Adsorption of Methylene Blue Dye from Aqueous Solutions by Modified Pumice Stone: Kinetics and Equilibrium Studies

Biogenic Synthesis of Copper Oxide Nanoparticles from Aloe vera: Antibacterial Activity, Molecular Docking, and Photocatalytic Dye Degradation

Green synthesis methods offer a cost-effective and environmentally friendly approach to producing nanoparticles (NPs), particularly metal-based oxides. This study explores the green synthesis of copper oxide nanoparticles using Aloe vera (Aloe barbadensis Miller) leaf extract. The characterization revealed a unique sago-shaped morphology revealed by field-emission scanning electron microscopy and X-ray diffraction analysis. Distinctive metal-oxygen bonds at 521 and 601 cm-1 were confirmed by Fourier-transform infrared (FT-IR) spectroscopy. Furthermore, UV-visible spectroscopy revealed absorbance at 248 nm, suggesting electron transitions across energy bands and varying surface conduction electrons. The band gap value indicated the presence of quantum confinement effects, which were probably caused by the distinctive morphology and surface structure of the biogenic NPs. Additionally, molecular docking studies were carried out against key proteins of Salmonella typhi and Listeria monocytogenes, namely, listeriolysin O (PDB ID: 4CDB), internalin (InlA) (PDB ID: 1O6T), Salmonella effector protein (SopB) (PDB ID: 4DID), and YfdX (PDB ID: 6A07) using AutoDock 4.2. The results revealed binding energies against S. typhi and L. monocytogenes proteins, indicating potential interactions establishing the foundation for further in-depth understanding of the molecular basis underlying the observed antibacterial effects in vitro against S. typhi, Klebsiella pneumoniae, Pseudomonas aeruginosa, and L. monocytogenes. Antibacterial activity evaluation yielded impressive results, with CuO NPs displaying significant activity against S. typhi and L. monocytogenes, exhibiting zones of inhibition values of 13 ± 0.02 and 15 ± 0.04 mm, respectively. Moreover, the CuO NPs demonstrated remarkable photocatalytic efficacy, resulting in the degradation of 77% of the methylene blue dye when exposed to UV irradiation. This study highlighted the potential of green-synthesized CuO NPs derived from A. vera with their unique morphology, interesting spectroscopic properties, and promising antibacterial and photocatalytic activities.

A review on sustainable management of biomass: physicochemical modification and its application for the removal of recalcitrant pollutants-challenges, opportunities, and future directions

Adsorption is one of the most efficient methods for remediating industrial recalcitrant wastewater due to its simple design and low investment cost. However, the conventional adsorbents used in adsorption have several limitations, including high cost, low removal rates, secondary waste generation, and low regeneration ability. Hence, the focus of the research has shifted to developing alternative low-cost green adsorbents from renewable resources such as biomass. In this regard, the recent progress in the modification of biomass-derived adsorbents, which are rich in cellulosic content, through a variety of techniques, including chemical, physical, and thermal processes, has been critically reviewed in this paper. In addition, the practical applications of raw and modified biomass-based adsorbents for the treatment of industrial wastewater are discussed extensively. In a nutshell, the adsorption mechanism, particularly for real wastewater, and the effects of various modifications on biomass-based adsorbents have yet to be thoroughly studied, despite the extensive research efforts devoted to their innovation. Therefore, this review provides insight into future research needed in wastewater treatment utilizing biomass-based adsorbents, as well as the possibility of commercializing biomass-based adsorbents into viable products.

Removal of Methylene Blue Dye from Aqueous Solutions Using Polymer Inclusion Membrane Containing Calix[4]pyrrole

The effective purification of aqueous solutions of methylene blue dye was tested using polymer inclusion membranes (PIMs) that contained cellulose triacetate (CTA) as a polymer base, o-nitrophenyl octyl ether (o-NPOE) as a plasticizer, and meso-tetra methyl tetrakis-[methyl-2-(4-acetlphenoxy)] calix[4]pyrrole (KP) as a carrier. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were used to define the microstructure and surface of PIMs. Experimental results showed that, with an increased concentration of methylene blue in an aqueous solution, the removal percentage also increased. Further observation showed that the flux increased with the rise in the source phase pH values from 3 to 10. The carrier and plasticizer content in the membrane significantly influenced the membrane's transport properties. The optimal composition of the membrane in percent by weight for KP was 74% plasticizer; 18% support, and 8% carrier. The maximum MB removal (93.10%) was achieved at 0.10 M HCl solution as the receiving phase. It was shown that the membrane with optimal composition showed good reusability and enabled the easy and spontaneous separation of methylene blue from aqueous solutions.

Novel ultrasonic technology for advanced oxidation processes of water treatment

Textile wastewater accounts for a significant proportion of industrial wastewater worldwide. In particular, dye wastewater accounts for a large proportion and consists of non-degradable dyes, which are substances resistant to biodegradation. Methylene blue is a representative example of such non-degradable dyes. It is not biologically degraded and exhibits toxicity. Various methods for their decomposition are currently being studied. Advanced oxidation processes (AOPs), which generate highly reactive hydroxyl radicals that oxidize and degrade pollutants, have been actively studied. Particularly, the photocatalytic degradation method using TiO2 nanoparticles is one of the most actively studied fields; however, there are still concerns regarding the toxicity of nanoparticles. Research is currently being conducted on AOPs using the cavitation phenomenon of ultrasonic waves. However, achieving high efficiency using existing ultrasonic equipment is difficult. Therefore, in this study, we evaluated a new water treatment technology through AOPs using a focused ultrasonic system with a cylindrical piezoelectric ceramic structure. After determining the optimal conditions for degradation, the degradation process was evaluated as a useful tool for mitigating the toxicity of methylene blue. We found that, under the optimal conditions of 100 W intensity at a frequency of 400 kHz, this system is a helpful instrument for degradation and a new water treatment technology suitable for removing ecotoxicity and genotoxicity.

Biodecolorization and biotransformation of methylene blue using mixed cultures of brown-rot fungus Daedalea dickinsii and filamentous fungus Aspergillus oryzae: identification of metabolites and degradation pathway

This study aimed to examine biodecolorization and biotransformation of methylene blue (MB) using mixed cultures of brown-rot fungus Daedalea dickinsii and filamentous fungus Aspergillus oryzae. In addition, the ratio of D. dickinsii and A. oryzae in mixed cultures was 1 : 1, and the sample was incubated at 30 °C for 7 days in liquid medium potato dextrose broth (PDB). The results showed that the sample had the ability to remove and transform 95.24 mg L-1 MB. In this study, mixed cultures had the highest removal percentage of 64.77%, while values of 5.94% and 36.82% were obtained for single cultures of D. dickinsii and A. oryzae, respectively. LC-TOF/MS analysis results showed that peak intensity of MB compound (m/z 284) in each treatment chromatogram decreased compared to the control. The metabolites of decolorization by D. dickinsii were C15H16N3S, C16H19N3SO, and C16H21N3SO, while C31H48N3S+ was obtained using A. oryzae. For mixed cultures, the metabolites obtained included C26H37N2O3S, C9H8N2O3S, C28H38NO2S, and C27H27N5S2. Based on the results, mixed cultures of D. dickinsii and A. oryzae had a high MB decolorization and could be used in the textile industry.

Enhanced ultrasonic degradation of methylene blue using a catalyst-free dual-frequency treatment

Methylene blue is one of the most common pollutants found in wastewater, primarily due to its widespread use in the dye industry. Consequently, it is imperative to explore environmentally friendly and efficient methods for degrading this pollutant into non-toxic byproducts. While ultrasonic degradation methods in combination with additives or catalysts have proven effective, such additives or catalysts may inadvertently contribute to secondary pollution. Moreover, the preparation of these catalysts imposes an additional burden in terms of effort and cost. To address these issues, this paper introduces a catalyst-free dual-frequency ultrasound degradation approach for methylene blue. The sonochemical quality of the cavitation bubbles is improved using this technique because the bulk solution is populated with two types of bubbles, whose mean sizes are determined by the dual ultrasound frequencies. The findings demonstrate that, under identical acoustic power density conditions, dual-frequency ultrasound consistently outperforms single-frequency modes across all investigated parameters. Furthermore, the larger the difference between the dual frequencies used, the more effective the degradation of methylene blue. Finally, after just 20 min of sonication, a degradation efficiency of 91% was achieved with dual frequencies of 20 and 80 kHz at an acoustic power density of 209.63 ± 6.94 W/L. Consequently, this technique offers an environmentally friendly, catalyst-free, and highly effective method for degrading methylene blue.

Visible light activated SnO2:Dy thin films for the photocatalytic degradation of methylene blue

This paper explores the impact of dysprosium (Dy) doping on structural, optical, and photocatalytic properties of tin oxide (SnO2) thin films fabricated via spray pyrolysis. Dysprosium doping levels ranged from 0 to 7 at%, and films were grown on glass substrates at 350 °C. X-ray diffraction (XRD) analysis revealed an increase in crystallite size with Dy doping, signifying improved crystalline quality. Simultaneously, dislocation density and strain decreased, indicating enhanced film quality. Texture coefficient (Tchkl) results showed a predominant crystal orientation along the (110) plane due to Dy doping. Optical band gap energy (Eg) decreased with Dy doping up to 5%. Urbach energy increased with Dy doping, suggesting atomic structural flaws and defects. Scanning electron microscopy (SEM) analysis revealed the presence of numerous micro-aggregates on the film's surface. Notably, the density of these micro-aggregates increased proportionally with higher Dy doping levels, particularly emphasizing the pronounced effect observed in SnO2:Dy 5% thin films. These findings underscore the potential of Dy-doped SnO2 thin films for advanced photocatalytic applications, with SnO2:Dy 5% exhibiting favorable properties and demonstrating a 90.99% degradation efficiency in three hours under solar irradiation.

Adsorptive removal of acid red 18 dye from aqueous solution using hexadecyl-trimethyl ammonium chloride modified nano-pumice

Discharging untreated dye-containing wastewater gives rise to environmental pollution. The present study investigated the removal efficiency and adsorption mechanism of Acid Red 18 (AR18) utilizing hexadecyl-trimethyl ammonium chloride (HDTMA.Cl) modified Nano-pumice (HMNP), which is a novel adsorbent for AR18 removal. The HDTMA.Cl is characterized by XRD, XRF, FESEM, TEM, BET and FTIR analysis. pH, contact time, initial concentration of dye and adsorbent dose were the four different parameters for investigating their effects on the adsorption process. Response surface methodology-central composite design was used to model and improve the study to reduce expenses and the number of experiments. According to the findings, at the ideal conditions (pH = 4.5, sorbent dosage = 2.375 g/l, AR18 concentration = 25 mg/l, and contact time = 70 min), the maximum removal effectiveness was 99%. The Langmuir (R2 = 0.996) and pseudo-second-order (R2 = 0.999) models were obeyed by the adsorption isotherm and kinetic, respectively. The nature of HMNP was discovered to be spontaneous, and thermodynamic investigations revealed that the AR18 adsorption process is endothermic. By tracking the adsorption capacity of the adsorbent for five cycles under ideal conditions, the reusability of HMNP was examined, which showed a reduction in HMNP's adsorption effectiveness from 99 to 85% after five consecutive recycles.

Nanocomposite with high adsorption activity developed using stabilized silver modified alumina and TiO2-NPs incorporated into β-cyclodextrin-graphene oxide

Multifunctional nanocomposites Ag/Al₂O₃/TiO₂@β-cyclodextrin-graphene oxide (AATG) incorporating graphene oxide sheets, TiO₂, and Ag/Al₂O₃ nanoparticles were prepared in two steps. We benefited from the inherent properties of β-cyclodextrin to create a stable aqueous graphene solution capable of self-assembling in situ grown TiO₂ nanoparticles on graphene nanosheets. Ag/Al₂O₃ catalysts with a high surface-to-volume ratio were prepared by a combustion technique in solution with urea as a new fuel. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analysis, and BJH pore analysis. FE-SEM was used to evaluate the morphology of β-cyclodextrin-graphene oxide, Ag/Al₂O₃ and AATG nanoplatforms. This research examined the use of AATG as a novel nanocomposite for removing methylene blue from water and compared its effectiveness with that of TiO₂@β-cyclodextrin-graphene oxide (TG) as an intermediate material to assess the impact of the final composite and its components on absorption. The effect of pH, temperature, time, and dye concentration on the reaction rate was investigated. The results showed that at pH above 4, the adsorption rate of MB by AATG gradually increased to about 98%. The results also show that methylene blue is more effectively removed at higher temperatures, implying that the adsorption is temperature dependent and the elimination process is endothermic. The adsorption kinetics, isothermal studies, and thermodynamic analysis were also evaluated. The adsorption data showed excellent agreement with pseudo-second order models (R² > 0.99) and the Langmuir isotherm. The AATG nanocomposites showed excellent adsorption activity, making them potential candidates for water treatment.

Investigation of the removal kinetics, thermodynamics and adsorption mechanism of anionic textile dye, Remazol Red RB, with powder pumice, a sustainable adsorbent from waste water

Excessive growth and abnormal use of dyes and water in the textile industry cause serious environmental problems, especially with excessive pollution of water bodies. Adsorption is an attractive, feasible, low-cost, highly efficient and sustainable technique in terms of green chemistry for the removal of pollutants from water. This study aims to investigate the removal kinetics, thermodynamics and adsorption mechanism of Remazol Red RB, which was chosen as a representative anionic reactive dye, from synthetic wastewater using powdered pumice, taking into account various experimental parameters such as initial dye concentration, adsorption time, temperature and pH. Moreover, to support the proposed adsorption mechanism, before and after adsorption of the samples, the Fourier transform infrared spectrophotometer (FTIR) spectra, X-ray powder diffraction (XRD) diffractograms and High resolution transmission electron microscopy (HRTEM) images were also taken and used. The results show that powder pumice can be an efficient adsorbent for anionic dye removal with a relatively high adsorption capacity of 38.90 mg/g, and it is very effective in 30-60 min in mild conditions. The experimental data showed a high agreement with the pseudo-second-order kinetic model and the Freundlich adsorption isotherm equation. In addition, thermodynamically, the process exhibited exothermic nature and standard isosteric enthalpy and entropy changes of -4.93 kJ/mol and 16.11 J/mol. K were calculated. It was determined that the adsorption mechanism was predominantly based on T-shaped pi-pi interactions and had physical characteristics.

Adsorption and Desorption Study of Reusable Magnetic Iron Oxide Nanoparticles Modified with Justicia adhatoda Leaf Extract for the Removal of Textile Dye and Antibiotic

The release of tetracycline hydrochloride (TCH) and methylene blue (MB) dye into the aquatic system uncontrollably caused major environmental and health problems; hence, their prevention required serious attention. Adsorption process is now being researched in order to increase adsorption efficiency and reprocess to alleviate environmental issues. The use of magnetic nanoparticle as an adsorbent for wastewater treatment has a lot of prospective. A magnetic iron oxide nanoparticle surface modified by Vasaka (Justicia adhatoda) leaf extract (JA-MIONs) is used to give a fast removal approach for MB dye and TCH antibiotics. Dynamic light scattering, UV-Vis and band gap measurement, powder X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy were operated to analyse the formation and size of these magnetic nanoparticles. The impacts of different factors such as contact time (30-150 min), adsorbate concentration (10-50 mg/L), pH (4-10), and adsorbent dose (2-10 mg) were explored. Adsorption kinetics and isotherms show that it follows the pseudo-first-order kinetic and the Freundlich isotherm, with maximum adsorption capacities of 76.92 mg/g for MB and 200 mg/g for TCH at 298 K. The reusability of the JA-MIONs eventually exhibited a decline in the adsorption percentage of MB and TCH after five and four times respectively. After the desorption-adsorption cycles, this adsorbent continued to exhibit significant adsorption capacity. This investigation furnished the significant reference data for the synthesis of JA-MIONs as a novel and auspicious adsorbent for the industrial clean-up of toxic dyes and heavily used antibiotics from water.

Synthesis and Characterization of Orange Peel Modified Hydrogels as Efficient Adsorbents for Methylene Blue (MB)

In recent years, due to the developments in the textile industry, water contaminated with synthetic dyes such as methylene blue (MB) has become an environmental threat based on the possible impacts in terms of chemical and biochemical demand, which leads to disturbance in aquatic plants photosynthesis, besides their possible toxicity and carcinogenicity for humans. In this work, an adsorbent hydrogel is prepared via free radical polymerization comprising acrylic acid (PAA) as a monomer and orange peel (OP) as a natural modifier rich in OH and COOH present in its cellulose and pectin content. The resulting hydrogels were optimized in terms of the content of OP and the number of cross-linkers and characterized morphologically using Scanning electron microscopy. Furthermore, BET analysis was used to follow the variation in the porosity and in terms of the surface area of the modified hydrogel. The adsorption behavior was found to follow pseudo-second-order as a kinetic model, and Langmuir, Freundlich, and Temkin isotherm models. The combination of OP and PAA has sharply enhanced the adsorption percent of the hydrogel to reach 84% at the first 10 min of incubation with an adsorption capacity of more than 1.93 gm/gm. Due to its low value of pHPZc, the desorption of MB was efficiently performed at pH 2 using HCl, and the desorbed OP-PAA were found to be reusable up to ten times without a decrease in their efficiency. Accordingly, OP-PAA hydrogel represents a promising efficient, cost-effective, and environmentally friendly adsorbent for MB as a model cationic dye that can be applied for the treatment of contaminated waters.

Adsorptive removal of humic substances using cationic surfactant-modified nano pumice from water environment: Optimization, isotherm, kinetic and thermodynamic studies

In this study, nano pumice (NP) and a cationic surfactant (hexadecyltrimethylammonium-chloride (HDTMA.Cl)) treated nano pumice (HMNP) were used for humic acid (HA) adsorption from an aqueous solution. The adsorption process was modeled and optimized using Response surface methodology-central composite design (RSM-CCD) and Artificial neural networks- Genetic algorithm (ANN-GA). The results show that the ANN model outperforms the RSM-CCD model in terms of response prediction. Optimization results based on the RSM-CCD approach proposed pH 3, adsorbent dose 3 g L^-1, reaction time 60 min, and initial HA concentration 5 mg L^-1 as optimal points of the variables, to reach the maximum adsorption efficiency of 100% and 65.4% by HMNP and NP adsorbents. The maximal adsorption capacity of NP was 1.21 mg g^-1, while that of HMNP was 27.34 mg g^-1. The optimal points of process parameters by the ANN-GA method are in accordance with the values suggested by the RSM-CCD method. In isotherm studies, Langmuir model was found to be the best-fitted model for both adsorbent with R² = 0.97 for NP and 0.992 for HMNP, and also among three different kinetic models which were assessed, Pseudo-second-order model with R² = 0.9989 for HMNP and R² = 0.9957 for NP were the best-fitted models for HA removal. Thermodynamic studies indicated that the HA adsorption process by both of the adsorbents is endothermic and the nature of HMNP was found spontaneous while for NP was non-spontaneous. The value of ΔH for both adsorbents was in the range of 34-36.8 kJ mol^-1 so the process is clarified as chemical-physical adsorption. The reusability test revealed that the adsorption effectiveness of HMNP drops from 100% to 82.4% after 10 consecutive recycles. The influence of interfacing anions indicated that the adsorption efficiency drops from 100% to 95.4% when the anions were added to the reaction solution.

Development, Synthesis and Characterization of Tannin/Bentonite-Derived Biochar for Water and Wastewater Treatment from Methylene Blue

Novel hybrid carbon–mineral materials were synthesized by the mechanochemical activation of a mixture of tannin and bentonite in a ball mill with further pyrolysis in an argon atmosphere at 800 °C. The influence of the initial mixture ingredients content on the structural, textural, and thermal characteristics of biochars has been described using X-ray diffraction, Raman and Fourier-transform infrared spectroscopy, nitrogen adsorption–desorption, and scanning electron microscopy. The influence of bentonite clay on the carbon phase characteristics due to the formation of more heat-resistant and structured nanocarbon particles in biochars has been proven. The adsorption effectiveness of the materials towards methylene blue was studied. The adsorption data were analyzed applying Langmuir and Freundlich isotherms with high determination coefficients (R2) in the range of 0.983–0.999 (Langmuir) and 0.783–0.957 (Freundlich). The maximum adsorption amount of MB was 5.78 mg/g. The adsorption efficiency of biochars with respect to phenol was also examined. It was shown that the hybrid biochars show differentiated selectivity to the adsorption of organic compounds. It was concluded that the physicochemical properties of the surface of biochars play an important role in the adsorption effectiveness, making them a good candidate for water and wastewater remediation processes.

Acid red 18 removal from aqueous solution by nanocrystalline granular ferric hydroxide (GFH); optimization by response surface methodology & genetic-algorithm

The need for fresh water is more than before by population growth, and industrial development have affected the quality of water supplies, one of the important reason for water contamination is synthetic dyes and their extensive use in industries. Adsorption has been considered as a common methods for dye removal from waters. In this study, Acid Red18 removal in batch mode by using Granular Ferric Hydroxide (GFH) was investigated. The GFH characterized by XRD, FESEM and FTIR analysis. Experiments were designed using RSM-CCD method. The maximum removal efficiency was obtained 78.59% at pH = 5, GFH dosage = 2 g/l, AR18 concentration = 77.5 mg/l and 85 min of contact time. Optimization with RSM and Genetic Algorithm carried out and is similar together. The non-linear adsorption Isotherm and kinetic fitted with Freundlich (R2 = 0.978) and pseudo-second-order (R2 = 0.989) models, respectively. Thermodynamic studies showed that the AR18 adsorption is endothermic process and GFH nature was found spontaneous.

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

Investigation of TiO2 Nanoparticles Synthesized by Sol-Gel Method for Effectual Photodegradation, Oxidation and Reduction Reaction

Metal oxide titanium dioxide (TiO2) nanoparticles were synthesized by using a simple and economical sol-gel method. The prepared nanoparticles were used to evaluate methylene blue dye degradation and as catalysts in the oxidation of benzaldehyde. The crystallite size of the titanium dioxide nanoparticle was 18.3 nm, which was confirmed by X-ray diffraction analysis. The spherical morphology was confirmed by scanning electron microscopy (SEM), and the elemental composition of the nanoparticle was found by energy dispersive X-ray (EDAX) analysis. The anatase form of the nanoparticle was confirmed by the bandgap 3.2 eV, which was measured using UV–DRS analysis. The bond between metal and oxygen was confirmed by the peaks at 485 and 606 cm–1 analyzed by Fourier transform infrared analysis (FTIR). The efficiency of the catalyst in dye degradation was 60.08, 68.38, and 80.89% with respect to 50, 75, and 100 mg catalyst weight. The yield % of benzoic acid was 94%, and the reduction efficiency against 4-nitrophenol was 98.44%.

Facile Microwave Hydrothermal Synthesis of ZnFe2O4/rGO Nanocomposites and Their Ultra-Fast Adsorption of Methylene Blue Dye

The industry development in the last 200 years has led to to environmental pollution. Dyes emitted by pharmaceutical and other industries are major organic pollutants. Organic dyes are a pollutant that must be removed from the environment. In this work, we adopt a facile microwave hydrothermal method to synthesize ZnFe2O4/rGO (ZFG) adsorbents and investigate the effect of synthesis temperature. The crystal structure, morphology, chemical state, and magnetic property of the nanocomposite are investigated by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and a vibrating sample magnetometer. Furthermore, the synthesized ZFGs are used to remove methylene blue (MB) dye, and the adsorption kinetics, isotherm, mechanism, and reusability of this nanomaterial are studied. The optimal ZFG nanocomposite had a dye removal percentage of almost 100%. The fitting model of adsorption kinetics followed the pseudo-second-order model. The isotherm model followed the Langmuir isotherm and the theoretical maximum adsorption capacity of optimal ZFG calculated by this model was 212.77 mg/g. The π-π stacking and electrostatic interaction resulted in a high adsorption efficiency of ZFG for MB adsorption. In addition, this nanocomposite could be separated by a magnet and maintain its dye removal percentage at almost 100% removal after eight cycles, which indicates its high suitability for utilization in water treatment.

Removal of methylene blue from textile waste water using kaolin and zeolite-x synthesized from Ethiopian kaolin

The wastewater generated from textile factories is linked to one of the main water pollution problems; therefore, it is important to reduce the pollutants in industrial effluents before their discharge into environment. The present study was to investigate the appropriateness zeolite-x and kaolin as effective adsorbents for removal of methylene blue from the textile wastewater. Batch adsorption experiments were carried out to assess parameters that influence the adsorption process. The prepared zeolite-x and kaolin were characterized by Fourier Transform Infrared and X-ray diffraction techniques. The results of this study showed that the particle size is 40.77 nm and 0.45 nm kaolin and zeolite-x respectively. The performance of zeolite-x adsorbent is best at the optimum pH 4 with removal efficiency of 97.77% and kaolin adsorbent at pH 6 with removal efficiency of 86.86%. The optimum contact time was obtained at 60 and 80 minutes for zeolite–x and kaolin respectively. While optimum adsorbent dosage was obtained at 0.4 and 0.6 grams with removal efficiency of 97.12% and 87.75% for the zeolite-x and kaolin adsorption experiment respectively. The confirmed square sum errors values are 1.0×10⁻⁴ and 1.0×10⁻³ for zeolite-x and kaolin, respectively. The Adsorption isotherms results have well fitted to Freundlich isotherm than Langmuir isotherm. The adsorption kinetics results were best fitted the pseudo second order model. The result shows that the zeolite-x has high removal efficiency than kaolin at the same operating conditions. Application of this method can be economically, environmentally, and socially feasible to address wastewater problems. Further research has to be carried out on the removal capacity of this adsorbent for organic dyes not only from the textile industry but also from leather industries and soap industries.

Treatment of Yellow Phosphorus Slag and Reuse of It as an Absorbent of Chromium (VI) Ions and Methylene Blue

Yellow phosphorus is used widely in the world for production of phosphoric acid, various phosphates, flame retardant, detergent, water treatment, metal surface treatment, etc. After the production of yellow phosphorus, a large amount of phosphorus sludge is discharged to environment, causing environment pollution. This work focused on treatment of yellow phosphorus slag (YPS) and application of it as an absorbent for chromium (VI) ion and methylene blue. The YPS was first washed with water to remove phosphoferrite (FeP) and impurities and then being milled and transferred to a float sorting system to obtain YPS particles. The characteristics of YPS particles were determined by inductively coupled plasma-mass-spectrometry (ICP-MS), energy-dispersive X-ray spectroscopy (EDX), infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), zeta potential, and nitrogen adsorption methods. The YPS particles were retreated with NaOH, HNO3, and EDTA solutions to evaluate the influence of these agents on metal ion and organic compound adsorption ability by YPS. The adsorption parameters of chromium (VI) ion and methylene blue (MB) by treated YPS particles were recognized by the ultraviolet-visible (UV-Vis) spectrometer. The effects of temperature, pH solution, and initial concentration of absorbed substances on the adsorption ability were investigated. The adsorption isotherms and adsorption kinetics of chromium (VI) ion and MB by YPS particles were also determined. The obtained results confirmed that the green technology used to treat the YPS2 particles is suitable to obtain an effective absorbent. The adsorption efficiency of YPS2 particles for removal of chromium (VI) ions is smaller than that for removal of MB in aqueous solutions. The adsorption isotherm of MB adsorption process is complied with the Langmuir isotherm while the adsorption kinetic fits well with the pseudo-second-order reaction model. The thermodynamic parameters of MB adsorption processed on YPS2 were calculated and discussed.

Survey dataset on the performance of combined process of coagulation and ceramic membrane for the removal of reactive black19

The aim of data article was to evaluate effectiveness of the combined process of coagulation, flocculation and filtration to remove reactive black 19 from solution aqueous. In this data article, alum and ferric chloride were selected as a coagulant for instability of color before ceramic membrane. All experiments were performed in batch conditions. The results showed that more than half of the ceramic membrane is made of silica. The BET surface area of the ceramic membrane was 1.877 m² g⁻¹. The size of RB19, alum, and ferric chloride was 996.2 mm, 1216 mm, and 86.26 mm, respectively. Also, the zeta potential of RB19, alum, and ferric chloride was 20.7 mV, 1.59 mV, and 34.7 mV, respectively. The findings showed that the best pH to remove the RB 19 by alum and ferric chloride was less than 7. With increasing concentrations of alum and chlorine ferric the removal of RB 19 increased. For RB19 concentration of 10 mg l⁻¹, with increasing time from 5 to 15 min, the removal efficiency for alum and ferric were 61–63% and 82–87%, respectively.

Designing metallic iron based water filters: Light from methylene blue discoloration

Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design.