Heavy metal removal using modified sol-gels derived powder matrices containing crude metallothionein extracts from Schizosaccharomyces pombe

In this study modified sol-gels derived matrices containing polymers or crude metallothionein (MT) extracts were applied for the first time to remove cadmium, zinc and copper from aqueous solutions. First a simple protocol was established for the preparation of crude MT extracts from Schizosaccharomyces pombe. Next the crude MT extracts or other non-biological chelating agents were entrapped in sol-gel derived powders of varying particle sizes. The adsorption capacity of these metals on MT-sol-gel derived powder was high. The adsorption was also rapid on 45 to 75 μm powders containing MT. The adsorption capacity of sol-gel derived powder (45 to 75 μm) containing crude MT extracts was found to be 621.9 mg of cadmium/g of MT-sol-gel derived matrices compared to 117.12 mg of cadmium/g of PEI (Polyethyleneimine). The sol-gel derived powder containing MT also effectively removed cadmium in presence of zinc and copper. Recovery of metals sol-gel derived matrices using a solution of 1 M NaCl resulted in 90% of metals removal.; The general-purpose adsorption isotherms such as Langmuir, Langmuir-Freundlich, Redlich-Peterson and Toth compared for the goodness of fit to the sorption data of cadmium, zinc and copper on both biopolymer and commercial polymers. The data showed a good fit on Langmuir isotherm. The kinetic modeling of metal removal using modified sol-gels was also carried out.; A small column containing sol-gel derived powder (45 to 75 μm) filter was designed, built and applied as a prototype device for investigation of Cd removal from aqueous solutions. The column was found to effectively remove of Cd from aqueous solutions. The MT containing sol-gels derived matrices represents an excellent and potentially inexpensive method for the large scale removal of heavy metals from the environment.