DEVELOPMENT OF NANOFILTRATION (NF) MEMBRANES FOR WATER TREATMENTS

Abstract

Water scarcity is an important issue worldwide, especially in arid regions. The situation is getting worse in the next decades. The lack of water has severe impacts on food production, industrial productivity and domestic needs. To deal with water scarcity, many efforts have been made to safely discharge and reuse the reclaimed wastewater. In this thesis, the development of nanofiltration (NF) membranes for wastewater treatment were investigated to remove pollutants, such as heavy metal, before discharge. By using different membrane substrates and tuning surface modifications thereafter, membranes with good rejection to heavy metal ions and comparable water permeability were achieved. The rejection of the best membrane in this thesis to heavy metals, for instance, Pb(NO3)2, CuSO4, NiCl2, CdCl2, ZnCl2, Na2Cr2O7 and Na2HAsO4, was higher than 98 %. The membranes also display excellent rejections to mixed ions with rejections more than 99 %.