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

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 Al-2 (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.