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The current study aims to use a facile and novel method to remove Congo red (CR) and Methyl Orange (MO) dyes from contaminated water with Maize offal biomass (MOB) and its nanocomposite with magnetic nanoparticles (MOB/MNPs). The MOB and MOB/MNPs were characterized with Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), BET, XRD and point of zero charge (pHPZC). The influence of initial CR and MO levels (20–320 mg/L), adsorbent dosage (1-3 g/L), pH (3-9), co-exiting ions, temperature (25–45 °C) and time (15–180 min) was estimated. The findings demonstrated that MOB/MNPs exhibited excellent adsorption of 114.75 and 29.0 mg/g for CR and MO dyes, respectively while MOB exhibited 81.35 and 23.02 mg/g adsorption for CR and MO dyes, respectively at optimum pH-5, and dose 2 g/L. Initially, there was rapid dye removal which slowed down until equilibrium was reached. The interfering/competing ions in contaminated water and elevated temperature favored the dyes sequestration. The MOB/MNPs exhibited tremendous reusability and stability. The dyes adsorption was spontaneous, and exothermic with enhanced randomness. The adsorption effects were well explained with Freundlich model, pseudo second order and Elovich models. It is concluded that MOB/MNPs showed excellent, eco-friendly, and cost-effective potential to decontaminate the water. Nanocomposite of Maize offal biomass demonstrated higher dyes removal. FTIR, SEM, BET, XRD and pHPZC provided vital evidence for dyes adsorption. MOB/MNPs displayed excellent stability and reusability for dyes adsorption. Groundwater samples exposed a higher dyes removal. Results were validated with equilibrium and kinetic adsorption models. [ABSTRACT FROM AUTHOR]

This study presents the synthesis and characterization of a copper-based layered double hydroxide (Cu-LDH) composite via the coprecipitation method. The composite material aimed to effectively remove the anionic dye "Coomassie Brilliant Blue" (CBB) and exhibit antibacterial properties against both gram-positive and gram-negative bacteria. The synthesized nanocomposites were characterized using various techniques. The adsorption of CBB dye was investigated by studying various physicochemical variables, including contact time, pH of the dye solution, and initial dye concentration. The optimal dosage and contact time for efficient CBB dye removal were determined as 0.07 g and 10 min, respectively. The results showed that Cu-LDHs exhibited a high adsorption capacity for CBB dye, with a maximum removal efficiency of 85% which could be achieved within 10 min, and the Cu-LDHs improved an experimental adsorption capacity at equilibrium qmax = 80 mg/g. The adsorption process followed a pseudo-second-order kinetic model. The Langmuir isotherm model provided a good fit to the equilibrium data, indicating monolayer adsorption. Furthermore, the antibacterial activity of Cu-LDHs was assessed against various bacterial strains using a diffusion method. The results demonstrated the inhibitory effects of Cu-LDHs and CBB-Cu-LDHs on bacterial growth at a dosage of 10 mg, indicating the potential of Cu-LDHs as antibacterial agents. The underlying mechanisms responsible for dye adsorption and antibacterial activity were discussed. [ABSTRACT FROM AUTHOR]

Food grade dyes pose severe health hazards when consumed in excessive amounts or enter body via contaminated water. Despite its harmful effects, Allura Red (AR) is very less explored dye for its removal, especially using agricultural/fruit waste. This study presents efficient removal of an important and unsafe food grade dye, AR via adsorption. Waste watermelon peel waste has been used for the first time for treatmenting wastewater contaminated with AR. Waste was converted to two types of adsorbents, with and without subjecting it to pyrolysis. Both the adsorbents were characterized for functionality and crystallinity and used for conducting adsorption studies. Removal of dye was evaluated by intrinsic strategy of monitoring the model solutions under pre‐ and post‐adsorption conditions. Removal percentage of dye was determined by calculating its initial (Co) and final (Cf) concentrations in solution using the formula (see Eq. (1)). Various reaction parameters important for adsorption, viz. pH, adsorbent dose, residence time, reaction temperature and particle size were optimized. Results indicate that ~80 % and >92 % dye could be removed using 0.5 g/L adsorbent before and after pyrolysis respectively in 3.5 h from its 2 ppm concentration in modelled water. [ABSTRACT FROM AUTHOR]

The degradability of an azo dye, Basic Blue 9 (BB9), by heterogeneous sonocatalytic, photocatalytic, and sonophotocatalytic oxidation process was examined using simultaneous irradiation of UV‐C at 254 nm and power ultrasound at 20 kHz accompanied with a heterogeneous catalyst zinc oxide (ZnO) in the study. The effect of ZnO dose and initial dye concentration was investigated on the dye degradation in sonocatalytic, photocatalytic, and sonophotocatalytic processes at pH 5.5 (natural pH). The results obtained from the experimental studies were evaluated with the parameters of color removal, pseudo‐first‐order rate constant, and half‐life time. It was observed that the degradation of BB9 dye by the sonophotocatalytic process was higher compared to both sonocatalytic and photocatalytic degradation. as follows: 97.46, 48.64 and 56.88 %. The combination of sono and photocatalytic showed a remarkable synergistic effect in BB9 degradation. The kinetics of sonophotocatalytic oxidations, depending on the initial BB9 dye concentration, were found to follow the Langmuir‐Hinshelwood model. In addition, the effect of ZnO on the sonophotocatalytic oxidation process was higher compared to titanium dioxide and zero‐valent iron as follows: 97.47, 80.77 and 80.62 %. [ABSTRACT FROM AUTHOR]

This study aims to reduce the band gap by doping wide band‐gap TiO2 with CoFe2O4 and PANI to improve the photocatalytic efficiency and examine the decolorization kinetic of Rhodamine B (RhB). The characteristics of the nanocomposites were thoroughly assessed through the utilization of SEM‐EDS, TEM, XRD, FTIR, VSM, UV‐Vis, PL, and XPS analyses. The SEM and TEM analyses revealed that CoFe2O4/TiO2/PANI has a homogeneously porous structure. XRD analysis results were found to show good agreement with the standard diffraction data cards. The band structures obtained by FTIR analyses were compatible with literature studies. The band gap energies determined by UV‐Vis analyses were determined as 2.86 eV for CoFe2O4/TiO2/PANI. The decrease of CoFe2O4/TiO2/PANI recombination rate was proven with PL results. The different initial dye concentrations, temperature, and light intensity parameters were used to determine the decolorization kinetics of RhB over CoFe2O4/TiO2/PANI. The photodegradation rates of RhB in reactions catalyzed by PANI, CoFe2O4, commercial‐TiO2, CoFe2O4/TiO2, and CoFe2O4/TiO2/PANI were determined as 7.6 %, 20.7 %, 26.6 %, 32.4 %, and 48.8 %, respectively. According to data obtained from the decolorization of RhB on CoFe2O4/TiO2/PANI nanocomposite, the appropriate kinetic model was determined Network kinetic. The adsorption equilibrium constant (KB) and activation energy (Ea) were calculated as 0.007 and 7.9 kJ/mol, respectively. [ABSTRACT FROM AUTHOR]

This work aimed to describe the adsorption behavior of Congo red (CR) onto activated biochar material prepared from Haematoxylum campechianum waste (ABHC). The carbon precursor was soaked with phosphoric acid, followed by pyrolysis to convert the precursor into activated biochar. The surface morphology of the adsorbent (before and after dye adsorption) was characterized by scanning electron microscopy (SEM/EDS), BET method, X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) and, lastly, pHpzc was also determined. Batch studies were carried out in the following intervals of pH = 4–10, temperature = 300.15–330.15 K, the dose of adsorbent = 1–10 g/L, and isotherms evaluated the adsorption process to determine the maximum adsorption capacity (Qmax, mg/g). Kinetic studies were performed starting from two different initial concentrations (25 and 50 mg/L) and at a maximum contact time of 48 h. The reusability potential of activated biochar was evaluated by adsorption–desorption cycles. The maximum adsorption capacity obtained with the Langmuir adsorption isotherm model was 114.8 mg/g at 300.15 K, pH = 5.4, and a dose of activated biochar of 1.0 g/L. This study also highlights the application of advanced machine learning techniques to optimize a chemical removal process. Leveraging a comprehensive dataset, a Gradient Boosting regression model was developed and fine-tuned using Bayesian optimization within a Python programming environment. The optimization algorithm efficiently navigated the input space to maximize the removal percentage, resulting in a predicted efficiency of approximately 90.47% under optimal conditions. These findings offer promising insights for enhancing efficiency in similar removal processes, showcasing the potential of machine learning in process optimization and environmental remediation. [ABSTRACT FROM AUTHOR]

One of the major environmental problems we have today is dye pollution, primarily caused by the textile industry. This pollution has detrimental effects on aquatic life, soil fertility, and human health. Many microbial biosorbents have been documented in the literature for the removal of a wide range of azo dyes commonly employed in the textile industry. However, Yarrowia lipolytica NBRC1658 is firstly used as both free and immobilized sorbents for the removal of Reactive yellow 18 (RY18), acid red 18 (AR18) and basic blue 41 (BB41) in this study. The effect of experimental conditions such as pH, biosorbent quantity, dye concentration, contact time, and temperature on dye removal capacity are examined. The research findings demonstrate that the adsorption capacity is higher in biomass compared to immobilized cells. The highest adsorption capacities are observed at pH 2 for RY18 and AR18, while pH 9 is optimal for BB41. Increasing the adsorbent dosage and initial concentration significantly improves the adsorption capacity. The Langmuir model best describes the adsorption process, indicating that the dye attaches to the biosorbent in a single layer, with a uniform biosorbent surface. The removal of the dye occurs through a chemical process on the biosorbent surface, as evidenced by the pseudo-second-order kinetic model. According to thermodynamic analysis, higher temperatures promote greater adsorption of dyes. Our study shows the effectiveness of Yarrowia lipolyica NBRC1658 as a biosorbent in the removal of a wide range of industrial dyes. [ABSTRACT FROM AUTHOR]

The use of color dyes in modern society presents a great challenge to the environment. Thus, extensive studies have been conducted in the last 30 years on the removal of color dyes from aqueous solutions such industrial wastewater. In this study, the removal of alizarin red S (ARS), an anionic dye, from solution by raw calcite (Cal) and heat-treated calcite (HCal) was conducted and compared under different physico-chemical conditions. Based on the isotherm study, the ARS removal capacities increased from 167 to 251 mmol/kg after the Cal was heated to 1000 °C for 3 h. The X-ray diffraction analyses showed no difference in the calcite phase between Cal and HCal after ARS sorption. Fourier-transform infrared results also showed no change in the calcite phase after ARS sorption, except a slightly increase in wavenumber from 713 to 727 cm−1 for the OCO bending of HCal at high ARS sorption levels. SEM observations showed about the same particle size and morphology before and after ARS sorption. The TGA data showed the formation of CaO after Cal was heated, and CaO converted back into calcite after being in contact with water or ARS solution for 24 h and then being air-dried. Thus, the high ARS removal could be due to CaO produced after Cal being heated. The findings from this research proved that there is great potential in the use of calcite, a low-cost and readily available Earth material, after heat treatment for the removal of contaminants from water. [ABSTRACT FROM AUTHOR]

In this work, methyl orange degradation was investigated using iron-modified dolomite prepared by simple impregnation of iron followed by calcination at 500 °C for 4 h. The natural dolomite before and after modification was subjected to comprehensive characterization utilizing various techniques. XRD and FTIR analysis confirmed the preservation of the dolomite structure and functional groups. The chemical composition obtained by XRF and EDX showed a successful insertion of iron into the dolomite structure with an increase from 1.3 to 5.3 wt % of this metal. The study of the reaction parameters showed that decolorization performance significantly depended on the temperature, catalyst dosage, H2O2 concentration and initial dye concentration. In addition, kinetics reaction followed the first-order model with rate constants in the range 3.2·10–2 to 45·10–2 min−1. The thermodynamic study revealed that the reaction was endothermic (ΔH° = 65.48 kJ/mol) and accompanied by a decrease in the disorder (ΔS° = -0.055 kJ/mol·K). The activation energy value (Ea = 63.98 kJ/mol) showed that the process was controlled by a surface reaction. The modelling using central composite design (CCD), with 40 experiments performed to complete the matrix of the experimental design established the optimum reaction conditions at C0 = 40 mg/L, 0.93 g/L of catalyst dosage and 7.26 mM of H2O2 concentration. The catalyst preserved high performance and stability after six successive cycles (90.23% decolorization efficiency) with a low iron leaching of less than 0.75 mg/L. The final effluent showed low ecotoxicity with a chemical oxygen demand (COD) lower than 8.23 mg O2/L. [ABSTRACT FROM AUTHOR]

Malachite green (MG) is extensively used in various industries including the food sector, despite having carcinogenic, mutagenic, and teratogenic effects. In the present study, sodium alginate/bentonite (SA/Bnt) nanocomposite was synthesized and characterized to evaluate its potential as an adsorbent to remove MG dye from aqueous solution. The response surface method (RSM) was utilized to optimize the process, and the kinetics of adsorption were evaluated based on experiments carried out thereon. The first-order model was shown to have a decent connection between some parameters and the outcome in this experimental situation. ANOVA results showed that only three of the five parameters (MG dye concentration, contact time, and adsorbent dosage) were important in the removal of the dye. The process parameters such as dye concentration (10–50 mg L−1), contact time (10–60 min), adsorbent dosage (0.5–1.5 g L−1), pH (3–8), and temperature (25–55 °C) were optimized to achieve maximum dye removal, which was around 96%. The correlation of pseudo-second-order kinetic was found to be best fitted with adsorption data with an R2 value of 1.00. The synthesized nanocomposites were found to be effective as bio-adsorbent agents. [ABSTRACT FROM AUTHOR]

Recently a large number of extensive studies have amassed that describe the removal of dyes from water and wastewater using natural adsorbents and modified materials. Methyl orange dye is found in wastewater streams from various industries that include textiles, plastics, printing and paper among other sources. This article reviews methyl orange adsorption onto natural and modified materials. Despite many techniques available, adsorption stands out for efficient water and wastewater treatment for its ease of operation, flexibility and large-scale removal of colorants. It also has a significant potential for regeneration recovery and recycling of adsorbents in comparison to other water treatment methods. The adsorbents described herein were classified into five categories based on their chemical composition: bio-sorbents, activated carbon, biochar, clays and minerals, and composites. In this review article, we want to demonstrate the capacity of natural and modified materials for dye adsorption which can yield significant improvements to the adsorption capacity of dyes such as methyl orange. In addition, the effect of critical variables including contact time, initial methyl orange concentration, dosage of adsorbent, pH, temperature and mechanism on the adsorption efficiency will be covered as part of this literature review. The novelty of this review article describes the utility of various natural and modified materials employed to remove methyl orange (MO) from water, wastewater and aqueous solutions. Natural sorbents are very popular adsorbents because the majority of them are affordable and readily accessible in terms of addressing key challenges concerning water security that are relevant to MO adsorption processes. This review is significant since it will be useful in guiding researchers on the selection of an adsorbent that would be suitable for MO adsorption. Furthermore, our findings provide a basis for researchers interested in the design of composite adsorbents based on the selection of constituent components. [ABSTRACT FROM AUTHOR]

Stenotrophomonas koreensis, was isolated from a textile effluent and employed to biologically degrade 98.8% of the recalcitrant toxic dye malachite green in 4 h in the absence of any supplements or media. Chromatographic and Spectroscopic analysis confirmed the degradation of the dye. According to Response Surface Methodology, the optimum conditions for biodegradation were pH 6, inoculum size 6 mL (initial concentration Log10CFU/mL = 6.2), and temperature 45 °C. More than 98% decolorization was achieved within 2.5 h of the addition of soymeal extract or peptone. One of the most promising features of this strain is that even in the presence of heavy metals, S. koreensis actively degraded the dye. The bacteria biodegraded malachite green following the first-order reaction kinetics. LC-MS analysis of the degradation product yielded several intermediates like Michler's ketone (m/z 269), 4-N,N-dimethylaminophenol (m/z 137), Benzophenone (m/z 182), N,N-dimethylaniline (m/z 121), 4-(N-methylamino)-benzophenone (m/z 211), 4-aminobenzaldehyde (m/z 121), anionic canonical form of 4-aminobenzaldehyde (m/z 120), 4-(N,N-dimethylamino)benzoic acid (m/z 165), 4-(N-methylamino) benzoic acid (m/z 152). The enzymes responsible for the malachite green degradation were tyrosinase, Malachite Green reductase, and NADH-DCIP reductase. The present work is the first to report the degradation of malachite green by S. koreensis. [ABSTRACT FROM AUTHOR]

It is established that anthryltricyanoethylene reacts with cysteine and glutathione. The addition of biothiols to an anthryltricyanoethylene solution leads to a strong change in the color of the latter compound, which potentially opens up the possibility of using this dye for quantitative determination of the concentration of biothiols in living cells. The study of the model reaction of anthryltricyanoethylene with benzyl mercaptan and the isolation of a new compound, 5-amino-4-(anthracen-9-yl)-2-(benzylthio)-1H-pyrrole-3-carbonitrile, made it possible to propose the mechanism for the reaction of anthryltricyanoethylene with biothiols. [ABSTRACT FROM AUTHOR]

This paper presents the preparation and characterization of bentonite coated with hydroxide double lamellar Mg/Al-bentonite and Zn/Al-bentonite as a potential adsorbent material. The coating process involved co-precipitation of mixed metal nitrate solution (Mg-Al) or (Zn-Al), followed by immersion of bentonite (B-Na+) dispersion. The structures and morphologies of the coated bentonites were characterized using XRD, FTIR, BET, and SEM analysis. The results of the BET analysis indicate that Mg/Al-bentonite and Zn/Al-bentonite have larger surface areas and pore volumes compared to bentonite alone. Specifically, the surface area of Mg/Al-bentonite is 209.25 m2/g with a pore volume of 0.423 cm3/g, while Zn/Al-bentonite has a surface area of 175.95 m2/g and a pore volume of 0.313 cm3/g. In contrast, the surface area and pore volume of bentonite alone are 110.43 m2/g and 0.132 cm3/g, respectively. The Mg/Al-bentonite reaches 85% uptake within 3 h (equivalent to 724.20 mg/g at 25 °C and pH 7), achieving rapid equilibrium. In contrast, the Zn/Al-bentonite achieves a maximum adsorption of 74% within 5 h under identical pH and temperature conditions, corresponding to 650.34 mg/g. The error function values, including the correlation coefficient R2, chi-square test χ2, and residual sum of squares RSS, were calculated to evaluate both kinetic and isotherm models. The kinetic adsorption data agreed well with a pseudo-second-order model. The adsorption process followed the Sips isotherm model, and the monolayer adsorption capacity of Mg/Al-bent and Zn/Al-bent composites was 872.41 (R2 = 0.974) and 678.45 mg/g (R2 = 0.983), respectively. The thermodynamic analysis of the adsorption process revealed that it occurred spontaneously with an endothermic characteristic. The parameters ΔS, ΔH, and ΔG were used to determine this. [ABSTRACT FROM AUTHOR]

The main challenges to overcome within the Fenton process are the acidic pH as an optimal reaction condition, sludge formation in neutral pH medium and high toxicity of treated printing wastewater due to the generation of contaminating by-products. This research discusses the catalytic activity of homogeneous (FeSO4/H2O2) and heterogeneous (Fe2(MoO4)3/H2O2) Fenton processes in treatment of Yellow azo printing dye in synthetic aqueous solution and real printing effluent, with an integration of adsorption on functionalized biochar synthesized from wild plum kernels. The definitive screening design (DSD), was used to design the experiment. Independent variables were initial dye concentration (20–180 mg L−1), iron concentration (0.75–60 mg L−1), pH (2–10) and hydrogen peroxide concentration (1–11 mM). Higher decolourization efficiency of 79% was obtained within homogeneous Fenton treatment of printing wastewater, in comparison to heterogeneous Fenton treatment (54%), after a reaction time of 60 min. Same trend of mineralization degree was established: COD removal was 59% and 33% for homogeneous and heterogeneous Fenton process, respectively. The application of adsorption treatment has achieved significant advantages in terms of toxicity reduction (95%) and decolourization efficiency (90% of TOC removal and 22% of dye removal) of treated samples, even at neutral pH medium. Degradation mechanisms within Fenton and adsorption processes were proposed based on the qualitative gas chromatography/mass spectrometry analysis, physico-chemical properties of dye degradation products and functionalized biochar. Overall, the homogeneous Fenton/adsorption combined process can be potentially used as a treatment to remove azo dyes from contaminated water. [ABSTRACT FROM AUTHOR]

In this paper, La-doped Ti/SnO2-Sb2O4 electrode was prepared by electrodeposition and used for electrochemical degradation of rhodamine B. The optimum preparation conditions of the electrode were optimized as deposition time of 15 min and calcination at 500 ℃ for 2 h. The water treatment conditions were selected as initial pH 3.0, electrolyte Na2SO4 concentration 0.1 M, current density 30 mA cm−2, and initial rhodamine B concentration 20 mg L−1; the color and TOC removal of RhB reached 99.78% and 82.41% within 30 min. The FESEM, XRD, XPS, CV, LSV, and EIS characterization studies demonstrated that Ti/SnO2-Sb2O4-1%La electrode had a dense structure and the highest oxygen evolution potential (2.14 V) and lowest charge transfer resistance (0.198 Ω cm−2), indicating that doped La has lower energy consumption. Moreover, La doping can expand the specific surface area, active site, performance of pollutant degradation, and service life of the electrode. Especially, the service life of Ti/SnO2-Sb2O4-1%La is increased by three times, and the maximum life span reaches 90 min (1000 mA cm−2, 1 M H2SO4). Free radical quenching experiments show that ·OH plays a major role in the degradation of RhB. The Ti/SnO2-Sb2O4-1%La electrode prepared in this paper and its results will provide data support and reference for the design of efficient electrocatalytic electrode. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of an oxidized pine needle-thiosemicarbazone Schiff base (OPN-TSC) from whole pine needles (WPN) as a dual-purpose adsorbent to remove a cationic dye, methylene blue (MB), and Hg2+ ions in separate processes. The adsorbent was synthesized by periodate oxidation of WPN followed by a reaction with thiosemicarbazide. The syntheses of OPN and OPN-TSC were confirmed by FTIR, XRD, FESEM, EDS, BET, and surface charge analysis. The emergence of new peaks at 1729 cm−1 (–CHO stretching) and 1639 cm−1 (–COO− stretching) in the FTIR spectrum of OPN confirmed the oxidation of WPN to OPN. FTIR spectrum of OPN-TSC has a peak at 1604 cm−1 (C = N stretching), confirming the functionalization of OPN to OPN-TSC. XRD studies revealed an increase in the crystallinity of OPN and a decrease in the crystallinity of OPN-TSC because of the attachment of thiosemicarbazide to OPN. The values of %removal for MB and Hg2+ ions by OPN-TSC were found to be 87.36% and 98.2% with maximum adsorption capacity of 279.3 mg/g and 196 mg/g for MB and Hg2+ ions, respectively. The adsorption of MB followed pseudo-second-order kinetics with correlation coefficient (R2 of 0.99383) and Freundlich isotherm (R2 = 0.97239), whereas Hg2+ ion removal demonstrated the Elovich (R2 = 0.97076) and Langmuir isotherm (R2 = 0.95110). OPN-TSC is regenerable with significant recyclability up to 10 cycles for both the adsorbates. The studies established OPN-TSC as a low-cost, sustainable, biodegradable, environmentally benign, and promising adsorbent for the removal of hazardous cationic dyes and toxic metal ions from wastewater and industrial effluents, especially the textile effluents. [ABSTRACT FROM AUTHOR]

Preformed flocs prepared by using coagulants, i.e. Fe2(SO4)3, MnSO4.4H2O, and MnCl2.4H2O, were applied as adsorbents for the decolorization of an aqueous C.I. Acid Red 1 dye solution. In order to determine the decolorizing efficiency of different adsorbents, kinetic and equilibrium studies were carried out at the optimum pH. Excellent color removal of 87 % was obtained with Fe2(SO4)3 at pH 4, good color removal of 65 % was achieved with manganese sulfate at pH 10, and moderate color removal of 58 % was obtained with manganese chloride at pH 10, at an optimum sorbent dose of 500 mg L−1 and an equilibrium contact time of 15 min. The sorption data of the equilibrium studies fitted well to the Langmuir isotherm, stating the occurrence of monolayer formation in the adsorption process of dye color removal. The maximum adsorption capacities of ferric sulfate and manganese sulfate are 47.619 and 23.474 mg g−1, respectively. The data of the kinetic studies fitted well to the pseudo‐second‐order equation, stating that chemisorption is the rate‐limiting step. [ABSTRACT FROM AUTHOR]

Pollution of water is mainly due to industrial wastewater. In current research work, Blue-XGRRL dye removal using green hybrid materials was optimized via batch and column study. The characterization study of prepared materials was carried out via scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infra-red (FTIR) spectroscopy, and thermal analysis. The pH for maximum adsorption capacity of wheat straw (WS), wheat straw-zinc oxide-polythiophene (WS-ZnO-PTh), wheat straw-zinc oxide-polyaniline (WS-ZnO-PANI), and wheat straw-zinc oxide-polypyrrole (WS-ZnO-PPY) was determined to be 10 (14.6 mg g−1), 10 (31 mg g−1), 10 (37.8 mg g−1), and 11 (43.9 mg g−1) correspondingly and optimum dosage was determined to be 0.05 g/50 mL. The highest adsorption potential for all hybrid materials was achieved within a time duration of 60 min and highest adsorption potential for WS (30.7 mg g−1), WS-ZnO-PTh (43.8 mg g−1), WS-ZnO-PANI (55.8 mg g−1), and WS-ZnO-PPy (66.8 mg g−1) was obtained utilizing 100 mg L−1 dye at 30 °C. The data obtained through adsorption experiments presented the best fitness to pseudo-second-order kinetics and Langmuir sorption isotherm giving significant R2 values of 0.94–0.99 and 0.994–0.9994 respectively. Thermodynamic study showed exothermic nature of sorption. During column approach, optimal adsorbent bed height, dye flow rate, and inlet initial dye concentration to attain highest adsorption (30 mg g−1) were determined to be cm, 1.8 mL min−1, and 70 mg L−1 respectively indicating these materials a good alternative for dye removal. [ABSTRACT FROM AUTHOR]

Malachite green (MG) is a synthetic cationic dye extensively utilized in the textile industry for colouring purposes. It is a mutagenic agent and potentially carcinogenic for living organisms in nature. Therefore, it is necessary to treat and discharge the industrial effluents covering MG to avoid irreversible and serious effects on both living organisms and the environment. The photocatalyst SnO2 was synthesized by a new method by complexation of sodium diethyldithiocarbamate with tin dichloride pentahydrate, followed by calcination at 450, 600 and 750°C and utilized for photocatalytic degradation of MG dye. The better degradation was obtained at calcination temperature 600°C. The fluorescent light exposure resulted better degradation % of MG dye within 20 min, and the absorbance measurements were noted after every 5 min. The degradation of MG dye improved with an increase in the dose of SnO2 photocatalyst up to 20 mg. The highest decomposition of MG dye was found at 10 pH which may be due to deprotonation. The effects of Na+, HCO3−, Ca2+, Cl−, K+, SO42− and Mg2+ on dye degradation were examined and results showed that the salts had no effect on degradation. The kinetics and isothermic studies were carried out where the kinetic model pseudo-second-order and Langmuir isotherm were highly fitted. The factorial design was also drawn to checked the combined effects of variables, such as pH, dose, concentration and irradiation time on the degradation of MG dye. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicle (UAV)-based geological mapping is significant for understanding the geological structure in the high-steep slopes, but the images obtained in these areas are inevitably influenced by the backlit effect because of the undulating terrain and the viewpoint change of the camera mounted on the UAV. To handle this concern, a novel backlit image restoration method is proposed that takes the real-world application into account and addresses the color distortion issue existing in backlit images captured in high-steep slope scenes. Specifically, there are two main steps in the proposed method, which consist of the backlit removal and the color and detail enhancement. The backlit removal first eliminates the backlit effect using the Retinex strategy, and then the color and detail enhancement step improves the image color and sharpness. The author designs extensive comparison experiments from multiple angles and applies the proposed method to different engineering applications. The experimental results show that the proposed method has potential compared to other main-stream methods both in qualitative visual effects and universal quantitative evaluation metrics. The backlit images processed by the proposed method are significantly improved by the process of feature key point matching, which is very conducive to the fine construction of 3D geological models of the high-steep slope. [ABSTRACT FROM AUTHOR]

BACKGROUND: Preparing catalysts with heterojunction structures is a strategy to achieve efficient charge separation and transfer of charges to enhance photocatalytic activity of photocatalysts. To optimize the graphitic carbon nitride (g‐C3N4)‐based photocatalysts, Bi2MoO6@ 2D g‐C3N4 catalyst was prepared. RESULTS: 2D Bi2MoO6 nanopiece@2D g‐C3N4 nanoflake composites in different proportions were prepared by the hydrothermal method. The prepared materials were characterized by various modern instrumental analyses, and their photocatalytic ability to decompose water and degrade rhodamine B under visible light irradiation was tested. Compared with pure Bi2MoO6 nanopiece and g‐C3N4 nanoflake, the hydrogen evolution rate of Bi2MoO6 nanopiece@g‐C3N4 nanoflake (1:10) composite was highest, at 4847 μmol h−1 g−1. The composite (3:10) exhibited significantly enhanced photocatalytic rhodamine B degradation for organic dye removal due to the formation of an excellent heterojunction to improve the separation and migration efficiency of photogenerated carriers. CONCLUSION: O2− and •OH were the two main active species in the photocatalytic degradation of rhodamine B. Bi2MoO6 formed a heterojunction with g‐C3N4, which accelerated separation and migration efficiency, thereby enhancing the photocatalytic activity. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

This study reports a simple and low-cost method for water purification using recyclable natural fibers (coarse wool fibers) as column-filling media for adsorption in the dynamic mode. As an instance of a dissolved organic pollutant, a cationic dye (basic blue 9, BB9) was assayed. According to the Langmuir isotherm (recorded at 300 K), the calculated maximum adsorption capacity of the fibrous material was found to be 24.86 mg/g for the retention of BB9. Response surface methodology (RSM) was employed for the design of experiments and the model-based optimization of the adsorption process performed in the dynamic regime (fixed-bed column). The optimal conditions provided by RSM indicated an adsorbent column height of H = 13.5 cm and a feed flow rate of Fv = 3 mL/min; these operating parameters ensured a color removal efficiency of 92.56% after 240 min of contact time. The recorded breakthrough curve under the optimal conditions was further interpolated using five quantitative mathematical models (Adams–Bohart, Thomas, Yoon–Nelson, Yan, and Clark) to assess the dynamic behaviors in the fixed-bed column. The best goodness-of-fit was achieved for the Thomas and Yoon–Nelson models. Thus, the coarse wool fibers used in a fixed bed demonstrated a relevant efficiency in the removal of cationic organic pollutants from contaminated water. [ABSTRACT FROM AUTHOR]

This research work demonstrates a highly efficient photocatalytic destruction of rhodamine B dye and tetracycline drug on the surface of S-scheme AgI/g-C3N4 heterojunctions under simulated solar radiations. The thermal decomposition of urea fabricates g-C3N4 nanosheets with auspicious physicochemical and photocatalytic properties. However, brilliant yellow AgI nanoparticles are synthesized by combined precipitation-ultrasonic routes. AgI/g-C3N4 heterojunctions containing different compositions of g-C3N4 and AgI nanoparticles are constructed sonochemically. The physicochemical properties of the heterojunctions are investigated by DRS, PL, HRTEM, Zeta potential measurements, BET, XPS and XRD analysis. The photocatalytic experiments have pointed out that g-C3N4 sheets decomposes 12% of RhB dye due to the poor separation efficiency of the electron-hole pairs and low surface area of solid specimen. With introducing AgI nanoparticles on g-C3N4 sheets, the surface properties of the photocatalyst improved and the ultra-fast recombination rate of the electron-hole pairs is inhibited. The decomposition of RhB dye approaches 67, 92 and 85% of initial dye concentration for heterojunctions containing 5, 10 and 15 wt% AgI, respectively. Superoxide, positive holes and hydroxyl radicals are the main reactive species for expelling RhB as elucidated from scrubber experiments. S-scheme charge transportation mechanism records a plausible explanation for production of charge carriers with auspicious redox power. Hopefully, this research study inspire the rational design of the photocatalysts for efficient destruction of organic pollutants. [ABSTRACT FROM AUTHOR]

The simultaneous determination of trace pesticides in complex matrices containing high concentrations of natural pigments remains challenging. In this study, quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation together with high-performance liquid chromatography with ultraviolet detection (HPLC–UV) was applied for the multi-residue analysis of seven sulfonylurea herbicides (SUHs) in tomatoes. SUH residue was extracted using the QuEChERS procedure, followed by solid-phase extraction (SPE) and dispersive SPE (d-SPE). To reduce the amount of carotenoids in tomato extracts, several d-SPE clean-up procedures were compared, and octadecylsilane (C18) provided the best color removal rate (%) of tomato extracts and recoveries (%) for all the tested SUHs. The validation results indicate good linearity (R2 > 0.9970), accuracy, and precision. Recoveries of 70–120% and relative standard deviations < 20% were achieved for all analytes at three spiked concentrations. The limits of detection and quantification for the 7 SUHs were 0.003 mg kg−1 and 0.008–0.009 mg kg−1, respectively. The developed method was subsequently used to quantify multi-residue SUHs during real sample analysis. None of the tested samples had SUH residue levels higher than the maximum residue limits established by the Korean Ministry of Food and Drug Safety. The results suggest that QuEChERS sample preparation employing a combination of C18 is a high-throughput and rapid clean-up procedure for the multi-residue analysis of SUHs in tomatoes. [ABSTRACT FROM AUTHOR]

Methylene blue is a synthetic and cationic dye that finds utility in different fields including pharmaceutical, paper, textile, printing, carpet, and photography industries. Adsorption is a very effective technique to decolorize contaminated wastewater. This study aimed to determine the efficacy of Multiwalled Carbon Nanotubes (MWCNTs) as an adsorbent for decolorization of MB dye from aqueous solutions. The study examined various characteristics affecting adsorption, including concentration of dye, pH value, dosage of MWCNTs, and contact time. The results that growing the adsorbent dosage from (25 to 120) mg increased the dye efficiency rate from 62% to 98%, respectively, were shown. The study also evaluated pH, which is among the most critical factors influencing removal efficiency. The best pH for the removal efficiency was 6 at an initial concentration of MB dye 20 mgL-1, a contact time 60 min, and an MWCNT dosage 100 mg. Langmuir, Freundlich, and Temkin isotherms were used to describe the adsorption equilibrium. The Langmuir isotherm with an R² value of 0.9968 and a maximum capacity for adsorption of 19.6 mgg-1 provided a suitable fit for the data of the experiment. In comparison between the suitability of kinetic models pseudo-first-order, pseudo-second order, and Weber-Morris, the kinetics model's correlation value was shown to be greater than that of the pseudo-second order kinetic model with an R² value of 0.9982. [ABSTRACT FROM AUTHOR]

This study presented a facile synthesis route via the precipitation method for the production of magnetic biochar from oil palm frond (OPF). The physicochemical characteristics including surface, functional, and magnetic properties of the synthesized magnetic biochar revealed that the surface morphology, porosity, and magnetic properties enhanced its adsorption capacity for the removal of crystal violet (CV) and sunset yellow (SY) from aqueous solution. The saturation magnetization of OPF biochar was found to be 8.41 emu/g, coercivity (Hc) of 83.106 G, and retentivity (Mr) of 1.475 emu/g which implies that OPF magnetic biochar can be facilely separated from aqueous solution. The result also demonstrated superparamagnetic properties which provided suitable magnetic responsive characteristics to an external magnetic field. The interactive effect of the operational conditions of pH, adsorbent dosage, initial concentration, and temperature was investigated in a batch adsorption study using the central composite design (CCD) of the response surface methodology (RSM). It was indicated that an increase in adsorbent dosage to 1.0 g/L at a lower initial concentration (50 ppm) conducted at 20 °C favoured optimum removal of CV and SY at pH 11 and 4, respectively. The Langmuir isotherm model with maximum adsorption capacity ( q max ) of 149.03 and 342.47 mg/g was achieved for CV and SY dyes, respectively. The kinetic data proved to be best fitted to the pseudo-second-order kinetic model. Thermodynamic parameters revealed spontaneous and endothermic reactions. The suitability and sustainability of the magnetic biochar were enhanced by its regeneration potential for effective adsorption of CV and SY after 5 cycles which indicates its outstanding reusability. Hence, OPF magnetic biochar exhibited prospective application for the removal of dyes from wastewater. [ABSTRACT FROM AUTHOR]

The entire ecology is contaminated by the synthetic dyes that are widely utilised in the textile industries. They can be handled using a variety of technologies, but an eco-friendly method called electrocoagulation has been used to prevent additional contamination. Textile wastewater containing disperse dyes are successfully treated in Electrocoagulation (EC) utilizing Al, Fe, and Stainless Steel (SS), but it is not cost effective, also the treated water contains certain mg/L of the metals used, along with dye components, which obstructs the reuse of the same. The effects of initial pH, applied voltage, dye concentration, supporting electrolyte, and treatment time on the colour removal efficiency (CRE) and consumption of energy were examined in EC process followed by activated charcoal filtration (hybrid process) with a monopolar Ti/Ti electrode on the remediation of aqueous solution of Dispersive Blue-79 (dye 3G). The maximum CREobtained was 99.4%, chemical oxygen demand (COD) 93%, and biological oxygen demand (BOD) 85%, under the following optimized operating conditions, applied voltage 15 V, pH = 7, concentration of dye, electrolyte 110 mg/L, 0.2 g/L and time = 15 min. The overall operating cost for the treatment of aqueous dye 3G was 0.455US/m3. The mechanism of EC was studied using XPS analysis in the sludge obtained. For the purpose of the reuse, FTIR, AAS, and ICP-OES analysis were done and compared with the aqueous dye 3G, after EC and hybrid process to ensure the maximum removal of the degraded dye components and metal. ICP-OES results showed that there were no traces of metal in the treated aqueous dye 3G using this method. Throughout the study, the experimental outcomes indicated that the hybrid process upgraded the quality of the treated aqueous dye 3G. [ABSTRACT FROM AUTHOR]

The oxidation of aqueous solutions containing Allura Red AC (AR–AC) using bicarbonate-activated peroxide (BAP) and cobalt-impregnated pillared clay (Co/Al–PILC) as the catalyst was investigated. Using the CCD-RMS approach (central composite design–response surface methodology), the effects of dye, H2O2, and NaHCO3 concentrations on AR–AC degradation were studied. The decolorization, total nitrogen (TN), and total carbon (TC) removals were the analyzed responses, and the experimental data were fitted to empirical quadratic equations for these responses, obtaining coefficients of determination R2 and adjusted-R2 higher than 0.9528. The multi-objective optimization conditions were [dye] = 21.25 mg/L, [H2O2] = 2.59 mM, [NaHCO3] = 1.25 mM, and a catalyst loading of 2 g/L. Under these conditions, a decolorization greater than 99.43% was obtained, as well as TN and TC removals of 72.82 and 18.74%, respectively, with the added advantage of showing cobalt leaching below 0.01 mg/L. Chromatographic analyses (GC–MS and HPLC) were used to identify some reaction intermediates and by-products. This research showed that wastewater containing azo dyes may be treated using the cobalt-catalyzed BAP system in heterogeneous media. [ABSTRACT FROM AUTHOR]

In this study, a cross-linked chitosan-epichlorohydrin/nanosilica (CS-EPH/NSi) bionanocomposite was prepared using a simple two-step process. First, functionalization of chitosan with nanosilica followed by crosslinking process with epichlorohydrin. The CS-EPH/NSi bionanocomposite's adsorption property toward the removal of reactive orange 16 (RO16) dye was evaluated. The adsorption process of RO16 by CS-EPH/NSi was optimized using Box-Behnken design (BBD). The desirability function results revealed that the highest removal of RO16 (96.32%) is achieved at the following experimental conditions: solution pH of 4.26, dosage of CS-EPH/NSi = 0.089 g/100 mL, and contact time of 9.69 min. The Langmuir isotherm model was found to describe the equilibrium behavior of the monolayer adsorption process at 25 °C. The kinetics data of RO16 adsorption by CS-EPH/NSi were appropriately described by a pseudo-second order model, which suggests that the adsorption process occurs via chemisorption. The high adsorption capacity of CS-EPH/NSi for RO16 (110.2 mg/g) can be attributed to the electrostatic forces between the positively charged CS-EPH/NSi and the negatively charged RO16 anions, as well as n-π and H-bond interactions. Overall, this study demonstrates the potential of CS-EPH/NSi as an adsorbent for the efficient removal of textile RO16 dye. [ABSTRACT FROM AUTHOR]

The present study is an attempt to investigate the potentiality of Rhizoclonium hieroglyphicum in the removal of reactive red 239 (RR239) from aqueous solution and to assess the toxicity of the treated dye solution. Optimisation of the process variables namely dye and biosorbent concentrations, pH, temperature and incubation time for RR239 removal was performed using Response Surface Methodology (RSM) assisted Box Behnken Design (BBD) model. The recycling and regeneration efficiency of the dye adsorbed alga was evaluated using different eluents under optimized conditions. Further to understand the adsorption mechanism, isotherms, kinetics and thermodynamic studies were performed. UV–vis and FT-IR spectroscopy was employed to confirm the interaction between the adsorbate and biosorbent. The nature of the treated dye solution was assessed using phyto, microbial and brine shrimp toxicity studies. On the basis of quadratic polynomial equation and response surfaces given by RSM, 90% decolorization of RR239 was recorded at room temperature under specified optimal conditions (300 mg/L of dye, 500 mg/L of biosorbent, pH 8 and 72 h of contact time). Desorption experiments demonstrated 88% of RR239 recovery using 0.1 N acetic acid as an eluent and 81% of dye removal in regeneration studies. The data closely aligned with Freundlich isotherm (R2 − 0.98) and pseudo-second-order kinetic model (R2 − 0.9671). Thermodynamic analysis revealed that the process of adsorption was endothermic, spontaneous, and favorable. UV–Vis and FT-IR analyses provided evidence for adsorbate–biosorbent interaction, substantiating the process of decolorization. In addition, the results of phyto, microbial and brine shrimp toxicity assays consistently confirmed the non-toxic nature of the treated dye. Thus, the study demonstrated that R. hieroglyphicum can act as a potent bioremediation agent in alleviating the environmental repercussions of textile dyeing processes. [ABSTRACT FROM AUTHOR]

A single-step dye removal strategy from wastewater is inadequate for concentrations above 100 mg/L. In order to address this limitation, the adsorption of high dye concentrations followed by phytoremediation is a potential approach for the treatment of dye-contaminated wastewater. This combined method utilizes physical adsorption and biological processes to remove dyes from wastewater. Herein, we investigated a pilot-scale multi-step cascaded process where batch adsorption and fixed-bed column adsorption were combined with phytoremediation to remove cellulose-reactive blue dye at 200 to 500 mg/L concentrations. The batch adsorption utilized low-cost water hyacinth root powder (WHRP) bioadsorbent having 670 m2/g surface area, whereas the fixed-bed column adsorption used sand having a surface area of 75 m2/g. The phytoremediation process utilized water hyacinth plants in a series of ponds. The effluent from one unit is fed to the next until the dye is removed to more than 98% for all concentrations considered in this study. Pilot-scale experimental data fitting to adsorption isotherms and kinetics were performed to gain insight into the pilot-scale adsorption mechanism. The fixed-bed sand column adsorption was conducted at different inlet dye concentrations, flow rates, and bed heights. The breakthrough curves were fit to the Thomas, Yoon–Nelson, and Bohart-Adams models. The effluent from the fixed-bed column was transferred to phytoremediation ponds, where complete dye removal was achieved. Overall, data collectively presented in this study demonstrated that the combined adsorption and phytoremediation approach offers a potential solution for the remediation of high dye concentration in wastewater, providing an effective and sustainable treatment option. [ABSTRACT FROM AUTHOR]

Constructing crystalline covalent organic frameworks (COF) robust 3D reusable macroscopic objects exposing more adsorption sites with high water flux for use as a filter is an unresolved challenge. A simple scalable procedure is shown for making a robust, highly compressible 3D crystalline COF nanowire interconnected porous open‐cell sponge. The compressive strength and Young's modulus (80% strain) of the sponge are 175 and 238 kPa, respectively. The sponge can withstand multiple compression‐release cycles and a load of 2800 times its weight without collapsing. As an exemplary application, the use of a COF sponge in the selective removal and separation of cationic model dye from a mixture of dyes in water by adsorption and filtration with >99% efficiency is shown. Depending on the dye concentration, the dye removal time can be as short as 2 min, and dye adsorption efficiency can be as high as 653 mg g−1 (COF in the sponge). During filtration, the sponges as filters show a high water flux of 2355 L h−1 m−2 under ambient conditions and maintain their performance for many cycles. The lightweight, reusability, and efficiency make present sponges sustainable materials as adsorbents and filters. [ABSTRACT FROM AUTHOR]

The extensive utilization of dyes across diverse industries has resulted in environmental pollution, leading to the degradation of water bodies. To prevent environmental contamination, the use of eco-friendly dyes and innovative processes for dye degradation is crucial. This study aimed to investigate the color removal process of cochineal dye (Dactylopius coccus Costa) using the atmospheric pressure plasma jet (APPJ: Atmospheric Pressure Plasma Jet) technique. The dye extracted from the cochineal insect was treated with APPJ and the resulting color removal process was analyzed. Optical emission spectroscopy (OES) was used to investigate the plasma emission lines, and UV-Vis spectroscopy was used to monitor the color removal process. The results revealed that the decolorization of cochineal dye was a result of an oxidative degradation process caused by the interaction of the reactive species (NO3− and NO2−) generated by the APPJ plasma discharge with the dye molecules. This color removal process occurs in an acidic medium, leading to a pH change from 5.4 to 2.7. These pH changes can be attributed to fluctuations in the concentrations of reactive species such as nitrates and nitrites in the liquid phase. UV-Vis spectroscopy measurements showed that 90% of the cochineal color was removed within the first 10 min of treatment. This study enhances our understanding of natural color removal and provides insights into its mechanism, opening up possibilities for controlled modification and applications in various fields. [ABSTRACT FROM AUTHOR]

Based on deep learning, an underwater image instance segmentation method is proposed. Firstly, in view of the scarcity of underwater related data sets, the size of the data set is expanded by measures including image rotation and flipping, and image generation by a generative adversarial network (GAN). Next, the underwater image data set is finally constructed by manual labeling. Then, in order to solve the problems of color shift, blur and the poor contrast of optical images caused by the complex underwater environment and the attenuation and scattering of light, an underwater image enhancement algorithm is used to first preprocess the data set, and several algorithms are discussed, including multi-scale Retinex (MSRCR) with color recovery, integrated color model (ICM), relative global histogram stretching (RGHS) and unsupervised color correction (UCM), as well as the color shift removal proposed in this work. Specifically, the results indicate that the proposed method can largely increase the segmentation mAP (mean average precision) by 85.7% compared with without the pretreatment method. In addition, based on the characteristics of the constructed underwater dataset, the feature pyramid network (FPN) is improved to some extent, and the preprocessing method is further combined with the improved network for experiments and compared with other neural networks to verify the effectiveness of the proposed method, thus achieving the effect and purpose of improving underwater image instance segmentation and target recognition. The experimental analysis results show that the proposed model can achieve a mAP of 0.245, which is about 1.1 times higher than other target recognition models. [ABSTRACT FROM AUTHOR]

Magnetic core–shell Fe3O4@SiO2 nanoparticles were synthesized by sol–gel method. Based on the characterization and experimental results, the adsorbent was found to have an average particle size of approximately 120 nm, a pore size range of 2–5 nm and superparamagnetic properties. It exhibited electrostatic and hydrogen bonding interactions during adsorption of methyl orange (MO). The adsorption of MO on the magnetic Fe3O4@SiO2 nanoparticles exhibited pseudo-second-order kinetics, the adsorption process is a spontaneous endothermic adsorption process, which conforms to the Langmuir adsorption isotherm model. he maximum amount of MO was adsorbed at pH = 2, T = 45 °C and t = 30 min, and the highest adsorption capacity was 182.503 mg/g; The unit adsorption capacity of the Fe3O4@SiO2 nanoparticles still reached 83% of the original capacity after 5 cycles, so the material was reusable and met the requirements of environmental protection. This study reveals the great potential of magnetic mesoporous nanoparticles for removal of dyes from wastewater. [ABSTRACT FROM AUTHOR]

Piezocatalysis technology emerges as a promising solution for environmental protection and wastewater pollution treatment. This study focuses on the synthesis of Pb(Zr 0.50 Ti 0.50)O 3 (PZT) ferroelectric thin films as piezocatalysts through a sol-gel method. The piezocatalytic performance of these PZT films under vibration is also evaluated through utilizing Rhodamine B(RhB) dye as a model pollutant. When vibrations are applied to the RhB solution for 3 h, the RhB dye decomposition ratio reaches 90.22 %. The influence of pH values, vibration power and dye concentration condition on the decomposition ratio of RhB dye wastewater during the piezocatalytic process. Furtherly, these inhibitor experiments indicate that these middlle active species in piezocatalysis of PZT film are mainly the ·O 2 − and ·OH radicals. The study demonstrates the tremendous potential of PZT film's piezoelectric effect in treating dye wastewater through harvesting mechanical vibration energy. [ABSTRACT FROM AUTHOR]

In this study, kocho was prepared from pseudostem and corm of Ensete ventricosum (enset). The behaviors of kocho were examined by using FESEM, TGA, XRD and FTIR spectroscopy. The biosorption potential of kocho, a possible low-cost new biosorbent for the efficient removal of MB dye from wastewater was investigated. Biosorption experiments were carried out in batch mode to study the effects of biosorbent dosages (0.025-0.2 g), pH (2-10), initial concentrations of MB (10 to 100 mg/L) and contact time (10 to 120 min). The highest removal efficiency of methylene blue dye (94.2%) was recorded at optimum experimental conditions. Following the removal study, it was determined that the pseudo-second order kinetics (R² = 0.997) and Langmuir isothermal (R²= 0.996) models may well describe the MB dye biosorption process. Furthermore, this newly developed biosorbent was fairly recyclable up to five cycles without significant loss of re-adsorption efficiency (around 9.6% loss) between 1st and 5th cycle. Thus, the findings of this study revealed that a new kocho biosorbent derived from Ensete ventricosum can be used as a promising low-cost, environmentally friendly and efficient biosorbent for the rapid removal of MB from aqueous solutions. [ABSTRACT FROM AUTHOR]

Background and Aim: The production of lignocellulosic biomass waste in the agricultural sector of Indonesia is quite high annually. Utilization of lignocellulosic biomass waste through fermentation technology can be used as feed and biofuel. Fermentation technology requires the involvement of micro-organisms such as bacteria (lactic acid bacteria or LAB). LABs can be isolated from various sources, such as duck excreta. However, there have not been many reports of LAB from duck excreta. The present study aimed to characterize LAB enzymes isolated from duck excreta and obtain LAB enzymes with superior fermentation properties. Materials and Methods: A total of 11 LAB cultures obtained from duck excreta in Yogyakarta, Indonesia, were tested. Enzyme characterization of each LAB was performed using the API ZYM kit (BioMérieux, Marcy-I'Etoile, France). The bacterial cell suspension was dropped onto the API ZYMTM cupule using a pipette and incubated for 4 h at 37°C. After incubation, ZYM A and ZYM B were dripped onto the API ZYM cupule, and color changes were observed for approximately 10 s under a strong light source. Results: Esterase activity was moderate for all LABs. The activity of a-chymotrypsin, ß-glucuronidase, a-fucosidase, and a-mannosidase was not observed in a total of 10 LAB. The phosphohydrolase and amino peptidase enzyme activity of seven LABs was strong. Only six LAB samples showed protease activity. The glycosyl hydrolase (GH) activity was observed in a total of 8 LAB, while the activity of 2 LAB was strong (Lactococcus lactis subsp. lactis K5 and Lactobacillus brevis M4A). Conclusion: A total of 2 LABs have superior properties. L. lactis subsp. lactis K5 and L. brevis M4A have a high potential to be used in fermentation. They have the potential for further research, such as their effectiveness in fermentation, lignocellulose hydrolysis, feed additives, molecular characterization to detect specific enzymes, and their specific activities. [ABSTRACT FROM AUTHOR]

Today, the importance of materials produced by natural means or by synthesis is increasing in the prevention of increasing water pollution. Sophora Japonica fruit seeds (SJfs) were pyrolyzed at 450 °C to produce SJfs-biochar (SJfsB) in this study. Iron nanoparticles were immobilized to the SJfsB structure to form a more active biosorbent matrix. SJfsB and the resulting novel biosorbent (nanomagnetic-Sophora Japonica fruit seeds biochar (nM-SJfsB) were used to remove malachite green (MG) from an aqueous solution. Fourier transform infrared analysis (FTIR) and scanning electron microscopy were used to elucidate the details of the biosorbent properties. The effect on removal was investigated using various parameters. A combined strategy was used to define the adsorption parameters such as adsorbent amount, time, initial dye concentration, pH, and temperature. The maximum adsorption capacity determined by the Langmuir model was 51.020 mg/g for SJfsB-MG and 101.010 mg/g was found for nM-SJfsB-MG. The pseudo second order equation made the equilibrium data suitable. After regeneration, nM-SJfsB can be used for re-adsorption studies and reused for multiple cycles in adsorption and desorption applications without discharging nano-iron particles into aqueous medium. [ABSTRACT FROM AUTHOR]

Wastewater contaminated with organic pollutants must be carefully treated before being discharged into the environment in order to reduce its negative effects on public health. Currently, much attention has been paid to the removal of dyes from industrial wastewater. The aim of this study is to investigate the removal of Acid Blue 113 (AB113) and Congo Red (CR) dyes by using Moroccan Prickly Pear Cactus Peel (MPPCP) from the binary system in a batch reactor. All the parameters influencing the adsorption of the dye in the binary system were studied namely the effect of mixture composition, contact time (20–210 min), initial dye concentration (20–300 mg/L), temperature (25–40 °C), and pH of the dye solution (2–12). The results showed that the uptake of both AB113 and CR dyes highly depends on initial dye concentration, solution composition dyes, and temperature. The kinetic study was performed by applying two kinetic models, the pseudo-first-order and the pseudo-second-order. The pseudo-second-order model better describes the adsorption of the dyes onto MPPCP adsorbent. The analysis of the obtained results shows that the correlation coefficients of the Freundlich model are higher which shows that the adsorption of AB113 and CR dyes in the binary mixture takes a multilayer form. The thermodynamic study showed that the adsorption of dyes in a binary system is spontaneous, physical, and exothermic. The obtained results in this work show that MPPCP can be considered a good material for the removal of anionic AB113 and CR dyes in the binary mixture and therefore used this material on an industrial scale. [ABSTRACT FROM AUTHOR]

The magnetic biochar was prepared using Ulva fasciata marine algae and used to remove Methylene blue (MB) as model organic molecule. A comprehensive characterization was conducted on pristine Ulva fasciata biochar (UFBC) and UFBC modified by Fe 3 O 4 (UFBC-MIO) by using SEM, EDX, FTIR, TEM, BET, and XRD along with the PZC. The adsorption of MB was noted as 20.83 mg g−1 for UFBC and 50.12 mg g−1 for UFBC–MIO, at pH = 9, 2 g L−1 dosage and T = 298 K with approx. 85 mg L−1 MB concentration. The higher performance of UFBC-MIO was explained by formation of higher surface area and pore volume. The mechanism of adsorption depicted as pore-filling and electrostatic interaction was identified as physisorption. The adsorption model followed the Langmuir isotherm and the kinetic studies disclosed pseudo-second-order for both adsorbents. The thermodynamic study revealed that the process is non-spontaneous, decreased in randomness and was exothermic. The UFBC–MIO was easily recovered and regenerated through its magnetic property and exhibited 89% MB removal after 5 cycles at pH = 9, 2 g L−1 dosage and T = 298 K with 86.37 mg L−1 of MB. The magnetic biochar of algae Ulva fasciata is an excellent adsorbent recommended for the removal of cationic dyes from wastewaters. [Display omitted] • Preparation of magnetic biochar from Ulva fasciata macro algae. • Elucidation of methylene blue adsorption mechanism. • Adsorption capacity of about 50 mg g− 1. • Predominant Langmuir adsorption isotherm. [ABSTRACT FROM AUTHOR]

Yttria‐stabilized zirconia (YSZ), although well known for a lot of excellent engineering applications, has limited footprints in the field of adsorption/dye removal. Through this work, we demonstrate the remarkable efficacy (adsorption capacity ∼550 mg/g) of 8 mol.% YSZ nano‐adsorbents for toxic azo‐dye (e.g., Congo red) removal. The consistency of our adsorption experiments was validated with the help of a series of tests, such as regeneration (via thermal and chemical routes), in real‐life river water, with mixed ion solution, and under varied pH (3–11). Noteworthy is also that the commercial trademark composition (with the same dopant concentration) showed little/no adsorption. Our success of the adsorption experiments is credited to the multitude of factors, namely, size refinement ∼6 nm, retainment of phase‐pure cubicity, and enhanced surface area (155 m2/g), which eventually led to the generation of massive oxygen vacancies on our synthesized doped‐zirconia surfaces. [ABSTRACT FROM AUTHOR]

The present work reports the adsorption of crystal violet dye (CVD) onto magnetized bentonite clay particles (MBCP). The MBCP adsorbent was synthesized by the co-precipitation method, where magnetic particles of Fe3O4 precipitated the bentonite clay particles. The synthesized MBCP showed a high capacity for CVD adsorption, removing 93.97% of the dye at an equilibrium adsorption time of 80 min at an optimum temperature of 303 K. The effects of adsorbent dosage, dye concentration, and pH, on adsorption were also assessed. Adsorption data were best described by the Langmuir adsorption isotherm with a maximum monolayer adsorption capacity of 588.23 mg g−1, while the pseudo-second-order kinetic model best fitted the adsorption kinetics. Adsorption was found to be thermodynamically feasible and led to an increase in entropy. The HCl was the most effective desorbing agent for regenerating MBCP up to four cycles. This study of MBCP, therefore, ensures the sustainability and cost-effectiveness of dye treatment in industrial effluents. Further, the magnetization of bentonite mineral clay makes it more effective with enhanced adsorption characteristics along with easy separability. [ABSTRACT FROM AUTHOR]

In this study, the removal of indigo dye, which is used in the denim industry, by using the electro-oxidation method was investigated. Experiments were carried out using Sn/Sb/Ni–Ti anode and Pt–Ti cathode electrodes of indigo dye aqueous solution with an initial concentration of 100 mg/L, which was prepared synthetically in the laboratory. In the first stage of the study, appropriate support electrolyte (NaCl, KCl, Na2SO4, K2SO4) detection investigations were carried out. As a result of the trials, NaCl electrolyte was chosen as the supporting electrolyte type because it is both affordable and has high removal efficiency compared to other electrolytes. Color and COD removal were established according to the effective factors (pH, current density, supporting electrolyte concentration and electro-oxidation time) for the electro-oxidation method using the central composite design (CCD) based response surface methodology (RSM). The design consists of four components and seven central experiments, each with three levels. According to the RSM result, ideal conditions were pH 11, current density 51.01 mA/cm2, supporting electrolyte concentration 1565.66 mg/L and duration 120 min. In ideal conditions, COD removal was determined as 97.43% and color removal as 98.93%, while energy consumption was determined as 17.49 kWh/kg COD. In the last stage of the study, pilot-scale tests were carried out in a spherical polyethylene (PE) tank with a bottom diameter of 65 cm and a height of 157 cm. Color and COD removal efficiencies obtained from the pilot scale under optimum conditions were calculated as 95.26% and 92.16%, respectively. [ABSTRACT FROM AUTHOR]

The seed layers were deposited on the activated glass lamellas by dip-coating using zinc solutions with and without diethanolamine (DEA). ZnO nanorods were grown on these two types of seed layers by chemical bath deposition (CBD) method at 95 °C. The nanorods were then annealed in air at 300, 400 and 500 °C and in an oxygen atmosphere at 400 and 500 °C. The influences of seed solution chemistry, annealing temperature and atmosphere on the structural properties of the ZnO nanorods were investigated via X-ray diffraction (XRD) and scanning electron microscopy (SEM). An improved vertical alignment of the nanorods along the c-axis was observed on the DEA-containing seed layer. Their diameters decreased with the increasing annealing temperature, whereas their crystallinities increased. Optical properties of the samples were also studied by ultraviolet–visible (UV–vis) and photoluminescence (PL) spectroscopies. Their optical band edges shifted to lower energies as the annealing temperature increased up to 400 °C. The PL intensities decreased with annealing at 500 °C in an oxygen atmosphere, which was attributed to the decrease in defect concentration. Their photocatalytic tests using AR88 azo dye and UVA irradiation revealed that the annealing process is beneficial in achieving improved color removals from the aqueous dye solutions. The well-aligned nanorods were successfully grown on the DEA-supported seed layer. However, their photocatalytic efficiencies remained relatively low, which was attributed to poor light interactions with their lateral surfaces. [ABSTRACT FROM AUTHOR]

This study investigated the color removal of C.I. Disperse Red 343 and Isolan Bordeaux 2S-B dyes through the electrocoagulation (EC) process using an aluminum (Al) electrode. It explored the effects of pH, current, and electrolysis time, essential factors influencing color removal in the EC process. The Box-Behnken Design (BBD) of the Response Surface Method (RSM) was utilized to comprehend the statistical behavior of the system. Both dyes exhibited color removal responses that were well-suited to the quadratic model. The coefficients of determination (R2) for color removal in the EC process were notably high, 0.9896 for C.I. Disperse Red 343 and 0.999 for Isolan Bordeaux 2S-B. Correspondingly, the R²-adj values were 0.9708 and 0.9972, respectively. These R² and R²-adj values approaching unity affirm the consistency between experimental outcomes and statistical inferences, indicating the effectiveness of the BBD in discerning process parameter effects. The optimized pH levels for color removal were determined as 6.76 for C.I. Disperse Red 343 and 5.66 for Isolan Bordeaux 2S-B. Ideal current values were found to be 0.06 A for C.I. Disperse Red 343 and 0.08 A for Isolan Bordeaux 2S-B, with corresponding times of 12.73 min and 14.95 min, respectively. Moreover, the calculated operating costs at optimum conditions were $0.055/m³ for C.I. Disperse Red 343 and $0.088/m3 for Isolan Bordeaux 2S-B. A comparison under identical conditions revealed a higher efficiency in color removal for the C.I. Disperse Red 343 when compared with Isolan Bordeaux 2S-B. [ABSTRACT FROM AUTHOR]