Experimental and theoretical investigations of divinylbenzene-based polymer as an efficient adsorbent for brilliant green dye removal

Water contamination caused by synthetic dyes is a growing environmental concern, necessitating the development of effective and sustainable remediation technologies. In this study, poly(divinylbenzene) (poly(DVB)) was synthesized <i>via</i> suspension polymerization and evaluated as a novel adsorbent for the removal of Brilliant Green (BG) dye from aqueous solutions. Characterization techniques including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) surface area analysis confirmed the polymer's porous morphology, thermal stability, and adsorption potential. Batch adsorption experiments were conducted to assess the influence of key operational parameters, and the results showed that the highest removal efficiency of 97.4% was achieved under optimal conditions of pH 7, temperature 298 K, contact time of 120 minutes, initial dye concentration of 7.5 mg L^-1 and adsorbent dose of 0.05 g 10 ml^-1. The adsorption kinetics followed the pseudo-second-order model, suggesting that chemisorption dominates the process, while isotherm modeling indicated that monolayer adsorption occurred on a homogeneous surface, as described by the Langmuir model. Thermodynamic analysis revealed that the adsorption process was endothermic and spontaneous, confirming enhanced dye-polymer interactions at elevated temperatures. DFT calculations were then applied to provide novel atomistic details that should help in better understanding of the chemical interaction that takes place between the dye and the adsorbent. Furthermore, regeneration studies demonstrated that poly(DVB) was sustainable and can be reused for up to four cycles, supporting its feasibility for real-world wastewater treatment applications. Comparisons with previously reported adsorbents highlighted the superior performance of poly(DVB), making it a promising, adsorbent for dye removal from contaminated water.