Reactive Green Research Articles

Enhanced photocatalytic degradation of Reactive Green 19 dye using earthworms like T-ZnO-CuO nano-composite material as a S-scheme heterojunction photocatalyst

Due to increasing organic dye pollution in the water environment, green and efficient photocatalyst are urgently needed to solve this problem. This study hypothesizes that green-synthesized nanocomposites, using plant leaf extracts, will significantly enhance the efficiency of organic dye degradation without the environmental drawbacks associated with traditional methods. Herein, enhanced degradation of Reactive Green 19 (RG 19) dye using earthworm like T-ZnO-CuO (TZC) nano-composite was reported. T-ZnO (TZ) and TZC nano-composite were synthesized using leaves extract of Thevetia peruviana plant. In the synthesis process, Thevetia peruviana leaves extract acts as a capping, stabilising and reducing agent, and additionally create a unique surface morphology of TZC nano-composite. The establishment of TZ and TZC nano-composite samples were investigated using FT-IR, XRD, FE-SEM with EDX, HR-TEM and UV–VIS DRS spectroscopy. Furthermore, band gap energy of TZ and TZC nano-composites were calculated using Tauc’s plot. The band gap energy of TZC2 nano-composite was determined to be 2.80 eV. The nano-composite photocatalyst (TZC) was utilised in the degradation of RG 19 dye with 96.89 % efficiency in 150 min at 20 mg/L dye concentration, pH=7.5, and 0.6 g/L catalyst dose. In order to investigate the tentative photocatalytic mechanism, scavenging study, recyclability experiment, and stability were also investigated. The findings show that O2− and OH radical species have higher degree of involvement in the degradation process. The kinetics of the degradation of RG 19 dye follows pseudo-first-order kinetics.

Long-term and high-efficiency capture of Escherichia coli using cellulose acetate nanofiber membrane functionalized with reactive 19 dye and polyhexamethylene biguanide

Cellulose acetate (CA) nanofibers have been popularly applied in various biomedical and textile products. In this work, a textile azo-dye Reactive Green 19 (RG19) was selected to be chemically coupled to the CA nanofiber membrane to form dyed CA nanofiber membrane (namely CA-RG19) and then poly(hexamethylene biguanide) (PHMB) as an antibacterial reagent was physically attached to the dyed CA nanofiber membrane, forming CA-RG19-PHMB nanofiber membrane. The nanofiber membranes were evaluated for their physical and mechanical properties, including functional group analysis, morphological characterization, and thermal stability assessment. To investigate the antibacterial properties of the nanofiber membrane, various concentrations of RG19 dye and PHMB were tested to evaluate the antibacterial efficiency (AE) against Escherichia coli of the membranes. It was found that the CA-RG19-PHMB nanofiber membrane exhibited an AE value of approximately 100 %, with the immobilization concentrations of RG19 dye and PHMB being 373.46 mg/g and 0.333 mg/g, respectively. The CA-RG19-PHMB nanofiber membrane showed 100 % antibacterial efficacy after 10 min against E. coli cells. Furthermore, the storage stability of the CA-RG19-PHMB nanofiber membrane remained at approximately 100 % of its initial antibacterial efficacy after 60 days, and it exhibited excellent antibacterial efficacy after five cycles.

Proactive vs. Reactive Green: How Political Connections Shape Corporate Environmental Practices

Proactive vs. Reactive Green: How Political Connections Shape Corporate Environmental Practices

Short Communication: Candida sp. isolated from mangrove soils for biological decolorization of textile reactive dyes

Abstract. Boontanom P, Chantarasiri A. 2024. Short communication: Candida sp. isolated from mangrove soils for biological decolorization of textile reactive dyes. Biodiversitas 25: 2595-2602. Effluent discharge from dye-related industries is a significant environmental pollution problem and a concern for human health. Dyes have harmful effects on aquatic organisms due to their toxic properties. One possible solution is using microorganisms for the biological decolorization of textile reactive dyes as an eco-friendly and potentially lucrative alternative to physicochemical processes. Therefore, this study isolated an effective dye-decolorizing yeast from mangrove soil samples in Thailand and investigated the decolorization efficiency of eight textile reactive dyes under experimental conditions. Yeasts have several advantages over other bacteria and fungi for the biological decolorization of textile reactive dyes, but the number of dye-decolorizing yeasts discovered in mangrove soils remains scarce. The most effective dye-decolorizing yeast, isolate RY21703, showed Remazol Brilliant Blue R (RBBR) decolorization of 37.50±0.07% within 72 h of incubation. This yeast isolate was genetically and phylogenetically identified as Candida sp. strain RY21703 and produced 0.97±0.08 U/mL of crude laccase activity, an essential enzyme in dye decolorization mechanisms. Candida sp. strain RY21703 showed strong decolorization efficiency after 72 h of incubation in all azo-reactive dyes, ranging from 27.32±3.34% (CI Reactive Orange 122) to 61.45±1.43% (CI Reactive Green 19). This strain also decolorized phthalocyanine reactive dye (CI Reactive Blue 21) by 60.71%. Findings suggested that this mangrove yeast can be used for the biological decolorization of dyeing wastewater.

Biodecolorization and biodegradation of Reactive Green 12 textile industry dye and their post-degradation phytotoxicity-genotoxicity assessments.

The employment of versatile bacterial strains for the efficient degradation of carcinogenic textile dyes is a sustainable technology of bioremediation for a neat, clean, and evergreen globe. The present study has explored the eco-friendly degradation of complex Reactive Green 12 azo dye to its non-toxic metabolites for safe disposal in an open environment. The bacterial degradation was performed with the variable concentrations (50, 100, 200, 400, and 500mg/L) of Reactive Green 12 dye. The degradation and toxicity of the dye were validated by high-performance liquid chromatography, Fourier infrared spectroscopy analysis, and phytotoxicity and genotoxicity assay, respectively. The highest 97.8% decolorization was achieved within 12h. Alternations in the peaks and retentions, thus, along with modifications in the functional groups and chemical bonds, confirmed the degradation of Reactive Green 12. The disappearance of a major peak at 1450cm-1 corresponding to the -N=N- azo link validated the breaking of azo bonds and degradation of the parent dye. The 100% germination of Triticum aestivum seed and healthy growth of plants verified the lost toxicity of degraded dye. Moreover, the chromosomal aberration of Allium cepa root cell treatment also validated the removal of toxicity through bacterial degradation. Thereafter, for efficient degradation of textile dye, the bacterium is recommended for adaptation to the sustainable degradation of dye and wastewater for further application of degraded metabolites in crop irrigation for sustainable agriculture.

Decolorization of reactive dyes by the white rot fungus Phanerochaete velutina in presence of Zn and ZnO nanoparticles

AbstractReactive organic dyes are hazardous pollutants that should be removed from wastewater from the textile industry. A remediation of dye polluted wastewater can be achieved by using the oxidative properties of nanomaterials, such as ZnO nanoparticles, or by microorganisms and their dye degrading enzymes. Promising approaches are expected from hybrid strategies, which use more than one approach. However, ZnO nanoparticles are also reported to be an antimicrobial and antifungal agent, which may undermine the decolorization ability of potent organisms, such as white rot fungi. Therefore, in this study we investigated the effects of soluble Zn and ZnO nanoparticles on the decolorization behaviour of the white rot fungus Phanerochaete velutina on commonly used reactive dyes, Reactive Orange 16 and Reactive Green 19. Zn ions led to a low decolorized rate of both dyes at low concentrations and restored the rate at higher Zn concentrations. However, ZnO nanoparticles showed highest decolorization rates, but only in a narrow concentration range. Overall, no toxic or inhibitory effects for decolorization of the dyes were found at the applied concentration of up to 20 mg Zn l−1 indicating that tolerant P. velutina will be suitable for remediation of dyes in multi polluted waste waters.

Highly efficient capture of E. coli using amidoximated polyacrylonitrile nanofiber membrane immobilized with reactive green 19 dye/polyhexamethylene biguanide: Antibacterial and cytotoxicity studies

In this study, we synthesized an amidoximated polyacrylonitrile nanofiber membrane (P-Oxime). Subsequently, we grafted reactive green 19 (RG19) dye onto its surface, resulting in the formation of the P-Oxime-RG19 membrane. Further enhancement was achieved by physically attaching poly(hexamethylene biguanide) hydrochloride (PHMB) to the P-Oxime-RG19 membrane, leading to the formation of the P-Oxime-RG19-PHMB membrane. Extensive characterization of the nanofiber membranes was conducted, focusing on crucial physical and mechanical properties such as functional group content, morphology, and thermostability. The optimization of various modification conditions, including initial dye and PHMB concentrations, duration, temperature, and nitrile group conversion to oxime concentrations, played a pivotal role in achieving superior antibacterial performance in P-Oxime-RG19-PHMB nanofiber membranes. In-depth analyses involved the application of kinetic and equilibrium thermodynamic models to unravel the modification processes of RG19 dye and PHMB in the nanofiber membranes. Under the carefully tuned optimal modification conditions, the P-Oxime-RG19-PHMB nanofiber membrane exhibited remarkable antibacterial efficacy, achieving nearly 100% disinfection of E. coli. In addition to exploring its antimicrobial capabilities, we thoroughly examined the repeatability and biocompatibility of the nanofiber membranes. The results indicated not only the P-Oxime-RG19-PHMB nanofiber membrane was a highly promising antibacterial material but also highlighted its potential for diverse applications, particularly in food and textile fabrication, owing to its exceptional performance and suitability.

Grafting 3-trimethoxysilylpropyl)diethylenetriamine on microcrystalline cellulose for the adsorption of dyes: Experimental and modeling studies

Textile dyes are one of the most commonly found pollutants in water, and it is necessary to remove them before textile industry effluents are released into the environment. In this study, cellulose-based adsorbents were prepared by grafting N1-(3-trimethoxysilylpropyl)-diethylenetriamine (TMSPDETA) on microcrystalline cellulose surface for the adsorption of reactive dyes from aqueous solution. Characterization of the produced adsorbents [Cel@TMSPDETA10; composite of cellulose + TMSPDETA (10% weight)] and the experimental and modeling studies were thoroughly investigated. Based on ΔBIC analysis (Bayesian Information Criterion), the fractal-like pseudo-first-order model (FPFO) was the model with the highest degree of adequacy to describe the kinetic behavior for RR-35 (Reactive Red 35) and RG-19 (Reactive Green 19) dye adsorption on Cel@TMSPDETA10. It was observed that the values of t0.95 (time necessary to attain 95% saturation) of RG-19 dye were 1.81 times slower than those of RR-35. This difference in times to attain 95% saturation of RG-19 with RR-35 could be assigned to the larger size of the RG-19 molecule. Based on the ΔBIC values, the Liu isotherm was better fitted to the experimental data. At 30 °C, the highest Qmax (Liu model) value was 197.0 mg g−1 for RR-35 dye. For RG-19, the highest value of Qmax (Liu model) was 210.5 mg g−1 at 45 °C. Alternatively, a statistical physics model that represents the general case of the Langmuir model was adopted to provide new insights into the adsorption mechanisms of RR-35 and RG-19 dyes on the adsorbents. Interestingly, this new approach showed that RR- 35 was adsorbed via a partial aggregation process, contrary to the RG-19 dyes.

GQD@NiFe-LDH Nanosheets for Photocatalytic Activity towards Textile Dye Degradation via Lattice Contraction.

The functionalized NiFe-LDH with photosensitized GQDs were synthesized through the hydrothermal route by differing the amount of GQDs solution and studied its efficacy towards the mineralization of textile dyes under visible light. The synthesized samples were characterized by XRD, FESEM, HRTEM, DRUV-Vis, RAMAN, XPS, and BET. The combined effect of the hexagonal carbon lattice in GQD and open layered porous structure of NiFe-LDH nanosheets results in the contraction of the lattice. Different reactive and conventional dyes were taken as representative dyes to evaluate the activity of the as-synthesized photocatalysts. The enhanced electron absorption/donor effect between GQDs and NiFe-LDH, and the growth of oxygen-bridged Ni/Fe-C moieties enable the composite to exhibit better photocatalytic activity. Both photocatalytic activity and characterization results confirmed that the GQD@NiFe-LDH nanocomposite heterostructure synthesized at 160 °C by taking 10 mL of GQDs aqueous solution named GNFLDH10 has a higher degree of crystallinity and has the best photocatalytic efficiency compared to other reported visible light catalysts. Specifically, the above optimized GQD@NiFe-LDH photocatalyst is capable of photo-mineralizing 50 ppm of Reactive Green in 20 min, Reactive Red in 20 min, and Congo Red in 25 min respectively following a direct Z-scheme mechanism with substantial reusability.

Modified emulsion polyvinyl chloride membranes for enhanced antifouling and dye separation properties by introducing tungsten disulfide (WS2) nanosheets

In this study, the fabrication and modification of emulsion polyvinyl chloride (EPVC) membranes were studied using tungsten disulfide (WS2) nanosheets. The layered WS2 nanosheets were synthesized, characterized, and applied in the modification of EPVC membranes. The nonsolvent induced phase inversion method was utilized to fabricate new membranes by introducing the WS2 nanosheets into the polymeric solutions with different percentages. The performance of the fabricated membranes was characterized and evaluated using scanning electron microscopy, atomic force microscopy, attenuated total reflection-Fourier transform infrared, mean pore radius, porosity, contact angle analyses, pure water flux, fouling parameters, rejection tests for bovine serum albumin (BSA) and two dyes, and long-term and reusability tests. The results indicated that the use of WS2 nanosheets in the membrane structure up to the optimum value (1 wt%) increased the water flux and improved the antifouling properties. The pure water flux enhanced from 56.4 L/m2.h in the bare membrane to 191.2 L/m2.h in the 1 wt% WS2/EPVC membrane. In addition, the flux recovery ratio parameter increased from 64.7% to 83.5%. dye rejection rates of 94.7% and 97.8% were obtained for Reactive Red 195 and Reactive Green 19, respectively. Reusability tests for the 1 wt% WS2/EPVC membrane indicated a slight flux drop and negligible BSA rejection changes. Long-term tests showed very high stability in dye rejection and a negligible flux drop.

Sustainable synthesis of biogenic ZnO NPs for mitigation of emerging pollutants and pathogens

Groundwater pollution is mostly caused by overuse of fertilizers, pesticides, contemporary agricultural practices, anthropogenic activities, home waste disposal, and the rapid expansion of the chemical industry. Drinking tainted water on a regular basis can have detrimental consequences on human health as well on environment. Nanoparticles (NPs) based contaminants alleviation strategy found to be most efficient, cost-effective and reliable. In this study, ZnO NPs were synthesized via citrus limon leaves extract as a sustainable/cost-effective method. Diverse microscopic and spectroscopic studies confirmed the formation of spherical ZnO NPs with size range 15–25 nm. Reactive green-19 (RG-19) was degraded photocatalytically under direct solar irradiation (degradation efficiency ∼ 92%, rate constant 0.03 min −1, 80 min) in the presence of ZnO NPs. These ZnO NPs also demonstrated highly substantial antibacterial action against two pathogenic Gram-positive (Bacillus subtilis, zone of clearance: 8.6 mm) and Gram-negative (Escherichia coli, zone of clearance: 9.8 mm) bacteria. Thus, the present study demonstrates the effective/sustainable NPs based platform for water remediation.

Reactive Green 19 dye-ligand immobilized on the aminated nanofiber membranes for efficient adsorption of lysozyme: Process development and optimization in batch and flow systems

The performance of lysozyme adsorption by the aminated nanofiber membrane immobilized with Reactive Green 19 (RG19) dyes was evaluated in batch and flow systems. The physicochemical properties of the dye-immobilized nanofiber membrane were characterized. The parameters of batch-mode adsorption of lysozyme (e.g., pH, initial dye concentration, and lysozyme concentration) were optimized using the Taguchi method. In a flow process, the factors influencing the dynamic binding performance for lysozyme adsorption in the chicken egg white (CEW) solution include immobilized dye concentration, adsorption pH value, feed flow rate, and feed CEW concentration. The impact of these operating conditions on the lysozyme purification process was investigated. Under optimal conditions, the recovery yield and purification factor of lysozyme achieved from the one-step adsorption process were 98.52% and 143 folds, respectively. The dye-affinity nanofiber membrane also did not exhibit any significant loss in its binding capacity and purification performance after five consecutive uses.

The evaluation of reactive textile dyes regarding their potential to cause organ-specific cyto- and geno-toxicity

The textile industry extensively uses synthetic chemicals such as dyes. Several studies report the deleterious effects (e.g., cell death and DNA damage) of dispersive dyes on humans. Humans can be exposed to toxic dyes by ingesting contaminated waters or dermal contact with colored garments. Thus, toxicity evaluations of textile dyes using organ-specific cell lines are relevant to estimating their hazard. Cyto- and geno-toxicity of the dyes Reactive Green 19 (RG19), Reactive Blue 2 (RB2), Reactive Blue 19 (RB19), Reactive Red 120 (RR120) and Reactive Orange 16 (RO16) were evaluated by the In Vitro MicroFlow® kit with immortalized human keratinocyte cell line (HaCaT) and immortalized human hepatic cell line (HepaRG). Concentrationdependent cytotoxicity was observed for HaCaT cells exposed to three of the five tested dyes (RB2, RB19, RO16), while in HepaRG cells, cytotoxic effects were only verified after exposure to RB19 and RO16 at the highest tested concentration (1000 µg/mL). Genotoxicity was not detected in any tested textile dyes under both test conditions (HaCaT and HepaRG). In conclusion, our data provide evidence that, although the tested reactive dyes are not genotoxic, which is in agreement with published literature, they can cause cytotoxicity in both target tissue, and the effect can be more severe in epidermal cells (HaCaT) than in liver cells (HepaRG). This differential cytotoxicity data emphasizes the need to assess the toxicity of textile dyes to the target organ specificity.

Adsorption, Modeling, Thermodynamic, and Kinetic Studies of Removal of Textile-dye using Low-Cost Adsorbents

Adsorption of reactive green (RG) dye using Syzgium aromaticum flower bud (SAFB) and ACTIVE -SAFB was studied in detail via conducting batch model kinetic, thermodynamic and desorption investigations. The experimental kinetic data at several primary reactive green dye concentrations were also analyzed through model first-order, model second-order. The obtained result appears that the model pseudo-first-order fits the adsorption kinetic result through (R2 0.9797) and (R2 0.9016) of SAFB and ACTIVE-SAFB in the same order. Finally, the thermodynamic factors appear that dye’s adsorption onto SAFB and ACTIVE-SAFB was endothermic and spontaneous. This suggests that SAFB and ACTIVE-SAFB is a viable adsorbents for effective dye removal from wastewater effluent.

Discerning the biodegradation of binary dyes in microbial fuel cell: Interactive effects of dyes, electron transport behaviour, autocatalytic mechanism, and degradation pathways

This research presented the first attempt to investigate the effect of biodegradation of binary Acid Orange 7 (AO7) and Reactive Green 19 (RG19) on the performances of wastewater treatment and bioelectricity generation, using anti-gravity flow microbial fuel cell (AGF-MFC) system. The influences of initial dye concentration, substrate loading, sulphate concentration and application of quinones on system performances were comprehensively evaluated. The decolourization efficiencies of AO7 were higher than RG19 in binary solutions, at every tested concentrations. The addition of higher concentration of RG19 in binary solution was also found to have increased the overall performances of MFC, owing to electron mediating characteristics of its decolourized intermediates. However, the power density declined with the addition in dye concentration. Further increase of substrate loading by 3-folds (2.43 g/L) improved the decolourization efficiency approximately by 7%, but deteriorated power performance by 42%, to 63.40 ± 0.07 mW/m2. Increasing sulphate concentration from 20 to 400 mg/L had resulted in a high decolourization extent of binary dyes ascribed to sulphide-mediated dye degradation, whereas the power generation was reduced. The increase of sulphate to 800 mg/L led to decrease in decolourization and power density of the system. These outcomes deciphered the competitions of electrons between different electron acceptors in the anodic compartment. Moreover, the autocatalytic mechanism of RG19 decolourized intermediates, 1-amino-2-naphthol-3,6-disulphonate (1A2N36S) as electronophore was thoroughly unearthed. Detailed degradation pathways of dyes were proposed based on UV-Visible spectra and gas chromatograph-mass spectrometer (GC-MS) analyses.

Adsorption Studies of Reactive Green 19 from Aqueous Solutions by Polyaniline/Montmorillonite Nanocomposite

Polyaniline-based composites are potential candidates for the treatment of anionic azo dyes from an aqueous solution. However, the related adsorption mechanisms are not clearly delineated. Here, polyaniline/ montmorillonite (PANI/MMT) nanocomposite was synthesized by incorporating polyaniline (PANI) into the interlayers of montmorillonite (MMT). The nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results indicated that polymerization of the aniline monomer within the MMT gallery led to an expansion of basal spacing of the silicate layers. The prepared PANI/MMT nanocomposite was subsequently used for the removal of anionic azo dye Reactive Green 19 (RG19) from aqueous solutions. The adsorption of RG19 onto the PANI/MMT nanocomposite was consistent with the pseudo-second order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity was found to be 46.88 mg/g at 25 °C, according to the linear regression analysis of the Langmuir isotherm. Thermodynamic parameters (ΔH° = −12.35 kJ/mol, ΔS° = −28.40 J/mol/K) revealed the spontaneous, exothermic, and enthalpy-driven nature of adsorption. Additionally, FTIR and X-ray photoelectron spectroscopy (XPS) analyses confirmed that the mechanism for adsorption of RG19 onto PANI/MMT nanocomposite involved hydrogen bonding and π-π interactions between the RG19 dye and adsorbent.

Stabilize thin nanoparticle layer of zeolitic imidazole framework-8 (ZIF-8) on different PVDF substrates by contra-diffusion method for high-efficiency ultrafiltration application

In this research, a contra-diffusion cell, which is an effective instrument for growing inorganic layers on porous substrates, was applied to prepare a thin layer of zeolitic imidazole framework-8 (ZIF-8) on polyvinylidene fluoride (PVDF) ultrafiltration membranes. With using of methanol as a solvent, a thin layer of ZIF-8 was fabricated resulted in a flexible inorganic coated organic membrane. The ZIF-8 nanoparticles were formed as a resistant layer on the outer surface and inner pores of PVDF support and its effect on permeability, flux recovery ratio (FRR) and treatment of colored wastewater was investigated. Manufacturing parameters such as the reaction time between Zn2+ ions and imidazole ligands (16, 24 and 36 h) and concentration of PVDF in the casting solution of the support membranes (18, 20 and 22 wt%) were considered. The SEM images showed the well-growing of uniform and a thin layer of ZIF-8. The membrane performance tests revealed that ZIF-8 decorated membranes have higher pure water flux, BSA protein rejection and FRR related to the uncoated PVDF membrane. The fabricated membranes indicated high removal efficiency in three different MW dyes (Rhodamine B, Reactive Green 19 and Direct Black 38), with 75, 85 and 98% rejection, respectively.

Method to determine the decolorization potential of persistent dyes by white rot fungi by colorimetric assays

Decolorization assays allow to assess the ability of white rot fungi to degrade persistent organic molecules such as textile dyes and can contribute to discover microorganisms that can be used for bioremediation. The decolorization can be overlayed by the absorption from metabolites that are produced by fungi during screening, which interfere with the results. To compensate for this interference a method was developed by using different controls to subtract interfering signals.The method was designed for simple screening in multiwell plates that can be operated with a plate reader. It was applied to four different textile dyes (Reactive Black 5, Reactive Blue 4, Reactive Green 19, and Reactive Orange 16) that were degraded by the white rot fungus Phanerochaete velutina. The four textile dyes showed different results with a different degree of interference. The controls allow to compensate for interfering signals and to calculate kinetic parameters for the decolorization reaction and the enzymatic degradation.•Determine the non-enzymatic degradation of the dyes in experiments without fungi.•Determine the absorbance of metabolites and subtract it from the decolorization data to obtain the degradation of the dye.•Determine kinetic parameters of the degradation to compare the efficiency of the enzymes towards dyes.

Removal of Reactive Green Dye from Textile Waste Water by Photo Fenton Process: Modeling, Kinetic, and Thermodynamic.

This work investigated the removal of the reactive green (R.G) dye from wastewater using the photo-Fenton process. Batch experiments were carried out to research the role of the Impacts of operating parameters. The dosage of H2O2; dosage Fe+2; pH; temperature, and irradiation time were examined. Maximum decolorization efficiencies green dye were achieved at the [H2O2]=100 ppm; [Fe2+]=20 ppm; pH 3; temperature=56 °C and irradiation time=90 min. This research focuses on modeling, kinetics and thermodynamics of the removal of pollutant (reactive green dye) of water. The results showed that the decolorization kinetic of R.G followed pseudo-first-order reaction kinetic. Also the thermodynamic parameters ∆G˚, ∆H˚ and ∆S˚ were determined using the Van't Hoff equation for the oxidation processes. The changes in Gibbs free energy showed the oxidation process under normal conditions is non-spontaneous.

Hyperbranched polyethylenimine functionalized silica/polysulfone nanocomposite membranes for water purification

Hyperbranched polyethyleneimine functionalized silica (PEI-SiO2) nanoparticles with considerable hydrophilicity were synthesized and incorporated into a polysulfone (PSF)/dimethylacetamide (DMA)/polyvinylpyrrolidone (PVP) membrane casting solution in five different ratios to fabricate PEI-SiO2/PSF nanocomposite membranes using nonsolvent-induced phase separation. The hydrophilic PEI-SiO2 nanoparticles were characterized by TEM, FTIR, TGA, and XPS analyses. Morphology, water contact angles, mean pore sizes, overall porosity, tensile strengths, water flux, antifouling and the dye separation performances of the PEI-SiO2/PSF membranes were also studied. The PEI-SiO2 nanoparticles were uniformly dispersed in the PSF-based membranes, where a fall in the water contact angle was observed from 65.4° to 49.7° by addition of 2 wt% nanoparticles. The fouling resistance parameters of the PEI-SiO2/PSF membranes were declined with an increase in the nanoparticle concentration, suggesting the superior hydrophilic nature of the PEI-SiO2 nanoparticles. The permeability of the nanocomposite membranes was increased from 38.5 to 70 L m−2 h−1 bar−1 by incorporation of 2 wt% PEI-SiO2. Finally, improvements were observed in the flux recovery ratio (95.8%), Reactive Green 19 dye rejection (99.6%) and tensile strengths of the PEI-SiO2/PSF membranes over the neat PSF and SiO2/PSF membranes, which were used as controls. The results of this study demonstrate the promising application of PEI-SiO2 nanoparticles in improving the separation and antifouling performances of the PSF membranes for water purification.