Kaolinitic clay-based ceramic microfiltration membrane for oily wastewater treatment: Assessment of coagulant addition

Abstract

Abstract Performance of inline coagulation-microfiltration (IMF) process for treatment of oily wastewater using a newly developed kaolinitic clay-Based ceramic membrane was investigated. Ceramic microfiltration (MF) membrane was fabricated utilizing kaolinitic clay as starting material and polyvinyl alcohol (PVA) as binder followed by characterizing employing Differential thermal analysis/Thermo-gravimetric (DTA/TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The efficiency of adding Al2 (SO4)3 as the prime coagulant for IMF of oily wastewater was assessed and modeled utilizing response surface methodology (RSM) based on Box-Behnken design (BBD). Moreover, the performance of long-term process was evaluated through periodic backwashing mode at the optimum condition within 17 cycles (90 min) including 240 s of forward filtration, backwashing for 15 s with 5 s of rest between each cycle. The results exhibited that water flux and rejection can be correlated with the input variables by the models with 2.29% and 1.67% relative deviation, respectively. The analysis of variance (ANOVA) results, which was employed to optimize the experiment input condition were as pH = 7.2, FC = 921 mg. L−1 and CC = 207 mg. L−1 and the corresponded responses after 90 min were water flux = 123.85 L m−2 h−1 (LMH) and rejection = 97.31%. The results of periodic backwashing showed that water flux could be intensified as 1.68 times compared to continuous forward IMF mode, while the oil rejection is equal to 98.06%. The overall results showed that the IMF system could be considered as a promising system for membrane fouling mitigation and filtration performance intensification.