Removal of brilliant green (BG) from aqueous solution by using low cost biomass Salix alba leaves (SAL): thermodynamic and kinetic studies

The removal of brilliant green dye (BGD) from aqueous solution by using Salix alba leaves (SAL) was carried out via batch studies. The maximum removal efficiency was found to be 95.2% with initial dye concentration 50 mg/L at 0.15 g adsorbent dosage, pH = 6, and 298 K temperature, and the equilibrium was observed within 3½ hours. The adsorption capacity increased (2.21–15.89 mg/g) from 10 to 50 mg/L of dye concentration. Kinetic and isotherm studies were also carried out. The results showed that pseudo-second order model better describes the adsorption mechanism. The isotherm equilibrium data analysis was carried out by using Freundlich and Langmuir models and the sorption process was observed to conform with the Langmuir isotherm with linear correlation coefficient (R2 = 0.99). The thermodynamic properties ΔG°, ΔH°, and ΔS° delineated that BGD adsorption over SAL was feasible, spontaneous, and endothermic between 303 and 323 K temperature.