removal of fuchsin dye from aqueous solutions using walnut shell-derived activated carbon

Water pollution, particularly from industrial dyes, poses a significant threat to the environment, making effective wastewater treatment essential. waste from walnut shells, previously considered a byproduct, has now gained considerable attention. this study investigates walnut shell-activated carbon as a natural adsorbent for removing fuchsin dye, a major contributor to water pollution. the activated carbon demonstrated high efficiency, achieving a removal rate of 99.10% under optimal conditions (ph 8, contact time 10 minutes, initial dye concentration 10 mg/l, adsorbent dosage 2 g/l, temperature 50 °c). the adsorption kinetics of fuchsin dye on walnut shell activated carbon demonstrated adherence to a pseudo-second-order model (r2 = 0.9999), indicating that the adsorption is chemical in nature. isotherm studies further revealed a better fit to the langmuir model (r2 = 0.9969). the maximum adsorption capacity for fuchsin at optimal concentration was found to be 45.45 mg/g. additionally, thermodynamic parameters such as δg°( -1.32 to -10.77 kj/mol), δh°( 50.47 kj/mol), and δs°(0.18 kj/mol·k) were determined. the thermodynamic analysis showed that the adsorption of fuchsin dye increases with the temperature of the adsorbent, suggesting that the process is endothermic. these findings underscore the potential of walnut shell-activated carbon as an effective and sustainable solution for treating dye-contaminated wastewater and promoting environmentally friendly practices in industrial waste management.