Ions from Aqueous Solutions by Biosorption Processes

Due to the disadvantages of heavy metal removal from aqueous sytems by conventional methods, alternative new methods have been investigated lately. Biosorption is one of these new methods. In this method, metal ions are transported into cell structure, and removal is ensured by several mechanisms that occured between living or non-living microorganisms and metal ions. The metal removal, the use of non-living microorganism is preferred to living ones since they don’t require continuous supply of nutrients and they can be easly implemented. Biosorption has been proved to be an effective and low-cost method of metal removal from even very dilute aqueous solutions. In this review, removal capacities of microbial biomass such as algae, fungi, yeast and bacteria are investigated for several heavy metals including Cu (II), Ni (II), Cd (II) and Cr (VI). Environmental factors , which have effect on biosorption capacity such as pH, temparature and pretreatment of biosorbent are evaluated. Isotherms used in mathematical expressions of biosorption process are also summarized.