Batch and continuous adsorptive removal of brilliant green dye using modified jamun seed powder: RSM based optimization
V. Vandhana Devi, R. Lakshmipathy, Venkatesa Prabhu Sundramurthy, Daoud Ali, Saud Alarifi, Mika Sillanpää
Abstract
Indian jamun seeds (JSs) were surface-modified with sulfuric acid in a 1:1 ratio of acid to adsorbent. The modified JS (MJS) was characterized using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDX) techniques. Response surface methodology (RSM) via central composite design (CCD) was utilized to investigate critical parameters like pH, contact time, and initial concentrations. At the optimal condition, the MJS exhibited a maximum adsorption capacity of 123.5 mg g−1 for brilliant green (BG). The adsorption process followed Langmuir and Freundlich models, supported by the correlation coefficients. Kinetic studies suggest that the pseudo-second-order model better explains the experimental data compared to the first-order kinetic equation, indicating that intraparticle diffusion is not the sole rate-limiting step. Thermodynamically, the process was found to be spontaneous, exothermic, and with increased entropy. Regeneration studies revealed that the MJSs can be reused for three cycles without compromising their efficiency. Continuous studies showed that lower flow rates, lower initial concentrations, and higher bed depths resulted in better adsorption efficiency. In essence, this study demonstrates that JS offer a simpler and environmentally friendly approach to remediating wastewater containing BG.