of La and Cu in the TiO2 matrix. Fourier-transform infrared (FTIR) spectroscopy identified characteristic vibrational modes of Ti–O, La–O, and Cu–O bonds, suggesting strong chemical interactions between dopants and TiO2 lattice. Ultraviolet-visible (UV-Vis) spectroscopy showed a red shift in absorption spectra with La2O3 and CuO addition, reducing the bandgap energy from 3.23 eV (pure TiO2) to 2.27 eV for the TiO2–0.1La2O3–0.2CuO composite. Photoluminescence (PL) spectroscopy indicated improved charge separation and reduced electron-hole recombination rates in the synthesized nanocomposites. Photocatalytic performance was evaluated by degrading Brilliant Green (BG) dye under visible light. The TiO2–0.1La2O3–0.2CuO (TLC0.2) nanocomposite achieved a maximum dye degradation of over 95% after 204 minutes under optimal conditions (C0 = 17 mg/L and a S/L ratio of 1 g/L). Adding the inorganic agent Na2SO4 to this process significantly enhanced photocatalytic activity, increasing degradation from 56% to 95% after 180 min of visible light irradiation under C0 = 20 mg/L and S/L = 0.5 g/L conditions, as it shows a high stability after six reuse cycles. In conclusion, La2O3 and CuO doping significantly enhance TiO2 nanocomposites' crystalline structure, morphology, optical properties, and photocatalytic efficiency, demonstrating their potential for environmental remediation and solar energy conversion.

Breakdown cost and recycling processes of Bentonite/TiO2 quantum dots of photo and solar degradation of Congo Red dye and industrial dyes wastes

This research presents the preparation, characterization, and application of a novel bentonite- TiO2 quantum dot (Bent/TQ) nanocomposite for the efficient photodegradation of Congo Red dye, a common pollutant in industrial wastewater. The composite was prepared via a co-precipitation method followed by calcination, which facilitated the uniform dispersion of TiO2 quantum dots within the bentonite matrix. The resulting material exhibited a high specific surface area of 205.45 m2/g and an optimized band gap of 3.15 eV, making it suitable for visible light photocatalysis. The photocatalytic efficiency of Bent/TQ was evaluated under both xenon lamp irradiation and natural sunlight. The composite demonstrated a significant degradation rate constant of 23.35 × 10⁻³ s⁻1, which is comparable to that of pure TiO2 quantum dots (28.86 × 10⁻³ s⁻1). Mechanistic studies revealed that the primary active species responsible for the degradation were hydroxyl radicals (•OH), generated through the interaction of photogenerated electron-hole pairs with H2O molecules and molecular oxygen. Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) analyses were employed to assess the mineralization efficiency of the composite. The Bent/TQ catalyst achieved a COD removal efficiency of 84.5% and a TOC reduction of 76.2% after 240 minutes of irradiation under natural sunlight. Reusability tests indicated that the photocatalyst retained approximately 80% of its original efficiency after seven consecutive cycles, though a slight decline was observed due to particle agglomeration under prolonged light exposure. The economic analysis suggested that the use of Bent/TQ nanocomposites could reduce operational costs by 29.12% compared to conventional TiO2-based systems, making it a cost-effective solution for large-scale wastewater treatment. This work highlights the potential of Bent/TQ nanocomposites as sustainable and efficient photocatalysts for environmental remediation, with future efforts aimed at enhancing their long-term stability and expanding their applicability to a broader range of pollutants.

Simulation and modeling of methylene blue dye removal by an agri-food waste (Peanut shells)

Our study explores the potential of utilizing peanut shells, an abundant and low-cost food waste, as a natural adsorbent for the removal of industrial dyes, specifically methylene blue. We conducted a detailed investigation of the adsorption process, which revealed that it conforms to both Langmuir and Freundlich isotherms, indicating the ability of peanut shells to adsorb methylene blue effectively. To optimize the adsorption yield, we employed a Box-Behnken experimental design. This approach allowed us to assess the impact of several key factors, including the mass of the adsorbent, dye concentration, pH, temperature, stirring rate, and the ionic strength of salts in the solution. The mathematical model and simulation of the adsorption process helped us identify the best conditions for maximizing the dye removal. Our experiments resulted in a maximum adsorption efficiency of 97%, achieved under optimal conditions: 1.5 g of adsorbent, a methylene blue concentration of 40 mg/L, pH 11, temperature of 65°C, 0 mg/L ionic strength, and a stirring rate of 165 rpm. These findings suggest that peanut shells are a viable, eco-friendly alternative for dye removal, offering a sustainable solution for wastewater treatment and contributing to waste reduction.

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.

Characterization of the Coriolopsis gallica DyP for Its Potential to Biotransform Various Fluoroquinolones.

Coriolopsis gallica (Cga) is a white-rot fungus renowned for its ability to secrete ligninolytic enzymes that are capable of oxidizing phenolic compounds. This study aimed to investigate the biochemical characteristics of a dye-decolorizing peroxidase named CgaDyP1 and test its ability to biotransform antibiotics. CgaDyP1 was cloned and heterologously expressed in Escherichia coli. We fully characterized the biochemical properties of CgaDyP1 and evaluated its dye-decolorizing potential to confirm that it belongs to the DyP class of enzymes. We also tested its fluoroquinolone antibiotic biotransformation potential for possible biotechnological applications. Alignment of the primary amino acid sequence with DyP homolog sequences showed that CgaDyP1 has high similarity with other fungal DyPs. The recombinant CgaDyP1 exhibited activity on substrates such as ABTS and 2,6-dimethoxyphenol (DMP) with optimal performance at a pH of 3, although activity at pH 2.5, pH 4, and pH5 diminished over time. Thermostability tests indicated that the enzyme remains stable at temperatures between 30 °C and 50 °C and retains 70% of its initial activity after 180 min at 50 °C. Tests on the effect of hydrogen peroxide on CgaDyP1 activity found peak activity at 0.25 mM H2O2. CgaDyP1 decolorized five industrial dyes, and kinetics data confirmed that it belongs to the DyP class of enzymes. CgaDyP1 was shown to biotransform some of the 7 recalcitrant fluoroquinolone antibiotics tested here, including levofloxacin, moxifloxacin, and norfloxacin, and thus holds potential for biotechnological applications.

Organic-Inorganic Hybridization of Silkworm Cocoon Filaments Using Nano Pastes of Silica-Phosphate-M (M = Cu, Fe, or Al).

Inorganic-organic hybrid biomaterials have recently attracted much attention because of their widespread use. Silkworm cocoon filaments resulting from sericulture as prospective nanobiomaterials need to be improved, and their properties need to be used for broader purposes. This study was aimed at investigating methods for siliconization of silkworm cocoon filaments and characterizing their cocoon filament properties in terms of their yarn quality, natural dyeing, and antibacterial properties. Three methods of hybridization processes were used in this experiment, namely, in situ natural dyeing of silk yarns while silk filaments were spined, feed engineering through spraying the mulberry leaves with natural dyes and silica-phosphate-M (M = Cu, Fe, or Al) nano pastes, and a combination of both methods. The resulting cocoon filaments were characterized by their siliconization of filament fibers by using FTIR, XRD, and SEM-EDS methods. The yarn tensile strength, color quality, color fastness properties affected by the siliconization of silk filament fibers, and antibacterial properties were also investigated. Results showed that the combination method produced better siliconization of silk fibers, and, consequently, the better siliconization of silk fibers produced better natural dyeing as well as antibacterial properties of their resulting silk yarns.

Characterization of Atlantic Forest Tucum (Bactris setosa Mart.) Leaf Fibers: Aspects of Innovation, Waste Valorization and Sustainability.

This study investigates the fibers of tucum (Bactris setosa Mart.), a palm species native to the Atlantic Forest. The fibers manually extracted from tucum leaves were characterized to determine important properties that help with the recognition of the material. The fibers were also subjected to pre-bleaching to evaluate their dyeing potential. The extraction and characterization of these fibers revealed excellent properties, making this material suitable not only for manufacturing high-quality textile products but also for various technical and engineering applications. The characterization techniques included SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared Spectroscopy), TGA (Thermogravimetric Analysis), and tensile strength tests. These analyses showed that tucum fibers possess desirable properties, such as high tensile strength, with values comparable to linen but with a much finer diameter. The fibers also demonstrated good affinity for dyes, comparable to cotton fibers. An SEM analysis revealed a rough surface, with superficial phytoliths contributing to their excellent mechanical strength. FTIR presented a spectrum compatible with cellulose, confirming its main composition and highly hydrophilic nature. The dyeing tests indicated that tucum fibers can be successfully dyed with industrial direct dyes, showing good color yield and uniformity. This study highlights the potential of tucum fibers as a renewable, biodegradable, and sustainable alternative for the transformation industry, promoting waste valorization.

Modelling and optimizing secondary metabolites production in Spirodela polyrhiza using machine learning

Spirodela. polyrhiza as one of the potential feedstocks for industrial natural dye and pharmaceutical products, efficient process to produce from it were scarce. Here, Artificial Neural Network (ANN) and Genetic Algorithm (GA) were employed for modelling and optimization respectively. Current study focus on establishing useable models and anticipating the optimal concentration of nitrate (NO3−), phosphate (PO43−) and ammonium (NH4+) to give highest relative growth rate (RGR) and produce maximum amount of anthocyanins, chlorophylls, phenolic compounds and antioxidants. In short, 12 and 11 neurons in hidden layer were found to be most suitable neuron numbers used for the modelling of growth and secondary metabolites respectively. All the models exhibited a high degree of robustness and performance with a high r2 value (higher than 0.75) and a low mean squared error (lower than 0.05). GA also anticipated the best concentration of macronutrients to achieve the maximum growth and metabolites production with significant low errors (below 7 %). The employment of machine learning was useful for such applications.

Tailored nano clay blends for enhanced dye mixture adsorption in wastewater treatment

Natural clays are eco-friendly, cost-effective, and industrially acceptable adsorbents employed in wastewater treatment. Textile effluents contains mixture of dyes where a single adsorbent often fails to treat completely. Herein, the simplest strategy for the efficient treatment of effluent with multicomponent pollutants using an tailored blend of two clay minerals has been presented. This strategy was studied using a binary blend of halloysite and montmorillonite clays (HAMT) to remove a mixture of industrial dyes, reactive Black-B (BB) and methyl red (MR) from the model effluent. Here, halloysite (HA) and montmorillonite (MT) selectively adorbs reactive black-B and methyl red respectively and could not completely treat model effluent individually whereas HAMT blend proved to be most effective. HAMT blend was prepared by convenient ultra-sonication assisted solution process and characterized using the various analytical techniques such as FT-IR, DR-UV spectra, XRD and SEM to determine structural, morphological features. Adsorption of model effluent studied as a function of pH, time, adsorbent loading and adsorbate concentration. The dye removal efficiency was remarkably enhanced when the HAMT blend was used according to the concentration of dyes present in the model effluent. The maximum dye removal efficiency was attained using HAMT (1:1) blend for effluent with an equimolar concentration of selected dyes. Similarly, HAMT (2:1) found suitable for the treatment of real textile effluent collected from local textile industries based on its assessment. This study aids in the development of a tailored adsorbent blend using conventional adsorbents for complex effluent treatment in a cost-effective way, eliminating the need for specialized materials.

A Novel Bromeliad Flower-Like Visible-Light Photocatalyst of CdS and Its Photocatalytic Activity for Industrial Dye Treatment Towards Environmental Remediation: Active Species, Mechanism, and Stability

A Novel Bromeliad Flower-Like Visible-Light Photocatalyst of CdS and Its Photocatalytic Activity for Industrial Dye Treatment Towards Environmental Remediation: Active Species, Mechanism, and Stability

Comparative Analysis for Bioremediation of Plastic and Dye Degradation

The leading environmental risk factor for disease and premature death is pollution, with plastic and dye pollutants being the most common in developing countries. The global textile industry contributes to pollution by releasing contaminated wastewater into water bodies, leading to a decline in water quality. Plastic pollution is a widespread issue affecting various environments, emphasizing the urgent need for a global response to combat the adverse effects of pollution on human health and the environment. Anoxybacillus sp. PDR2 is a soil bacterium possessing natural competence. By nature, it is a thermophile, capable of biodegrading industrial dyes. Pseudomonas sp. B10, Gram-negative bacteria, is a strain capable of degrading Polyethylene Terephthalate (PET) plastic. To detect the genome-level mutations, comparative genomic analysis was performed using a free and open source software, Galaxy. Using five different variant callers (Samtools, Varscan, Freebayes, Sniffles, Ivar), mutations were detected at various loci resulting in the modifications of the genes. The primary goal of this investigation was to perform a comparative analysis of the whole genome sequencing of two bacterial species, along with their reference strains. The purpose was to identify potential solutions for the degradation of plastics and industrial dyes. By examining the genetic composition of these bacteria, this analysis had provided valuable insights into the genetic makeup of these bacteria and their ability to break down PETs and dyes.

Recycling and breakdown photodegradation processes cost of BEN-TiQD via different photodegradation processes of Brilliant Green S dye and industrial effluents

The development of efficient photocatalytic materials for environmental remediation is of paramount importance. This study reports the synthesis and characterization of novel bentonite-titanium dioxide quantum dot (BEN-TiQD) nanocomposites for the photodegradation of Brilliant Green S, a prominent industrial pollutant. The nanocomposites were prepared via a co-precipitation method, ensuring uniform dispersion of TiO2 nanoparticles on the bentonite (BEN) surface, followed by heat treatment to achieve optimal crystallinity and surface properties. Comprehensive characterization techniques, including FTIR, XRD, SEM, BET surface area analysis, and optical spectroscopy, were employed to elucidate the structural, morphological, and photophysical characteristics of the composites. The BEN-TiQD nanocomposites exhibited an augmented surface area of 277.75 m2/g, surpassing BEN alone by more than threefold, and an intermediate bandgap of 3.17 eV, rendering them suitable for visible light absorption and photocatalytic applications. The photocatalytic efficacy of BEN-TiQD was evaluated by monitoring the degradation of Brilliant Green S under various operational parameters. The nanocomposites demonstrated superior photocatalytic performance, with a rate constant of 22.24 × 10−3 s−1, significantly only lower than TiQD (28.32 × 10−3 s−1) by nearly about 21.5 %. The enhanced activity was attributed to the quantum size effect of the incorporated TiO2 quantum dots, optimizing light absorption and charge separation. Mechanistic studies revealed the generation of reactive oxygen species, particularly hydroxyl radicals, as the primary drivers of dye degradation. The reusability of BEN-TiQD was evaluated through multiple photocatalytic cycles, exhibiting remarkable stability for up to six consecutive cycles. However, a gradual decline in photodegradation efficiency was observed after prolonged sunlight exposure, likely due to particle agglomeration and reduced surface area. This research contributes to the field of environmental remediation by developing a novel composite material that synergistically combines the adsorptive properties of BEN with the photocatalytic capabilities of titanium dioxide quantum dots. The findings pave the way for further exploration and optimization of these composites for sustainable and efficient treatment of industrial dyes and effluents, addressing critical environmental challenges.

Development of the novel advanced electrooxidation process for decolorization of recalcitrant dyes (Methylene Blue, Rhodamine B, Congo Red): Effect of operating factors

The research aims to develop an advanced electrooxidation process for decolorization of recalcitrant dye. To enhance the radical formation, a combination of UV irradiation and electrooxidation (UV/EO) is used. Methylene Blue (MB), Rhodamine B (RB) and Congo Red (CR) dyes were used as model compounds to represent recalcitrant dyes. The performance of UV/EO process was investigated under various operating factors (i.e., current density (CD), voltage, pH, NaCl, anodic material), and compared with chlorination, UV irradiation, and electrooxidation (EO) process. MB was the highest resistant dye to the UV/EO process. The UV/EO process exhibited a synergistic effect on decolorization, and it removed MB 1.35 time faster than the EO process. Based on indirect determination of •OH, the •OH formation in the EO process was 2.4 ×10−13 M, which lower than that in the UV/EO process by 4 times. The second-order rate constant for MB oxidation by HO• (kHO•,MB) was 3.31 × 109 M−1s−1. The pseudo 1st-order decolorization kinetic (k’) was independent with voltages, but directly depended on CD and NaCl concentrations. Lower pH enhanced the k’ value. The specific energy consumption was in a range of 0.408 – 5.303 kWh/m3, depending on the k’ value. The energy consumption decreased with higher the k’ value, except for increasing CD. The Boron Doped Diamond (BDD) was more effective in the decolorization rate than dimensional active anode (DSA) by 1.6 times. Treatment of industrial dye wastewater by the UV/EO process eliminated color intensity (ADMI), COD, and BOD5 by 80 %, 91 %, and 9 %, respectively.

Evaluation of blue textile dye decolorization by immobilized polyphenol oxidase using pumice stone under optimum conditions

Industrial dyes are major pollutants in wastewater and river water with an initial visible concentration of 1 mg/L. Recent studies have shown the possibility of using polyphenol oxidase in catalytic biological treatment due to its ability to oxidize a large number of dyes and pollutants in wastewater and the flexibility to work in wide ranges of temperature, pH and salinity. It is easy availability as well as the low economic cost resulting from its use in biological treatments, this enzyme polyphenol oxidase was used. The findings in this study showed that the extraction of polyphenol oxidase (PPO) from potato peel was homogenized with potassium phosphate buffer (0.1 M, pH 7) at a ratio of 1:10 (weight: volume) for two min. The result of enzyme purification by ion exchange chromatography showed that the yield of this step was 64 % and the specific activity was 6541.67 U/mg. The polyphenol oxidase was immobilized covalently on the functionalized pumice stone (25.2 U/gm) compared with other methods. The characterization results demonstrated that the optimum pH for immobilized and free enzyme activity was 6.0 while the pH range of free and immobilized polyphenol oxidase stability was from 4.5 -7.0 and 3.5 - 8.5 respectively. The better temperature for free and immobilized polyphenol oxidase activity was 25 ºC, whereas the free and immobilized polyphenol oxidase was stable at 15-35 and 15-50 °C respectively. The outcomes showed that the decolorization efficiency of blue textile dye employing immobilized polyphenol oxidase reached 99.85 % after 24 hr. for 100 mg/L concentration while for other concentrations 200, 300, 400, 500 and 1000 mg/L the decolorization efficiencies were 85.96, 76.15, 72.54, 66.94 and 63.5 % respectively. Based on the results, the immobilized polyphenol oxidase on pumice stone is highly efficient in removing textile dyes at large concentrations and in different environmental conditions.

Enhancing Azo Dye Mineralization and Bioelectricity Generation through Biocathode-Microbial Fuel Cell Integration with Aerobic Bioreactor

This study explores the efficient decolorization and complete mineralization of the diazo dye Evans blue, using an integrated aerobic bioreactor system coupled with a double-chamber microbial fuel cell (DCMFC) including a bio-cathode and acetate as a cosubstrate. The research addresses the environmental challenges posed by dye-laden industrial effluents, focusing on achieving high decolorization efficiency and understanding the microbial communities involved. The study utilized mixed strains of actinomycetes, isolated from garden compost, to treat initial dye concentrations of 100 mg/L and 200 mg/L. Decolorization efficiency and microbial community composition were evaluated using 16S rRNA sequencing, and electrochemical impedance spectroscopy (EIS) was used to assess anode and DCMFC resistance. The results demonstrated decolorization efficiencies ranging from 90 ± 2% to 98 ± 1.9% for 100 mg/L and from 79 ± 2% to 87% ± 1% for 200 mg/L. An anode resistance of 12.48 Ω indicated a well-developed biofilm and enhanced electron transfer. The microbial community analysis revealed a significant presence of Pseudomonadota (45.5% in dye-acclimated cultures and 32% in inoculum cultures), with key genera including Actinomarinicola (13.75%), Thermochromatium (4.82%), and Geobacter (4.52%). This study highlights the potential of the integrated DCMFC–aerobic system, utilizing mixed actinomycetes strains, for the effective treatment of industrial dye effluents, offering both environmental and bioenergy benefits.

Fabrication of nanocomposite membranes containing Ag/GO nanohybrid for phycocyanin concentration

In this research, silver/graphene oxide (Ag/GO) nanohybrid was first synthesized and used in production of polysulfone (PSF) ultrafiltration (UF) membranes via phase inversion method for concentrating phycocyanin (PC) and treating methylene blue (MB) dye effluent. Designing the experiment (DOE) using Box-Behnken method by Design Expert software helped to calculate the optimal values of the variables under study. The studied variables included PSF polymer concentration, polyvinyl pyrrolidone (PVP) pore-former concentration and Ag/GO nanohybrid content, which were investigated for their effects on pure water flux (PWF) and MB pigment rejection. According to the results of the DOE, the membrane containing 19.485 wt% PSF, 0.043 wt% PVP and 0.987 wt% Ag/GO was selected as the optimal membrane. Due to the high price of PC as drug, and the importance of removing MB pigment from the effluent of dyeing and textile industries, the membranes were first optimized with MB pigment and then the optimal membrane was used for concentrating PC. The results showed that PWF reaches from 40.05 L.m− 2.h− 1 (LMH) for the neat membrane to 156.73 LMH for the optimized membrane, which shows about 4 times improvement. Compared to the neat membrane, flux recovery ratio (FRR) of the optimized membrane increased by about 20% and its total fouling (Rt) decreased by about 10%. Also, the results showed that the optimized membrane can remove 81.6% of MB, as well as to reject 93.8% of PC.