Irvan Dahlan

The increasing need for efficient CO ₂ capture methods has led to the exploration of NaOH-modified nanoclay montmorillonite as an adsorbent. This study utilizes response surface methodology (RSM) and artificial neural networks (ANN) for modelling and optimizing CO ₂ adsorption. Data from previous experiments were used to develop the models. RSM employed a central composite design (CCD) and was evaluated using analysis of variance (ANOVA), while ANN models were created with various training methods (Levenberg–Marquardt, Bayesian regularization, and scaled conjugate gradient). The ANN model using Bayesian regularization (R ² = 0.98719; MSE = 0.00049) demonstrated the best predictive accuracy. ANOVA revealed that NaOH concentration, pressure, and temperature significantly affected CO ₂ adsorption capacity. Sensitivity analysis confirmed NaOH concentration as the most influential variable. Optimization results indicated that maximum CO ₂ adsorption (72.873 mg/g) occurs at 35 °C, 9 bar pressure, 5 mol/L acid concentration, and 30% w/w NaOH. This study effectively applies RSM-CCD and ANN models for optimizing CO ₂ adsorption with NNM adsorbent.

This review evaluates the effectiveness of metal–organic frameworks (MOFs) in treating dye wastewater. MOFs are highly effective in dye effluent removal due to their multifunctionality, water stability, and recyclability. They offer exceptional dye removal and degradation capabilities, with significant surface area and adjustable pore size. Among various dye removal techniques (chemical, physical, and biological), adsorption has emerged as a cost-effective and highly efficient method. Researchers analyse adsorption isotherms and kinetics to understand the efficiency of MOFs in dye absorption from wastewater. Characterization studies confirm the effectiveness of MOFs. Conventional adsorbents fall short of industrial dye removal, thus making MOFs a promising alternative. This review assesses MOFs’ efficacy in treating dye wastewater, highlighting their superior adsorption capacity over conventional materials. Various MOF types, including modified and gel-based variants, show promise. Research into inexpensive and efficient adsorbents from available resources for colour removal is increasingly vital. Studies demonstrate the efficacy of numerous affordable adsorbents in wastewater colour removal.

The sorption mechanisms, point of zero charge, and isosteric heats involved in the adsorptive dephenolization of aqueous solutions using thermally modified corn cob (TMCC) were studied at different initial phenol concentrations (100–500 mg/l), TMCC dosage (0.4–2.0 g), contact time (5–60 min), pH (2–10), and temperature (30–60°C). Analysis of the adsorbent material showed that it possessed the properties typical of a good adsorbent. The adsorption experiments revealed that phenol uptake is favored by an increase in TMCC dosage and contact time and a decrease in temperature and concentration of phenol in the solution. The experimental data were well-fitted to the Sips, Langmuir, Toth, and Redlich–Peterson isotherm models. Thermodynamic studies suggested that the sorption of phenol onto TMCC is feasible, spontaneous, and endothermic. The isosteric heats of adsorption obtained are in the range 47.43-79.38 kJ/mol, confirming that the adsorption process is predominantly a physical process depicting the van der Waals interactions, and it is inversely proportional to surface loading. The analysis of the adsorption mechanisms showed that the intraparticle, film, and pore diffusion mechanisms were significantly involved in the phenol adsorption process. The involvement of electrostatic attraction, electron-donor interaction, and hydrogen bonding was also demonstrated. The point of zero charge () was obtained at a pH of 5.83; being slightly lower than the optimum pH of 6 indicates that the sorbent surface is obviously not negatively charged at . The discoveries of this study have shown that the dephenolization process is feasible, spontaneous, endothermic, dominated by a physical process, and governed by intraparticle, film, and pore diffusion mechanisms.