Textile Wastewater Research Articles

High-quality mesoporous adsorbent derived from pomegranate pomace for efficient removal of azo dye from textile wastewater: Influencing factors, reusability, and mechanism studies

The solid waste from the processing of pomegranate (Punica granatum L.) juice, known as pomegranate pomace, was utilized as an economical and readily available precursor to produce high-quality activated carbon (AC). The AC was synthesized using a low-cost method at a carbonization temperature of 600 °C, employing a 1:1 impregnation ratio (precursor/H3PO4), and activating for 1 h. Various characterization techniques, including SEM imaging, XRD analysis, FT-IR analysis, BET surface area analysis with pore size determination, and other physicochemical assessments, were conducted on the produced AC. To assess its efficacy in treating textile wastewater, Basic Yellow 28 (BY 28) dye was selected as a representative pollutant. The results displayed a mesoporous structure in the produced AC with a mesopore content of 78.82 %. Notably, it exhibited a high BET surface area of 1089.08 m2/g and a total pore volume of 1 cm3/g. The Langmuir non-linear isotherm model emerged as the most fitting for explaining the adsorption equilibrium data, revealing a substantial monolayer adsorption capacity of 659.13 mg/g at 20 °C. The experimental data fit into a pseudo-second-order kinetic model, where the rate-determining step was found to be intra-particle diffusion. Thermodynamic analysis revealed that the adsorption of BY 28 dye onto the produced AC was an exothermic process. The produced AC exhibited high stability, as demonstrated in desorption studies, maintaining effectiveness through multiple uses. These results signify the potential of using pomegranate pomace, an environmentally problematic waste, as a novel precursor for producing sustainable and cost-effective AC.

Sustainable removal of pigment dye from traditional batik textile wastewater using ZnO photocatalysis

Wastewater management in the textile industry poses significant challenges, especially for small-scale facilities lacking proper treatment systems. As an alternative solution, in-situ wastewater treatment has gained prominence. Presently, solar-driven photocatalytic materials offer a promising avenue for effective wastewater remediation. This study employed a one-step probe ultrasonication method to synthesize ZnO nanoparticles with exceptional photocatalytic properties. Comprehensive optimization was undertaken to achieve ZnO particles with superior photocatalytic performance. The effects of various parameters, including wave amplitude (ranging from 0 to 80 %), ultrasonication time (from 0 to 45 min), and precursor zinc acetate concentration (between 0.1 to 0.3 M), were thoroughly investigated. By carefully controlling these conditions, non-agglomerated ZnO particles significantly improved photocatalytic activity, especially under visible-light conditions, when treating wastewater from the textile industry. The produce particle at 0.1 M in conjunction with maximum ultrasonication time and amplitude, provide more dispersed particle with smaller particle sizes. The photocatalytic process exhibited remarkable efficiency, with up to 98 % of the textile waste degraded within 60 min of reaction time using the ZnO particle produced under this condition. Moreover, this higher photocatalytic activity was supported by the rate of kinetic constant of 0.0365 min⁻¹, representing the pseudo-first-order kinetic. Furthermore, this research highlights the robust reusability of ZnO as a photocatalytic material, which remained stable even after three consecutive cycles. These findings affirm that ZnO particles synthesized through the probe ultrasonication method hold great potential for treating dye-containing textile effluents, providing a sustainable and effective solution for addressing this environmental concern.

Novel Bubble Column Design Constructed for Catalytic Ozonation – Effectiveness Assessment by Hydrodynamics and Kinetic Regime Determination

ABSTRACT This article introduces an innovative design for a bubble column tailored for catalytic ozonation. A semi-batch reactor was employed with strategically positioned baffles to accommodate catalysts throughout the column. These baffles, constructed with a specially designed mesh-type material, not only served as catalyst supports but also provided an additional active surface for efficient mass transfer on both macro and micro scales. This groundbreaking approach has advanced heterogeneous catalysis by utilizing a multi-structured scaffold enriched with chemically active species. The dual role of the baffles was envisioned to enhance the physical absorption of ozone gas into the liquid and catalytic action in the production of reactive oxygen species (ROS) through ozone decomposition. However, it is crucial to note that any alteration in the column’s geometry can influence the mass transfer resistance. The primary objective of this study was to assess the efficiency of the newly constructed bubble column by determining hydrodynamic parameters. For the column without mesh, the volumetric mass transfer coefficient (kLa) ranged between 0.007 and 0.009 1/s. Upon the incorporation of the mesh, kLa increased to values between 0.007 and 0.01 1/s. Simultaneously, the overall interphase surface rose from 42.16 ± 6.2 1/m to 53.29 ± 7.9 1/m, and the film mass transfer coefficient (kL) improved from (1.68 ± 0.1) × 10−4 to (2.13 ± 0.2) × 10−4 m/s after the mesh installation. This novel column design was specifically engineered for the treatment of textile wastewater. Dye degradation experiments demonstrated a higher rate of color removal when the mesh was inserted, surpassing traditional ozonation methods. Furthermore, the Hatta number increased from 3 to 5 with mesh usage, and the enhancement factor (E) shifted from 2.6 to 4. These enhanced Hatta values and improvement factors suggest that the new column construction successfully transitioned the operating regime from moderate to high speed.

Photocatalytic degradation of toxic basic blue 41 and reactive orange M2R dyes using green synthesized zinc oxide nanoparticles

Zinc oxide nanoparticles (Cm-ZnO NPs) were synthesized to eliminate organic dye pollutants from textile dye effluents. The present study reports Cucumis maderaspatanus L. leaves utilized as a green reducing/stabilizing agent for Cm-ZnO NPs synthesis. The nanoparticles underwent thorough analysis using techniques such as XRD, UV–vis, TEM, and FT-IR. Photocatalytic degradation of toxic basic blue 41 (BB41) and reactive orange M2R (ROM2R) dyes using Cm-ZnO NPs, showed a degradation rate of 97.69 % and 94.30 % respectively under optimized conditions. The kinetics of photocatalytic degradation of BB41 and ROM2R dyes followed first-order kinetics. The scavenger studies were conducted to identify the photogenerated reactive species involved in dye degradation. The singlet oxygen (1O2) and hydroxyl radicals (●OH) are mainly responsible for the degradation of BB41 and ROM2R dye respectively. LC-MS analysis was used to identify the photocatalytic degraded products, and ECOSAR software assessed their toxicity. The recyclability was performed up to four cycles and the stability of Cm-ZnO NPs was confirmed by XRD analysis. Thus, the as-synthesized Cm-ZnO NPs are suitable for industrial textile wastewater treatment.

Sequestration of Dyes from Water into Poly(α-Olefins) Using Polyisobutylene Sequestering Agents

Trace concentrations of dyes are often present in textile wastewater streams and present a serious environmental problem. Thus, these dyes must be removed from wastewater either by degradation or sequestration prior to discharge of the wastewater into the environment. Existing processes to remove these wastewater contaminants include the use of solid sorbents to sequester dyes or the use of biochemical or chemical methods of dye degradation. However, these processes typically generate their own waste products, are not necessarily rapid because of the low dye concentration, and often use expensive or non-recyclable sequestrants or reagents. This paper describes a simple, recyclable, liquid–liquid extraction scheme where ionic dyes can be sequestered into poly(α-olefin) (PAO) solvent systems. The partitioning of anionic and cationic dyes from water into PAOs is facilitated by ionic PAO-phase anchored sequestering agents that are readily prepared from commercially available vinyl-terminated polyisobutylene (PIB). This is accomplished by a sequence of reactions involving hydroboration/oxidation, conversion of an alcohol into an iodide, and conversion of the resulting primary alkyl iodide into a cationic nitrogen derivative. The products of this synthetic sequence are cationic nitrogen iodide salts which serve as anionic sequestrants that are soluble in PAO. These studies showed that the resulting series of cationic PIB-bound cationic sequestering agents facilitated efficient extraction of anionic, azo, phthalein, and sulfonephthalein dyes from water into a hydrocarbon PAO phase. Since the hydrocarbon PAO phase is completely immiscible with water and the PIB derivatives are also insoluble in water, neither the sequestration solvent nor the sequestrants contaminate wastewater. The effectiveness and efficiency of these sequestrations were assayed by UV–visible spectroscopy. These spectroscopic studies showed that extraction efficiencies were in most cases >99%. These studies also involved procedures that allowed for the regeneration and recycling of these PAO sequestration systems. This allowed us to recycle the PAO solvent system for at least 10 sequential batch extractions where we sequestered sodium salts of methyl red and 4′,5′-dichlorofluorescein dyes from water with extraction efficiencies of >99%. These studies also showed that a PIB-bound derivative of the sodium salt of 1,1,1-trifluoromethylpentane-2,4-dione could be prepared from a PIB-bound carboxylic acid ester by a Claisen-like reaction and that the sodium salt of this β-diketone could be used to sequester cationic dyes from water. This PIB-bound anion rapidly and efficiently extracted >99% of methylene blue, malachite green, and safranine O from water based on UV–visible and 1H NMR spectroscopic assays.

Photo Fenton-like oxidation of real textile wastewater: Operating conditions, kinetic modelling and cost analysis

The reusability of the pretreated textile wastewater was improved by using bismuth ferrite/activated carbon hybrid photocatalysts in photo-Fenton-like oxidation process. BiFeO3/WAC (WAC: walnut shell based activated carbon) and BiFeO3/CAC (CAC: Commercial activated carbon) catalysts were synthesized and used for the photocatalytic oxidation of in-situ pretreated textile wastewater. The influences of the mixing speed, oxidant dosage, light source, catalyst loading, and temperature were studied. The highest TOC removal efficiencies were evaluated as 56.3% and 76.2% in the presence of BiFeO3/WAC and BiFeO3/CAC, respectively. A kinetic study was performed to derive the kinetic models expressing the TOC removal as a basis for the semi-pilot and industrial scale studies. The kinetic data fit to a two-step second order reaction rate model in the presence of both of the catalysts. The activation energies of the first and the second steps were calculated as 36.0 and 16.0 kJ/mol, respectively, on BiFeO3/WAC catalyst while 43.4 and 13.3 kJ/mol of activation energies were calculated on BiFeO3/CAC.

Unleashing the potential of electrooxidation and PVDF/TiO2 photocatalysis for textile dye wastewater treatment

Unleashing the potential of electrooxidation and PVDF/TiO2 photocatalysis for textile dye wastewater treatment

Photocatalytic nanohybrid UV-light-driven PVDF/GO-NiFe@SiO2 membrane coupled with bentonite adsorption and ozonation process for a sustainable textile wastewater treatment

The textile industries face significant environmental challenges due to the presence of complex pollutant dyes in its wastewater, making it one of the world's major sources of industrial water pollution. Numerous studies have been employed to overcome this problem, including physical, chemical, and biological treatments. However, most of those methods still suffered to achieve higher dye removal performance. This study provides new insight regarding textile wastewater treatment containing indigo red as the main colorant by carrying out a hybrid process combining bentonite adsorption, ozonation, and photocatalytic membrane filtration. For the membrane, we propose a modified polyvinylidene fluoride (PVDF) membrane incorporated with graphene oxide (GO) and nickel-iron doped silica (NiFe@SiO2) photocatalyst, which is named PVDF/GO-NiFe@SiO2 membrane. The membrane was employed under different sets of filtrations (dark and under ultraviolet irradiation) to treat natural dye wastewater from textile industry effluent. Further improvement was achieved when UV light irradiation was subjected to the process. This sequential adsorption-ozonation-membrane process under UV exposure exhibited improved dye removal from 55.11 % to 97.22 %. The results show that the proposed hybrid process successfully improved the membranes' antifouling behavior, thus boosting the membranes' performance and durability. From a broader perspective, our work promotes new insights for the integration of other physical, chemical, and biological treatment methods to improve the performance and durability of membrane-based processes, particularly for dye wastewater treatment.

Role of fabrication parameters on microstructure and permeability of geopolymer microfilters

A new method for preparing geopolymer filtrations was suggested, using silica fume in an alkali activator as an environmentally and economically sustainable material. The geopolymer filtration was fabricated by activating metakaolin with a blend of sodium hydroxide and silica fume. Different phase structures and microstructures were fabricated with varying preparation parameters, such as silica fume content, Na2O/Al2O3 molar ratios, and curing temperatures. The filters were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersion spectroscopy, and mercury intrusion porosimetry. Filters were tested for pure water flux, compressive strength, and wastewater permeability using industrial textile wastewater. The geopolymer-zeolite composite filter, including 10 wt% silica fume, Na2O/Al2O3 molar ratio of 1, and curing temperature of 60 °C exhibited the highest pure water permeability of 144 L/m2.h.bar, wastewater permeability of 77 L/m2.h.bar, and achieved 95.5 % turbidity reduction for the textile wastewater.

The scope of alum coagulation-flocculation assisted by slaked lime for the treatment of industrial wastewater containing highly concentrated Acid Black 194 dye. Optimization, molecular weight distribution and toxicity analysis

This work evaluated the capacity of the alum coagulation-flocculation (C–F) process, assisted by slaked lime, for the treatment of industrial textile wastewater (ITWW) containing highly concentrated Acid Black 194 dye. By optimizing the operating conditions ([Alum] = 16.09 g/L, [Ca(OH)2] = 5.16 g/L) through experimental design, response surface methodology, and multi-objective optimization analysis, the C–F process removed 95 % of the dye, 63 % of the COD, 60 % of the TOC, and 94 % of the total Cr concentration, with a total operating cost of 5.99 USD/m3. This improved the biodegradability index (from 0.20 to 0.26), the COS parameter (from 0.14 to 2.46), and the toxicity of the effluent (LC50 for Artemia salina increased from 15.16 mg/L to 56.7 mg/L). The calcium hardness and total hardness were also reduced by 40 % and 44 %, respectively. The C–F supernatant was composed mainly of molecules with molecular weights less than and equal to 10 kDa. An LC-MS spectral analysis revealed the presence of four residual aromatic and recalcitrant compounds in the C–F supernatant, indicating that its further treatment is required before it can be safely discharged or recycled for industrial purposes. The alum C–F process, assisted by slaked lime, demonstrated greater performance, surpassing the individual processes in effectiveness and efficiency, and confirming their synergetic effect. The alum process alone (16.09 g/L) achieved a 37 % reduction COD and 91 % color removal, at a total cost of 4.49 USD/m3. The lime process alone (5.16 g/L) achieved a 37 % COD reduction and 64 % color removal, at a total cost of 1.36 USD/m3.

Strategic Design of Conductive Biopolymer Surface Coatings for Sensing and Remediation Applications

Advancement in the utility of conductive polysaccharide-based (i.e., agar, alginate, pectin, cellulose) composite materials for charge transfer applications requires effective surface functionalization and dopant matching to overcome limitations in electron transfer in these dielectric materials. A promising approach is the design of a biomimetic nanocomposite material, coupled with Fe-carboxyl coordination chemistry to photoinitiate the radical polymerization of polyaniline (PANI) in a uniform manner throughout a templated polymer matrix. Results have shown the feasibility of establishing a responsive carbon-based sensor, capable of modulating charge transfer performance in the presence of differing dopants (i.e., hydrochloric acid, sulfuric acid, polyelectrolyte). The aim of this work is to expand upon previous findings by unraveling the dopant-specific charge transport mechanisms as they relate to the polarizability and mobility of the dopant. Additionally, a network-level understanding of how changing the identity of the polymer backbone and the conductive polymer (i.e., aniline, pyrrole, thiophene) alters the charge transfer efficiency and overall stability of the conductive matrix. Current-voltage (I-V) sweeps reveal that these n-doped conductive polymer nanocomposites show enhanced current flow and reduced internal resistance compared to non-functionalized controls. Lastly, once the network reached an equilibrated state, the addition of a model contaminant (mucin) showed a decrease in the potential; however, upon an applied voltage, the contaminant was removed, and the system recovered to its original state. Alternatively, the network was also evaluated for the remediation of model pollutants. Results show that upon an applied voltage in simulated textile wastewater, there was a 10% degradation of methylene blue within 1 hour. Thus, the backbone/dopant/conducting polymer relationship is critical to achieving optimal performance with various applications.

Potential of halophiles and alkaliphiles in bioremediation of azo dyes-laden textile wastewater: a review.

Azo dye-laden textile wastewater must be treated before release due to various health and environmental concerns. Bioremediation of textile wastewater, however, is a challenge owing to its alkaline and saline nature as mesophilic microbes, in general, are either not able to thrive or show less efficiency under such hostile environment. Thus, pre-treatment for neutralization or salinity removal becomes a prerequisite before applying microbes for treatment, causing extra economical and technical burden. Extremophilic bacteria can be the promising bioremediating tool because of their inherent ability to survive and show toxicants removal capability under such extreme conditions without need of pre-treatment. Among extremophiles, halophilic and alkaliphilic bacteria which are naturally adapted to high salt and pH are of special interest for the decolorization of saline-alkaline-rich textile wastewater. The current review article is an attempt to provide an overview of the bioremediation of azo dyes and azo dye-laden textile wastewater using these two classes of extremophilic bacteria. The harmful effects of azo dyes on human health and environment have been discussed herein. Halo-alkaliphilic bacteria circumvent the extreme conditions by various adaptations, e.g., production of certain enzymes, adjustment at the protein level, pH homeostasis, and other structural adaptations that have been highlighted in this review. The unique properties of alkaliphiles and halophiles, to not only sustain but also harboring high dye removal competence at high pH and salt concentration, make them a good candidate for designing future bioremediation strategies for the management of alkaline, salt, and azo dye-laden industrial wastewaters.

Treatment of Textile Wastewater from Spinning Mill Using Electrocoagulation-Flocculation Process

Textile spinning mills generate wastewater containing high levels of pollutants such as suspended solids, dyes, oils, and organic compounds. This study investigates the electrocoagulation-flocculation (ECF) process as a sustainable treatment method. ECF combines electrocoagulation, where an electric current induces pollutant coagulation, and flocculation, which aggregates these pollutants for removal. Extensive lab experiments were conducted, analyzing setup, procedures, and results. The study found that ECF significantly reduced pollutants, achieving high removal efficiencies for suspended solids, COD, color, and oil/grease. Economic analysis confirmed ECF's cost- effectiveness over conventional methods. A case study demonstrated successful implementation, highlighting operational efficiency and environmental compliance. The paper concludes with recommendations for future research and industrial applications. Key Words: Electrocoagulation, Textile Wastewater, Sustainable Wastewater Treatment, Spinning Mill, Pollutant Removal

Study on the adsorption efficiency and mechanism of Sb(V) in aqueous solutions using enhanced surfactant-modified iron-calcium composite

The presence of Sb(V) in aqueous solutions poses a significant threat to the surrounding environment, and current treatment methods are inadequate. In this study, a magnetic surfactant (CTAB)-modified iron-calcium composite (CTAB-IC) was successfully synthesized using iron-calcium composite as the base material. This novel composite was used for the efficient removal of Sb(V) from textile wastewater solutions. Characterization analyses revealed that the CTAB-IC material exhibits a rich long-prismatic structure and superparamagnetic properties, classifying it as a soft magnetic material. Post-adsorption particle agglomerates were found to comprise Ca, S, and O. Sequential batch experiments demonstrated a maximum adsorption capacity of 54.05 mg/g, with adsorption kinetics data fitting the pseudo-second-order model. The intraparticle diffusion model indicated the presence of multiple diffusion steps during the adsorption process. Additionally, the adsorption of Sb(V) by CTAB-IC was identified as a heterogeneous surface adsorption process, best described by the Freundlich model. The primary adsorption mechanisms involved the formation of surface Ca-O-Sb complexes and inner-sphere Fe-O-Sb complexes, as well as amorphous surface precipitation and electrostatic adsorption. Notably, the treatment of textile wastewater often results in iron-calcium-rich sludge, which is challenging to manage and valorize. This study explored the potential for resource recycling by utilizing CTAB to harness the Fe elements in textile wastewater sludge, thereby promoting waste-to-resource conversion.

Capsaicin mimic-based antifouling and antibacterial polyester nanofiltration membranes with tunable crosslinked structures

Polyester thin-film composite (PE TFC) nanofiltration membranes based on the interfacial polymerization (IP) of polyols/polyphenols and acyl chloride continue to attract considerable attention for textile wastewater treatment due to their excellent antifouling properties. Herein, N-(5-methyl acrylamide-2,3,4 hydroxy benzyl) acrylamide (AMTHBA), a polyphenol-inspired capsaicin derivative, was first utilized as an aqueous monomer for the preparation of antifouling and antibacterial PE TFC membranes via the IP process. The moderate reactivity of AMTHBA and its unique solubility enabled a rational control of the crosslinking density of PE membranes, allowing the formation of structures from loose to dense through an adjustment of the AMTHBA concentration. The densely crosslinked AM-TMC PE membrane exhibited favorable desalination performance, with a water permeance of 21.8 L m−2 h−1 bar−1 and a Na2SO4 rejection of 83.8 %. The loosely crosslinked AM-TMC PE membrane exhibited excellent dye/salt separation performance, with high dye rejections (e.g., 98.5 % for MB) and low salt rejections (e.g., 4.0 % for NaCl), as well as high water permeance (30.4 L m−2 h−1 bar−1). In contrast, the capsaicin-containing PE TFC membranes also demonstrated markedly enhanced resistance to bacterial growth and organic fouling. These findings indicate that AM-TMC PE membranes present novel avenues for the advancement of task-specific separation membranes.

Revolutionizing textile wastewater treatment: Enhanced degradation of dyes using bimetallic Zinc Ferrite-GO nanocomposites

A novel bimetallic nickel-copper doped zinc ferrite based catalyst has been synthesized using the hydrothermal method. The nano-sized bimetallic (Ni-Cu) zinc ferrites were embedded with graphene oxide (GO). The characterization of nano-sized bimetallic (Ni-Cu) zinc ferrites with graphene oxide (GO) involves a comprehensive set of analytical techniques to determine their elemental composition, structural properties, and morphological features. The prepared materials were also subjected to structural and morphological evaluation through FTIR, Raman, XRD, TGA, UV–vis spectroscopy, and SEM with EDX. The experiment for the photodegradation of the selected model pollutant dye, methylene blue was conducted using the prepared materials. This means that the present photocatalyst has a high efficiency of degrading the pollutant to a tune of 99 % within 3 h. When the amount of GO in the prepared nanocomposite was 40 %, there was the perfect result in terms of no degradation of MB. It reduced and deteriorated the degree of band gap energy of the MB dye. The photocatalyst activity was proven to be repeatable; the sample's use was again possible. A decrease in the band gap energy implies that the improved photocatalyst material becomes more efficient at absorbing light energy. This enhanced light absorption promotes the generation of electron-hole pairs, which are essential for catalytic reactions. Therefore, the reduction in band gap energy likely contributes to the catalyst's heightened ability to initiate the degradation of the MB dye, ultimately leading to more effective pollutant removal. In the future, the synthesized sample can be reused without significant loss in its catalytic efficiency, underscoring the stability and durability of the material. The current study has paramount importance for real-world applications; reliable performance over multiple cycles ensures that the catalyst remains effective in addressing pollution challenges over prolonged periods.

Textile dyeing wastewater negatively influences the hematological profile and reproductive health of male Swiss albino mice

Objective: To determine the effects of textile dyeing industrial wastewater on the hematological parameters and reproductive health including histoarchitecture of male gonad (testes) of mice. Methods: Twenty-four Swiss albino mice at 4-weeks old were divided into four groups (n=6 per group). Mice of group 1 supplied with normal drinking water were served as the control group. Mice of group 2, 3 and 4 were supplied normal drinking water mixed with textile dyeing wastewater at 5%, 10% and 20% concentration, respectively. After completing 24 weeks of treatment, different hematological profile, weight of testes, gonadosomatic index (GSI), sperm concentration and morphology were measured. Moreover, histopathological changes in testes were examined. Results: Hematocrit value and hemoglobin concentrations were decreased in all groups of wastewater-treated mice compared to the control group. Likewise, weight of testes, GSI and sperm concentration were decreased significantly in wastewater-treated mice in comparison to the control group. The percentage of morphologically healthy epididymal sperm was significantly reduced in wastewater-treated mice. Histopathological examination revealed degenerative changes in seminiferous tubules, a smaller number of spermatogenic cells, elongation of seminiferous tubules and degenerative changes of seminiferous tubules in wastewater- treated mice. Conclusions: Textile dyeing wastewater has harmful effects on hematological profile and reproductive health of male mice.

Removal of acid red dye 1 from textile wastewater by heterogenous photocatalytic ozonation employing titanium dioxide and iron zeolite

Clean water is a necessity for all life to survive and flourish. However, natural waters are being continuously contaminated due to the release of waste streams in water. Hence, it is important to remove pollutants from wastewater to fulfill human needs. Conventional treatment methods are neither efficient nor economical for wastewaters that especially contain refractory toxic pollutants. This requires novel techniques like Advanced oxidation processes (AOPs), that may successfully degrade persistent micropollutants more efficiently. In this study, an azo dye Acid Red 1 was removed by three AOPs, namely Photocatalytic oxidation, Ozonation and Photocatalytic Ozonation, by employing heterogenous catalysts. TiO2 was used as photocatalyst, whereas Fe-Zeolite has been further added as Ozonation catalyst. The study revealed that photocatalysis degraded only 28% Acid red dye after 15 min, whereas for ozonation, the degradation percentage was 95% in same time. In combined photocatalytic ozonation process using TiO2, 95% degradation was achieved in just 9 min and treatment time further reduced to 5 min when Fe-zeolite was added. Optimization studies for initial concentration, UV intensity and catalyst loading were performed. Finally, rate constants and Electrical Energy per Order (EEO) values were determined for all AOPs, and mechanism was proposed.

ZnO/TiO2 photocatalytic nanocomposite for dye and bacteria removal in wastewater

This study investigates ZnO/TiO2 nanocomposites synthesized by the sol–gel method for their potential application in textile wastewater treatment. The physicochemical properties of these materials were comprehensively characterized using various analytical techniques, including transmission electron microscopy (TEM), x-ray diffraction (XRD) analysis, x-ray fluorescence (XRF) spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis, and UV–visible (UV-Vis) spectroscopy. XRD and XRF analyses confirmed the formation of a ZnO/TiO2 heterostructure. TEM images revealed a quasi-spherical morphology with slight agglomeration. The ZnO/TiO2 nanocomposite with a 1:5 molar ratio of Zn(II):Ti(IV) showed the highest BET surface area (91.345 m2 g−1) and the narrowest band gap (Eg = 3.06 eV). This composite demonstrated efficient degradation of methylene blue dye under sunlight irradiation and exhibited 100% antibacterial activity against S. typhi and S. aureus at concentrations ≥5 mg ml−1, indicating its potential for treating textile wastewater.

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.