Method For Removal Of Dyes Research Articles

ZnS Honey‐Hump Nanocrystals: Efficient Green Catalysis for Remazol Black Dye Removal in Wastewater Treatment

AbstractThe extensive use of synthetic dyes in a variety of sectors, including textiles, leather, food, and paints are resulted in substantial environmental issues due to their persistence and toxicity in water bodies. Moreover, about twenty to forty gallons of water is used for two pounds of fabric in conventional textile industries around the globe. Hence, it is vital to develop effective and fast catalytic dye removal methods or devices. Citrullus lanatus rind is primarily researched for its effective removal of dye from aqueous solution. The ZnS nanocrystals are well known for its photocatalytic property to remove dyes. In this research, ZnS extracted from the Citrullus lanatus rind was used for investigating the removal of Remazol Black dye. The dye is said to increase heart rate and cause eye problems in humans. The ZnS is extracted using green synthesis and the work focuses on the goal of contributing to long‐term and successful water treatment solutions. The generated ZnS nanocrystals were validated using UV–vis spectroscopy, indicating the successful formation of nanoparticles. The presence of polyphenolic groups responsible for reducing metal sulfide nanoparticles was verified using FTIR spectroscopy. Transmission electron microscopy (TEM) research indicated that the produced ZnS nanocrystals had a morphology with a mean size of roughly 6 nm. The impact of nanocrystals in removing Remazol Black dye was examined, with a phenomenal clearance efficiency of 99.8% achieved in 6 min. The rapid and successful dye decomposition was attributable to the chemisorption process, demonstrating ZnS honey‐hump‐like nanocrystal potential as useful catalysts in ecological cleanup purposes.

Kinetic and Isothermal Analysis of the Adsorptive Elimination of Direct Yellow 26 Dye Utilizing Activated Bioadsorbent From Textile Effluent.

Due to their widespread usage in recent years, synthetic dyes may be difficult to remove and pose a health concern. Bioadsorbents proved a low-cost and sustainable method for dye removal. In this study, straight yellow 26 is extracted from textile effluent using sugarcane bagasse. Sugarcane bagasse was treated with propionic acid to enhance the adsorption capability and 0.25 mm particle size was used for further studies which was confirmed by BET analysis. Standard solutions of direct yellow 26 dye were prepared from 10 to 100 ppm concentrations and absorbance was recorded with the help of a UV visible spectrophotometer. After optimizing different parameters (concentration of dye and bioadsorbent dose, pH, time, and particle size), the studies explored that the maximum dye removal percentage was 89% obtained at pH 3, contact time 120 min, particle size 0.25 mm, high adsorbent, and low concentration of dye solution. The kinetic studies were also employed to comprehend the adsorption isotherm and Freundlich isotherm that revealed the pseudo-first-order adsorption process.

Valorizing pig hooves for activated carbon production with efficient Methyl green adsorption, DFT insights and bacterial removal via bio-adsorbent column

ABSTRACT This study describes the use of a novel activated carbon (AC) adsorbent produced from pig hoove waste for the effective removal of Methyl Green (MG) from aqueous solutions. The AC, synthesized through KOH activation, boasts a substantial surface area of 334.031 m2/g and a total pore volume of 0.007 cm³/g. Comprehensive characterization was performed using proximate and ultimate (CHNS) analysis, BET, SEM, TEM, EDX, XRD, FT-IR, XPS, TGA, particle size analysis, zeta potential and zero-point charge (pHZPC). Adsorption data fit the Langmuir isotherm model exceptionally well (R 2 = 0.99) indicating monolayer adsorption and followed pseudo-second-order kinetics implying chemisorption. The thermodynamic studies revealed that the adsorption of the MG dye is a spontaneous and endothermic phenomenon. Density Functional Theory (DFT) computations elucidated the adsorption mechanism, highlighting the critical role of oxygen functional groups. The AC’s unique properties enabled the development of a bio-adsorbent carbon column capable of removing Escherichia coli and Staphylococcus aureus from raw water samples with a 99% removal efficiency. The study also explored the potential for AC regeneration, demonstrating its versatility and sustainability for various applications. This research not only presents an efficient method for dye removal but also underlines the significance of repurposing waste materials, thereby supporting waste reduction and promoting eco-friendly practices for long-term environmental solutions and pollutant mitigation.

La-supported SnO2–CaO composite catalysts for efficient malachite green degradation under UV–vis light

This study presents the development and optimization of La@SnO2–CaO composite catalysts for efficient photocatalytic degradation of malachite green dye in aqueous solutions under UV–vis light irradiation. The catalysts were prepared via conventional incipient-wetness impregnation and thoroughly characterized using advanced analytical techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 adsorption–desorption analysis, and scanning electron microscopy. To optimize photodegradation efficiency, the effects of three independent factors were systematically investigated using response surface methodology: Temperature, pH, and Sn/Ca molar ratio. Our results reveal optimal conditions for maximum dye degradation: pH 7, Sn/Ca molar ratio of 0.33, and a process time of 35 min, resulting in a maximum photodegradation efficiency of 98.80% for malachite green dye. Notably, visible light exhibited a more pronounced effect on dye degradation compared to UV light over time, with visible light achieving 25% greater dye removal after 60 min of illumination. Furthermore, the catalyst showed excellent recyclability, retaining 85% of its initial activity after five consecutive cycles. These findings contribute significantly to the development of sustainable methods for dye removal from wastewater and highlight the potential of La@SnO2–CaO composite catalysts in environmental remediation processes, particularly in treating textile industry effluents.

Composites based on cellulose and metal-organic frameworks for dye removal from wastewater

Industrial effluents from enterprises using dyes are among the main production wastes polluting the environment and surface waters. In order to solve this problem, much attention has recently been paid to innovative processes for their removal. The review considers research works over the past 10 years on various biological, chemical and physical methods for dye removal and assesses their effectiveness. The possibility of using cellulose and cellulose-based materials for dye removal from aqueous solutions is shown. The main attention is paid to composites based on cellulose and metal-organic frameworks (Cell-MOF). The main approaches to the creation of Cell-MOF materials and the possibility of regulating their properties are considered. Examples of using Cell-MOF materials for removing dyes from aqueous solutions by adsorption and catalytic methods are given. Prospects and problems of their practical use are discussed.

Simplex-lattice design and decision tree optimization of endophytic Trichoderma-multi-walled carbon nanotube composite for enhanced methylene blue removal

This study investigates a novel approach for enhancing methylene blue (MB) removal from water using a composite of endophytic Trichoderma mate and multi-walled carbon nanotubes (MWCNTs). For the first time, a unique combination of simplex-lattice design and decision tree learning algorithm was employed to optimize MB removal. This innovative approach effectively identified the optimal composite ratio of hyphal mate (0.5354 g/L) and MWCNTs (0.4646 g/L) for maximizing MB removal, which achieved remarkable removal efficiency ranging from 63.50 to 95.78 % depending on the combination used. The DT model further demonstrated promising potential for predicting MB removal efficiency. SEM revealed a unique hybrid material formed by the intertwining or entrapment of MWCNTs within the hyphal network of Trichoderma mate. FT-IR analysis confirmed the presence of novel functional groups on the MWCNTs' surface at 2438.79 and 528.25 cm−1, likely due to interactions with the endophytic fungi's biomolecules. These functional groups presumably act as reducing and stabilizing agents, promoting efficient MB adsorption. This research paves the way for utilizing the combined biological and chemical approach (fungal biomass and MWCNTs) in bioremediation applications. The findings suggest significant potential for practical applications in wastewater treatment, providing an eco-friendly and cost-effective method for dye removal. Furthermore, the proposed method shows promise for scaling up to industrial wastewater treatment and applicability in resource-limited settings, offering a sustainable solution for global water pollution challenges. Further investigations with larger datasets incorporating additional influencing factors are necessary to refine the predictive power of the DT model for practical applications.

Comparative study of anodized TNTs and S-TNTs on Ti plates for effective methylene blue degradation under UV LED and direct sunlight

The key findings of this research are focused on enhancing the degradation of methylene blue dye with titania nanotubes acting as catalysts under benign UV LED and sunlight. By comparing pristine and sulfur-doped titania, the study reveals that the doped-titania with anatase phase demonstrates a superior photocatalytic activity than pristine titania with mixed phases, achieving a remarkable 98 % degradation of dye within 120 min under direct sunlight with a small amount of hydrogen peroxide. This enhanced performance is attributed to the 10.7 μm longer and well-arranged nanotubes, effective surface area, better bandgap of 2.39 eV, effective anatase phases, and a lower 20 nm crystallite size. The study underscores the importance of anodization and sulfur doping using titanium plates to tailor the properties of the resultant nanotubes. Also, it indicates a cost-effective dye removal method without secondary pollution, offering a practical and optimistic solution to environmental challenges. The effective titania nanotubes for photocatalytic application in environmental remediation were identified through field emission scanning electron microscope, energy dispersive X-ray analysis, X-ray diffraction analysis, and diffuse reflectance analysis, providing valuable insights and inspiring future research and application in this field.

Scale-bridging and modelling study of graphene shell composite adsorption for dye removal in water treatment

Continuous fixed-bed adsorption is a cost-effective water-treatment method for dye removal. This research examined parameters such as bed heights (5, 7, and 9 cm), initial methylene blue (MB) concentrations (10, 15, and 20 mg/L), and feed flow rates (8, 10, 12 and mL/min) on fixed-bed adsorption performance. Our findings showed that the performance was improved under longer exhaustion times not only with increasing column bed heights, but also with decreasing initial MB concentrations and feed flow rates. Of note, the Thomas and Yoon-Nelson models accurately described MB adsorption in a fixed-bed column, with R2 values from 0.7525 to 0.9833. Response surface methodology via central composite design optimized column bed heights and feed flow rates on the duration required to achieve 50 % of column breakthrough. The coefficient of determination (R2) and analysis of variance demonstrated the significance of the Two Factor Interaction (2FI) model in fitting the actual values. The optimum conditions were determined to be as follows: a bed height of 5 cm; a feed flow rate of 8 mL/min; and a duration of 54.74 min to achieve 50 % of column breakthrough. Lastly, a confirmatory test further verified the precision of the proposed optimum conditions with an error of only 0.02 %.

Central composite experimental design for Indigo Carmine dye removal from solutions by applying electro-coagulation and electro-oxidation processes

Textile and food industries produce toxic or harmfull dye-containing wastewaters that should be treated for safely discharge. The electro-coagulation (EC) and the electro-oxidation (EO) methods for removal of dyes from wastewaters are being investigated nowadays by researchers. In this study, the Indigo Carmine, a textile and food coloring agent, removal was investigated by applying the electro-coagulation and the electro-oxidation methods. For this purpose, aluminum electrodes for EC and graphite plates for EO were used. The central composite experimental design was applied as the optimization method for the EC and the EO processes. The optimization parameters were selected as time (10-30 minutes), current density (0.4-2 Ampere/500 mL) and concentration (50-250 mg/L), natural pH (5.78-6.90) and room temperature (20-25 °C). The EO process was determined to be effective than the EC process. Statistically important parameters were concentration and time-current density interaction for the EC, but all the parameters were statistically unimportant for the EO. Dye removal percentages by the EC were calculated between 82.75% and 98.38%, and dye removal percentages by the EO were calculated between 46.88% and 100% for the determined experimental matrix. Electrical consumptions were almost equal for the EO and the EO prosesses. A column ion exchange process (Selion SBA 2000 resin) was applied to the dye residue after the EO treatment. From the oxidation reduction measurements, the treated solutions were determined as dischargeable.

Recent Advances in Utilizing Lignocellulosic Biomass Materials as Adsorbents for Textile Dye Removal: A Comprehensive Review.

This review embarks on a comprehensive journey, exploring the application of lignocellulosic biomass materials as highly effective adsorbents for the removal of textile dyes (cationic and anionic dyes) from wastewater. A literature review and analysis were conducted to identify existing gaps in previous research on the use of lignocellulosic biomass for dye removal. This study investigates the factors and challenges associated with dye removal methods and signifies their uses. The study delves into the pivotal role of several parameters influencing adsorption, such as contact time, pH, concentration, and temperature. It then critically examines the adsorption isotherms, unveiling the equilibrium relationship between adsorbent and dye and shedding light on the mechanisms of their interaction. The adsorption process kinetics are thoroughly investigated, and a detailed examination of the adsorbed rate of dye molecules onto lignocellulosic biomass materials is carried out. This includes a lively discussion of the pseudo-first, pseudo-second, and intra-particle diffusion models. The thermodynamic aspects of the adsorption process are also addressed, elucidating the feasibility and spontaneity of the removal process under various temperature conditions. The paper then dives into desorption studies, providing insights into the regeneration potential of lignocellulosic biomass materials for sustainable reusability. The environmental impact and cost-effectiveness of employing lignocellulosic biomass materials in textiles including Congo Red, Reactive Black 5, Direct Yellow 12, Crystal Violet, Malachite Green, Acid Yellow 99, and others dyes from wastewater treatment are discussed, emphasizing the significance of eco-friendly solutions. In summary, this review brings together a wealth of diverse studies and findings to present a comprehensive overview of lignocellulosic biomass materials as adsorbents for textile cationic and anionic dye removal, encompassing various aspects from influential parameters to kinetics, adsorption isotherms, desorption, and thermodynamics studies. Its scope and other considerations are also discussed along with its benefits. The collective knowledge synthesized in this paper is intended to contribute to the advancement of sustainable and efficient water treatment technologies in the textile industry.

Removal of Commercial Textile Dye DRMD from Wastewater Using Two-Dimensional Mesoporous Graphene Oxide Adsorbent

Environmental toxins from textile effluents, including organic contaminants, heavy metals, and dyes, pose significant health risks such as renal illness, allergies, dermatitis, and cancer when released into the aquatic environment. While various dye removal methods exist, adsorption is highlighted as a potentially effective solution due to its low cost, simplicity, and ease of use. An adsorbent of two-dimensional mesoporous Graphene Oxide (GO) was produced using Hummer’s method from cost-effective graphite powder. This was then utilized to eliminate the Doracryl Red MD (DRMD) textile dye from the aqueous system. To characterize the synthesized material, XRD, FTIR, and SEM analyses were performed. Zeta Potential and AFM analysis were used to determine surface charge and roughness, respectively. BET analysis was performed to obtain information regarding the surface area and porosity of the mesoporous GO. The highest adsorption capacity for the adsorption of the dye DRMD was found at 917.62 mg/gm. A variety of factors, including the influence of solution pH, adsorbent dosage, adsorption temperature, concentration of dye solution, and contact time, were thoroughly investigated. Adsorption data best fit the Langmuir model and demonstrated pseudo-second-order reaction kinetics. After repeatedly washing used adsorbents with 2% HCl solution, 88.62% of its initial adsorption capacity was retained after the 4th cycle. Hence, the enhanced adsorption capacity and recyclability of Graphene Oxide (GO) render it a promising candidate for the treatment of wastewater polluted with organic dyes.

A simple, efficient, and rapid method for dye removal from wastewater using an IDA-GO@Fe3O4 magnetic nanocomposite.

With the rapid advancement of the dye and textile industry, there has been increasing concern regarding the contamination of wastewater with dyes and its potential influence on human health. Therefore, the removal of dye pollutants from wastewater has become a matter of significant importance. In this study, a magnetically responsive iminodiacetic acid-functionalized graphene oxide (IDA-GO@Fe3O4) nanocomposite was utilized for the adsorption of both cationic and anionic dyes. The IDA-GO@Fe3O4 nanocomposite was synthesized and thoroughly characterized using several analytical techniques such as XRD, SEM, FT-IR, TGA and BET analysis. The prepared magnetic nanocomposite had a much higher thermal stability than pure graphene oxide. The negatively charged surface of the IDA-GO@Fe3O4 magnetic nanocomposite made it an excellent candidate for removing cationic dyes. The effects of various factors, including pH, initial concentration (isotherms), amount of adsorbent, and contact time (kinetics), on adsorption efficiency were investigated. The optimal conditions for the removal of methylene blue were determined to be 0.005 g of adsorbent, a pH of 10, and a contact time of 160 minutes. In contrast, the optimal conditions for the removal of methylene orange were found to be 0.005 g of adsorbent, a pH of 2, and a contact time of 120 minutes. Experimental data shows that the adsorption capacity for MB is reported as 437.10 mg g-1 at pH 10, while for MO it is 165.65 mg g-1 at pH 2. Furthermore, the adsorption process followed a pseudo-second-order kinetic model and Langmuir isotherm model. The proposed adsorption mechanism of MB and MO dyes onto the IDA-GO@Fe3O4 nanocomposite involve various interactions, such as electrostatic interactions, H-bonding, n-π, and π-π interactions. Importantly, the IDA-GO@Fe3O4 nanocomposite exhibited outstanding recyclability, retaining its effectiveness even after five successive cycles for MB. This suggests a straightforward method for developing high-performance IDA-GO@Fe3O4 magnetic nanocomposites for efficient wastewater purification and environmental remediation applications.

Aqueous Phase Textile Dye Degradation by Microbes and Nanoparticles: A Review

Textile industries utilize a variety of dyes and chemicals, resulting in wastewater that contains numerous hazardous components. The release of these dyes into aquatic systems poses a serious environmental and harms human health due to their persistence, recalcitrance, and nonbiodegradability. To address this, microbial bioremediation and nano‐photocatalysts are commonly employed for the effective removal of dyes and toxic compounds from textile effluents. This review explores the ecofriendly and efficient use of microbes, such as fungi, yeast, bacteria, and algae, in dye treatment, emphasizing their role in decolorization and degradation. Additionally, microbial remediation is highlighted as a clean, effective, and safe technology for detoxifying azo dyes in wastewater. The review also compares microbial and nanoparticle methods for dye removal from textile wastewater, examining the environmental impact of each approach. Furthermore, we have highlighted challenges and prospects for the development direction and future of this field.

Fabrication of high-crystallinity covalent organic framework and its nylon based membrane: Application in the enrichment and interception of dyes

Because of their high carcinogenicity and mutagenicity, dyes pose a great threat to the environment and humans, and the development of highly efficient dye removal methods is of great significance. Herein, a novel fluorine-rich COF (TPTF-COF) with high crystallinity was synthesized by connecting 1,3,5-tris(4-aminophenyl) benzene (TPB) and 1,3,5-tri(3-fluoro-4-formylphenyl) benzene (TF) at room temperature using acetonitrile as solvent. Owing to its large specific surface area (1084.61 m2·g−1), high crystallinity, high thermal stability, and rich functional group properties, TPTF-COF showed good adsorption capacities (20.63–386.30 mg·g−1) for six selected dyes. Based on TPTF-COF, a six-well plate assisted in-situ assembly method that can achieve the simultaneous synthesis of six sheets of TPTF-COF-based nylon membranes at a relatively low temperature (40 ℃) and within a short reaction time (48 h) was developed using aminodized nylon membrane as supports. The membrane with good uniformity showed high adsorption for the selected dyes, and thus showed good rejection, especially for Congo red (rejection >94%). Owing to the large gap between the aminodized nylon membranes, the TPTF-COF-based nylon membrane also exhibited superior water flux. The results of experimental and computational studies revealed that the pore size selectivity of TPTF-COF, π-π interaction, hydrogen bond and electrostatic interactions between TPTF-COF and dyes led to these selective adsorption effects. In this study, a new six-well plate assisted in-situ synthesis strategy for the preparation of imine-linked COF-based nylon membranes for dye removal, was developed. This approach may establish a viable route for the high-throughput and gentle fabrication of COF-based membranes for various applications.

Rice Husk-Cellulose-Based Agricultural Waste Enhances the Degradation of Synthetic Dyes Using Multiple Enzyme-Producing Extremophiles.

The brightly colored synthetic dyes used in the textile industry are discharged at high concentrations-for example, various azo dyes including Methylene Blue (MB) and Methyl Orange (MO)-which is a matter of global concern, as such dyes are harmful to humans and the environment. Microbial degradation is considered an efficient alternative for overcoming the disadvantages of conventional physical and chemical dye removal methods. In this study, we investigated the potential of multiple types of the enzyme-producing extremophilic bacteria Bacillus FW2, isolated from food waste leachate, for the decolorization and bioremediation of artificial synthetic dyes. The screening of enzyme production and assaying of bacterial strain enzymes are essential for enhancing the breakdown of azo bonds in textile azo dyes. The degradation efficiencies of the water-soluble dyes MB and MO were determined at different concentrations using rice husk, which is an efficient substrate. Using the rice husks, the MO was removed completely within 20 h, and an estimated 99.8% of MB was degraded after 24 h by employing shaking at 120 rpm at 40 °C-whereas a removal efficiency of 98.9% was achieved for the combination of MB + MO. These results indicate the possibility of applying an extremophilic bacterial strain, Bacillus sp., for large-scale dye degradation in the future.

Incorporation of graphene oxide/titanium dioxide with different polymer materials and its effects on methylene blue dye rejection and antifouling ability.

Exposure of synthetic dye, such as methylene blue (MB), in water bodies led to a serious threat to living things because they are toxic and non-degradable. Amongst the introduced dye removal methods, membrane separation process can be considered a powerful technique for treating dye contamination. However, this method commonly suffered from drawbacks, such as short membrane lifetime, low permeability and selectivity. To overcome these issues, graphene oxide (GO) and titanium dioxide (TiO2) were used as additives to fabricate polyethersulfone (PES)- and polyvinylidene fluoride (PVDF)-based hybrid membranes via non-solvent-induced phase separation method. Prior to membrane fabrication, GO was synthesised via electrochemical exfoliation method assisted by customised triple-tail surfactant. The potential of PES- and PVDF-based hybrid membranes for wastewater treatment has been discussed widely. However, direct comparison between these two polymeric membranes is not critically discussed for MB dye separation application yet. Therefore, this study is aimed at evaluating the performance of different types of polymers (e.g. PES and PVDF) in terms of membrane morphology, properties, dye rejection and antifouling ability. Results showed that the incorporation of GO and TiO2 alters the morphology of the fabricated membranes and affects dye rejection further, as well as their antifouling performance. In contrast with pristine membrane, PES-GO/TiO2 and PVDF-GO/TiO2 possessed high hydrophilicity, as indicated by their low contact angle (67.38° and 62.12°, respectively). Based on this study, PVDF-GO/TiO2 showed higher porosity value (94.88%), permeability (87.32 L/m2hMPa) and MB rejection rate (92.63%), as well as flux recovery ratio value of > 100% as compared with others. Overall, the incorporation of GO and TiO2 with PVDF polymer are proven to be effective hybrid materials of membrane fabrication for dye rejection application in the near future. The polymer material's intrinsic properties can affect the attributes of the fabricated membrane.

Activation of persulfate by TiO2 -Fe3 O4 nanocomposite for reactive red 198 degradation along with modeling and optimization approach

Background: Recently, sulfate radical-based photocatalytic processes have attracted significant interests because of unique advantages in pollutants purification. In this study, TiO2 -Fe3 O4 nanocomposites in the presence of persulfate and under ultraviolet light-emitting diode (UV-LED) irradiation were applied for reactive red 198 removal with a focus on the main operating parameters such as pH, persulfate molar concentration, irradiation time, and catalyst dosages in different initial concentrations. Methods: The nanoparticles were synthesized by co-precipitation technique. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR) analysis were used to evaluate TiO2 - Fe3 O4 nanocomposites. The response surface methodology (RSM) was employed for modeling and optimization. The kinetics and mechanisms of decolorization by sulfate and hydroxyl radicals were investigated. The mineralization of dye was evaluated using total organic carbon (TOC) analysis. Results: Modeling and optimization through RSM showed that the maximum decolorization of reactive red 198 is accursed an initial concentration of 10-50 mg/L was reached under UV-LED irradiation of 62- 85 min, persulfate concentration=0.8-1 mM, 0.19-0.3 g/L TiO2 -Fe3 O4 nanocomposites concentration, and pH=3. The kinetics of process was in agreement with pseudo-first order. The mineralization of reactive red 198 during the optimum conditions was determined at about 61.1% and 49.6%, meanwhile, the decolorization efficiency in the same conditions was approximately 98.1% and 87.6%, respectively. Conclusion: The use of TiO2 -Fe3 O4 nanocomposites under UV-LED irradiation in the presence of persulfate can be used as an efficient and promising method for dye removal from textile wastewater.

Hydrothermal-assisted synthesis of Co-doped ZnO nanoparticles catalyst for sodium borohydride dehydrogenation and photodegradation of organic pollutants in water

In recent years, studies on dye removal and hydrogen energy have gained momentum. However, these studies are still not in the desired position. Existing biological and physical methods for dye removal are quite inadequate. In hydrogen production, the efficiency is very low when a catalyst is not used. It is important to obtain inexpensive catalysts for both purposes. For this purpose, Cobalt doped Zinc oxide nanoparticles (Co-doped ZnO NPs) were synthesized using a one-pot flash combustion approach. The photocatalytic activity and hydrolysis process of the produced catalyst on NaBH4 were evaluated. The photocatalytic activity of Co-doped ZnO NPs was investigated for decolorization against certain dyes under sunlight irradiation. Co-doped ZnO NPs were analyzed for hydrogen production from NaBH4 hydrolysis. It has been determined that the nanomaterial has a superior catalytic activity with Turnover frequency (TOF) of 1682.3 min−1, 32.45 kJ/mol enthalpy (∆E),-158.4 J/mol.K entropy (∆S), and 34.94 kJ/mol activation energy (EA) obtained as a result of the hydrolysis reaction of Co-doped ZnO NPs. Their reusability was found to be 72.5% at the 4th cycle. The photocatalytic activity of the Co-doped ZnO NPs was found 81.22% (120 min) and 86.98% (90 min) against RhB and MB dyes, respectively. According to the results obtained, it has been seen that Co-doped ZnO NPs are reusable catalysts with high catalytic activity for hydrogen production as a clean energy source. At the same time, it was emphasized that a photocatalyst with high catalytic activity was obtained for wastewater treatment.

Effect of Activated Carbon Particle Size on Methylene Blue Adsorption Process in Textile Wastewater

Up to 60–70% of the total textile dyes produced are azo dyes. An example of azo dye is methylene blue, which is commonly used in dyeing wool, silk, and cotton. This substance possessed harmful effects on the environment. Therefore, the removal process is mandatory. The adsorption process is a common method for dye removal in wastewater. One innovation to increase adsorption efficiency even further is by reducing adsorbent particle size. To understand the effect of adsorbent particle size on the adsorption process, in this study, granular activated carbon (GAC) was pulverized into powder (PAC) and superfine powder (SPAC). Adsorbent characterizations, isotherm, kinetics, and thermodynamics tests were conducted. Based on this study, surface area, pore volume, and adsorption capacity were increased for smaller adsorbent particle sizes. Isotherm and kinetic analysis showed that there was no difference in the isotherm and kinetic models that applied to each activated carbon, but there was an increase in the isotherm and kinetic coefficient values at smaller particle sizes. Meanwhile, based on the thermodynamic test, there were differences in the dominant adsorption mechanism for each activated carbon. In GAC and SPAC, the dominant adsorption mechanism was electrostatic interactions, while in PAC was van der Waals forces.

Efficient removal of synthetic dye by employing H2O2/nZVI-rGO nanocomposite system

We reported a method for the removal of crystal violet (CV) dye from wastewater excreted by textile industries. Here, we employed the use of reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) nanocomposite along with H2O2 for CV removal. For this purpose, nZVI/rGO nanocomposite was prepared by reduction of ferrous sulfate heptahydrate (FeSO4·7H2O) and graphene oxide (GO) with sodium borohydride (NaBH4) and used as a potential sorbent for removal and/ or minimization of CV from aqueous solution. Zeta, transmission electron microscopy (TEM), UV–Visible spectroscopy, and Fourier-transform infrared spectroscopy (FTIR) were performed to characterize nZVI/rGO nanocomposite. Further, the chemical method for dye removal was also investigated using hydrogen peroxide (H2O2) as a chemical reductant. The effects of nanocomposite concentration, temperature, and time were examined to evaluate their role in dye elimination. The concentration of CV in the aqueous solution was calculated by studying absorbance using a UV–Visible spectrophotometer. The use of both H2O2/ nZVI-rGO provided a synergistic effect and resulted in efficient and fast removal of CV from an aqueous solution.