Adsorption of Bisphenol-A from aqueous solution using amberlite XAD-7 impregnated with aliquat 336: Batch, column, and design studies

Abstract

Bisphenol-A (BPA) was removed from water solution using washed (WX7) and impregnated (IX7) Amberlite XAD-7 resin with Aliquat-336 (A336). 0.5 g (IX7-0.5) and 1 g (IX7-1) of A336 per g of WX7 were loaded on the resin. Characterization of prepared adsorbents was done by FTIR, FE-SEM, EDS, BET. Point of zero charge study was also conducted to find the point at which the surface of adsorbent became neutrally charged. Equilibrium and kinetic experiments in the batch mode were carried out to observe the influence of contact time, amount of adsorbent, the initial concentration of BPA, pH, temperature, and ionic strength of solution (NaCl and Na₂SO₄) on the adsorption. IX7-1 showed comparatively better removal efficiency than that of IX7-0.5 or WX7. 5 g L^-1 was determined to be the optimum mass of adsorbent (WX7, IX7-0.5, and IX7-1). Equilibrium (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and kinetic (pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich) models were fitted to the experimental results. Used IX7-1 was regenerated up to 5 times, and showed almost the same removal and good reusability of impregnated resin even after 5^th cycle. Studies in a fixed bed column were also done by changing the flow rate, the height of the bed, and initial BPA concentration to evaluate the performance of IX7-1. Models like Thomas, Adham Bohart, and BDST were used to predict the column behavior, and to estimate the parameters for the scale-up of the process. Finally, the economic analysis of prepared resin was done, and the cost of impregnated resin (IX7-1) was found to be $2.055/g.