Waste Based Separation Media for Environmental Applications

Abstract

With an increased pace of industrialization especially in developing countries, environmental problems have also increased. More waste is being generated and thus there is an emerging interest in waste utilization. At the same time, with growing population and economic development, there is a rise in water consumption and wastewater generation. Due to the large variety of pollutants that are now entering our water resources, there is a need for improved technologies for removing different contaminants in water. In this context, hybrid membranes combining both adsorption and filtration present an interesting alternative for the treatment of contaminated waters. This work reports the use of low cost carbon membranes prepared from fly ash (generated from burning of sugarcane bagasse) and different commercial activated carbons. The removal of two organic contaminants viz. low molecular weight phenol and high molecular weight humic acid was examined. Different filtration set-ups were used and the most suitable one identified. The filtration performance in terms of % contaminant removal, flux and transmembrane pressure was studied. The changes in membrane properties were examined by mercury porosimetry and surface area analysis. Select batch adsorption studies were also conducted to verify some of the findings. This work proves that carbon membranes can be used for removal of low and high molecular compounds from aqueous streams. Membranes prepared with lower surface area activated carbons were more stable and suitable for treating aqueous streams. Compared to testing in a closed filtration cell, testing in an open reactor using a submerged membrane module is recommended for these membranes. The membrane configuration (straight or reverse placement) appears to have an effect on the removal of organic pollutants. Of the membranes tested, Innova coated membrane (CI) in straight configuration appears to be most suited for phenol removal. For humic acid removal, the carbon coating appears unnecessary and the uncoated membrane in reverse configuration is most suitable.