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With the development of modern industry, the discharge of dye wastewater is increasing year by year, and the damage caused by this wastewater to the ecosystem is often irreversible. Therefore, the research on the harmless treatment of dyes has attracted much attention in recent years. In this paper, commercial titanium dioxide (anatase nanometer titanium dioxide) was heat treated with anhydrous ethanol to synthesize titanium carbide (C/TiO2). Its maximum adsorption capacity for cationic dyes methylene blue (MB) and Rhodamine B is 27.3 and 124.6 mg g−1, respectively, which is much higher than that of pure TiO2. The adsorption kinetics and isotherm model of C/TiO2 were studied and characterized by Brunauer–Emmett–Teller, x-ray photoelectron spectroscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and other methods. The results show that the carbon layer on the surface of C/TiO2 promotes the increase in surface hydroxyl groups, which is the main reason for the increase in MB adsorption. Compared with other adsorbents, C/TiO2 showed excellent reusability. The experimental results of adsorbent regeneration showed that the adsorption rate R% of MB was almost unchanged after three cycles. During the recovery of C/TiO2, the dyes adsorbed on its surface are removed, which solves the problem that the adsorbent cannot degrade dyes simply by adsorption. Additionally, C/TiO2 has a stable adsorption effect, is insensitive to the pH value, has a simple preparation process, and has relatively low raw material prices, making it suitable for large-scale operation. Therefore, it has good commercial prospects in the organic dye industry wastewater treatment. [ABSTRACT FROM AUTHOR]

In the present study, silver nanoparticles were synthesized via green synthesis using fenugreek (Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min−1), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min−1) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min−1). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg2+, making them excellent solid bio‐based sensors for mercury sensing. [ABSTRACT FROM AUTHOR]

Adsorption, a crucial method for removing dyes from wastewater, has been extensively studied in the context of eliminating Acridine Orange (AO), a cationic dye, from contaminated water. This review underscores the environmental risks posed by AO, given its high toxicity, and delves into various adsorption techniques developed to eliminate it from water. It covers works on AO removal published from 1981 to April 2024, highlighting the effectiveness of different adsorbents, including natural, synthetic, composite, and nanomaterials, under varying conditions like pH, initial dye concentrations, temperature, and adsorbent dosages. Most studies on adsorption isotherms, kinetics, and thermodynamics have yielded favorable results, with common models including the Langmuir and Freundlich and pseudosecondorder kinetics. As identified by these studies, the main driving force for adsorption is electrostatic interactions between AO and the adsorbents. The review also encompasses competitive adsorption, adsorbent regeneration, alternative decontamination methods, and the pivotal role of computational research in optimizing adsorption processes. [ABSTRACT FROM AUTHOR]

In the present study, silver nanoparticles were synthesized via green synthesis using fenugreek (Trigonella foenum‐graecum L.) seeds of variety HM 425. The AgNPs were characterized by using UV‐Visible spectroscopy, Particle size analyzer, Field emission scanning electron microscopy coupled to Energy dispersive X‐ray spectroscopy, XRD, High resolution transmission electron microscopy and Fourier Transform Infrared Spectroscopy. The AgNPs were spherical and had an average particle size of 28 nm. The reduction of cationic dyes Methylene blue, Rhodamine B, and an anionic azo dye Methyl Orange by Sodium borohydride was used as a model reaction to investigate the catalytic ability of AgNPs. The results demonstrated an efficient catalytic dye degradation of methylene blue (95.81 %, 25 min, 0.1737±0.01 min−1), Rhodamine B (90.23 %, 15 min, 0.1388±0.01 min−1) and methyl orange (83.63 %, 39 min, 0.0412±0.002 min−1). The synthesized AgNPs had an excellent detection limit of 12.50 μM for Hg2+, making them excellent solid bio‐based sensors for mercury sensing. [ABSTRACT FROM AUTHOR]

A BODIPY-containing conjugated microporous polymer (CMP, LBFD-1) was modified with calixarene to develop a hydrophilic CMP (LBFD-2) with broader absorption extending to the near-infrared-II region. LBFD-2 exhibited an H2O2 production rate of 2.14 mmol g−1 h−1 in the air without any sacrificial agents. The removal efficiency (η) of LBFD-2 towards methylene blue and rhodamine B reached >99.5% within 20 and 40 min in light. LBFD-2 can withstand diverse environmental changes, showing excellent reusability and potential for practical applications in real-water systems. [ABSTRACT FROM AUTHOR]

Dopamine modified peanut husks (PH/DA), a novel adsorbent, were investigated to enhance the adsorption capacity of dyes (neutral red, NR and crystal violet, CV) and fluoroquinolone antibiotics (ofloxacin, OFLX and enoxacin, ENO). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermo-gravimetric analysis and differential scanning calorimetry (TG-DSC) and Brunauer-Emmett-Teller (BET) method were used to characterize PH and PH/DA. The findings demonstrated that the physical and chemical properties of the peanut husks were changed after dopamine-modification. As for adsorption kinetics, NR adsorption properties were satisfactorily explained by the Elovich model, whereas CV adsorption processes suited to the pseudo-second order model. Both OFLX and ENO followed the pseudo-first order model. Isotherm data showed that CV and ENO conform to the Temkin model while NR and OFLX fitted better to the Langmuir model. The qmax of NR, CV, OFLX and ENO by PH/DA were 52.37, 45.92, 46.57 and 58.40 mg/g at 290 K, respectively, according to Langmuir model. The adsorbent maintained an adsorption efficiency of above 70% even after three adsorption-desorption cycles. These findings proved that PH/DA's successful development offers important insights into the production of sorbents for water treatment based on biomass. The adsorption of dyes and antibiotics on dopamine-modified peanut husk was investigated. The adsorbent was characterized by SEM, FTIR, XRD, XPS, BET and TG-DSC. Adsorption isotherm and kinetics models were fitted with the experimental data. Mechanism for the adsorption of dyes and antibiotics were elucidated. [ABSTRACT FROM AUTHOR]

Herein, this work targets to employ the blended fruit wastes including rambutan (Nephelium lappaceum) peel and durian (Durio zibethinus) seed as a promising precursor to produce activated carbon (RPDSAC). The generation of RPDSAC was accomplished through a rapid and practical procedure (microwave-ZnCl2 activation). To evaluate the adsorptive capabilities of RPDSAC, its efficacy in eliminating methylene blue (MB), a simulated cationic dye, was measured. The Box–Behnken design (BBD) was utilized to optimize the crucial adsorption parameters, namely A: RPDSAC dose (0.02–01 g/100 mL), B: pH (4–10), and C: time (2–6 min). The BBD design determined that the highest level of MB removal (79.4%) was achieved with the condition dosage of RPDSAC at 0.1 g/100 mL, contact time (6 min), and pH (10). The adsorption isotherm data is consistent with the Freundlich concept, and the pseudo-second-order versions adequately describe the kinetic data. The monolayer adsorption capacity (qmax) of RPDSAC reached 120.4 mg/g at 25 °C. Various adsorption mechanisms are involved in the adsorption of MB dye onto the surface of RPDSAC, including π–π stacking, H-bonding, pore filling, and electrostatic forces. This study exhibits the potential of the RPDSAC as an adsorbent for removal of toxic cationic dye (MB) from contaminated wastewater. [ABSTRACT FROM AUTHOR]

Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents. The use of nitric acid-modified corn silk has been reported to enhance its adsorption performance over the unmodified cob for pollutants such as cadmium ions and malachite green. Although there may be no recorded data on the adsorption efficiency of acid-treated corn silk for selected pollutants, it can be considered as a prospective bio-sorbent owing to its chemical composition and functional groups for exchange of hydrogen ions for other cations. [ABSTRACT FROM AUTHOR]

The present work describes the colour removal of Rhodamine B (Rh B), a cationic dye by photo-electrocatalysis and sono-photo-electrocatalysis on MgFe2O4 as an anode. The spinel MgFe2O4 synthesized by sol–gel route was characterized by physical and electrochemical methods, a preamble of Rh B oxidation. The XRD pattern shows the formation of the single phase, which crystallizes in a face-centred cubic lattice (space group, Fd − 3 m), with spherical crystallites (0.42 nm). The Zeta-sizer analysis gives an average grain size of 0.46 µm and a zeta potential of − 30 mV. The SEM analysis revealed the porosity of the oxide and the Mg-O and Fe–O bonds were confirmed by the FT-IR analysis. The direct optical gap (2.16 eV) assigned to d − d internal transition comes from the crystal field splitting of Fe3+ octahedrally coordinated. The low electron mobility is assigned to a narrow conduction band of Fe3+—3d parentage with activation energy (0.12 eV) in conformity with a conduction mechanism by small lattice polaron hopping. The intensity potential J(E) profile in Na2SO4 (10−2 M) exhibits a small hysteresis similar to a chemical diode. The semi-logarithmic plot (logJ − E) indicates the chemical stability of MgFe2O4 in the working solution (Na2SO4). Curiously and unlike most spinels, the capacitance plot exhibits n-type conduction confirmed by chrono-amperometry, plotted at the free potential (+ 0.5 V) with a flat band potential (Efb) of 0.29 V, due to Fe3+ insertion. As an application, Rh B (20 mg L−1) was successfully oxidized by photo-electrocatalysis on MgFe2O4 with an abatement of 75% under solar irradiation and a direct current of 150 mA which has a bactericidal effect. An enhancement up to 97% has been reached by sono-photo-electrocatalysis at a frequency of 60 kHz; almost complete discoloration occurred within 90 min in the "US-Electric Current-Sunlight-MgFe2O4". The Rh B elimination follows a pseudo-first-order kinetic with a rate constant of 3.9 × 10−2 mn−1 (t1/2 = 18 min), and a reaction mechanism is suggested. [ABSTRACT FROM AUTHOR]

This study focuses on the development of a nanocomposite membrane using polyvinyl chloride and nanocellulose@titanium aluminate to effectively filter and adsorb dye from wastewater. Various analytical techniques were used such as FTIR, XRD, SEM, and TGA to characterize the synthesized adsorptive nanocomposite membrane. The thermal and electrical properties of the membrane were measured using a static system. The study investigated the effect of different adsorbent dosages, pH levels, and dye concentrations on the membrane's adsorption ability. The PVC-NC@TALCM nanocomposite membrane was found to remove 98.6% of MB dye when loaded with 5% titanium aluminate at pH 10. Kinetic and isotherm studies revealed that the adsorption of MB onto the membrane followed pseudo-second-order kinetics and Freundlich isotherms, respectively. The researchers also highlighted the economic and eco-friendly nature of the PVC-NC@TALCM nanocomposite membrane as a viable option for the removal of MB from industrial wastewater. [ABSTRACT FROM AUTHOR]

The presence of heavy metals and pollutant dyes can have detrimental effects on aquatic ecosystems and compromise aquatic aesthetics. This study investigates the use of unprocessed waste gem meerschaum powder as a new adsorbent in the removal of both Cu(II) and methylene blue (MB) from aqueous solutions to reduce water pollution. The structure of the waste powder was characterized by FT-IR, XRD, SEM and BET methods. Optimization of Cu(II) and MB dye removal was carried out using design of experiment technique. Under optimum conditions, remarkable removal efficiencies of 95.5% (± 3.7) for Cu(II) and 97.8% (± 0.4) for MB were achieved. The removal of Cu(II) followed the Freundlich isotherm model, while the removal of MB dye adhered to the Langmuir isotherm model. Both adsorption processes obeyed the pseudo-second-order kinetic model and occurred spontaneously. This innovative approach offers a promising solution to water pollution by highlighting the importance of sustainable and cost-effective waste use. [ABSTRACT FROM AUTHOR]

AbstractThe aim of this work is to investigate the influence of an alkaline pretreatment of the Mediterranean plant Carpobrotus edulis on the adsorption capacity toward the dye methylene blue and to estimate the content of soluble organic matter that can be released into the aqueous solution by this biomaterial. The biomaterial used was characterized by SEM-EDX, SS, FT-IR, pHZ, COD and BOD5. Removal of methylene blue (MB) dye by this biomaterial was carried out and the effects of physicochemical factors such as initial pollutant concentration, adsorbent dose, contact time, pH and temperature were investigated. After adsorbent treatment, the soluble organic matter was reduced by 97%, 96%, and 96% for biological oxygen demand, chemical oxygen demand, and organic matter, respectively. Kinetics and equilibrium studies of MB adsorption on the bioadsorbents were fitted with a pseudo-second order kinetic model and a Langmuir model, respectively. The maximum adsorption amount of the modified C. edulis plant was 153.9 mg/g at 298°K. The thermodynamic parameters show that the adsorption process was possible and spontaneous in nature. The adsorption mechanism of MB on the surface of biomaterials was attributed to the electrostatic interaction and H-bonding. The prepared biomaterial (0.016 U$ per gram) was easily regenerated with aqueous HNO3 solution, with a slight decrease in adsorption capacity up to five cycles. The results of Taguchi experimental design and analysis of variance showed that contact time, adsorbent mass and initial concentration are the most important factors affecting the removal efficiency with a contribution of 43.91%, 32.68%, and 22.95%, respectively. The maximum removal capacity of MB dye in optimal operating conditions was 99.39%, which was obtained at the optimum conditions of m = 1 g, pH 4, T = 35 °C, Ci = 1000 mg/L, tc = 5 min. These results confirm previous results obtained with the batch system and show that this absorbent is also promising for the removal of cationic dyes from wastewater. [ABSTRACT FROM AUTHOR]

Developing synthetic strategies for smart materials for the adsorption and separation of toxic chemicals is of great importance. Metal–organic frameworks (MOFs) have been proven to be outstanding adsorbent materials that possess excellent pollutant removal performances in wastewater treatment, including dye recycling. In this work, a neutral Cd(II) based 2D framework with a dual ligand strategy involving –OH functionalized 5-hydroxyisophthalic acid (5-OH-H2IPA) and the amide decorated Schiff base ligand (E)-N′-(pyridin-4-ylmethylene)isonicotinohydrazide (L) has been synthesized by different synthetic routes and characterized by various analytical methods. Thus, crystals of {[Cd(5-OH-IPA)(L)]·CH3OH}n synthesized via diffusion (ADES-7D) and the phase pure bulk product synthesized by conventional reflux (ADES-7C) and the mechanochemical grinding method (ADES-7M) have been established using PXRD data of the respective product showing identical simulated SXRD data to those of ADES-7D. The mechanochemically synthesized ADES-7M possesses a better surface area and CO2 adsorption capability compared to ADES-7C, which is also supported by electron microscopy and particle size measurements. Furthermore, ADES-7 can be used as an efficient adsorbent material for the reversible, selective adsorption (42–99%) and separation of the cationic dyes malachite green (MG), methyl violet (MV), methylene blue (MB), and rhodamine B (RhB) from the mixture of cationic/anionic dyes (methyl orange (MO) and bromocresol green (BCG)) in the aqueous phase. Specifically, ADES-7M possesses better dye capture capability compared to ADES-7C, even in the case of the bigger dye RhB with adsorption differences of 2.38 to 1.01 mg g−1, respectively. The dye adsorption kinetics follows pseudo-second-order kinetics, and the dye adsorption isotherm fits well with the Langmuir/Freundlich adsorption isotherm models. The probable mechanism of adsorption involving the supramolecular interaction between the host MOF and the guest dye has also been proposed. [ABSTRACT FROM AUTHOR]

In the current report, both response surface methodology (RSM) and artificial neural network (ANN) were employed to develop an innovative way for removing crystal violet (CV) from aqueous media using Haloxylon salicornicum (HS) as a cost‐effective, eco‐friendly adsorbent. HS was characterized using scanning electron microscopy (SEM) and Fourier‐transform infrared (FTIR) spectroscopy. The effects of operational parameters such as adsorbent dosage, initial dye concentration, and pH on HS were studied using a central composite design (CCD). A comparative analysis of the model findings and experimental measurements revealed high correlation coefficients (R2ANN = 0.994, R2RSM = 0.971), indicating both models accurately predicted HS. The predictive performance of the ANN and RSM models was evaluated using metrics such as mean absolute deviation (MAD), mean absolute percentage error (MAPE), root mean square error (RMSE), mean square error (MSE), and the correlation coefficient (R2). The results indicate that the ANN model provides greater accuracy compared to the RSM model. The experimental data were analyzed using both linear and nonlinear forms of pseudo‐first and pseudo‐second order kinetic models (LPFO, NLPFO, LPSO, and NLPSO). Statistical error analysis was conducted to identify the best‐fitting kinetic or isotherm models for the adsorption data. The adsorption process of CV/HS was best described by NLPSO and LPSO. Additionally, the adsorption isotherms were analyzed using linear and nonlinear regression methods. The findings indicated that the linear Langmuir and Freundlich isotherms provided a more accurate fit compared to the nonlinear models, demonstrating greater effectiveness in accounting for the adsorption parameters. Thermodynamic investigations clearly demonstrate that the biosorption of CV is spontaneous and exothermic. This cost‐effective adsorbent is highly promising for treating textile wastewater. [ABSTRACT FROM AUTHOR]

The aim of this work was to determine the sorption capacity of the cationic dyes Basic Red 46 (BR46) and Basic Violet 10 (BV10) on the prepared sorbents: beech bark (BBe) and birch bark (BBi). Two fractions of bark were used in the research: fine (2–3 mm) and coarse (4–5 mm). The carried out tests made it possible to determine the influence of the pH value on the sorption efficiency, the sorption equilibrium time and the maximum sorption capacity of the two tested sorbents. The Langmuir model and the Freundlich model were used to describe the obtained experimental data. Beech and birch barks are effective sorbents for cationic dyes; however, the efficiency of dye sorption on both bark sorbents depends on the type of cationic dye. According to the obtained data, beech and birch bark sorbents showed higher sorption efficiency for Basic Red 46 than for Basic Violet 10. The pH correction was a necessary condition for sorption, and the sorption pH value for the cationic dyes Basic Red 46 and Basic Violet 10 was be determined individually for each dye. The most favourable pH value for the sorption of the BR46 dye on the beach and birch bark sorbents was pH = 6, while for the dye BV10, it was pH = 3. The sorption equilibrium time for Basic Red 46 was 300 min and for Basic Violet 10–240 min. The fine fraction of beech bark had the highest sorption capacity for both BR46 (128.45 mg/g dry matter) and BV10 (18.07 mg/g dry matter). [ABSTRACT FROM AUTHOR]

Na-kenyaite materials are available in nature and can easily be prepared in the laboratory. These materials exhibit interesting adsorption properties; therefore, they can be invested in the new wastewater treatment technologies. This study investigates the removal of basic blue-41 (BB-41) dye from artificially contaminated water using Na-kenyaite materials in batch mode. Firstly, Na-kenyaites were prepared by the hydrothermal process at a temperature of 150 to 170 °C for a period of 2 to 7 days using different silica sources and ratios of SiO2/NaOH/H2O. The prepared materials were characterized by different techniques such as XRD, FTIR, 29Si MAS NMR, TGA/DTA, SEM, and nitrogen adsorption isotherms. A pure Na-kenyaite phase was successfully obtained using a fumed silica source and 5SiO2/Na2O/122H2O ratio. The removal experiments of basic blue-41 estimated the effectiveness of Na-kenyaites in removing properties, investigating the influence of the solid dosage, initial basic blue-41 concentration, and solution pH or Na-kenyaite solid. Results showed optimal dye removal of around 99% at pH levels above 7. Furthermore, the estimated maximum removal capacity from the Langmuir isotherm was between 124 and 165 mg/g. The results demonstrated efficient removal by Na-kenyaites and its prominence for wastewater treatment. Finally, this study explored the regeneration and reuse of Na-kenyaites through seven cycles and reported a design of a batch adsorber system to reduce the initial concentration of 200 mg/L at different percentages. [ABSTRACT FROM AUTHOR]

AbstractBentonite-gelatin (BT-Ge) and bentonite-sucrose (BT-Su) composites were fabricated using a simple solution mixing method and employed as adsorbents for extracting dyes from aqueous solutions. The structural characteristics of the fabricated composite materials were elucidated using x-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The adjustable adsorption capabilities of the developed adsorbents toward methyl red (MR) and methylene blue (MB), representing anionic and cationic dyes, respectively, were examined by varying the mass ratio of bentonite to gelatin and sucrose. The impact of contact time, adsorbent dosage, and pH on the adsorption process of MR and MB onto BT-Ge and BT-Su was investigated. Kinetic data fitting indicated a good agreement with the pseudo-second-order model, with equilibrium typically achieved within 30 min, resulting in 99.69 ± 0.550, 99.56 ± 0.344, 99.90 ± 0.488% removal of MB with BT, BT-Su, and BT-Ge, respectively and 99.50 ± 0.854, 99.50 ± 0.658, and 99.57%±0.501% of MR with BT, BT-Su, and BT-Ge, respectively from the aqueous solutions. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models, with the Langmuir model showing the best fit and indicating a maximum adsorption capacity of 666.66 mg g−1 of MR and 285.71 mg g−1 of MB at 25 °C. These findings underscore the remarkable efficacy of BT-Ge and BT-Su composites in eliminating dyes from wastewater, particularly colored effluents. [ABSTRACT FROM AUTHOR]

A three‐dimensional (3D) anionic cadmium‐organic framework, namely [(CH3)2NH2][Cd1.5(DMTDC)2] ⋅ 2DMA ⋅ 0.5H2O (Cd‐MOF; DMA=N,N‐dimethylacetamide), was successfully synthesized under solvothermal conditions by using a linear thienothiophene‐containing dicarboxylate ligand, 3,4‐dimethylthieno [2,3‐b]‐thiophene‐2,5‐dicar‐boxylic acid (H2DMTDC). Single‐crystal X‐ray diffraction analysis reveals that Cd‐MOF exhibits a 3D anionic framework with pcu α‐Po topology, featuring rectangle and rhombus‐shaped channels along b‐ and c‐ axis direction. Cd‐MOF demonstrates selective adsorption of cationic dyes over anionic and neutral dyes. Additionally, Tb3+‐loaded Cd‐MOF serves as a fast‐response fluorescence sensor for the sensitive detection of Fe3+ ions with a low limit of detection (8.90×10−7 M) through fluorescence quenching. [ABSTRACT FROM AUTHOR]

This study synthesized mesoporous magnetic Fe3O4 nanoparticles with two pore sizes. First, two different pore sizes of SiO2 were synthesized using polyethylene glycol with molecular weights of 6000 kDa and 35,000 kDa. Next, mesoporous SiO2 was used as a template, and Fe3O4 was coated with a precursor. Then, the silica present in mesoporous SiO2 was leached. The adsorption capacities of the prepared mesoporous magnetic Fe3O4-NPs were compared using an azo cationic dye, Basic Red 18. Parameters such as solution pH, adsorbent amount, and dye concentration were optimized in the adsorption experiments. Additionally, the reusability of Fe3O4-NPs was investigated. The optimum conditions for P6-Fe3O4-NPs were the original pH, 0.5 g/L dose, 50 ppm dye concentration, 60 min contact time, and 100% removal efficiency. For P35-Fe3O4-NPs, the optimal conditions were original pH, 0.75 g/L dose, 20 ppm dye concentration, and 60 min of contact time, with 100% removal efficiency. The second-order kinetic model and Langmuir isotherm were found to be suitable for describing the adsorption of both nanoparticles. Under the optimum conditions, complete dye removal efficiency was achieved for both nanomaterials. Furthermore, in the real wastewater, the adsorption experiment utilizing P6-Fe3O4-NPs yielded a 98% efficiency in color removal at 620 nm. [ABSTRACT FROM AUTHOR]

Metallic nanoparticles with optical, electrical, catalytic, magnetic, and biological properties are structures that can be used in environmental pollution. The use of iron nanoparticles in environmental rehabilitaion is gaining interest due to their large surface area to volume ratio. The aim of this study is to synthesize and characterize iron oxide nanoparticles by using cherry plant extracts through a green synthesis approach, and to evaluate the use of cherry plant extracts as an adsorbent of methylene blue in wastewater. The physicochemical characterization of nanoparticles was performed with UV–Vis, FT-IR, XRD spectroscopies, SEM microscopy and Zetasizer particle size analysis. As a result of the experiments, the adsorption percentage increased depending on the time and 67.34% methylene blue removal was achieved at the 150th minute. This study highlights the importance of innovative approaches and the increasing use of biocompatible, environmentally friendly, and economical green materials in applications. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTA rapidly growing problem for life on earth is contamination of fresh water which is addressed in this article. By taking a glimpse on the causes of contaminations, persistent organic pollutants, especially synthetic dyes got prominent role. Here, out of commonly used techniques, adsorption using plant wastes was chosen for phytofiltration of such dyes. A natural adsorbent from plant source was selected and processed with acid, characterized with FTIR and SEM and then checked the efficacy on cationic dye brilliant green. Phytofiltration of dye was done to check the effectivity of both untreated (OA) and acid treated (OA-AC) form of Acacia concinna biowaste. Results were obtained, evaluated and presented here, giving maximum adsorption capacities (Qm) of AC and OA-AC 95.24 and 909.09 mg.g−1, respectively following Langmuir, pseudo second order kinetics and spontaneous exothermic nature, indicating their suitability to adopt on larger scale wastewater treatment effectively using green technology.In this work, Acacia concinna both in untreated and acid treated form is used as an efficient adsorbent for the removal of Brilliant green dye from waste water, as not reported earlier, which proves its novelty. The values of adsorption capacities of both the adsorbent types are compared with different natural and synthetic adsorbents reported earlier, this comparison elaborate the efficacy of AC to be used as adsorbent and consider it as one of the efficient adsorbent materials naturally available. [ABSTRACT FROM AUTHOR]

This work deals with promoting the efficiency of removing the cationic and ionic dyes by new aerogel–carbon nanostructures. For cleaner production the rice straw-pulping black liquors, which regards serious environmental risk during routine disposing, is used in preparing the aerogel precursors. These aerogels (AGBs) depend on using pulping black liquor in hybrid with resorcinol and the less carcinogenic formaldehyde butyraldehyde. Black liquors from five pulping processes are used, Elemental, thermogravimetric (TGA and DTG), and FTIR-ATR analyses are used to characterize the carbon precursors. While their adsorption behavior toward cationic and anionic dyes are accessed via iodine-value, adsorption capacity and kinetic models, textural characterization, and SEM. The TGA measurements reveal that AGBs from BLs of neutral sulfite and soda-borohydride pulping reagents have higher activation and degradation energies than other aerogels. In terms of cationic and anionic dyes adsorption as well as textural characterization, the AGB-CNSs surpass that made from BLs. The discarded KOH/NH4OH black liquor is used to synthesize the best aerogel precursor for producing cationic methylene blue dye (MB) adsorbent, where it provides an adsorption capacity 242.1 mg/g. The maximum anionic brilliant blue dye (BB) adsorption capacity, 162.6 mg/g, is noticed by Kraft BL-aerogel-CNSs. These finding data overcome the literature carbon adsorbents based on lignin precursors. All examined CNSs toward MB dye follow the Langmuir adsorption equilibrium; while primarily the Freundlich model for BB dye. The pseudo-second-order kinetic model well fits the adsorption kinetics of investigated AGB-CNSs. The textural characterization and SEM revealed a mixture of mesoporous and micro porous features in the CNSs. [ABSTRACT FROM AUTHOR]

In the present work, biosynthesis of two nanocomposites (NC1 and NC2) with different dopants (boron or sulfur) was carried out by utilizing secondary metabolites of Eucalyptus citriodora leaf extract for degradation studies of cationic and anionic dyes. Biosynthesized nanocomposites were characterized by UV–Vis spectroscopy, FTIR spectroscopy, SEM imaging, and EDX spectra, which confirmed their functional groups, uniform structure, and the presence of desired dopants. Optimum response for crystal violet dye was observed with 2 mL and 1.5 mL volume, in alkaline medium (pH = 8) at room temperature with dye concentration = 5 mg/L within time interval of 60 and 45 min for NC1 and NC2, while eriochrome black T has shown maximum degradation at 1.5 mL and 1 mL volume in acidic medium at room temperature with 5 mg/L dye concentration in time period of 90 and 60 min for NC1 and NC2. Interference and radical scavenging experiment was performed to elaborate the efficiency and working mechanism of nanocatalysts. The proposed mechanism regarding nanoparticles formation was also discussed. [ABSTRACT FROM AUTHOR]

Developing high value-added utilization of waste cotton provides a promising approach for the sustainable development. Herein, the carboxylated cellulose aerogels (CCAs) featuring in micro/nanostructure and directional channel are fabricated from cotton fabrics via the ingenious combination of selective oxidation, high-speed cutting, and freeze-drying. The as-prepared 2.0-CCA demonstrates not only excellent adsorption capacity for cationic dyes in water but also recyclability due to the abundant carboxyl groups (3.20 mmol/g) and the robust porous structure. And it shows a static maximum adsorption capacity (qm) of 751 mg/g and a dynamic breakthrough amount more than 700 mg/g for methylene blue (MB), more efficient than most reported cellulose-based adsorbents. In addition, the 2.0-CCA shows a high equilibrium adsorption capacity (qe) about 680 mg/g for MB at pH = 6 and keeps qe above 600 mg/g even in a broad pH range of 3‒10, indicating a high tolerance to the solution pH value. At an ion concentration lower than 0.25 mol/L, the additional cations such as Na+ and K+ or anions such as Cl‒, SO42‒, and NO3‒ show a little effect on the qe (higher than 500 mg/g) of 2.0-CCA for MB. The treated dye wastewater can be recycled for fabric dyeing, and there is no significant color difference (∆E) between fabrics dyed with dye liquors prepared with fresh or recycled water. The theoretical study confirms the importance of the electrostatic attraction between carboxyl groups of 2.0-CCA and dye molecules for the efficient adsorption. [ABSTRACT FROM AUTHOR]

In this comprehensive investigation, we evaluate the efficacy of the Fenton process in degrading basic fuchsin (BF), a resistant dye. Our primary focus is on the utilization of readily available, environmentally benign, and cost-effective reagents for the degradation process. Furthermore, we delve into various operational parameters, including the quantity of sodium percarbonate (SPC), pH levels, and the dimensions of waste iron bars, to optimize the treatment efficiency. In the course of our research, we employed an initial SPC concentration of 0.5 mM, a pH level of 3, a waste iron bar measuring 3.5 cm in length and 0.4 cm in diameter, and a processing time of 10 min. Our findings reveal the successful elimination of the BF dye, even when subjected to treatment with diverse salts and surfactants under elevated temperatures and acidic conditions (pH below 3). This underscores the robustness of the Fenton process in purifying wastewater contaminated with dye compounds. The outcomes of our study not only demonstrate the efficiency of the Fenton process but highlight its adaptability to address dye contamination challenges across various industries. Critically, this research pioneers the application of waste iron bars as a source of iron in the Fenton reaction, introducing a novel, sustainable approach that enhances the environmental and economic viability of the process. This innovative use of recycled materials as catalysts represents a significant advancement in sustainable chemical engineering practices. [ABSTRACT FROM AUTHOR]

The discharge of dye waste by industries has caused environmental impacts on water properties, aquatic species, and human life. The production of eco-friendly materials for dye removal from wastewater has gained increasing interest, particularly through adsorption, as it is an efficient method for removing pollutants. However, the selectivity and limited adsorption capacity of materials for simultaneously adsorbing cationic and anionic dyes make it challenging to address the prevailing dye effluent issue. In this work, a poly(glycerol citrate) polyester was prepared without a solvent, using microwave heating, and was combined with cetyltrimethylammonium bromide (CTAB) to modulate the simultaneous adsorption of cationic (Rhodamine B, RB) and anionic dyes (acid blue 113, AB and acid red 27, AR). The formation of the polyester was successfully confirmed by ATR-FTIR and the thermal properties were evaluated by TGA and DCS. In the presence of CTAB 5 mM, the material removes almost 100% of the dyes, reaching the kinetics equilibrium in 30 min following the Pseudo-second order model. Additionally, dye adsorption on the polyester in the presence of CTAB was described by the Freundlich isotherm model, indicating a heterogeneous polyester surface that promotes a multi-layer adsorption driven by electrostatic interaction and hydrogen bonds. The material showed an adsorption capacity of 73.7 ± 3.2, 82.1 ± 4.4, and 21.2 ± 0.6 mg/g for RB, AB, and AR, respectively. Our results provide evidence that the poly(glycerol citrate)/CTAB has a higher potential for application in wastewater treatment to remove both anionic and cationic dyes. [ABSTRACT FROM AUTHOR]

Banana fibers being highly strong and biodegradable, have always been an interesting aspect of polymer science. The research examines the pretreatment process to enhance the dyeability of banana fibers with synthetic dyes, followed by the preparation of polypropylene (PP) composites with dyed fibers to explore their mechanical properties. Raw banana fibers were extracted from the pseudo stems of banana plants for pretreating with sodium hydroxide and hydrogen peroxide and further dyed in the exhaust method using direct, basic, reactive, and vat dyes. Despite a decrease in fiber strength, the scoured‐bleached fibers appeared whiter and lustrous compared to untreated fibers. Direct dye exhibited a higher color strength (K/S) value of 20.7 and better wash fastness on average of 4‐3 rating compared to basic dye. Later polypropylene sheets were prepared using a Hot Plate Molding Machine, and composite specimens were fabricated by sandwiching the fibers between PP sheets and hot pressing. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed minor bond formations between the dyed fibers and polypropylene matrix in composites showing significant bonding at NH, CH, and OH regions. The composites containing dyed fibers showed slight improvements in tensile strength and modulus which is at best 2% than that of untreated fiber. Highlights: Direct and basic dyes were determined as the most suitable synthetic dyes.FTIR analysis revealed minimal bond formation between the fiber and PP matrix.Composites having dyed banana fiber showed little better mechanical features. [ABSTRACT FROM AUTHOR]

This study focuses on the development of a novel self-cleaning nanofiltration membrane for the efficient removal of the cationic dye methylene blue (MB) from industrial wastewater. The membrane is composed of vinyl resin (VR), cellulose nanofibrils (CNF), and titanium alpha aluminate (TAAL) nanoparticles. The TAAL loading ranged from 1 to 5 wt%, the pH varied from 5 to 10, and the initial MB concentration ranged from 10 to 50 ppm. Using a dead-end filtration system, the (VR/CNF@TAAL) membrane with 5 wt% TAAL at pH 10 demonstrated excellent performances. It achieved a remarkable 98.6% removal efficiency for 30 ppm MB dye, with a maximum adsorption capacity of 125.8 mg/g. The adsorption kinetics analysis revealed that the process followed the pseudo-second-order model, indicating a chemisorption mechanism. The rate constant was determined to be 1.2732 × 10–3 g mg−1 min−1. The Freundlich isotherm model provided a better fit (R2 = 0.996) than the Langmuir model, suggesting multilayer adsorption on the nanocomposite membrane surface. In addition to its high adsorption and filtration capabilities, the (VR/CNF@TAAL) nanocomposite membrane exhibited cost-effectiveness and environmental friendliness as an adsorbent for MB removal from industrial wastewater. The membrane's self-cleaning property further contributes to sustainability by reducing the need for additional chemical treatments. [ABSTRACT FROM AUTHOR]

Textile-toxic synthetic dyes, which possess complex aromatic structures, are emitted into wastewater from various branches. To address this issue, the adsorption process was applied as an attractive method for the removal of dye contaminants from water in this article. An unprecedented integrated experimental study has been carried out, accompanied by theoretical simulations at the DFT-B3LYP/6-31G (d,P) level of theory to investigate how single Maxilon Blue GRL (MxB) dye or and its mixture with MG (Malachite Green) dyes interact with the adsorbent and compare the obtained results with the data obtained through experimentation. The full geometry optimization revealed the physical adsorption of dyes on the Al2O3 surface. Non-linear optical properties (NLO) results emphasized that the complex MG-Al2O3-MxB is a highly promising material in photo-applications, and the adsorbed binary system is energetically more favorable compared to the adsorbed sole dye system. The experimental results for (MxB) dye adsorption onto γ-Al2O3 affirmed that the optimum conditions to get more than 98% uptake were at dye concentration 100 ppm, pH 10, adsorbent content 0.05 g, and equilibrium time only 20 min. The kinetic and isothermal studies revealed that the adsorption accepted with the pseudo-second-order and Freundlich isotherm model, respectively. The removal efficiency of the mixture of MxB and MG dyes was the highest but did not change clearly with increasing the % of any of them. The details of the interaction mechanisms of the sole and binary dyes were proven. [ABSTRACT FROM AUTHOR]

In this study, a hydrothermal approach was employed to graft chitosan (Chit)/algae (ALG) with salicylaldehyde (SA), resulting in the synthesis of a biocomposite named salicylaldehyde-based chitosan Schiff base/algae (Chit-SA/ALG). The main objective of this biocomposite was to effectively remove methyl violet (MV), an organic dye, from aqueous solutions. The adsorption performance of Chit-SA/ALG toward MV was investigated in detail, considering the effects of three factors: (A) Chit-SA/ALG dose (ranging from 0.02 to 0.1 g/100 mL), (B) pH (ranging from 4 to 10), and (C) time (ranging from 10 to 120 min). The Box–Behnken design (BBD) was utilized for experimental design and analysis. The experimental results exhibited a good fit with both the pseudo-second-order kinetic model and the Freundlich isotherm, suggesting their suitability for describing the MV adsorption process on Chit-SA/ALG. The maximum adsorption capacity of Chit-SA/ALG, as calculated by the Langmuir model, was found to be 115.6 mg/g. The remarkable adsorption of MV onto Chit-SA/ALG can be primarily attributed to the electrostatic forces between Chit-SA/ALG and MV as well as the involvement of various interactions such as n–π, π–π, and H-bond interactions. This research demonstrates that Chit-SA/ALG exhibits promising potential as a highly efficient adsorbent for the removal of organic dyes from water systems. The novelty of this work comes from introducing a new bio-organic based composite adsorbent of chitosan (Chit) biopolymer and algae (ALG) biomass. Moreover, the functionality and chemical stability of Chit–ALG composite was further developed by grafting process with salicylaldehyde (SA) using hydrothermal process. The incorporation of ALG biomass into polymeric matrix of Chit and grafting process with SA makes Chit a unique hybrid adsorbent toward cationic dye (methyl violet dye). [ABSTRACT FROM AUTHOR]

In this work, green method to synthesize chromium-doped zinc oxide (ZnO) nanorods (NRs) using an aqueous flower extract from Rhododendron arboretum is explored. Herein, chromium-doped ZnO NRs were prepared with different amount of chromium doping, varied as 2–10%. The green synthesized products underwent substantial analysis through X-ray diffraction (XRD), spectroscopic such as ultraviolet spectroscopy(UV-Vis) and scanning electron microscopy (SEM) methods. All samples were found to have hexagonal wurtzite ZnO, with average particle sizes of 52.41, 56.6, 54.44, 53.05, and 56.99 nm, respectively, for 2, 4, 6, 8, and 10% chromium doping in ZnO NRs. The Cr-doped ZnO NRs exhibited remarkable photocatalytic degradation activity of cationic dyes under UV-light, i.e., Malachite Green and Fuchsin Basic with degradation of 99.604 and 99.881%, respectively in 90 min. The reusability tests for these green synthesized Cr-doped ZnO NRs have also been carried out, showed 9–11 cycles with 85% of degradation efficiency. In addition, the Cr-doped ZnO NRs exhibited high selectivity for cationic dyes when experiments against mixture of dyes were performed. Photodegradation kinetics followed the pseudo-first-order model. The flower-extract-stabilized chromium-doped ZnO NRs demonstrated high photocatalytic activity toward malachite green and fuchsin basic dyes, potential material for pollution remediation. Cr-doped ZnO NRs by green method using flower extract of Rhododendon arboretum were prepared for the first time under ambient reaction conditions. Effect of Dopant i.e. Cr on Photocatalytic activity have been exploited. Selective photocatalytic degradation of cationic dyes i.e. MG, and FB has been achieved in 60–90 minutes. Optimization of reaction condition and various parameters has also been carried out. Recyclability of Cr-doped ZnO NRs was also evaluated and were found to be reusable for 11 cycles for degradation. [ABSTRACT FROM AUTHOR]

In this study, pineapple crown (PC) feedstock residues were utilized as a potential precursor toward producing activated carbon (PCAC) via pyrolysis induced with ZnCl2 activation. The PCAC has a surface area (457.8 m2/g) and a mesoporous structure with an average pore diameter of 3.35 nm, according to the Brunauer–Emmett–Teller estimate. The removal of cationic dye (Fuchsin basic; FB) was used for investigating the adsorption parameters of PCAC. The optimization of significant adsorption variables (A: PCAC dose (0.02–0.1 g/100 mL); B: pH (4–10); C: time (10–90); and D: initial FB concentration (10–50 mg/L) was conducted using the Box-Behnken design (BBD). The pseudo-second-order (PSO) model characterized the dye adsorption kinetic profile, whereas the Freundlich model reflected the equilibrium adsorption profile. The maximum adsorption capacity (qmax) of PCAC for FB dye was determined to be 171.5 mg/g. Numerous factors contribute to the FB dye adsorption mechanism onto the surface of PCAC, which include electrostatic attraction, H-bonding, pore diffusion, and π–π stacking. This study illustrates the utilization of PC biomass feedstock for the fabrication of PCAC and its successful application in wastewater remediation. [ABSTRACT FROM AUTHOR]

Waste-derived polystyrene microparticles loaded with cobalt hydroxide were prepared and tested as adsorbents for water treatment. The structure of the obtained adsorbent was analyzed by FT-IR, SEM-EDX and XRD techniques. Two dyes, namely, Reactive Red 195 and Methylene Blue were used to evaluate the adsorption behavior of the adsorbent toward anionic and cationic dyes, respectively. The effects of solution pH, contact time, temperature and adsorbent dose on the adsorption process were investigated. The adsorption data were analyzed using the Langmuir and Freundlich isotherms and the pseudo-first and pseudo-second order kinetic models. The thermodynamic parameters of the adsorption process (changes in enthalpy, entropy, and Gibbs free energy) were estimated. The maximum adsorption capacities estimated using the Langmuir model were 37.20 and 32.06 mg g−1 for Reactive Red 195 and Methylene Blue, respectively. The pseudo-first-order equation provided the best description for the adsorption kinetics. The evaluated thermodynamic parameters for adsorption indicated that the process was endothermic, random, and spontaneous. These results suggest that the cobalt hydroxide-loaded polystyrene waste could serve as an effective adsorbent for the removal of dyes from water. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the removal of harmful cationic dyes, namely brilliant green and safranin-O, from wastewater produced by industries like textile, pigment, and pharmaceutical, which pose a direct threat to human health and the environment. An emulsion liquid membrane (ELM) was employed to eliminate these dyes, and the efficiency of the membrane was measured by calculating the percentage of dye removal and the breaking rate. The study successfully optimized the ELM process to remove the dyes within an hour and demonstrated the membrane's stability for more than 60 minutes. The results showed that the prepared ELM could remove 100% of the brilliant green dye and 99.6% of the safranin-O dye. A maximum breaking rate of 0.029% was obtained for brilliant green and 0.008% for safranin-O. Furthermore, the study resulted in the maximum removal of 99.36% and 99.15% for brilliant green and safranin-O dyes, respectively, in the binary system. When both dyes were present simultaneously, the maximum breakage observed was only 0.16%. The experimental results were analyzed using a UV–visible spectrophotometer and an optical microscope, and the optimization and analysis of the variance of means and signal-to-noise (S/N) ratio were carried out using the Taguchi L16 orthogonal array. [ABSTRACT FROM AUTHOR]

Indium-based quantum dots (QDs), such as copper indium disulfide and zinc copper indium sulfide, have been the center of research for decades due to their low toxicity and unique photophysical properties. In contrast, versatile indium-based materials like In2S3 and ZnIn2S4 have been rarely studied in their QD form because of the challenges in their synthesis and used in solid-state material based applications because of their colloidal nature. In this study, a one-pot single-step method to synthesize In2S3, ZnIn2S4, and Cu-doped ZnIn2S4 QDs trapped in insoluble solid-state oleic acid matrices was developed. The QDs in solid-state matrices exhibited bright orange colored fluorescence with controllable emission properties achieved by altering the chemical composition. Among these QDs, the ZnIn2S4 QDs displayed thermo-responsive properties. As the temperature increased, the fluorescence intensity of ZnIn2S4 QDs decreased. In addition, all QDs demonstrated high removal efficiency for micropollutants in the aqueous medium, especially against cationic organic dyes. This study represents one of the first attempts at the direct development of QDs trapped in insoluble solid-state matrices. The QDs in solid-state matrices hold promise for applications in thermal sensors and studies related to the micropollutant removal. [ABSTRACT FROM AUTHOR]

In this study, chitosan nanoparticles (ChNs) were used as an adsorbent for single and simultaneous uptake of cationic (methylene blue (MB)) and anionic (methyl orange (MO)) dyes. ChNs were prepared based on the ionic gelation method using sodium tripolyphosphate (TPP) and characterized by zetasizer, FTIR, BET, SEM, XRD, and pHPZC. The studied parameters that affect removal efficiency included pH, time, and dyes' concentration. The results showed that in single-adsorption mode, the removal of MB is better in alkaline pH, contrary to MO uptake which presents higher removal efficiency in acidic media. The simultaneous removal of MB and MO from the mixture solution by ChNs could be achieved under neutral conditions. The adsorption kinetic results showed that adsorption of MB and MO for both single-adsorption and binary adsorption systems comply with the pseudo-second-order model. Langmuir, Freundlich, and Redlich-Peterson isotherms were used for the mathematical description of single-adsorption equilibrium, while non-modified Langmuir and extended Freundlich isotherms were used to fit the co-adsorption equilibrium results. The maximum adsorption capacities of MB and MO in a single dye adsorption system were 315.01 and 257.05 mg/g for MB and MO, respectively. On the other hand, and for binary adsorption system, the adsorption capacities were 49.05 and 137.03 mg/g, respectively. The adsorption capacity of MB decreases in solution containing MO and vice versa, suggesting an antagonistic behavior of MB and MO on ChNs. Overall, ChNs could be a candidate for single and binary removal of MB and MO in dye-containing wastewater. [ABSTRACT FROM AUTHOR]

A novel method for synthesizing cationic styryl dyes through a nucleic acid‐templated reaction has been developed. This approach overcomes issues associated with traditional synthesis methods, such as harsh conditions, low throughput, and wasteful chemicals. The presence of a nucleic acid template accelerated the styryl dye formation from quaternized heteroaromatic and cationic aldehyde substrates. These styryl dyes show remarkable optical properties change when bound to nucleic acids, hence the success of the synthesis could be readily monitored in situ by UV‐Vis and fluorescence spectroscopy and the optical properties data were also observable at the same time. This method provides the desired products from a broad range of coupling partners. By employing different substrates and templates, it is possible to identify new dyes that can bind to a specific type of nucleic acid such as a G‐quadruplex. The templated dye synthesis is also successfully demonstrated in live HeLa cells. This approach is a powerful tool for the rapid synthesis and screening of dyes specific for diverse types of nucleic acids or cellular organelles, facilitating new biological discoveries. [ABSTRACT FROM AUTHOR]

Hypercrosslinked porous polymers have become a hotspot of research by virtue of their high specific surface area, mild synthesis conditions, and wide source of monomers, which are promising adsorbents for water treatment. In this paper, 4-vinylbenzylchloride (VBC), acrylic acid (AA) and divinylbenzene (DVB) were used to prepare crosslinked microspheres as a template by reflux precipitation polymerization. On this basis, porous microspheres were prepared by hypercrosslinking reaction using FeCl3 as catalyst. Next, excess FeCl3 was used as iron sources for the next solvothermal reaction to prepare magnetic hypercrosslinked P(VBC-DVB-AA)@Fe3O4 microspheres (MHCPMs). The elution step of the hypercrosslinked product was omitted, while magnetic Fe3O4 was introduced. MHCPMs have uniform particle size, high specific surface area, superparamagnetism and abundant functional groups. After synergistic preparation, the specific surface area of the MHCPMs-60 was still as high as 654.56 m2/g, and the saturation magnetization strength reached 29.0 eum/g. The magnetic microspheres could be directly aggregated and separated in the presence of an applied magnetic field. In addition, MHCPMs were well dispersed in water after vigorous shaking and could be used to adsorb the cationic dye quickly and efficiently. The adsorption results for methylene blue (MB) well conformed to the Langmuir model (R2 = 0.999) with a maximum adsorption of 214.26 mg/g and followed the pseudo-first-order kinetic model. In addition, the MHCPMs-60 showed good reusability and stability over seven cycles. Therefore, this study proposed a synergistic strategy for the preparation of magnetic porous polymer microspheres, which exhibited a significant potential application value in many fields. [ABSTRACT FROM AUTHOR]

Adsorption is now recognized as an effective and economic method for wastewater treatment. Thus, in recent years, development of low cost adsorbent for dye loaded wastewater remediation has become an important area of research. Algerian phosphate was tested as an effective adsorbent for the removal of cationic dye methylene Blue (MB) as well as the anionic dye blue bezaktiv S-GLD 150 (BB) from synthetic wastewater. The phosphate was characterized by XRD, FT-IR, TGA, SEM, EDX and BET analysis. pHPZC analysis was performed to determine pH sensitive adsorptive removal of cationic and anionic dyes. Batch adsorption experiments of the dyes from aqueous solution were conducted, taking into account the influence of initial dye concentration (10–500 mg/L), adsorbent dosage (1–6 g/L), contact time (5–120 min) and solution pH ((2–12) ± 0.2). The experimental results show that, the adsorption was pH dependent with a high adsorption capacity of MB in basic range and high adsorption of BB in the acidic range. Experimental adsorption data were modeled by different equilibrium isotherms such as Langmuir, Freundlich, Redlich Peterson and Sips. The adsorption process fitted well to pseudo-second-order kinetics and the Langmuir model. The calculated maximum adsorbed quantity qmax of MB and BB were found 30.61 (mg/g) and 20.78 (mg/g) successively. The adsorption process was found to be exothermic in nature in the case of the MB and endothermic for BB. Accordingly; the phosphate has been shown to be a very efficient and low-cost adsorbent, and a promising alternative for eliminating dyes from industrial wastewater. [ABSTRACT FROM AUTHOR]

In this work, we explored the adsorptive detoxification potential of titania–bentonite clay composite for removing a cationic dye (crystal violet) from aqueous medium. Fresh clay composite sample were prepared by impregnated method, followed by spectroscopic characterization by SEM, FTIR, and EDX. After that, in batch studies dye removal were examined. The results under optimum conditions showed that this composite material has a 96% elimination capacity. Maximum removal of crystal violet was 49.26 mg/g, following Pseudo-second order kinetic model occurred at pH 8, at 125 rpm and 25 ppm initial concentration at 45 °C. Kinetics of reactions and isotherm models were investigated. Adsorption data showing the presence of monolayer adsorption were fitted using the Langmuir isotherm model. Chemisorption was shown to prevail according to Temkin isotherm criteria. Pseudo-second-order kinetics was followed in this case. For removing dye from industrial effluents, this titania–bentonite composite serves as a nonbiodegradable, low-cost, reliable, and ecologically safe adsorbent. [ABSTRACT FROM AUTHOR]

The wide use of mono- or bis-styryl fluorophores in biomedical applications prompted the presented design and study of a series of trimeric and tetrameric homo-analogues, styryl moieties arranged around a central aromatic core. The interactions with the most common biorelevant targets, ds-DNA and ds-RNA, were studied by a set of spectrophotometric methods (UV-VIS, fluorescence, circular dichroism, thermal denaturation). All studied dyes showed strong light absorption in the 350–420 nm range and strongly Stokes-shifted (+100–160 nm) emission with quantum yields (Φf) up to 0.57, whereby the mentioned properties were finely tuned by the type of the terminal cationic substituent and number of styryl components (tetramers being red-shifted in respect to trimers). All studied dyes strongly interacted with ds-DNA and ds-RNA with 1–10 nM−1 affinity, with dye emission being strongly quenched. The tetrameric analogues did not show any particular selectivity between ds-DNA or ds-RNA due to large size and consequent partial, non-selective insertion into DNA/RNA grooves. However, smaller trimeric styryl series showed size-dependent selective stabilization of ds-DNA vs. ds-RNA against thermal denaturation and highly selective or even specific recognition of several particular ds-DNA or ds-RNA structures by induced circular dichroism (ICD) bands. The chiral (ICD) selectivity was controlled by the size of a terminal cationic substituent. All dyes entered efficiently live human cells with negligible cytotoxic activity. Further prospects in the transfer of ICD-based selectivity into fluorescence-chiral methods (FDCD and CPL) is proposed, along with the development of new analogues with red-shifted absorbance properties. [ABSTRACT FROM AUTHOR]

Organic dyes can inflict environmental harm and pose risks to human health, thereby presenting challenges in their treatment within industrial wastewater. Currently, numerous research groups have conducted investigations on the adsorption of organic dyes in industrial wastewater. Herein, this work focuses on the selective adsorption approach towards dyes molecules based on an Anderson-type polyoxometalate (noted as POM-1) as potential adsorbent, which has been functionalized with organic ligands to enhance its negative charge. Adsorption experiments revealed that POM-1 displayed efficient adsorption capabilities towards the cationic dye methyl blue with almost complete adsorption within 25 min, and the adsorption rate was calculated as 98%. A rapid and consecutive filtering experiments have also been performed and further proved the excellent adsorption behavior of POM-1 towards MB. [ABSTRACT FROM AUTHOR]

Scientists have become interested in treating dye-contaminated water due to the health issues and ecological imbalances caused by the presence of these injurious compounds in water. Herein, two MnO2 polymorphs i.e. ε- and γ-MnO2 were prepared by the comproportionation reaction between KMnO4 and MnCl2. In comparison to γ-MnO2, ε-MnO2 has greater surface area, pore width, and pore volume. According to the thermal study, ε-MnO2 contains more surplus mass in the form of negatively charged surface hydroxyl groups than γ- phase. The adsorption capability of both polymorphs was examined for the removal of both cationic (methylene blue, malachite green and crystal violet) and anionic dyes (eosin yellow). The efficient adsorption for the cationic dyes using ε-MnO2 was occurred in the neutral medium, where it had a highly negative surface as determined by zeta potential measurements. It only took few minutes to complete the removal. The electrostatic interactions of the cationic dye molecules with the OH- groups account for this result. While, complete dye removal (40 min) was occurred in the acidic medium using γ-MnO2. On the other hand, in the neutral medium the adsorption of the anionic dye molecules on the surface of both MnO2 phases was hampered by the repulsion forces. As a result, despite extending the contact time to 180 min and the adsorbent dose to 50 mg, no anionic dye removal was seen. On the contrary, in the acidic medium very fast removal occurs for Eosin Y as the surface of both MnO2 phases acquired a positive charge. The influence of the ionic strength on MB elimination was investigated. The results showed that as the content of NaCl was increased, the removal effectiveness decreased from 100% to 35%. The kinetics of cationic dye adsorption on the ε-MnO2 surface was studied, and it was discovered that the mechanism follows a pseudo-second order model. [ABSTRACT FROM AUTHOR]

In this study, the objective was to examine the utilization of the pyrolyzed by-products biomass as an adsorbent for extracting the dye Basic Red 46 (BR 46) from a solution. The pyrolyzed by-product containing Pleurotus mutilus biomass was characterized by thermogravimetric analysis (TGA), FTIR and µXRF. Different parameters effects such as, adsorbent dose, solution pH, contact time, temperature and initial dye concentration on the adsorption capacity of the pyrolyzed by-product biomass were examined. The solution was analyzed before and after the adsorption studies. With adsorbent dose of 1 g/L, contact time of 14 min, and solution pH of 7.5, the optimum yield of 88% was achieved. In order to fit the equilibrium data, the Langmuir, Freundlich, Temkin, and Khan isotherm models were used, and in order to fit the kinetics data, the pseudo-first-order, pseudo-second-order, Elovich, and Ritchie models were employed. Statistical analysis such as R2, RMSE, χ 2 and ARE was used to assess which model has the best fit with the experimental data. The results demonstrated that the experimental equilibrium data are well described by the Langmuir model, and the kinetic studies indicated that the adsorption of BR46 followed the Ritchie model. The greatest BR 46 adsorption capacity determined from experimental equilibrium data was around 135 mg/g at pH = 7.5, adsorbent dosage of 1 g/L. Moreover, thermodynamic analysis has demonstrated that the adsorption process was physical, exothermic, and spontaneous in nature. These results indicated that pyrolyzed by-product biomass might be used as a cheap material to extract textile colors out of aqueous effluents. [ABSTRACT FROM AUTHOR]

Hydrogels based on natural polysaccharides have received special attention in the last decade due to their interesting features, such as availability, biocompatibility, biodegradability and safety. Such characteristics may make them sustainable and eco-friendly materials for water and wastewater treatment, meeting the concept of circular economy. In this study, a novel double-cross-linked alginate-based hydrogel has been successfully synthesized using epichlorhydrin and sodium trimetaphosphate (STMP) as cross-linker agents and then used for the removal of methylene blue (MB) dye under different operating conditions. The obtained hydrogel was deeply characterized by using various analytical techniques, namely Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and differential scanning calorimetry. Experimental results showed that the synthesized double cross-linked hydrogel with relatively high STMP concentration (0.26 M) has promising structural and textural properties. This material exhibited excellent removal ability towards MB with a maximum adsorption capacity of about 992 mg/g for an initial pH of 10. The kinetic and isotherm modeling study revealed that the pseudo-second-order and Freundlich models fitted well the measured adsorption experimental data. The MB adsorption process onto the synthesized hydrogel is exothermic, feasible and spontaneous. It mainly includes electrostatic interaction and hydrogen bonds. These findings suggest that double-cross-linked alginate-based hydrogel can be considered as an attractive and potential adsorbent for an effective cationic dye removal from aqueous environments. The use of such a green adsorbent for the treatment of organic-pollutants-rich industrial wastewaters promotes sustainability and circular economy concepts. [ABSTRACT FROM AUTHOR]

Magnetic nanosorbents efficiently capture substances, particularly basic dyes, and can be easily recovered using a magnetic field in water treatment. Adsorption is a cost-effective and highly efficient method for basic dye removal. This study compared eight nonlinear kinetic adsorption models using Microsoft Excel 2023, which provided a detailed analysis and statistical results comparable to advanced programs like MATLAB and OriginPro. The Fractal Like-Pseudo First Order (FL-PFO) model showed the best fit for the kinetic adsorption model, closely predicting experimental data at 33.09 mg g−1. This suggests that the diffusion rate of basic dye within the magnetic nanosorbent pores is a crucial factor. The statistical parameters confirmed the suitability of these kinetic adsorption models for describing the observed behavior. Overall, Microsoft Excel emerged as a reliable tool for predicting adsorption behavior using various kinetic models for basic dye removal, offering a wide range of functions for diverse applications, including environmental monitoring and modeling. Corrected Akaike's information criterion was used to determine the optimal model. It found the lowest AICcorrected value of about −3.8479 for the FL-PFO kinetic model, while the Elovich kinetic adsorption model had the highest AICcorrected value of 29.6605. This indicates that the FL-PFO kinetic model effectively correlated the kinetic data. It can be concluded that Microsoft Excel's accessibility, familiarity, and broad range of capabilities make it a valuable resource for many aspects of environmental engineering. [ABSTRACT FROM AUTHOR]

In this paper, the flocculation and dye recovery potential of a cationic dye, C.I. Basic Blue 41 (BB41), were explored using a natural, fungus-derived flocculant. The influence of various factors on the flocculation, characterization before and after flocculation, as well as adsorption kinetics were investigated. It was observed that an initial pH of 4, without any pH adjustment, favored flocculation, resulting in over 80% decolorization efficiency, whereas a pH of 2 was found to be unfavorable. Because of this acidic-pH responsive property, dyestuffs can be regenerated at pH 2 with a dye recovery efficiency exceeding 60%. The concentration increased by over 3 times when the regeneration occurred in one-tenth of its original volume. Scanning electron microscope (SEM) morphological analysis observed that the dye particles accumulated on the surface of the flocculant. The adsorption process fitted a pseudo-second-order kinetics model. Fourier transform infrared (FTIR) analysis suggested that amide, amine, and hydroxyl groups played important roles in flocculation. These findings were further confirmed with two other textile cationic dyes, C.I. Basic Red 29 (BR29) and C.I. Basic Blue 54 (BB54), both of which exhibited excellent flocculation performance, achieving nearly 100% decolorization efficiency and approximately 40% recovery efficiency. These results suggest that the flocculant used in this study has the potential not only to remediate dyestuffs from textile wastewater but also to recover dyestuffs in a simple manner. [ABSTRACT FROM AUTHOR]

Organic dye pollutants are the most common type of pollutant found in water and wastewater as a result of various industrial activities. In particular, one of the largest contributors is the textile industry, which uses a lot of organic dyes to produce its goods. Organic dyes that remain in the effluents are typically permanent and difficult to detoxify using traditional wastewater treatment strategies. Photocatalysis using semiconductors have emerged as an attractive wastewater treatment method for resolving the major drawbacks of traditional methods. Montmorillonite has been presented as a conceivable dye adsorbent. When a semiconductor is incorporated, its adsorptive capability assists in imposing heterogeneous photoactivity. It is widely employed in a variety of applications due to fundamental characteristics such as high flexibility, swelling, ion exchange ability, acidity, usage in catalytic amounts, milder reaction conditions, benefit in reusability, selectivity, high yield, cheap cost, and so on. In this review, we specifically describe the last 3 years' development of dye degradation employing recently developed montmorillonite (MMT)‐based materials, as well as their preparation methods. In addition, the photocatalytic degradation of various types of organic dye pollutants, such as anionic and cationic dyes, was also studied in this review. The findings reveal that MMT‐based materials have a wide range of applications in the photocatalytic degradation of contaminants existing in the environment. [ABSTRACT FROM AUTHOR]