Influences of chemically controlled Ca-bearing minerals in chitosan on Pb 2+ removal efficiency

This study investigated to the influences of chitin with different purities on the HM removal of corresponding chitosan. Sea shrimp waste was used as raw materials and Pb2+ was used as target HM. The results of orthogonal experimental analysis showed that only acid concentration played an important role in the deproteinization and demineralization processes of the chitin preparation under HCl, H2SO4 and CH3COOH treatment. Ca-bearing minerals (CBM) but not free –NH2 group of chitosan played a major role in the removal of Pb2+ from solution. Partly purified chitosan mainly removed Pb2+ by precipitation and then biosorption. The dissociation of Ca2+ from CBM elevated pH value of Pb2+ solution which benefited to precipitation and the formation of NH2-Pb2+. Partly purified chitosan prepared from HCl and CH3COOH treated chitin showed 720 –753 mg/g of Pb2+ adsorption at the initial pH value of 6.0; however, highly purified chitosan prepared from HCl treated chitin showed only 45 –160 mg/g. Chitosan prepared from H2SO4 treated chitin showed 720 –752 mg/g of Pb2+ adsorption. This research found the unexplored information for the industrial application of chitosan with minimum cost but the highest HM removal efficiency.
Source: Journal of Environmental Health Science and Engineering - Category: Environmental Health Source Type: research