Ahmad Azari

In this research, single and multi-bed adsorption columns for oily wastewater treatment were investigated both experimentally and numerically. For this purpose, two mineral adsorbents, namely natural zeolite and calcined bentonite, were used. The adsorbent characteristics were analyzed by XRD, BET, and SEM. Adsorption isotherm and single fixed-bed adsorption column performance for both adsorbents were experimentally assessed at different concentrations. In addition, single- and multi-fixed-bed column applicability with two different configurations, series and parallel connections, were simulated. The experimental results showed that Freundlich and Langmuir isotherms had the best performance to describe the adsorption of calcined bentonite and natural zeolite, respectively. Moreover, natural zeolite has better performance for oily wastewater treatment than calcined bentonite. The maximum capacity of calcined bentonite and natural zeolite was obtained at 3.06 mg/g and 5.37 mg/g, respectively. The simulation results indicated that the maximum separation yields of single fixed-bed, multi-fixed-bed with series connections, and multi-fixed-bed with parallel connections were 39.3%, 99.98% and 74.58%, respectively. Adsorbent mass optimization indicated that the required adsorbent mass decreased by 33.1% when four beds were presented in an operation instead of a single bed. This research recommends a promising application of natural zeolite as an economic adsorbent in multi-bed adsorbers for oily wastewater treatment.