Adsorption of cu2+ on white poplar and oak sawdust

Abstract

The studies of Cu (II) adsorption were conducted by testing various sawdust types. Two biomass, oak sawdust wood (Querqus robur) and white poplar sawdust wood (Populus alba), have been compared considering their efficiency for copper removal from diluted water solutions. Raw sawdust proved no efficiency in adsorption. Therefore, pre-treatment processes were developed and optimized, to enhance the sawdust affinity for heavy metals adsorption. The optimized pre-treatment conditions are: solvent - aqueous solution of NaOH 3n at 22 C and a contact time 60 min for oak sawdust, respectively 30 min for poplar sawdust. The treated samples allow Cu(II) ions removal efficiency of 89% on oak sawdust and 67% on poplar sawdust. Metal ion sorption increased as the ratio of metal solution to the biomass quantity decreased. The increase of the metal ion concentration resulted in a steep increases in biosorption at lower concentrations, progressively reaching a plateau at higher metal concentrations, corresponding to multilayer mechanism.