Development of new tubular ceramic microfiltration membranes by employing activated carbon in the structure of membranes for treatment of oily wastewater

Abstract

Abstract In this research, the application of activated carbon and natural zeolite as absorbents and hydrophilic agents in the structure of a low-cost and high performance tubular ceramic microfiltration membrane for oily wastewater treatment was investigated. In this respect, Mullite, Mullite-Zeolite, and Mullite-Zeolite-Activated Carbon membranes were fabricated and characterized as ceramic MF membranes by using kaolin clay, natural zeolite and activated carbon powder. Performance of these membranes were assessed by comparing the quantity of permeation flux (PF) and total organic carbon (TOC) rejection during oily wastewater treatment where harsh conditions such as high oil concentration in various concentration of saline feed (0–200 g/L) were considered. Fouling and cleaning experiments were performed on oily waste water using a laboratory scale cross-flow test unit when NaOH was selected as a cleaning agent. Experimental results showed that the presence of activated carbon and natural zeolite in the structure of the membrane can enhance the permeation flux and total organic carbon rejection. Also, the permeation flux was highly dependent on the salt content of the feed solution. Actually, the flux improved sharply with the increase of salt content from 0 to 50 g/L, and then reduced slightly with further increase in salt concentration. In addition, total organic carbon rejection of up to 99.99% for Mullite-Zeolite-Activated carbon membrane was observed. The results of cleaning membrane process illustrated that the NaOH agent was able to clean the fouled MF membrane effectively. The exponential triple smoothing model was also used to predict the permeation flux in long periods.