title: Comparison of natural adsorbents for metal removal from acidic effluent.
abstract: Adsorption tests were carried out in acidic synthetic solutions (pH 2.0) using 20 g l(-1) of various natural adsorbents and 0.25 mM of 11 different metals. In decreasing order, the most efficient adsorbents tested were: oyster shells, cedar bark, vermiculite, cocoa shells and peanut shells. In contrast, weak metal adsorption was demonstrated by: red cedar wood, peat moss, pine wood, corn cobs and perlite. Metal adsorption capacities in acidic synthetic solution followed the order: Pb2+> Cr3+> Cu2+> Fe2+> Al3+> Ni2+> Cd2+ > Mn2+ > Zn2+ >> Ca2+, Mg2+. Alkaline treatment (0.75 M NaOH) increased the effectiveness of metal removal for the majority of adsorbents. In contrast, acid treatment (0.75 M H2SO4) either reduced or did not affect the adsorption capacity of the materials tested. Finally, oyster shells, red cedar wood, vermiculite, cocoa shells and peanut shells, were effective natural adsorbents for the selective recovery of lead and trivalent chromium from acidic effluent.
authors.affiliation: Institut National De La Recherche Scientifique (Inrs-Eau), Université Du Québec, 2800, Rue Einstein, Bureau 105, C.P. 7500, Sainte-Foy Qc G1v 4c7, Canada.
authors.forename: J F
authors.initials: JF
authors.lastname: Blais
authors.forename: S
authors.initials: S
authors.lastname: Shen
authors.forename: N
authors.initials: N
authors.lastname: Meunier
authors.forename: R D
authors.initials: RD
authors.lastname: Tyagi
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates; D000818:Animals; D010367:Arachis; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000737:chemistry / Q000302:isolation & purification*; D010125:Ostreidae; D024301:Plant Bark; D018508:Water Purification / Q000379:methods*; D014934:Wood
chemical_list: D000538:Aluminum Silicates; D008670:Metals; C003760:vermiculite