A new approach using polyvinylidene fluoride immobilised calf-intestinal alkaline phosphatase for uranium bioprecipitation

Abstract

Uranium is a predominant radionuclide arising out of operations of mining, milling and fuel fabrication for nuclear power plants. While chemical and biological methods using several micro-organisms have been employed for the remediation of uranium from such effluents, use of immobilised enzymes for the purpose has not been reported. The current investigation deals with a purified calf-intestinal alkaline phosphatase which is capable of driving uranium precipitation in the presence of a phosphate-containing substrate. The enzyme, both in free form and in an immobilised form on polyvinylidene fluoride membrane, was investigated for the precipitation of uranium using para-nitrophenyl phosphate as substrate. The results indicated that while the enzyme in free form could precipitate most of the uranium within 6 h, the immobilised enzyme could achieve the same in 24 h. There was a spurt in the precipitation of uranium by the immobilised enzyme during the initial period of 3 h followed by a linear increase for the remaining period. The immobilised enzyme was found to be stable and catalytically active for 3 years in precipitating uranium. The results obtained offer polyvinylidene fluoride immobilised alkaline phosphatase from calf intestine as a new tool for the remediation of uranium from effluents. Further, evidence has been also shown that no requirement for any cellular architecture/ scaffolding exists for uranium mineralisation to occur.

Indole-functionalized cross-linked chitosan for effective uptake of uranium(vi) from aqueous solution

“…4,5 Consequently, the pollution by U(VI) is one of the most pressing concerns regarding nuclear power at present. Various remedia-tion strategies have been proposed and constructed to handle U(VI) contaminants including precipitation, 6,7 photocatalytic reduction, [8][9][10] membrane separation, [11][12][13] ion exchange 14,15 and adsorption. [16][17][18][19][20] Unfortunately, the precipitation technique is limited by the vast amount of secondary waste.…”