A review of potentially low-cost sorbents for heavy metals

The use of low-cost sorbents has been investigated as a replacement for cur rent costly methods of removing heavy metals from solution. Natural materia ls or waste products from certain industries with a high capacity for heavy metals can be obtained, employed, and disposed of with little cost. Modifi cation of the sorbents can also improve adsorption capacity, fn this review , an extensive list of sorbent literature has been compiled to provide a su mmary of available information on a wide range of potentially low-cost sorb ents, including bark, chitosan, xanthate, zeolite, clay, peat moss, seaweed , dead biomass, and others. Some of the highest adsorption capacities repor ted for cadmium, chromium, lead and mercury are: 1587 mg Pb/g lignin, 796 m g Pb/g chitosan, 1123 mg Hg/g chitosan, 1000 mg Hg/g CPEI cotton, 92 mg Cr( III)/g chitosan, 76 mg Cr(III)/g pear, 558 mg Cd/g chitosan, and 215 mg Cd/ g seaweed. (C) 1999 Elsevier Science Ltd. All rights reserved.