Heavy metal removal from solid waste e.g. power station fly ash - by forming an aq. slurry of the material, adding chitosan or tannin as chelating agent, standing and sepg. the solid from the heavy metal-contg. soln. etc.

摘要

Removing heavy metals from solid waste materials by slurrying in water or from slurries of waste prods., by (a) adding chitosan or tannin or a mixt. of these to the slurry; (b) allowing the slurry to stand, opt. with stirring; (c) sepg. the solid components and (d) treating the soln., which contains the heavy metals. Pref. 5-20 % chitosan or tannin is added w.r.t. the waste material. After addn. of the chitosan or tannin the mixt. is allowed to stand pref. for 5 hours to 5 days. Chitosan and tannin are effective with different spectrums of heavy metals and a mixt. of the two reagents is esp. effective in some cases. USE/ADVANTAGE - Chitosan and tannin form chelate cpds. with the heavy metals and can thus be used to treat problem heavy metal contg. wastes such as fly ash from power stations and refuse burning installations, waste prods. from domestic refuse, clarifier sludges, domestic waste slurries and filter residues, from the treatment of waste prods.. Chitosan and tannin form heavy metal chelate cpds. whereas many known chelate forming cpds. (EDTA, NTA, DTPE, salicylates, tartaric acid and tartrates, ethylenediamine) and its derivs., etc. are not suitable as chelate formers for this purpose