ABSTRACT This study investigates the use of natural bentonite as a low-cost, eco-friendly adsorbent for removing sunitinib, a cytotoxic anticancer drug, from aqueous solutions. XRF and XRD analyses confirmed the smectite structure of bentonite with typical aluminosilicate composition and exchangeable cations. FT-IR analysis indicated interactions between sunitinib and bentonite through shifts in –OH, C=O, and –CH vibrations. BET results showed a surface area of 67.93 m2/g and a Type II isotherm, suggesting a macroporous structure. SEM images revealed rough, heterogeneous surfaces in raw bentonite, which became partially covered after adsorption. EDX analysis confirmed the presence of key elements (Si, Al, O, Na, Mg) and showed increased surface carbon after drug loading, verifying organic adsorption. Under optimal conditions (pH 8, 35°C, 15 mg adsorbent, 75 ppm initial concentration), maximum removal efficiency reached 90%. Adsorption kinetics followed the pseudo-second-order model, indicating a combined physico-chemical mechanism, while intra-particle diffusion analysis revealed a multi-step process. Thermodynamic analysis (ΔH° = –4.52 kJ/mol; ΔG° < 0; ΔS° > 0) suggested the process was spontaneous and exothermic with increased disorder. Desorption studies showed high reusability in alkaline media. Overall, natural bentonite presents a promising, sustainable solution for the effective removal of hazardous pharmaceutical pollutants like sunitinib from water.

ABSTRACT The current study utilized Terminalia catappa seed husk (TCB), an eco-friendly lignocellulosic adsorbent, carbonized and activated through acid treatment and is employed for the removal of a hazardous organophosphate pesticide – monocrotophos (MCP) – from simulated solution. pH 5.0 offered optimal conditions for the maximum efficiency along with various operational parameters like 70-min contact time and an initial concentration of 100 mg L−1 for the adsorption efficiency. Kinetic modeling revealed that MCP uptake followed a pseudo-first-order model, and the equilibrium of the adsorption process was best described by the Freundlich & Langmuir Isotherm models, indicating heterogeneous multilayer adsorption governed by hydrogen bonding and electrostatic interactions. The process attained a maximum adsorption efficiency of 99.3% with adsorption capacity of 115.62 mg g−1 when 0.25 g of adsorbent was introduced in 25 mL of solution with the initial concentration of 600 mg L−1 at optimal pH and temperature. The surface characteristics were analyzed by CHNS analysis, SEM-EDX and FTIR. The pore volume was confirmed using BET isotherm analysis, which revealed a surface area of 59.09 m2/g. To test the practical applications in water treatment, reusability tests were performed, and the biochar retained ~53%. Hence, this biochar offers a sustainable approach in MCP remediation in water treatments.

ABSTRACT Co(II)TETA has been tried to eliminate nitric oxide from flue gases. Activated carbon can be applied to act as a catalyst to aid the regeneration of Co(II)TETA to keep the NO removal efficiency. The adsorption of TETA(triethylenetetramine) onto activated carbon is the process crucial for the catalytic regeneration of Co(II)TETA. A systematic study over the adsorption of TETA onto activated carbon has been made. The results reveal that the TETA adsorbed by activated carbon at balance is found to increase with temperature and initial TETA concentration but decrease with activated carbon dosage. The adsorption rate is also quickened by initial TETA concentration and elevated temperature. Kinetic analysis reveals that the pseudo-second-order equation describes the adsorption process more accurately than the pseudo-first-order model. Adsorption isotherm fitting indicates that Freundlich formula predicts the relationship between TETA adsorption on activated carbon and TETA concentration in solution at equilibrium better than Langmuir model. Thermodynamic studies confirm that TETA adsorption onto activated carbon is spontaneous and endothermic, with an enhancement in disorder. These findings provide valuable insight into the TETA adsorption onto activated carbon and contribute to the study over the catalytic regeneration of Co(II)TETA.

ABSTRACT The rapid rise in multilayer packaging waste, exemplified by Tetra Pak cartons (70% paperboard, 25% LDPE, 5% Al), poses a major challenge to global waste management. This study presents a closed-loop pyrolysis – activation strategy that fully upcycles this urban waste. Pyrolysis at 600°C yields 24.2 wt% syngas, 35.4 wt% liquid fuel, and 40.4 wt% solid residue, enabling 97.1% recovery of high-purity metallic. The carbon-rich char is KOH-activated (2:1 ratio, 750°C) to produce hierarchical porous biochar with SBET = 586 m2/g, total pore volume = 0.135 cm3/g, and 1.07 mmol/g acidic sites (Boehm titration). Methylene blue adsorption reaches 151.5 mg/g, fitting the Langmuir model (R2 = 0.986) and pseudo-second-order kinetics (R2 = 0.9998, k2 = 0.0061 g mg−1 min−1), confirming monolayer chemisorption. The process is endothermic (ΔH° > 0) and spontaneous at higher temperatures, with pHPZC = 8 favoring uptake above pH 8. Compared to agricultural biomass, Tetra Pak biochar shows comparable capacity yet excels in sustainability: it avoids food-chain competition, requires no land or fertilizers, and generates multiple products, activated biochar, aluminum, fuels, and wax. This integrated approach transforms a recalcitrant waste into efficient dye-removal adsorbents and strategic materials, demonstrating a scalable circular-economy model.

ABSTRACT This study investigates the adsorption performance of humic acid-functionalized lignin-based microspheres (HA@LGMS) in eliminating Acid Orange 7 (AO7) and tetracycline (TC) contaminants from wastewater. Lignin, a residual material from pulp manufacturing processes, was utilized to synthesize lignin-based microspheres (LGMS) via reversed-phase suspension polymerization. Subsequently, humic acid was incorporated into LGMS to enhance their adsorption capacity. Comprehensive material characterization involving SEM, FTIR, XPS, etc. revealed the structural features and surface chemistry of the microspheres. Systematic batch adsorption studies examined the adsorption kinetics, isotherms, and thermodynamics of AO7 and TC onto HA@LGMS. Analysis demonstrated chemisorption-driven mechanisms supplemented by boundary layer diffusion and pore penetration phenomena. The adsorption processes were spontaneous and endothermic, with higher temperatures favoring adsorption. HA@LGMS exhibited high adsorption capacities for AO7 (434.81 mg/g) and TC (93.98 mg/g), outperforming many existing adsorbents. The adsorbent also demonstrated excellent reusability and stability in multiple adsorption-desorption cycles. Moreover, HA@LGMS effectively removed AO7 and TC from real water samples, highlighting its potential for practical wastewater treatment applications. This study provides a sustainable and cost-effective solution for the removal of dyes and antibiotics from wastewater using lignin-based materials.

ABSTRACT This study investigates the corrosion protection of carbon steel in 1.0 M HCl solution using two newly synthesized tricationic surfactants with heterocyclic structures, CS1 and CS2, as model inhibitors for highly corrosive acidic media in oil industry applications. The inhibition performance was evaluated using electrochemical techniques. Surface-active properties of the surfactants were determined from surface tension measurements obtained by axisymmetric drop shape analysis. The results confirmed the strong adsorption of CS1 and CS2 onto the steel surface, leading to high inhibition efficiency even at low concentrations. At 250 ppm, the maximum inhibition efficiencies of CS1 and CS2 reached 96.64% and 98.36%, respectively. Both surfactants acted as mixed-type inhibitors, and their adsorption behavior followed the Langmuir isotherm model. Quantum chemical calculations were performed to further support the experimental findings. Additionally, antimicrobial activity tests based on inhibition zone diameter revealed that both compounds exhibit strong antibacterial and antifungal properties.

ABSTRACT Microplastics, as emerging pollutants, pose significant environmental challenges, necessitating innovative solutions for their removal. This study introduces a highly efficient sustainable composite material, Dawson-based polyoxometalate ionic liquids (POM-ILs) combined with silica coated magnetic nanoparticles, designed for microplastic remediation from industrial wastewater. Comprehensive characterization confirms the successful synthesis of the composite, featuring uniform distribution, high thermal stability, and excellent magnetization. The material exhibits remarkable hydrophobicity, attributed to the water-insoluble POM-ILs, and a mesoporous structure with a high surface area, enabling effective adhesion of water repellent microplastics. Achieving 100% removal efficiency, the composite demonstrated exceptional thermal and kinetic stability across five reuse cycles. Kinetic analysis revealed the physical adsorption interactions between Q8[S2W18] @ SiO2 @ Fe3O4 and microplastics, while thermodynamics studies indicate enhanced adsorption efficiency at elevated temperature, making the material suitable for diverse environmental conditions. The high magnetization of the composite facilitated rapid and efficient magnetic separation post-adsorption, underscoring its practicality and sustainability. These outstanding results underscore the potential of Q8[S2W18] @ SiO2 @ Fe3O4 as a reliable, eco-friendly solution for microplastic removal under real-world and extreme environmental conditions, paving the way for its applications in advanced industrial wastewater treatment.

ABSTRACT Liquid-liquid phase-change absorbents for CO2 have garnered significant attention due to their superior CO2 absorption capacity and lower regeneration energy consumption. During desorption, only the CO2-rich phase requires processing, significantly reducing sensible heat loss. In this study, a MAPA/DMCA liquid-liquid phase-change absorbent was formulated using 3-(methylamino)propylamine (MAPA) and N, N-dimethylcyclohexylamine (DMCA), and its phase-change behavior following the reaction with CO2 was investigated. Results demonstrated that under optimal conditions – absorption temperature of 298.15 K, total amine concentration of 4 mol/L, and MAPA/DMCA molar ratio of 1:3—the MAPA/DMCA absorbent exhibited the highest CO2 absorption performance: the volume fraction of the rich phase was 59.80%, the CO2 loading in the rich phase accounted for 92.38% of the total loading, and the total absorption loading reached 0.56 mol CO2/mol amine. This total loading is superior to that of the conventional monoethanolamine (MEA) absorbent (0.50 mol CO2/mol amine). Furthermore, the rich phase achieved the best desorption performance at 368.15K, with a desorption rate reaching 52.18%.

ABSTRACT Electrodialysis (ED) based desalination is widely recognized as an effective water purification technique that conserves water by selective removal of dissolved salts and impurities. Herein, machine learning (ML) models such as Multiple Linear Regression (MLR), Support Vector Regression (SVR) Multi-Layer perceptron (MLP), and Random Forest (RF) have been developed to accurately forecast salt removal ratio, energy consumption, and current efficiency of electrodialysis toward the desalination. An electrodialysis system having 65 membrane cell pairs of 30 × 60 cm2 is used for the present study. The 144 datasets of selected independent variables such as time, feed concertation, treated flow rate, concentrated flow rate, and applied potential were used for the ML study. The models underwent validation through the assessment of the determination coefficient (R2) and Mean Squared Error (MSE). The MLP and RF algorithm prediction accuracy was higher than MLR and SVR. The MLP model prediction was higher due to R2 of 0.9730, and 0.8292 than the R2 of 0.9496, and 0.8053 for salt removal and current efficiency, respectively. However, RF predicts energy consumption more effectively than MLP (R2: 0.8875 vs. 0.8157). Additionally, RF achieved the fastest computational time among all models. Additionally, physicochemical and electrochemical properties of membranes ensured the stability of membranes.

ABSTRACT An environmentally friendly and simple method was developed for the simultaneous separation and determination of Rhodamine B (RhB) and Rhodamine 6 G (Rh6G) in red pencil samples by vortex assisted microextraction using NADES (Natural Deep Eutectic Solvent). A two-phase system was established using lactic acid-based DES (Deep Eutectic Solvent) and tetrahydrofuran (THF) for the extraction of RhB and Rh6G. In method optimization, sample amount, pH, DES type, DES volume, solvent type and solvent volume parameters were investigated. Limit of detection (LOD) and limit of quantification (LOQ) values were 4.13, 5.03 and 12.5, 15.3 µg/mL for RhB and Rh6G, respectively. The correlation coefficients obtained at concentrations ranging from 1–12 µg/mL are 0.9973 and 0.9985. Red pencil samples were spiked at two different concentrations (3–5 µg/mL). The recovery values obtained were in the range of 84.7%-107.4%. The relative standard deviation (RSD) values of the developed method are in the range of 2.77%-5.45%, indicating that the method is reproducible. The results showed that the developed microextraction method can be successfully applied for the separation and determination of RhB and Rh6G from red pencil samples.