Continuous industrial operation generates numerous contaminants, including synthetic dyes, which may ultimately culminate in water contamination for humans and aquatic life. The burning issue was tackled via facile synthesis of agar grafted polyacrylamide (Agr-g-pAAm@Sn-Ni-ZrO2 hydrogel sorbent for efficient sorption of lowacryl blue-3 (LAB-3). The current studies involved comprehensive investigations regarding optimization of various parameters like contact time, pH, sorbent dosage, initial concentration and temperature for efficient LAB-3 sorption. The Agr-g-pAAm@Sn-Ni-ZrO2 superabsorbent demonstrated Fickian diffusion for water absorption and swelled up to a maximum limit 1330% at pH 12 in 23 h. Notably, the current sorption followed pseudo second order kinetics which further implied chemisorption as the rate limiting step in LAB-3 uptake by Agr-g-pAAm@Sn-Ni-ZrO2 sorbent. The sorption was most appropriately described by the Langmuir model which characterized the attachment of LAB-3 to the sorbent in monolayer fashion on identical binding sites of a homogenous surface presented by Agr-g-pAAm@/Sn-Ni-ZrO2 sorbent. Thus, the promising swelling (1330%) and sorption (909.09 mg/g) capacities along with retained > 90% of its adsorption efficiency after the third adsorption-desorption cycles, which may recommend the Agr-g-pAAm@Sn-Ni-ZrO2 material for industrial wastewater treatment on commercial scale.

This work presents the solvothermal synthesis of a trimetallic CuCrFe-BDC Metal-Organic Framework (CuCrFe-BDC MOF), designed for highly efficient and stable adsorption of Methyl Violet 6B (MV-6B) dye from aqueous media. Detailed characterization via SEM, XRD, FTIR, BET, TGA, zeta potential, EDX, and elemental mapping was carried out. FTIR analysis verified all pivotal functionalgroup signatures, while XRD confirmed a highly crystalline phase exhibiting sharp, well-defined diffraction peaks. TGA demonstrated exceptional thermal resilience up to 600 degrees C. BET measurements revealed a remarkable specific surface area (626 m(2)/g) with pronounced microporosity, ideal for high-performance adsorption. The material was synthesized with an average nanoscale particle size of 87 nm, forming larger aggregates around 289 nm. Under optimized conditions of 0.01 g adsorbent dosage, 333 K, pH 8, and a 60 min contact time, the trimetallic CuCrFe-BDC MOF achieved over 91 % removal of MV-6B dye. Adsorption kinetics followed a pseudo-secondorder model (R-2 > 0.99), indicating chemisorption dominance. Equilibrium data conformed closely to the Langmuir isotherm (R-2 = 0.99), with a maximum monolayer adsorption capacity of 416 mg/g at 333 K. Thermodynamic analysis revealed an endothermic process, by positive enthalpy change (Delta H degrees = 17.79 kJ/mol ) that is spontaneous across the temperature range studied, as evidenced by consistently negative Delta G degrees values. The adsorption mechanism likely includes chemisorption combined with pi-pi stacking, pore-filling, electrostatic interactions, and hydrogen bonding. Importantly, the CuNiZnBDC MOF maintained its structural integrity and recyclability over seven adsorption-desorption cycles, retaining 65 % removal efficiency. These findings underline the potential of this robust, high-capacity MOF as an effective adsorbent for industrial wastewater applications.

The uncontrolled discharge of textile dyes such as Pollen Yellow G (PY-G) and Nile Blue A (NB-A) into aquatic systems poses serious environmental and health risks due to their toxicity, persistence, and resistance to biodegradation. In this study, xanthan gum-grafted poly(acrylic acid) (XG-g-PAA) hydrogel was successfully synthesized and evaluated as an efficient adsorbent for dye removal using batch adsorption experiments. The hydrogel was characterized by SEM, EDX, FTIR, TGA, and BET/BJH analyses, confirming a rough, highly porous, and sponge-like morphology with abundant active sites and good thermal stability up to 250 degrees C, which are favorable for adsorption applications. Under optimized conditions of contact time 60 min, adsorbent dose 0.01 g, initial dye concentration 250 mg/L, temperature 298 K, and pH 6 (PY-G) and 8 (NB-A), the adsorption process exhibited excellent performance. Kinetic analysis showed that the adsorption followed the pseudo-second-order model with R2 > 0.99, indicating chemisorption as the dominant mechanism, while equilibrium data were best fitted to the Langmuir isotherm, yielding maximum adsorption capacities of 327 mg/g for PY-G and 636 mg/g for NB-A. Thermodynamic parameters further supported the adsorption behavior, where Delta H degrees values of 9.396 and 6.450 kJ/mol and Delta S degrees values of 31.32 and 40.53 J/mol. K were obtained for PY-G and NB-A, respectively, while Delta G degrees values decreased from (-220.06 to -1,032.7 J/mol) for PY-G dye and from (-5,422.41 to -7,043.31 J/mol) for NB-A with increasing temperature (293-333 K), confirming that the adsorption process is spontaneous, endothermic, and entropy-driven, consistent with previously reported xanthan-based hydrogel systems showing high adsorption capacities and Langmuir behavior. Furthermore, the hydrogel demonstrated good reusability with only a slight reduction in efficiency after multiple adsorption-desorption cycles. Overall, the results indicate that XG-g-PAA hydrogel is a highly effective, recyclable, and eco-friendly adsorbent for the removal of hazardous dyes from wastewater.

Rapid industrial progress may ultimately culminate in water contamination with recalcitrant dyes which seriously disrupt aquatic life, humans and natural environment. The underscored risks stemmed from dye contamination was significantly mitigated via facile sorption of acid yellow-34 (AY-34) onto gum Arabic grafted polyacrylamide (GA-g-pAAm) hydrogel sorbent. The sorbent was facilely fabricated, in single step, through free radical polymerization method. Then detailed sorption tests were systematically performed by exploring the effect of contact time, pH, initial AY-34 concentration and temperature. The current sorption data essentially followed pseudo second order kinetic and Freundlich isotherm model. The GA-g-pAAm sorbent reached maximum sorption capacity (qm) of 697.67 mg g-1 at 60 degrees C. The positive triangle H degrees (52.767 kJ/mol) and triangle S degrees (169.222 J/mol. K) values unequivocally demonstrated the current sorption as endothermic and accompanied with rise in entropy at the liquid/solid interface, respectively. The negative triangle G degrees (-3.584 kJ mol-1) value at 60 degrees C indicates spontaneous sorption of AY-34 by GA-g-pAAm hydrogel. During regeneration, the sorbent maintained promisingly high performance (72.5%) even after fifth regeneration cycle, which highlights promising sustainability of the subject material for the treatment of industrial wastewater in commercial applications.

Herein, corn cobs (maize) have been converted into an activated carbon by subjecting to carbonization which were then treated with 1:1 solution of HCl and HNO3 and finally passed through C6H12 solution and finally activated at a high temperature of 400◦C. The obtained activated sample was subjected to XRD, EDX, and SEM analysis. The surface area was estimated as 913 m2/g using a reported method in literature. The synthesized activated carbon was utilized as sorbent for acid blue 129 and Erioglaucine dyes. The kinetics of the process was evaluated at 20, 40, and 60 °C with best fitting achieved with pseudo-2nd order kinetics model. The correlation coefficient (R2) of the Langmuir model was high approaching to 1 thus exhibited best fitting of the data. The maximal adsorption capacity was 769.23 mg/g for erioglaucine and 833.33 mg/g for acid blue 129 recorded at 333 K. The thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes were also determined. The ΔG° and ΔH° (− 16.805 kJmol− 1 − 9.054 kJmol− 1) values were negative indicated the feasibility of the process and its exothermic nature. The increase in disorder at solid-solution interface during the adsorption process was evident from the positive values of ΔS° (79.253 JK− 1 mol− 1 39.633 JK− 1) indicated the spontaneity of the process. Further equilibrium was established from 5 to 7 min for both the dyes whereas optimum adsorbent dosage selected was 0.01 g. The synthesized activated carbon has been prepared from a renewable biomass source therefore; it could be the best alternative of synthetic water reclamation methods subjected to further validation by other researchers.

The study focuses on the synthesis CuNiZn-BTC metal-organic framework; a potential adsorbent for the removal of patent blue VF dye; a significant contributor to water contamination and has adverse impacts on the environment and human health. The CuNiZn-BTC MOF was synthesized by assimilating metal salt precursors with organic linker BTC using DMF as solvent; a solvothermal method at 150 degrees C for 48 h. Instrumental techniques like SEM, FTIR, XRD, BET, TGA, and zeta potential analyzer were used to characterize the synthesized MOF. The study investigated spherical particles in the nanoscale range of 94 nm and agglomerate size of 245 nm as confirmed from SEM. FTIR analysis reports various peak values (3200-3500 cm-1) for uncoordinated -COOH and hydrogen- bonded water molecules, (3000-3100 cm-1) for C-H bond, 1500 cm-1 for C--C which indicates the presence of benzene ring in the structure and 1650 cm-1 strong peak attributed to the C--O stretching vibration of the COOH functional group indicating the coordination between metal ion and BTC ligand. XRD indicated high crystallinity with distinct peaks, and TGA analysis demonstrated the thermal stability up to 450 degrees C, while BET analysis revealed a high surface area of 659 m2/g with a microporous structure, which contributed to the enhanced adsorption efficiency. The impact of several operational factors, including contact time, adsorbent dose, pH, temperature, and initial dye concentration on adsorption process was investigated following batch adsorption strategy. The optimized conditions established were; 60 min of contact time, 0.01 g adsorbent dose, pH 5, and 200 mg/L initial dye concentration. Moreover, the findings of kinetic studies established a pseudo-second-order model with good agreement with the experimental results (R2 >= 0.999), indicating the dominance of chemisorption. The adsorption isotherm data was best fitted to the Langmuir model with a maximum adsorption Qm of 909 mg/g at 333 K. The adsorption mechanism followed chemisorption, characterized by monolayer coverage. The thermodynamic analysis confirmed the adsorption process as endothermic, with an enthalpy change (Delta H degrees) of 12.39 kJmol-1, and spontaneous, as the estimated Delta G degrees values at all temperatures were negative. A positive Delta S degrees value implied the increase in disorder at the solid-solution interface. The adsorption process of CuNiZn-BTC MOF for PBVF dye was proposed to entail many potential mechanisms, including chemisorption, pi-pi bonding, pore-filling, electrostatic interactions, and hydrogen bonding. Additionally, the synthesized MOF as an adsorbent has exceptional structural stability, and the adsorbent's recyclability was evaluated over seven adsorption-desorption cycles still with 71 % removal capacity indicating its feasibility as adsorbent to be used as on industrial-scale.

In the present study, we report the solvothermal synthesis of a novel trimetallic CuNiZn-PDC Metal Organic Framework (CuNiZn-PDC MOF) engineered for robust and efficient adsorption of Rhodamine B (RhB) dye from aqueous media. Comprehensive characterization, including SEM, XRD, FTIR, BET, TGA, zeta potential, EDX, and elemental mapping, confirmed its crystalline morphology, thermal stability up to 220 °C, and high specific surface area (529 m2/g) with pronounced microporosity. The material exhibits an average particle size of about 97 nm and an aggregate size of about 348 nm. Under optimized conditions (0.01 g adsorbent amount, 333 K, pH 8, 60 min contact time, 200 mg/L initial dye concentration), the MOF achieved > 93% RhB removal. Adsorption kinetics conformed to a pseudo-second-order model (R2 > 0.99), indicating chemisorption dominance, while equilibrium data fit the Langmuir isotherm (R2 = 0.99), yielding a maximum monolayer adsorption capacity of 395 mg/g at 333 K. Thermodynamic parameters (ΔH° =  + 11.77 kJ/mol, consistently negative ΔG° across the studied temperature range) denote an endothermic and spontaneous adsorption process. The adsorption mechanism likely arises from synergistic interactions of chemisorption, π-π stacking, pore-filling, electrostatic interactions, and hydrogen bonding. Impressively, the MOF retained 69% of its removal efficiency after seven adsorption-desorption cycles. These findings underscore the MOF's strong potential as a stable, high-capacity, and recyclable adsorbent for industrial wastewater treatment.

In this study, trimetallic organic frameworks (CuCrFe-BTC MOF) was synthesized via the solvothermal method and applied for the adsorptive removal of diamond green G dye from aqueous medium. The synthesized CuCrFe-BTC MOF was characterized by SEM, FTIR, XRD, TGA, Zeta potential analyzer, and surface area analyzer. The results revealed that the synthesized MOF has spherical particles in the nanoscale range (80 nm), FTIR analysis confirmed the presence of necessary functional groups, XRD indicated high crystallinity with distinct peaks and TGA analysis demonstrated the thermal stability up to 500 degrees C. The moderate negative charge value (-14.7 mV) as predicted by zeta potential analysis suggests its suitability for remediation of cationic pollutants. BET analysis revealed a high surface area of 767 m2/g, with a microporous structure. The synthesized MOF were then employed for the removal of diamond green G dye from water using batch adsorption approach. The effect of contact time, adsorbent dosage, pH, initial dye concentration, and temperature on adsorption was also evaluated to optimize the adsorption process. The maximum adsorption was achieved at optimum contact time of 60 min, adsorbent dosage of 0.01 g, pH 8, initial dye concentration of 100 ppm, and temperature 298 K. Different isotherm and kinetic models were applied to the adsorption experimental data. Kinetic data analysis revealed the best fit of the data with pseudo-second-order model confirming the chemisorption nature of the adsorption process. The isotherm studies data fitted well into Langmuir isotherm model, indicating monolayer adsorption with a maximum adsorption capacity Qm of 434 mg.g-1. Thermodynamic studies revealed that the adsorption process was endothermic with an enthalpy change triangle H degrees of 14.74 kjmol-1 and an entropy change triangle S degrees of 53.44 jmol-1 K-1. Gibbs free energy triangle G degrees was negative at all tested experimental temperatures. The Gibbs free energy value increased with increase in temperature (-0.921, -1.989, and -3.058 at 293, 313, and 333 K respectively) indicated the feasibility of the process at high temperature. The overall adsorption process might involve several potential mechanisms including chemisorption involving pi-pi bonding, pore-filling, electrostatic interactions, and hydrogen bonding. The adsorbent was regenerated with sodium hydroxide and ethanol for many cycles and very little differences in adsorption capacity were recorded till 7th cycle. The study verified the structural stability and performance of CuCrFe-BTC MOF and showed its regeneration potential in industrial applications and could therefore, be considered as best alternative of commercial activated carbon.

The operational industries continuously contribute significant volumes of synthetic dyes along with other pollutants into the aquatic environment. The global issue of dye induced water contamination was addressed through facile synthesis of hydrophobically associated poly(lauryl methacrylate-acrylamide) [p(LMA-AAm)] hydrogel by free radical polymerization method. The SEM (Scanning Electron Microscope) micrographs depicted suitability of the hybrid sorbent for crystal violet (CV) uptake owing to porous, rough and spongy texture. The fabricated sorbent was utilized for CV sorption by performing different tests like contact time, pH, and initial concentration effect on the CV sorption. The obtained kinetic and isothermal data fitted well into the non-linear versions of pseudo second order and Langmuir models respectively. The thermodynamics tests signified the sorption process of spontaneous and endothermic nature. After sorption, the resultant [CV/p(LMA-AAm)] waste was applied for toluene (oil probe) separation from water which performed excellent separation in the range of 83-74 % during the first three tests. Thus, the desirable sorption properties, facile fabrication and promising oil separation power may recommend the composite sorbent for applications in the relevant fields like water treatment, separation and sorption.

Herein, the adsorption of nonionic surfactant on slaked lime was investigated. The slaked lime, after being converted into fine structures, were characterized by FTIR, SEM and pHPzc. The CO3 group on the lime surface was confirmed by FTIR analysis, while its surface area was estimated to be 398 m2 g-1. The adsorbent/adsorbate interactions were evaluated using batch adsorption approaches. The effect of experimental conditions such as temperature, pH, and contact time was also evaluated. The maximum adsorption of the selected surfactant on the slaked lime occurred at pH 7 and equilibrium was reached in 30 min. The results of kinetic studies revealed the best fit of the data with a pseudo-second-order model, i.e. chemisorption (R2 = 1). The Langmuir model best fitted the adsorption isotherm data. The thermodynamic analysis showed the process to be exothermic with an enthalpy change (Delta H degrees) of -25.75 kJ mol-1, spontaneous with negative Delta G degrees values at all tested temperatures. A positive Delta S degrees value of 2.162 kJ mol-1 K-1 pointed towards the increase in disorder at the solid-solution interface. Thus, slaked lime, being a cheap material, could thus be used as an alternative to other expensive adsorbents, as indicated by the parameters studied, but further validation requires more studies to fully evaluate the potential of this adsorbent.

A composite material; Magnetite Carbon Nanocomposite (AMCNC), was synthesized using almond shell waste biomass following a co-precipitation method. The prepared nanocomposite was characterized using instrumental techniques such as BET/BJH surface area measurement, scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis/differential thermal analysis (TG/DTA), determination of the point of zero charge and energy dispersive X-ray (EDX) analysis. The EDX, FTIR and XRD analysis revealed the presence of iron oxide on the surface of AMCNC, crystallinity and magnetic character. The BET surface area was 74.99 m2 g-1 and the BJH pore size distribution was 61.08 m2 g-1, total pore volume of 0.073 cm3 g-1 and a pore diameter of 15.55 Å. The FTIR analysis of AMCNC identified surface functional groups like carboxylic acid, phenols, and ethereal groups along with a band at 580 cm-1, corresponds to FeO linkage. The pHpzc of the AMCNC was 7.7. The nanocomposite was used as sorbent for the remediation of cetyldimethylethylammonium bromide (CDEAB), a surfactant, from aquatic media. Effect of contact time, initial concentration of CDEAB, pH solution, AMCNC dosage, ionic strength, and temperature were evaluated. Regeneration study of the surfactant AMCNC was also performed. Fast adsorption occurred at initial few minutes and finally reached to equilibrium in 2 h with best fitting of the data recorded for Pseudo 2nd order kinetics model whereas the adsorption isotherm studies was well described by the Freundlich and Jovanovich models. The thermodynamic parameters revealed the process as exothermic and spontaneous. Improved permeate fluxes and the percentage retention of surfactant were observed for AMCNC/UF (magnetite carbon nanocomposite/ultrafiltration), AMCNC/NF (magnetite carbon nanocomposite/nanofiltration) and AMCNC/RO (magnetite carbon nanocomposite/reverse osmosis) hybrid processes. The fouling was minimized to considerable level for AMCNC/RO and AMCNC/NF operations which in turn could enhance the membranes efficacies in large scale commercial operations.

Most of the dyes used in various industries are non-biodegradable and carcinogenic in nature. Therefore, elimination of dyes from textile wastes is mandatory to safeguard the life of human, aquatic animals and aquatic plants. In this connection an effective and eco-friendly hydrogel was synthesized from acrylamide, cellulose, clay, and copper salt abbreviated as AMPS(PHE-Ce)/MCCu. The fabricated hydrogel was used as sorbent and catalyst for the adsorption and catalytic reduction of basic blue 3. SEM analysis showed granular texture with small holes or cracks which is basic criteria for an adsorbent surface. The results showed that the BET surface area and the Langmuir surface area were, respectively, 27.87 and 40.32 m2/g. The FTIR analysis confirmed the synthesis of hydrogel, as is evident from peaks at 3500, 3439, 2996, 2414, and 1650 cm-1, which indicated the presence of OH or NH, -C-O-C-, CH3, (C--O), C-N bonds correspondingly. Thermal stability was confirmed by TGA analysis where weight loss in three stages has been observed. The presence of copper was confirmed through EDX (5.02%) indicating the incorporation of cupper nanoparticles in hydrogel surface. The high adsorption capability of 1590 mg/g as recorded for basic blue-3 dye indicates it to be an efficient adsorbent. The swelling behavior characterized by Fickian diffusion up to 7898% clearly indicated significant swelling. Pseudo 2nd-order kinetics and the Langmuir isotherm models were more fit in unfolding kinetics and isothermal data indicating chemisorption with monolayer sorption as evident from the high R2 values (0.999) of each model. Thermodynamics considerations indicated that the adsorption process is endothermic with a positive enthalpy value of 1371.32 Jmol-1. The positive entropy value of 19.70 J/ mol.K signifies a higher degree of disorder at the solid-liquid interface. The findings provided a valuable insights into the hydrogel's capacity to adsorb cationic dyes and reduce them catalytically, pointing towards its potential applications in addressing environmental challenges.

Various dyes often used in industries are not only non-biodegradable but also carcinogenic. It is vital to eliminate these dyes from textile waste to maintain the health of humans, aquatic animals, and plants in water ecosystems. To tackle this issue, herein a new hydrogel designated as [AMPS (PHE-Ce) /MoC-Ni] was developed by combining acrylamide, cellulose, clay, and nickel salt. The prepared hydrogel was then characterized using various techniques, such as Scanning Electron Microscopy (SEM), UV/visible Spectroscopy, Thermogravimetric Analysis (TGA), Fourier-Transform Infrared (FTIR) spectroscopy, and BET surface area analysis. The prepared hydrogel was proven to be a powerful tool for adsorbing Basic Red-1 dye, a common environmental pollutant, with an notable adsorption capability of 1570 mg/g. The swelling behavior under different pH conditions was also explored; exhibited remarkable swelling properties up to 6139% after 25 h of contact with water. Langmuir isotherm was found to be the best one that explains the sorption data with high regression constant value (0.999), confirming a monolayer adsorption mechanism. The kinetics data was well accommodated by pseudo second order kinetics model with R2 value of 0.9999. The thermodynamics evaluations indicated the process to be endothermic, with a positive enthalpy value of 1548.403 Jmol−1. The positive entropy value of 18.50 J/mol.K was also recorded showing the increase in disorderness at adsorbent and sorbate interface. The prepared hydrogel could be effectively used as alternative of activated carbon due its high swelling capacity which further increases its surface area available for adsorption. The adsorbent also used as catalyst for the reduction of basic red 1 dye.

Herein, iron oxide nanocomposites were prepared using corn cob waste biomass and Fe (NO3)3.9 H2O as iron source. The dried corn cob in grinded form were mixed with Fe (NO3)3.9 H2O solution heated for 60 min at 300 °C in nitrogen atmosphere to ensure complete carbonization. The exterior morphology, particle sizes, crystallinity, and elemental content etc. of the fabricated composite were SEM, XRD, and EDX analysis respectively. The XRD confirmed the presence of iron oxide on activated carbon framework and also validated the nano sized dimensions of resulting magnetic adsorbent. The nanocomposites were then employed as adsorbent for the removal of acid orange 8 and acid red 4 dyes from aqueous medium. To get maximum adsorption of selected dyes the experimental conditions like dosage of the adsorbent, temperature, and contact time were optimized. Langmuir and pseudo second order kinetics models best fitted experimental isotherm and kinetics data respectively. The optimum removal of selected dyes was achieved with 0.01 g of adsorbent dosage whereas equilibrium for both the dyes were achieved in 1 h. Additionally, the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) of the adsorption were enumerated using Vant's Hof plot. The adsorption processes were found to be endothermic, as evident from positive values of ΔH° = 9.651 kJ/mol for AO 8 and 16.493 kJ/mol for AR 4. The processes in both the cases were found as spontaneous at higher temperature, evident from the positive to negative trending values of ΔG° (714.29, 104.28, and −505.733 J/mol for AO 8 and 271.93, −835.306, and −1942.54 J/mol for AR 4 at 20 °C, 40 °C, and 60 °C respectively. The positive entropy change (ΔS°) values of 30.5007 J/mol.K and 55.362 J/mol.K recorded, indicates the increasing disorder at the solid-solution interface for both the dyes. An attempt was made to recycle adsorbent using suitable solvents and up to 5 cycles the removing efficiency retained was still 76%.

Co-Cu-Ni and Co-Cu-Zn trimetallic nanoparticles (NPs) were prepared by chemical reduction method which were then used as adsorbent to remove Crocein Orange G dye from solution. The elemental composition of the fabricated NPs was determined by EDX analysis, surface morphology was assessed by SEM, and its crystalline nature was confirmed by XRD analysis. The functional groups on nanoparticles were confirmed by FT-IR analysis. The optimum dosage was found to be 0.01 g. Langmuir model as well as linear pseudo 2nd order kinetics models best explained the obtained data. The maximum adsorption capabilities were found to be around 497.618 mg/g and 683.093 mg/g, respectively for Co-Cu-Ni and Co-Cu-Zn trimetallic NPs. The adsorption process was exothermic, as evidenced from the positive Delta H degrees values. The negative values of Delta G degrees at the corresponding temperatures support the spontaneous nature of the adsorption processes. The positive entropy changes (Delta S degrees) suggested that there is more disorderness at the interface between the solid and the solution during the adsorption. The fabricated trimetallic nanoparticles have effectively adsorbed Crocein Orange G, which may be considered as an attractive option in wastewater treatment and environmental remediation applications due to diversity of metal ions on surface offering differential attractive forces for pollutant.

Hydrogels have emerged as promising “smart sorbents” for wastewater treatment due to their simple fabrication, environmentally friendly nature, and quick regeneration. In the present study, hydrogels comprising polyacrylamide and gellan gum/acrylamide (GG-co-pAAm) were synthesized through free-radical polymerization, incorporating varying percentages of gellan gum as a biopolymer backbone. The hydrogels were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The swelling behavior of the synthesized hydrogels was evaluated in tap and distilled water at neutral pH and within the pH range of 4.2–11.2. Swelling at neutral pH was 2623

Herein bimetallic nanoparticles of Co-Mn were prepared using metal-organic framework (CoMn2 (C2O4)(3)6H(2)O) as a starting material. Initially, the bimetallic organic frame work was prepared which was then subjected to pyrolysis to get the desired product. Techniques like scanning electron microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) were used to characterize the bimetallic nanoparticles. These analyses revealed that the Co-Mn nanoparticles consisted of finely distributed Mn and Co, along with O in the composites. XRD data confirmed the presence of nano-scale ranges and alloy formation between Co-Mn. The nanoparticles were employed as adsorbent for methyl violet adsorption, with optimized conditions found to be pH 9, temperature 333 K, adsorbents dosage of 0.01 g, and 30 min of contact time. The pseudo-second-order kinetic model best described the adsorption kinetics data whereas Langmuir isotherm exhibited the closest fit, with a maximum adsorption capacity of 625 mg/g at 333 K. Thermodynamic parameters indicated endothermic processes, with Delta H degrees = 15.155 kJ mol(-1), and the process to be spontaneous with negative Delta G degrees values -0.303, -0.831, and -1.886 (kJ mol(-1)) at 293 K, 313 K, and 333 K, respectively. The Delta S degrees value of 52.76 J mol(-1)K(-1) suggested increased disorder at the solid-solution interface during adsorption. The adsorbent could be effectively used in reclamation of dyes loaded water as alternative of activated carbon.

Gellan Gum (GG) grafted poly-acrylic acid (GG-g-pAAc) hydrogels of different composition were synthesized by changing the concentration of GG through free radical polymerization. The hydrogels were characterized through SEM, TGA, and FTIR. The FTIR spectra confirmed the grafting of GG into the network of polyacrylic acid and evidenced the GG-g-pAAc formation. The rough surface nature of the hydrogels was elaborated through SEM analysis provided the information about the materials to be utilized for removal purpose. The thermal stability was confirmed by TGA analysis and the hydrogels were found stable upto a high temperature range. With an efficiency of 96%, Basic Orange-2 dye (BO-2) was successfully removed from wastewater using synthesized hydrogels as an adsorbent. The adsorption parameters were calculated using a number of different kinetic models. According to the findings, the pseudo-second order kinetics model best suited to the kinetics data, while the Langmuir isotherm provided the most comprehensive explanation of the process of adsorption. BO-2 was removed to the greatest extent (257.5 mg/g). Additionally, the results showed that the adsorption process on synthesized hydrogels was exothermic with values of Delta H = -13.2, -219.4 and -12.9 kJ/mol for pAAc, 10%GG-g-pAAc, and 20%GG-g-pAAc respectively. The adsorption process is spontaneous, with negative values of Delta G = -8.2, -214.4 and -7.947 kJ/mol for pAAc, 10%GG-g-pAAc and 20%GG-g-pAAc at 293K, respectively. The adsorption process on synthesized hydrogels showed no dis-orderness with negative values of Delta S = -17.2, -461.16 and -16.42 kJ/mol for pAAc, 10%GG-g-pAAc and 20%GG-g-pAAc, respectively. [GRAPHICS] .

A novel adsorbent designated as terpolymer hydrogel (gellan gum-co-acrylamide-co-methacrylic acid) was prepared by free radical polymerization of gellan gum (GG), methacrylic acid (MAA), and acrylamide (AAm) using N,N-methylene bis-acrylamide (MBA) as cross-linker and ammonium per sulfate (APS) as the initiator of the reaction. The synthesized gel was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and thermogravimetric analysis (TGA) and was used for the adsorptive removal of methyl violet (MV) and Fuchsin Basic (FB) dyes from aqueous solution. The effect of temperature, contact time, pH, and concentration on them under the study adsorption process was evaluated. Freundlich isotherm and pseudo-second-order kinetic models were found to be best in fitting the isothermal and kinetics data. The water diffusion and % swelling of hydrogel were studied at various pH in distilled water and at neutral pH in tap water. The diffusion was found to be of Fickian type with a maximum swelling of 5132%. The maximum adsorption capacity was 233 mg/g against MV and 200 mg/g against FB dyes. The swelling and adsorption were pH dependent and increased with increase in pH. The enthalpy, Gibbs free energy, and entropy changes of adsorption for both the dyes indicated the adsorption process to be exothermic, feasible, and spontaneous. The hydrogel was successfully regenerated using acetone and distilled water for five cycles and still, its dye removal efficiency was 80% of its original value. The poly(GG-co-AAm-co-MAA) hydrogel successfully removed the selected dyes from water and could thus be used as an efficient alternative sorbent for cationic dye removal from aqueous solutions.

Novel hydrogels of hydroxy ethyl cellulose and polyacrylic acid (HEC-G-pAAc) were created by varying the ratio of hydroxy ethyl cellulose to acrylic acid and were characterized using analytical techniques. The synthesized hydrogels were characterized through SEM, TGA, FTIR, pH studies and Fick’s law. The SEM images revealed that the fabricated hydrogels have different adsorption sites for the dyes. According to the TGA results the decomposition of the hydrogels occurs in three successive stages (22-200 °C, 200-310°C, 310-500°C). The optimum pH for the adsorption of basic yellow-28 is on the HEC-G-pAAc is pH-8 as it was observed in the pH studies. The optimum temperature for the adsorption of basic yellow-28 is on the HEC-G-pAAc was found to be 293K.The Basic Yellow-28 dye was successfully removed from wastewater with a 98 percent effectiveness using synthetic hydrogels as an adsorbent. The adsorption parameters were calculated using a number of different kinetic models like pseudo-second order, Elovich, intraparticle-diffusion and Bangham kinetic models. The pseudo-2nd order kinetics model was found to best fit the kinetics data, while the Langmuir isotherm offered the most thorough explanation of the adsorption process. Basic Yellow-28 dye was removed to the greatest extent by the synthesized hydrogels (pAAc = 156mg/g, 10%HEC-G-pAAc =166.3mg/g, 20%HEC-G-pAAc =176.2mg/g) after 90min of contact at 293K. The process was exothermic because the values of ΔH were found to be negative (ΔH = -4.93, -6.49 and -5.741kJ/mol for pAAc, 10%HEC-G-pAAc and 20%HEC-G-pAAc respectively). The adsorption process in this study is spontaneous, as clear from the negative values of ΔG, (ΔG = -4.81, -5.34 and -5.40kJ/mol for pAAc, 10%HEC-G-pAAc and 20%HEC-G-pAAc at 293K respectively). The adsorption process on synthesized hydrogels showed decrease in dis-orderness that was clear from its negative values.