Performance evaluation of mullite ceramic membrane for oily wastewater treatment using response surface methodology based on Box-Behnken design

Abstract

Nowadays, oily wastewater is increasing along with the growth of various industries. So, wastewater treatment is necessary in order to protect the environment. In this study, a mullite ceramic membrane was prepared. Then, oily wastewater treatment with 200 mg L^-1 concentration was investigated by the response surface methodology based on Box-Behnken design (BBD) using Design-Expert 7.0.0 software. Membrane characterization was done using XRD, SEM, and porosity analysis. Based on XRD results, the major phase of the membrane was mullite. Furthermore, according to SEM image and porosity analysis, the pore size and the membrane porosity were 1.7 μm, 47 %, respectively. The experimental parameters were temperature (T, 20 - 40 ºC), pressure (P, 2 - 4 bar) and cross flow velocity (CFV, 0.5-1.5 m s^-1). In addition, the flux was considered as the response. The optimum conditions for achieving the maximum response were 39.62 ºC of T, 3.92 bar of P, and 1.34 m s^-1 of CFV. The maximum permeate flux was 42.93 L m^-2 h^-1. The rejection was investigated under different pressure from 2 to 4 bars. The maximum rejection was observed at 2 bars with the amount of 97.4 %.