Adsorption of phenolic compounds by polyacrylonitrile nanofibre membranes : a pretreatment for the removal of hydrophobic bearing compounds from water

Although Membrane Distillation (MD) is envisaged as a cost-effective alternative desalination technology, it remains severely affected by membrane fouling. In Direct Contact MD mode, membrane fouling is exacerbated by the presence of compounds bearing hydrophobic functional groups, e.g., phenols. In this study, polyacrylonitrile (PAN) and polyethylene-imine (PEI) functionalized-PAN nanofibre membranes were synthesized and tested as a pretreatment for the removal of chlorophenol and nitrophenol from solutions. PAN and PEI-modified nanofibres displayed different isoelectric points (IEP: 3.8 and 6.2, respectively), indicating the impact of the imination process. PEI-modified nanofibres showed a higher adsorption capacity for chlorophenol than for nitrophenol, and a higher adsorption capacity than PAN nanofibres for each phenolic species in the pH range tested (5-11). Electrostatic forces were the dominant interacting mechanisms influencing the adsorption capacity of nanofibres towards phenolic species, based on their IEPs and pKa. Under optimized experimental conditions, adsorption capacities ranging from 27.3 to 38.4 mg g(-1) for PAN and PEI-modified nanofibres, respectively, were recorded. Chemisorption and physisorption were proposed as main mechanisms for PEI-functionalized and PAN nanofibres, respectively; where phenols formed multilayers on the nanofibres surface leading to decreased adsorbent regeneration cycles. PEI-functionalized nanofibres showed a high potential for the removal of phenols from aqueous solutions and opens a promising research direction for their use as an innovative polymeric adsorbent during pretreatment in MD processes.

Jaar van publicatie:2019

BOF-keylabel:ja

IOF-keylabel:ja

Auteurs:International

Authors from:Higher Education

Toegankelijkheid:Closed