Ammonia removal from raw water by using adsorptive membrane filtration process

Abstract

The contamination of ammonia in surface water should be given a critical outlook as it easily exceeds the regulated standard limit especially in rivers located in many parts of the world. Several conventional methods for the removal of ammonia have been widely used but its effectiveness in removing ammonia is not impressive. Membrane technology is gaining wider application in removal of nitrogen compounds from water and wastewater. In this study, polyvinylidene fluoride (PVDF) flat sheet membrane incorporated with adsorbent material (zeolite and gypsum) were fabricated to study its efficiency in ammonia removal. The morphology of the blended PVDF membrane by using both additive materials showed that some changes were observed at the bottom layer of the membrane where an extremely wide finger-like structure has been formed. This modified membrane exhibits hydrophobicity properties with contact angle value of 89.0 ± 0.48° and 96.3 ± 0.54° for zeolite and gypsum, respectively. Meanwhile, the crystallinity of the fabricated membrane increases from 20% for pure PVDF to 25.9% and 26.4% for the respective additive of gypsum and zeolite. Furthermore, a comparable separation performance was obtained for the blended membrane with the pure PVDF and the commercial membrane of NF1. Thus, the presence of zeolite or gypsum in the synthesized PVDF membrane could potentially enhance the removal of ammonia by becoming an adsorption material as it commonly functions.