Removal of humic acid from water using adsorption coupled with electrochemical regeneration

Abstract

A novel and economic waste water treatment technology comprised of adsorption coupled with electrochemical regeneration was introduced at the University of Manchester in 2006. An electrically conducting adsorbent material called Nyex™ 1000 (Graphite intercalation based material) was developed for the said purpose. This adsorbent material delivered significantly lower adsorption capacity for the removal of a number of organic pollutants. With the aim to expand the scope of newly developed adsorbent material called Nyex™ 2000, we studied the adsorption of humic acid followed by electrochemical regeneration. Nyex™ 2000 is a highly electrically conducting material with an adsorption capacity almost twice that of Nyex™ 1000 (intercalation based graphite compound) for humic acid. The adsorption of humic acid onto both Nyex™ adsorbents was found to be fast enough keeping almost the same kinetics with approximately 50% of the adsorption capacity being achieved within the first twenty minutes. The parameters affecting the regeneration efficiency, including the treatment time, charge passed and current density, were investigated. The regeneration efficiency at around 100% for Nyex™ 1000 & 2000 adsorbents saturated with humic acid was obtained using the charge passed of 8 and 22 Cg−1 at a current density of 7mA cm−2 during a treatment time of 30minutes, respectively.