Comparison of pyrophyllite- and alumina-coated membrane treating industrial wastewater in aspect of membrane fouling and organic removal

Abstract

In this study, two ceramic membranes such as coated alumina-based (ACA) and low cost coated pyrophyillite-based (ACP) membranes were compared for elucidating the effect of feed charge on fouling control and fluidization of adsorbent on the treatment of organic solution. The granular activated carbon (GAC) was fluidized along the surface of ceramic membrane to provide physical scouring and adsorption capability. Results revealed that the surface of ACP membrane was rougher than that of ACA membrane showing surface roughness of 81.2 and 61.6 nm, respectively. Furthermore, contact angle of ACP membrane was higher than that of ACA membrane (32° vs. 10°). Without GAC fluidization, the fouling rate resulting from ACP membrane was dependent upon the type of wastewater. With ACP membrane, membrane fouling was higher with cationic dye-based wastewater than that with anionic dye-based one. Regardless of different types of wastewaters, relatively low fouling was observed for ACA membrane. The intrinsic properties of membranes such as surface roughness, surface charge and hydrophilicity played important roles in determining membrane fouling. Low organic rejection efficiency (less than 40 %) was observed during membrane filtration without GAC. However, almost 98 % of organic rejection efficiency was reached within initial 30 min of filtration under the GAC fluidization at 50 % of packing ratio based upon effective reactor volume. Under the 10 % of packing ratio with GAC particles, membrane fouling was controlled successfully during 12 h filtration with almost complete UV removal efficiency within initial 4 h of filtration.