Synthesis of MoS2/Fe3O4/aminosilane/glycidyl methacrylate/melamine dendrimer grafted polystyrene/poly(N-vinylcaprolactam) nanocomposite for adsorption and controlled release of sertraline from aqueous solutions

Study of the adsorption of phenol by two soils based on kinetic and isotherm modeling analyses

Comparative evaluation of sorption kinetics and isotherms of pyrene onto microplastics

The study is a first-time investigation into the use of Eucalyptus leaves as a low-cost herbal adsorbent for the removal of arsenic (As) and mercury (Hg) from aqueous solutions. The adsorption capacity and efficiency were studied under various operating conditions within the framework of response surface methodology (RSM) by implementing a four-factor, five-level Box–Wilson central composite design (CCD). A pH range of 3–9, contact time (t) of 5–90 min, initial heavy metal (As or Hg) concentration (C 0) of 0.5–3.875 mg/L, and adsorbent dose (m) of 0.5–2.5 g/L were studied for the optimization and modeling of the process. The adsorption mechanism and the relevant characteristic parameters were investigated by four two-parameter (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich) isotherm models and four kinetic models (Lagergren’s pseudo-first order (PFO), Ho and McKay’s pseudo-second order (PSO), Weber–Morris intraparticle diffusion, and modified Freundlich). The new nonlinear regression-based empirical equations, which were derived within the scope of the study, showed that it might be possible to obtain a removal efficiency for As and Hg above 94% at the optimum conditions of the present process-related variables (pH = 6.0, t = 47.5 min, C 0 = 2.75 mg/L, and m = 1.5 mg/L). Based on the Langmuir isotherm model, the maximum adsorption or uptake capacity of As and Hg was determined as 84.03 and 129.87 mg/g, respectively. The results of the kinetic modeling indicated that the adsorption kinetics of As and Hg were very well described by Lagergren’s PFO kinetic model (R 2 = 0.978) and the modified Freundlich kinetic model (R 2 = 0.984), respectively. The findings of this study clearly concluded that the Persian Eucalyptus leaves demonstrated a higher performance compared to several other reported adsorbents used for the removal of heavy metals from the aqueous environment.

Amoxicillin (AMX) is a widely used antibiotic, which induces harmful effects to nature via bioaccumulation and persistence in the environment if discharged untreated into water bodies. In the current study, a novel bionanocomposite, bismuth oxyiodide-chitosan (BiOI-Ch), was synthesized by a facile precipitation method and its amoxicillin (AMX) adsorption capacity in the presence of ultrasonic waves has been explored. Multiple batch experiments were performed to achieve the optimum operational parameters for maximum adsorption of AMX and the obtained results were as follows: pH 3, 80mgg-1 AMX concentration, 1.7g L-1 adsorbent dose, temperature 298K and ultrasonication time 20min. Composite removed approximately 90% AMX from the solution under optimized conditions, while the maximal adsorption capacity was determined to be 81.01mgg-1. BiOI-Ch exhibited superior adsorption capacity as compared to pure BiOI (33.78mgg-1). To understand the dynamics of reaction, several kinetic and isotherm models were also examined. The adsorption process obeyed pseudo-second-order kinetic model (R2 = 0.98) and was well fitted to Freundlich isotherm (R2 = 0.99). The addition of biowaste chitosan to non-toxic bismuth-based nanoparticles coupled with ultrasonication led to enhanced functional groups as well as surface area of the nanocomposite resulting in superior adsorption capacity, fast adsorption kinetics and improved mass transfer for the removal of AMX molecules. Thus, this study demonstrates the synergistic effect of ultrasonication in improved performance of novel BiOI-Ch for potential application in the elimination of persistent and detrimental pollutants from industrial effluent after necessary optimization for large-scale operation.

Adsorption equilibrium, kinetic, and thermodynamic studies on the removal of paracetamol from wastewater using natural and HDTMA-modified clay

Determination of optimum isotherm and kinetic models for phosphate sorption onto iron oxide nanoparticles: nonlinear regression with various error functions

This study investigated the ability of anaerobically digested sewage sludge biochar (ADSSBC), pretreated with nanoscale zero-valent iron (nZVI) prior to anaerobic digestion (AD), to remove lead (Pb(II)) ions from aqueous solutions. Batch adsorption experiments were conducted to evaluate the effects of various parameters, including nZVI dosage, O2-exclusion method (aluminum foil wrapping or N2 purging), pyrolysis temperature (300–800 °C), adsorbent dosage, pH, coexisting ions, contact time, and initial Pb(II) concentration. Experimental data were fitted to adsorption kinetic and isotherm models. The characteristics of nZVI30-ADSSBC-700 before and after Pb(II) adsorption were analyzed using FTIR, SEM–EDS, XPS, and XRD to identify the adsorption mechanisms. The results showed that nZVI addition at 30 mg/g-TS prior to AD significantly enhanced Pb(II) removal efficiency compared with the control. Among the investigated pyrolysis temperatures and O2-exclusion methods, the biochar produced at 700 °C using aluminum foil wrapping exhibited the highest Pb(II) removal efficiency (99.4%) at an initial Pb(II) concentration of 200 mg/L. The maximum Langmuir adsorption capacity obtained for this biochar was 139.3 mg/g. The pseudo-second-order kinetic model best described the Pb(II) adsorption kinetics. The investigated models and the results of physicochemical analyses indicated the involvement of both physical and chemical adsorption mechanisms, including surface precipitation, ion exchange, pore filling, and, to some extent, complexation.

The presence of chromium in aquatic streams due to the discharge of industrial effluents is of great concern because of its toxic nature. Removal of Cr(VI) ion from wastewater is a necessary task. To enhance the adsorption capacity of sawdust for heavy metals, sawdust was modified with formaldehyde and used for the adsorption of heavy metal Cr(VI). The process of modifying was characterised by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The effects of various parameters such as pH, contact time, adsorbent dose and initial metal ion concentration on the adsorption process were investigated. The maximum removal of chromium (VI) was found to be 100% at pH 2.0, initial Cr(VI) concentration of 10 mg/L, and adsorbent dose of 4 g/L. Equilibrium isotherms for the removal of Cr(VI) were analysed by the Langmuir, Freundlich, and Temkin isotherm models and the experimental data were well explained by the Freundlich isotherm model. The maximum adsorption capacity was found to be 8.84 mg/g. Kinetic studies were performed by pseudo-first-order, pseudo-second-order, intraparticle diffusion and Elovich models. The R2 value of the pseudo-second-order model is higher than other kinetic models. Therefore, the obtained data were the best fit with the pseudo-second-order kinetic model. The thermodynamics indicated that the adsorption process of sawdust for Cr(VI) was endothermic and spontaneous in nature.

Dyes containing effluents constitute hazards to the environments and endanger human and aquatic lives. Although activated charcoal has been adjudged the best for adsorption treatment of wastewater, its regeneration and high cost have limited their applications, hence the quest for alternative adsorbent. Magnetic tuned biosorbent was prepared from sorghum husks by in situ co-precipitation of Fe3O4. It was characterized using Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy. The biosorbent was then used for the removal of crystal violet (CV) and methylene blue (MB) dyes from aqueous solutions in a batch process. The effects of temperature, initial dye concentration, dosage, contact time as well as pH were investigated, and data obtained were analysed with appropriate kinetic and isotherm models. Response surface method was used for the optimization study of the adsorption using Box–Behnken experimental design. Pseudo-second-order kinetic model was the most appropriate model for both dyes with correlation coefficient (R2) > 0.9 and low % standard error values. The equilibrium data were best fitted with Langmuir isotherm with maximum adsorption capacity (Qmax) of 18.87 and 30.00 mg g−1 for CV and MB, respectively. The thermodynamic parameters for the adsorption processes showed that it was spontaneous, endothermic and random systems with free energy changes less than zero, enthalpy changes (∆H) of + 49.81 and + 51.18 kJ mol−1, entropy changes (∆S) of + 178.39 and + 177.34 J mol−1 K−1 for MB and CV dyes, respectively. Optimization studies revealed that 95% of the dyes are removable at 1.0 g adsorbent dosage and pH of 4.05 at 50 °C with initial dye concentration of 50 mg L−1. The prepared adsorbent is cheap, easily recycled and highly effective for the treatment of dye-contaminated water.

The present study investigates the potential of Arachis hypogaea skin-derived carbon nanospheres (CNSs) as an efficient adsorbent for the rapid removal of cationic dyes from aqueous solutions. The CNSs were synthesized through a facile, cost-effective, catalyst-free and environmentally friendly process, utilizing Arachis hypogaea skin waste as a precursor. This is the first reported study on the synthesis of mesoporous carbon nanospheres from Arachis hypogaea skin. The structural and morphological characteristics of the CNSs were confirmed by different nano-characterization techniques. The adsorption performance of the carbon nanospheres was evaluated through batch adsorption experiments using two cationic dyes-methylene blue (MB) and malachite green (MG). The effects of the initial dye concentration, contact time, adsorbent dosage, and pH were investigated to determine the optimal conditions for dye removal. The results revealed that the obtained CNSs exhibited remarkable adsorption capacity and rapid adsorption kinetics. Up to ∼98% removal efficiency was noted for both dyes in as little as 2 min for a 5 mg L-1 dye concentration, and the CNSs maintained their structural morphology even after adsorption. The adsorption data were fitted to various kinetic and isotherm models to gain insights into the adsorption mechanism and behaviour. The pseudo-second-order kinetic model and Redlich-Peterson model best described the experimental data, indicating multi-layer adsorption and chemisorption as the predominant adsorption mechanism. The maximum adsorption capacity was determined to be 1128.46 mg g-1 for MB and 387.6 mg g-1 for MG, highlighting the high affinity of the carbon nanospheres towards cationic dyes. Moreover, CNS reusability and stability were examined through desorption and regeneration experiments, which revealed sustained efficiency over 7 cycles. CNSs were immobilised in a membrane matrix and examined for adsorption, which demonstrated acceptable efficiency values and opened the door for further improvement.

In this study, a core-shell nanocomposite was successfully prepared using NiAlFe-LDH as a core coated with polystyrene (PS) nanoparticles with an LDH:PS ratio of 3:1 (PS @NiAlFe-LDH) for the removal of cadmium (Cd2+) from aqueous solutions. PS nanospheres were prepared from styrene monomer recovered from Styrofoam waste. The prepared PS@NiAlFe-LDH was characterized for its structural morphology, elemental composition, surface area, and pore morphology. Results indicated the successful formation of PS nanosphers core coated by platelet LDH shell and a successful adsorption of Cd2+ ions. The maximum adsorption efficiency (95.53%) was achieved under the optimal conditions: pH of 6, PS@NiAlFe-LDH dosage of 0.15 g/100 mL, shaking speed of 200 rpm, and an initial Cd2+ concentration of 100 mg/L at a 90-minute contact time. Langmuir isotherm model was the most accurate in describing the adsorption process with a maximum adsorption capacity of 227.273 mg/g. The pseudo-second-order (PSO) kinetics model described the adsorption behaviour of cadmium ions on PS@NiAlFe-LDH surface as the calculated values from the model were close to the experimental values. The adsorption mechanism was a combination of electrostatic attraction, surface complexation/ion exchange and internal diffusion within the pores. PS@NiAlFe-LDH demonstrated significant reusability, with an efficiency of 57.56% after six regeneration cycles. In conclusion, this study indicates that PS@NiAlFe-LDH nanocomposite exhibits high quality and excellent efficiency in removing cadmium ions from aqueous solutions, owing to its porosity and abundance of active groups on its surface, as well as structural stability after adsorption, which makes it a promising material for environmental remediation applications. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

In the present work, alginate magnetic graphene oxide biocomposite was synthesized for the removal and extraction of aromatic amines (aniline, p-chloroaniline (PCA), and p-nitroaniline (PNA)) from water samples. The biocomposite was investigated for its physiochemical characteristics such as surface morphology, functional groups, phase determination, and elemental composition. The results revealed that the functional groups of graphene oxide and alginate retained in biocomposite with magnetic properties. The biocomposite was applied to water samples for the removal and extraction of aniline, p-chloroaniline, and p-nitroaniline through adsorption process. The adsorption process was studied under various experimental conditions like time, pH, concentration, dose, and temperature, and all the parameters were optimized. The maximum adsorption capacities at room temperature have an optimum pH = 4 for aniline = 18.39mgg-1, for PCA = 17.13mgg-1, and for PNA = 15.24mgg-1. Kinetic and isotherm models showed that the experimental data is best fitted to pseudo-second-order kinetic model and the Langmuir isotherm model. Thermodynamic study suggested that the adsorption process is exothermic and spontaneous. Ethanol was found to be the best eluent for the extraction of all the three analytes suggested by the extraction study. The maximum percent recoveries from spiked water samples were calculated for aniline = 98.82%, PCA = 96.65%, and PNA = 93.55% which showed that alginate magnetic graphene oxide biocomposite could be a useful and ecofriendly adsorbent for the removal of organic pollutants in water treatment processes.

Alkali modified oak waste residues as a cost-effective adsorbent for enhanced removal of cadmium from water: Isotherm, kinetic, thermodynamic and artificial neural network modeling

In this study, chitin was extracted from shrimp shells (SS) and characterized by scanning electron microscopy, X-ray diffraction, and Fourier transforms infrared spectroscopy. And investigate the adsorption of vanadium (V) and palladium (Pd) toxic metals onto the chitin. The effect of parameters such as the concentration of V and Pd, contact time, solution pH, adsorbent dose, cations, and anions were studied on the adsorption process. Kinetic, isotherm, and thermodynamic models were investigated. Genetic programming (GP) is used to obtain an appropriate equation showing the relationship between the variables. Experimental optimum conditions were found in the V and Pd concentrations of 25 mg/L, pH of 9, an adsorbent dose of 0.8 g/L and a contact time of 15 minutes. The maximum adsorption capacities (q m) of 13.15 and 12.65 mg/g were obtained for V and Pd, respectively. Among the anions and cations examined in this study, Ca2+ and SO4 2- had the greatest effect on the absorption of V and Pd on chitin. The adsorption kinetics followed a pseudo-second-order kinetic model and the equilibrium data showed a good fit of the Langmuir model and demonstrated a monolayer and favorable physisorption process. The thermodynamic analysis depicted that the process of adsorbing V and Pd using chitin was endothermic and spontaneous. Findings also presented GP as a potential tool for identifying the behavior of V and Pd adsorption. It can be concluded that chitin extracted from SS wastes, as a nontoxic and cheap adsorbent, could efficiently remove V and Pd from aqueous solutions.

Evaluation of single and tri-element adsorption of Pb2+, Ni2+ and Zn2+ ions in aqueous solution on modified water hyacinth (Eichhornia crassipes) fibers