utilization of some agricultural wastes in treating water pollutants

Rice husks, a locally available agricultural by-product, were investigated with aim of producing good adsorbing materials suitable for remediating water pollution . Raw lignocellulose was treated through various procedures: simple carbonization to high temperature, pyrolysis under flowing steam at moderate temperatures and chemical activation with H3PO4 followed by pyrolysis at moderate temperature . A partially deashed precursor was obtained by boiling in alkali solution, thereafter botanical residue was steam activated at a single temperature, and leachate acidified whereby silica was precipitated, many types of adsorbents were thus derived: chars, activated carbon and silica. the obtained various categories of sorbents were characterized by different techniques to asses their physico-chemical and adsorptive properties . this involved: ash content, thermogravimetry, FTIR, electron microscopy, N2 gas adsorption at 77 k and adsorption capacity from solution using probe molecules