Methyl Red Adsorption on Biochar Obtained by Physical Activation of Caraway Seeds with Carbon Dioxide.

In this study carbon adsorbents were produced from caraway (Carum carvi L.) seeds, through direct and physical activation by carbon dioxide. The resulting biochar adsorbents were analyzed using low-temperature nitrogen adsorption-desorption isotherms and Boehm titration. Furthermore, the acid-base properties of the biochar samples obtained were examined, and the pH of their aqueous extracts was determined. The obtained adsorbents had a specific surface area ranging between 10 to 70 m2 /g. Resulting carbon materials exhibited a predominance of basic groups on their surfaces. The sorption capacities of methyl red for the samples varied from 3 to 20 mg/g. Conducted adsorption studies determined, that the adsorption kinetics of the dye on biochar materials followed a pseudo-second order model and the adsorption process was best described by the Freundlich isotherm, indicating the development of a multi-layer adsorbate on their surfaces. The effectiveness of adsorption in aqueous solutions of methyl red increased with the rise in process temperature. Moreover, the adsorption process was found to be spontaneous and endothermic based on thermodynamic investigations.

Genome-Scale Investigation of the Regulation of azoR Expression in Escherichia coli Using Computational Analysis and Transposon Mutagenesis.

Bacterial azoreductases are enzymes that catalyze the reduction of ingested or industrial azo dyes. Although azoreductase genes have been well identified and characterized, the regulation of their expression has not been systematically investigated. To determine how different factors affect the expression of azoR, we extracted and analyzed transcriptional data from the Gene Expression Omnibus (GEO) resource, then confirmed computational predictions by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Results showed that azoR expression was lower with higher glucose concentration, agitation speed, and incubation temperature, but higher at higher culture densities. Co-expression and clustering analysis indicated ten genes with similar expression patterns to azoR: melA, tpx, yhbW, yciK, fdnG, fpr, nfsA, nfsB, rutF, and chrR (yieF). In parallel, constructing a random transposon library in E. coli K-12 and screening 4320 of its colonies for altered methyl red (MR)-decolorizing activity identified another set of seven genes potentially involved in azoR regulation. Among these genes, arsC, relA, plsY, and trmM were confirmed as potential azoR regulators based on the phenotypic decolorization activity of their transposon mutants, and the expression of arsC and relA was confirmed, by qRT-PCR, to significantly increase in E. coli K-12 in response to different MR concentrations. Finally, the significant decrease in azoR transcription upon transposon insertion in arsC and relA (as compared to its expression in wild-type E. coli) suggests their probable involvement in azoR regulation. In conclusion, combining in silico analysis and random transposon mutagenesis suggested a set of potential regulators of azoR in E. coli.

Influence of Polar Solvents on Third-Order Nonlinear Optical Features of Methyl Red Dye.

This study emphasis the solvent effect on third-order nonlinear optical (NLO) features of methyl red (MR) dye dissolved in polar solvents including ethanol, methanol, acetone, 1-propanol, DMF and DMSO using low power diode laser. Z-scan technique operating at 405 nm wavelength, is used to estimate the third-order NLO features of MR dye in various solvents. The dye discloses self-defocusing nonlinear index of refraction (n2), which is determined to be the order of 10-7 cm2/W. The nonlinear coefficient of absorption (ß) of MR dye displays both negative and positive value owing to saturable absorption (SA) and reverse saturable absorption (RSA), respectively. The real and imaginary components of the third-order NLO susceptibility of MR dye in polar solvents are measured to be the order of 10-6 esu and 10-7 esu, respectively. The dye exhibits a large NLO susceptibility in DMSO, which is estimated to be 1.21 × 10-6 esu. The effect of solvent spectral features on MR dye is determined by applying a multi-parameter scale called Kamlet-Abboud-Taft. The experiment results indicate that MR dye is a promising NLO material that may find applications in photonics and optoelectronics.

Investigating the effectiveness of rice husk-derived low-cost activated carbon in removing environmental pollutants: a study of its characterization.

The chemically activated biochar was produced through the pyrolysis of rice husk. Thermal gravimetric and elemental analysis were conducted to characterize the raw rice husk. The activated biochar product underwent evaluation through SEM, BET and, FT-IR analysis. This cost-effective activated carbon was utilized as an adsorbent for the elimination of environmental pollutants. At a temperature of 25 °C, the activated biochar product exhibited an impressive maximum CO2 adsorption capacity of 152 mg/g. This exceptional performance can be attributed to its notable surface area and porosity, measuring at 2,298 m2/g and 0.812 cm3/g, respectively. This product was also utilized to remove methyl red (MR) dye from an aqueous solution. The optimal parameters for the removal of MR were determined as follows: a pH of 6.0, a temperature of 25 °C, an initial MR concentration of 50 mg/L, and an adsorbent dosage of 0.4 g/L. At a duration of 140 min, the system attained its maximum equilibrium adsorption capacity, reaching a value of 62.06 mg/g. Furthermore, the calculated maximum MR removal efficiency stood at an impressive 99.31%. The thermodynamic studies demonstrated that the MR removal process was spontaneous, exothermic, and increased randomness. Kinetic studies suggested that the pseudo-second-order model can fit well.

Rice is the staple food for a significant portion of the world's population. Rice husk, which is released during the production and processing of rice, is one of the most important agricultural wastes worldwide. In this study, low cost activated carbon was produced by converting renewable resource such as rice husk biomass into a product with high added value. The resulting product, with its high surface area, can offer a more sustainable, cost-effective, and versatile alternative for a range of industrial, environmental, and medical applications.

Efficacy of activated carbon using Salvadora persica stem for remediation of potentially toxic dyes from aqueous solution.

Potentially toxic dyes are introduced mainly to rivers through industrial effluents which have a high risk to human health and aquatic life. Activated carbon (AC) from the stem of Salvadora persica was synthesised to take off toxic industrial dyes from an aqueous solution. KOH was used as the activating agent throughout the preparation process for the AC. The morphology and composition of the prepared AC were studied by various analytical methods. From the overall results, it was found that the prepared AC is highly porous and thermal stability gained around 800 ℃. At room temperature, remediation of the dyes (cationic dye, methyl red and anionic dye, methylene blue) using the adsorption method was carried out to ascertain the impact of time and the quantity of AC on methylene blue (MB) and methyl red (MR) removal. During the initial 60 min, equilibrium was attained for the optimum dye concentration (200 mg/L). The data for adsorption on the AC obtained at equilibrium were examined by the Langmuir and Freundlich isotherm models. Both the isotherms accurately predicted the data, with regression values of 0.99 for MR and 0.90 for MB, respectively. The equilibrium adsorption data was also analysed by kinetic models. The adsorption data well fitted in 2nd order kinetic model. The results of MB and MR adsorption from solutions have demonstrated that the stem of Salvadora persica is one of the cheap and more eco-friendly options for remediation of toxic dyes from aqueous solutions.

In vitro and in silico analysis of Brilliant Black degradation by Actinobacteria and a Paraburkholderia sp.

The soil bacteria isolated in this study, including three strains of actinobacteria and one Paraburkholderia sp., showed decolorization activity of azo dyes in the resting cell assay and were shown to use methyl red as the sole carbon source to proliferate. Therefore, their ability to degrade, bioabsorb, or a combination of both mechanism was investigated using the substrate brilliant black. The strains DP-A9 and DP-L11, within 24 h of incubation, showed complete biodegradation of 173.54 mg/L brilliant black and the strains DP-D10 and DP-P12 showed partial decolorization of 83.3 mg/L and 36.4 mg/L, respectively, by both biosorption and biodegradation. In addition, the shotgun assembled genome of these strains showed a highly diverse set of genes encoding for candidate dye degrading enzymes, providing avenues to study azo dye metabolism in more detail.

Nanomaterials Based on Collaboration with Multiple Partners: Zn3Nb2O8 Doped with Eu3+ and/or Amino Substituted Porphyrin Incorporated in Silica Matrices for the Discoloration of Methyl Red.

Designing appropriate materials destined for the removal of dyes from waste waters represents a great challenge for achieving a sustainable society. Three partnerships were set up to obtain novel adsorbents with tailored optoelectronic properties using silica matrices, Zn3Nb2O8 oxide doped with Eu3+, and a symmetrical amino-substituted porphyrin. The pseudo-binary oxide with the formula Zn3Nb2O8 was obtained by the solid-state method. The doping of Zn3Nb2O8 with Eu3+ ions was intended in order to amplify the optical properties of the mixed oxide that are highly influenced by the coordination environment of Eu3+ ions, as confirmed by density functional theory (DFT) calculations. The first proposed silica material, based solely on tetraethyl orthosilicate (TEOS) with high specific surface areas of 518-726 m2/g, offered better performance as an adsorbent than the second one, which also contained 3-aminopropyltrimethoxysilane (APTMOS). The contribution of amino-substituted porphyrin incorporated into silica matrices resides both in providing anchoring groups for the methyl red dye and in increasing the optical properties of the whole nanomaterial. Two different types of methyl red adsorption mechanisms can be reported: one based on surface absorbance and one based on the dye entering the pores of the adsorbents due to their open groove shape network.

A Series of Polymer-Supported Polyoxometalates as Heterogeneous Photocatalysts for Degradation of Organic Dye.

Photocatalytic degradation technology has developed rapidly in the treatment of organic pollutants due to its high efficiency, mild reaction conditions and easy control. In this paper, a series of heterogeneous photocatalysts, BWZ-en-R (BWZ = [BW11Z(H2O)O39]7-, Z = Zn, Cd, Mn, en = ethylenediamine, R = Merrifield resin), were prepared by using ethanediamine as a linker to immobilize Keggin-type transition elements substituting tungstoborates on Merrifield resin and characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The photocatalytic properties of BWZ-en-R (Z = Zn, Cd, Mn) for the degradation of methyl red (MR) were investigated. The results show that the BWZ-en-R (Z = Zn, Cd, Mn) photocatalysts exhibited high photodegradation ability for MR under the irradiation of ultraviolet light, and were easily separated from the reaction media. The maximum degradation rate (%) of MR (40 mL, 25 µM, pH = 2) reached 96.4% for the BWMn-en-R photocatalyst (40 mg) after being irradiated for 30 min, making this a promising photocatalyst candidate for dye degradation. Moreover, the influences of some factors, such as the Z-substituted elements in the BWZ, the BWZ-en-R dosage and the MR initial concentration, on the photocatalytic degradation rate of MR were also examined.

Removal of Methyl Red from Aqueous Solution Using Biochar Derived from Fennel Seeds.

In this study, fennel (Foeniculum vulgare) seeds were used as a precursor to obtain carbon adsorbents through physical activation with carbon dioxide and chemical activation by impregnating the precursor with sodium carbonate. The physical activation involved the carbonization of the precursor at a temperature of 600 °C for 60 min and activation at a temperature of 800 °C for 30 min with carbon dioxide. Chemical activation included impregnation of the precursor with sodium carbonate at a mass ratio of a precursor to activator of 1:2. The mixture was activated in a nitrogen atmosphere with a flow rate at a temperature of 700 °C for 45 min. The resulting biochar samples were washed with 5% hydrochloric acid and subsequently rinsed with boiling distilled water. The biochar adsorbents were characterized using low-temperature nitrogen adsorption-desorption isotherms, Boehm titration, and pH measurements of their aqueous extracts. The specific surface area of the obtained adsorbents ranged from 89 to 345 m2/g. Biochar adsorbents exhibit a predominance of acidic groups over basic groups on their surfaces. The sorption capacities of the obtained samples towards an aqueous solution of methyl red range from 26 to 135 mg/g. Based on adsorption studies, it was found that the adsorption of the dye on the obtained biochar materials follows a pseudo-second-order model. The Freundlich isotherm best describes the studied process, indicating the formation of a multilayer of adsorbate on the adsorbent surface. The efficacy of adsorption in aqueous solutions of methyl red was found to increase with the elevation of the process temperature. Moreover, thermodynamic studies have shown that the adsorption process is spontaneous and endothermic. Consequently, this work provides a description of the physicochemical parameters of two biochars obtained by physical and chemical activation of a little-studied precursor-fennel seeds-and studies on their potential use as adsorbents for contaminants from the aqueous phase.

Removal of Methylene Blue and Methyl Red from Aqueous Solutions Using Activated Carbons Obtained by Chemical Activation of Caraway Seed.

In this study, activated carbons were produced through the chemical activation of caraway seeds using three different activators: Na2CO3, K2CO3, and H3PO4. A 1:2 weight ratio of precursor to activator was maintained in every instance. Comprehensive analyses were conducted on the resultant activated carbons, including elemental analysis, textural parameters determination, Boehm titration for surface oxygen functional groups, pH assessment of aqueous extracts, and quantification of ash content. The produced materials were subjected to adsorption tests for methylene blue and methyl red sodium salt from the liquid phase and the effects of adsorbent dosage, pH of the aqueous dye solution, process temperature, and adsorbent-adsorbate contact time on sorption capacity obtained. To characterize the adsorption model of the examined pollutants, both the Langmuir and Freundlich equations were employed. In addition, the sorption capacity of the obtained carbon materials against an iodine aqueous solution was assessed. The specific surface area of the obtained adsorbents ranged from 269 to 926 m2/g. By employing potassium carbonate to chemically activate the starting substance, the resulting activated carbons show the highest level of specific surface area development and the greatest sorption capacity against the tested impurities-296 mg/g for methylene blue and 208 mg/g for methyl red sodium salt. The adsorption rate for both dyes was determined to align with a pseudo-second-order kinetic model. The experimental adsorption data for methylene blue were well-described by the Langmuir model, whereas the Freundlich model was found to be congruent with the data pertaining to methyl red sodium salt.

Microporous Biocarbons Derived from Inonotus obliquus Mushroom and Their Application in the Removal of Liquid and Gaseous Impurities.

Biocarbons were obtained by physical and chemical activation of the residue of the extraction of chaga fungi (Inonotus obliquus). The residue was subjected to heat treatment carried out in a microwave oven and in a quartz tubular reactor. The materials were characterized by elemental analysis, low-temperature nitrogen adsorption, determination of pH, and the contents of acidic and basic oxygen functional groups on the surface of biocarbons by the Boehm method. The final biocarbon adsorbents have surface areas varying from 521-1004 m2/g. The physical activation of the precursor led to a strongly basic character of the surface. Chemical activation of Inonotus obliquus promoted the generation of acid functional groups. All biocarbons were used for methyl red sodium salt adsorption from the liquid phase. The sorption capacities of biocarbons towards the organic dye studied varied from 77 to 158 mg/g. The Langmuir model was found to better describe the experimental results. The results of the kinetic analysis showed that the adsorption of methyl red sodium salt on the biocarbons followed the pseudo-second-order model. The acidic environment was conducive to the adsorption of the dye on the obtained biocarbons. Moreover, thermodynamic studies confirmed that the organic dye adsorption on the biocarbons was a spontaneous endothermic process. The biocarbons obtained were also tested as adsorbents of hydrogen sulfide in dry and wet conditions. The sorption capacities towards hydrogen sulfide varied in the range of 21.9-77.9 mg. The results have shown that the adsorption of hydrogen sulfide depends on the process conditions and the activation procedure of biocarbons (method of activation and thermochemical treatment of samples). It has been shown that the initial material used can be a new precursor for obtaining cheap and-more importantly-universal bioadsorbents characterized by high effectiveness in the removal of air and water pollutants.

Biodegradation and decolourization of methyl red by Aspergillus versicolor LH1.

Azo dyes constitute a significant environmental burden due to its toxicity, carcinogenicity, and hard biodegradation. The report here is focused on the decolorization and degradation treatment of azo dye methyl red (MR). Decolorization of MR using Aspergillus versicolor LH1 isolated from activated sludge was investigated. The maximum decolorization rate of 92.3% was obtained under the optimized conditions of sucrose as carbon source, 5d incubation age, pH 6.0, 140 mg/L initial concentration of MR and 2.5 g/L initial concentration of NaNO3. Biodegradation products of MR were investigated using HPLC-MS, FTIR, and GC-MS assays. It was revealed the three bonds of -C-N = in MR aromatic nucleus were disrupted, and benzoic acid was detected. Micronucleus test with Glycine max L. and Vicia faba L. demonstrated that MCN‰ (micronucleus permillage) of MR metabolites was less than MR solution. These findings provided evidence that A. versicolor LH1 is a candidate for MR degradation in industrial wastewater treatment.

A Novel N-Doped Nanoporous Bio-Graphene Synthesized from Pistacia lentiscus Gum and Its Nanocomposite with WO3 Nanoparticles: Visible-Light-Driven Photocatalytic Activity.

This paper reports the synthesis of a new nitrogen-doped porous bio-graphene (NPBG) with a specific biomorphic structure, using Pistacia lentiscus as a natural carbon source containing nitrogen that also acts as a bio-template. The obtained NPBG demonstrated the unique feature of doped nitrogen with a 3D nanoporous structure. Next, a WO3/N-doped porous bio-graphene nanocomposite (WO3/NPBG-NC) was synthesized, and the products were characterized using XPS, SEM, TEM, FT-IR, EDX, XRD, and Raman analyses. The presence of nitrogen doped in the structure of the bio-graphene (BG) was confirmed to be pyridinic-N and pyrrolic-N with N1 peaks at 398.3 eV and 400.5 eV, respectively. The photocatalytic degradation of the anionic azo dyes and drugs was investigated, and the results indicated that the obtained NPBG with a high surface area (151.98 m2/g), unique electronic properties, and modified surface improved the adsorption and photocatalytic properties in combination with WO3 nanoparticles (WO3-NPs) as an effective visible-light-driven photocatalyst. The synthesized WO3/NPBG-NC with a surface area of 226.92 m2/g displayed lower bandgap and higher electron transfer compared with blank WO3-NPs, leading to an increase in the photocatalytic performance through the enhancement of the separation of charge and a reduction in the recombination rate. At the optimum conditions of 0.015 g of the nanocomposite, a contact time of 15 min, and 100 mg/L of dyes, the removal percentages were 100%, 99.8%, and 98% for methyl red (MR), Congo red (CR), and methyl orange (MO), respectively. In the case of the drugs, 99% and 87% of tetracycline and acetaminophen, respectively, at a concentration of 10 mg/L, were removed after 20 min.

Selective sorptive removal of Methyl Red from individual and binary component solutions by mesoporous organosilicas of MCM-41 type.

Organosilicas with chemically immobilized 3-aminopropyl and Methyl Red-containing surface groups were prepared by sol-gel condensation of tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane in the presence of dye as part of the mixed micelles or dye-containing silane as silica source. The hexagonally arranged mesoporous structure of synthesized materials was confirmed by low-temperature nitrogen adsorption-desorption, x-ray diffraction, and TEM studies. Chemical composition of MCM-41-type organosilicas was established by FT-IR spectroscopy and chemical analysis of surface layer. Sorption of Methyl Red by organosilicas was studied from diluted phosphate buffer solutions in dependence of medium pH, duration of contact, and equilibrium concentration of dye. It was found that effective removal of Methyl Red takes place at pH values within a range of 2.5-5. Kinetic curves of Methyl Red sorption on organosilicas were analyzed by the Lagergren, Ho-McKey, and Weber-Morris kinetic models. It was found that the pseudo-second-order model fits the kinetics of Methyl Red sorption on all synthesized materials and the intraparticle diffusion is not the only one mechanism controlling the rate of Methyl Red sorptive removal. The parameters of equilibrium sorption of Methyl Red on organosilicas of MCM-41 type were calculated using Langmuir, Freundlich, Redlich-Peterson, and Brunauer-Emmett-Teller models. Sorption of acid dyes with geometry similar or substantially different from Methyl Red on mesoporous silicas was studied from single and binary component mixtures in aqueous solutions with pH 4.8 and 5.5. It was found that selective sorption process is highly dependent on the structural characteristics and protolytic state of silica surface as well as acid dye.

Degradation of azo dye methyl red by alkaliphilic, halotolerant Nesterenkonia lacusekhoensis EMLA3: application in alkaline and salt-rich dyeing effluent treatment.

Effluents from textile industries are highly colored due to vast use of various azo dyes and color is the first visual indicator of pollution. Biological treatment of textile effluent is often hampered due to the alkaline pH and high salinity; a common characteristic of many textile industrial wastewaters. Considering this, the present study explores the potential of a newly isolated halotolerant and alkaliphilic bacterium Nesterenkonia lacusekhoensis EMLA3 for degradation of methyl red (MR) dye under alkaline condition. Strain EMLA3 showed 97% degradation of 50 mg L-1 MR after 16 h at initial pH of 11.5 in nutrient medium. Dye degradation by the isolate is supported by the formation of low-molecular weight metabolites as divulge through GC-MS & FTIR studies Optimum dye degradation was observed in the pH range of 8.0-11.5 and temperature range of 30-35 °C. Significant MR degrading activity of the strain could be achieved in the presence of very high salt level (100-120 g L-1 NaCl) and in co-presence of different heavy metals. Application of strain to alkaline pH, salt, and heavy metals laden-textile effluent resulted in overall 83% dye removal from the effluent after 120 h of treatment under static condition. Furthermore, the property of microbe to drop-down the pH of wastewater from 11.5 to 8.60 after treatment also lowers the need of additional neutralization treatment. The entire study thus comes out with novel application of N. lacusekhoensis-a less explored extremophilic bacterium-for treatment of alkaline and salt-rich azo dye-containing wastewaters.

Methyl Red degradation by a subseafloor fungus Schizophyllum commune 15R-5-F01: efficiency, pathway, and product toxicity.

Synthetic dyes pose a significant environmental threat due to their complex structures and resistance to microbial degradation. S. commune 15R-5-F01 exhibited over 96% degradation efficiency of Methyl Red in a medium with 100 mg L-1 Methyl Red within 3 h. The fungus demonstrated adaptability to various environmental conditions, including different pH levels, temperatures, oxygen concentrations, salinity, and heavy metals. S. commune 15R-5-F01 is capable of achieving repeated cycles of Methyl Red reduction with sustained degradation duration minimum of 6 cycles. It showed a maximum Methyl Red biodegradation capacity of at least 558 mg g-1 dry mycelia and a bioadsorption capacity of 57 mg g-1. Gas chromatography-mass spectrometry analysis confirmed the azo reduction of Methyl Red into N,N-dimethyl-p-phenylenediamine and 2-aminobenzoic acid. Enzymatic activity assays indicated the involvement of lignin peroxidases, laccases, and manganese peroxidase in the biodegradation process. Phytotoxicity tests on Triticum eastivum, Oryza sativa, and Vigna umbellata seeds revealed reduced toxicity of the degradation products compared to Methyl Red. This study identifies S. commune 15R-5-F01 as a viable candidate for the sustainable degradation of synthetic dyes in industrial wastewater.

Fabrication of freshness indicators based on methylcellulose-containing color indicator solutions for monitoring the quality of coconut water.

This is the first study to apply intelligent packaging to coconut water. The purpose of this study was to determine the best color indicator solution for making freshness indicator labels based on methylcellulose along with the color change profile of coconut water during storage at room temperature. Three color indicator solutions were used, namely phenol red, bromothymol blue, and methyl red, which were then continued with the fabrication of freshness indicator labels based on methylcellulose from each of these color indicator solutions and applied to coconut water at 25 °C room temperature storage for 24 h with observations every 4 h in the form of pH, total dissolved solids, total acid, turbidity, total microbes, CO2 gas, O2 gas, and freshness indicator label color changes. The values of pH, total soluble solids, and O2 gas decreased with storage time, whereas the values of total acid, turbidity, total microbes, and CO2 gas continued to increase. The methylcellulose-based phenol red freshness indicator label provides the best color change profile that matches the freshness condition of coconut water, namely purplish red (fresh), orange (immediately consumed), and yellow (damaged) so that it can be used as intelligent packaging to monitor the quality of coconut water.

Engineering 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets for improving decomposition of organic dyes and doxycycline hydrochloride drug.

Herein, it is demonstrated that 0D/2D design of zinc sulfide quantum dots encapsulated with yttrium tungstate nanosheets, which were subsequently used to increase the removal of brilliant blue (BB), methyl red (MR) dyes and doxycycline drug using UV-visible light. The produced ZnS-Y2WO6 nanohybrids exhibited excellent catalytic activity, reaching degradation efficiencies of around 89.92%, 80% and 85.51 % for BB, MR dyes and doxycycline drug, respectively, with a minimum irradiation duration of 120, 60 and 125 min. These nanohybrids outperformed Y2WO6 in terms of photocatalytic efficacy due to enhanced light absorption, efficient charge transfer, and decreased charge carrier recombination between ZnS and Y2WO6 nanoparticles. The synergistic combination of ZnS and Y2WO6 nanoparticles resulted in multiple active sites on the composite surface. Furthermore, the ZnS-Y2WO6 nanohybrids maintained excellent degradation efficiencies of 79.45% and 70.12% for BB and MR dyes, respectively, even after five consecutive cycles, with no significant loss of catalytic activity. The produced ZnS-Y2WO6 nanohybrids were thoroughly analyzed utilizing a variety of analytical methods. Furthermore, the degradation of organic dyes and doxycycline drug related possible mechanism were examined using experimental data, indicating the potential of ZnS-Y2WO6 nanohybrids as excellent photocatalytic materials for oxidizing organic dyes and drugs in aquatic conditions.

Isothermal and kinetic screening of methyl red and methyl orange dyes adsorption from water by Delonix regia biochar-sulfur oxide (DRB-SO).

In this study, Delonix regia seed pods (DRSPs) as a locally available material were refluxed in 90% H2SO4 to yield a novel D. regia seed pods biochar-sulfur oxide (DRB-SO). FTIR, BET, BJH, SEM, EDX, XRD, DSC and TGA were applied to investigate the characterizations of the prepared DRB-SO. Various adsorption parameters like pH effect, dye concentration effect, adsorbent dose, reaction time isotherm and kinetic study were carried out to explain the process of adsorption of methyl orange (MO) and methyl red (MR) onto DRB-SO. Langmuir's adsorption model perfectly explained the adsorption process onto the surface of DRB-SO as a monolayer. The maximum adsorption efficiency of DRB-SO was (98%) and (99.6%) for MO and MR respectively which attained after 150 min with an adsorbent dose of 0.75 g/L. The pseudo-second-order kinetic model best explained the process of adsorption of MO and MR dyes by DRB-SO. The highest observed adsorption amount was as high as 144.9 mg/g for MO dye and 285.7 mg/g for MR dye, comparable with other reported materials based on activated carbon materials. All of the outcomes signposted a prodigious perspective of the fabricated biochar composite material in wastewater treatment. Using the regenerating DRB-SO through an acid-base regeneration process, six cycles of adsorption/desorption were examined. Over the course of the cycles, there was a minor decrease in the adsorption and desorption processes. Also, it was revealed what the most plausible mechanism was for DRB-SO to absorb the ions of the MO and MR dyes.

Preparation and potential of chitosan-based/Al2O3 green hydrogel composites for the removal of methyl red dye from simulated solution.

Different dyes are discharged into water streams, causing significant pollution to the entire ecosystem. The present work deals with the removal of acid red 2 dye (methyl red-as an anionic dye) by green sorbents based on chitosan derivatization. In this regard, two classes of chitosan derivatives-a total of six-were prepared by gamma irradiation at 30 kGy. The first group (group A) constitutes a crosslinked chitosan/polyacrylamide/aluminum oxide with different feed ratios, while the second group, identified as group B, is composed of crosslinked carboxymethyl chitosan/polyacrylamide/aluminum oxide with different ratios. Glycerol was added to soften the resultant hydrogels. The products were characterized by different tools, including FTIR for confirming the chemical modification, TGA for investigating their thermal properties, and XRD for verifying their crystalline structure. The morphology of the prepared derivatives was studied through SEM, while their topography before and after dye adsorption was monitored via the AFM. The removal efficiencies of the prepared sorbents were verified at different operation conditions, such as pH, temperature, adsorbent dose, initial concentration of dye solutions, and contact time. The data revealed that the optimum conditions for maximum dye uptake were as follows: pH 4, contact time 120 min, 0.1-g sorbent dose, and 50-ppm dye concentration. Additionally, the prepared sorbents demonstrated potent adsorption capacity and removal efficiency. It was found that the elements of the second group displayed higher performance than their counterparts. The data showed also that the adsorption process best fits with the Freundlich model and obeyed pseudo-first-order kinetic isotherm. In addition, the synthesized composites showed observable antibacterial potency toward E. coli as a Gram-negative bacterium and S. aureus as a Gram-positive bacterium.