چكيده لاتين :
Zinc ions are present in differenttypes of industrial efiluents,being responsiblefor environmentalpollution.Biosorption is a processin whichsolidsofnatural origin are employed for
binding heavy metals. It is a promising alternative method to treat heavy metal wastes mainly because ofhigh metalbindingcapacity. Theeffect ofsomeimportantparameterson sorptioncapacity ofcyanobacterial biosorbentfor zinc uptakewas studied.The optimumconditionspfl, time, initial ionconcentration, adsorbent dose; werefound tobe8,90mins, 100ppmand lgm/100mLrespectively. Immobilization of biomasswasdonein calciumalginate and agar matrices forreuse ofbiosorbent. Freundlich and Langmuir isothermswereapplied to equilibriumdata of zincions biosorptionand Freundlich isotherm wasfound to fit thedata. Themaxim.urn adsorption capacitywas71.42mg/g for
A. variabilis. Thevalueof value of Kf, andn wererangedfrom 0.4458 to 2.797and0.7726 to 2.797 for the cyanobacterial biosorbents. 0.1. MEDTAwasused as an eluant and the biosorbentwasreused up to five biosorption desorption cyclesand percentage desorption of zinc ions was 93 to 84 from first to fifth cycle for the cyanobacterial biosorbents. Fouriertransform. infra-red analysis of algae with and without biosorption revealedthe presenceof carboxyl, hydroxyl, amino, amide and imine
groups, which were responsible for biosorption of Zn^+2 ions. The rate law for a pseudo-secondordermodelfitsthe experimental data with a veryhigh correlation coefficient and it wasgreaterthan 0.9771.
