A comparative study of seven materials as sorbents for removal of metal ions from real storm water runoff

Abstract

Among the various non-point sources, storm water runoff from urban areas has been recognized as a major contributor to a variety of water pollution problems in adjacent receiving bodies of water. Urban storm water runoff contains pollutants such as heavy metals, polycyclic aromatic hydrocarbons, and mineral oil hydrocarbons which are generally regarded as hazardous to water. In particular, the presence of heavy metals in runoff is of great concern due to their non-biodegradability. Sorption-based technology has been recognized to be a promising remediation method for removal of metal ions from aqueous streams. The present work examined the efficiency of seven low-cost materials (crab shell, Sargassum sp., Amberlite, chitosan, sawdust, peat and bagasse) as sorbents for metal removal from urban storm water runoff. The urban storm water runoff used in the study contained a range of metal ions (Cu, Ni, Co, Pb, Cd, Fe, Zn, Ca, Mg, A1, Na and K). The comparative evaluation indicated that both crab shell and Sargassum sp. performed exceedingly well in the removal of metal ions compared to other sorbents examined. SEM-EDX analysis of sorbents prior to and after sorption experiments was performed to provide mechanistic insights into the removal of metal ions from the storm water. Kinetic studies revealed that the sorption of metal ions by both crab shell and Sargassum sp. was very fast, which implies that these materials could be used in continuous storm water treatment processes. According to desorption experiments conducted in the study, it is possible to recover industrially-relevant metals such as Cu, Ni, and Zn and reuse the sorbents for next cycle of sorption. Copyright © 2009, AIDIC Servizi S.r.l.