Fixed-Bed Adsorption of Ranitidine Hydrochloride Onto Microwave Assisted—Activated Aegle marmelos Correa Fruit Shell: Statistical Optimization and Breakthrough Modelling

In this study, the feasibility of using microwave-irradiated Aegle marmelos Correa fruit shell was investigated in a fixed-bed column towards sorptive removal of ranitidine hydrochloride (RH) from simulated aqueous solution. Characterizations of adsorbent such as SEM, point of zero charge, BET surface area, Boehm surface functional groups, thermal and elemental analysis were carried out. Box–Behnken response surface methodology was utilized to optimize the process parameters such as influent flow rate (2.5–4.5 ml min −1 ), initial RH concentration (100–200 mg l −1 ), adsorbent particle size (0.082–0.20 mm), and fixed-bed height (5–10 cm). The highest fixed-bed adsorptive removal of RH at optimum conditions viz. bed height 9.19 cm, initial RH concentration 184.94 mg l −1 , flow rate 3.76 ml min −1 and adsorbent particle size 0.2 mm was estimated to be 72.86%. Fixed-bed adsorption experiments were carried out at optimum conditions obtained at different bed heights, and the data obtained were fitted into different kinetic models to predict the applicable breakthrough curve model. Dose–response model was observed to be the best suited model for mathematical description of RH removal in fixed-bed column studies over other selected models.