ADSORPTIVE REMOVAL OF 4 CARBOXY-BENZALDEHYDE

Abstract

In this work, 4-carboxybenzaldehyde (4-CBA) removal from aqueous solution onto low cost adsorbent- bagasse fly ash (BFA) was carried out. A 4-factor 5-level Central composite design under response surface methodology was used to optimize the 4-CBA removal and adsorption uptake. Variable considered for the study were pH, adsorbent dose, initial concentration and time. The optimum value of these parameters were found as pH=4, adsorbent dose=9 g/l, initial concentration=100 mg/l and time 7.5 h. At optimized condition the removal efficiency and adsorption uptake of 4-CBA onto BFA were found to be 79% and 9.9 mg/g, respectively. Quadratic regression model was developed to evaluate impact of linear and quadratic interaction and R2 (=0.873) value suggest that the model was significant. Adsorption capacity of BFA and GAC was compared. BET surface area of BFA and GAC was found to be 284 m2/g and 591 m2/g, respectively. Both the adsorbents were predominately mesoporous in nature. Kinetic study was carried out by employing pseudo first and pseudo second order model and possibility of intra particle diffusion controlling the adsorption mechanism was also investigated. Adsorption equilibrium data were fitted for Langmuir, Freundlich, Redlich- Peterson, Sips, Hills, Temkin model. Positive value of DH 0 suggest that the adsorption process was endothermic. Change in the entropy was found to be positive. Negative values of 0 ads DG indicates that the adsorption process is feasible and spontaneous...