Comparative Study on the Ni2+ Biosorption Capacity and Properties of Living and Dead Pseudomonas putida Cells

Microbial cells have been successfully used as biosorbents to remove heavy metalsfrom wastewater. in some cases, dead cells appear to offer more advantages than living cellsin the removal and recovery of heavy metal ions from industrial wastewater. maintaining higherbiosorption capability and understanding the biosorption properties of dead cells are the keysto heavy metal removal and recovery from wastewater using dead cells as biosorbents. the presentexperiment showed that the dead pseudomonas putida 5-x cells killed by dilute hcl had a higherni2+ biosorption capacity due to the retention of a complete cell structure during the acid treatmentprocess. the biosorption process of the dead cells was faster than that of the living cells. metabolicindependentphysical adsorption played a major role in the ni2+ sorption by the dead cells.the ph obviously affected the biosorption capacity of the dead cells, because of the variation ofthe hydrogen ion concentration and cell surface property, as well as occurrence of micro-precipitationalong with the change of solution ph. considering both biosorption capacity and desorptionefficiency, ph 6.5-7.0 is a suitable condition for ni2+ biosorption by dead p. putida 5-x cells killedwith dilute hcl.