DESIGN AND DEVELOPMENT OF THIN-FILM COMPOSITES AND NANOCOMPOSITES MEMBRANES FOR SELENIUM AND ARSENIC REMOVAL VIA NANOFILTRATION

Abstract

Selenium is widely used in a number of products such as semiconductors, drugs and photosensitive materials. It can be released into environments from anthropogenic activities, for example, the discharge of industrial wastewater and agricultural runoff. Though it is an essential trace element for human and animals, it would be harmful above daily recommendation. In the natural aquatic system, selenite SeO32- and selenate SeO42- are the dominant species of selenium because of their high solubility and mobility nature. On the other hand, arsenate As (V), the major species of arsenic, is fatal and can cause serious health problems. Due to the toxicity of selenium and arsenate ions in water along with their ease of accumulation, proficient removal of those ions is essential for the remediation of environments.

Se and As removal from wastewaters can be challenging and pricy due to the combination of high volume but low concentration (low ppm or ppb) polluted streams. There are several treatment methods including chemical precipitation, adsorption, ion exchange, membrane filtration, chemical reduction and biological removal. Nanofiltration (NF) has received intensive attention recently for water treatment owing to its capability and sustainability.