Reduction and long-term immobilization of technetium by Fe(II) associated with clay mineral nontronite

摘要: Abstract 99 Tc is formed mostly during nuclear reactions and released into the environment weapons testing inadvertent waste disposal. The long half-life, high environmental mobility (as Tc(VII)O 4 − ) its possible uptake food chain cause to be a significant contaminant. In this study, we evaluated role of Fe(II) in biologically reduced clay mineral, nontronite (NAu-2), reducing poorly soluble Tc(IV) species as function pH concentration. rate Tc(VII) reduction by NAu-2 was higher at neutral (pH 7.0) than acidic basic pHs when concentration low ( + -birnessite, it reoxidized previously Tc(IV). Nitrate neither enhanced nor promoted reoxidation Approximately 11% oxidized oxygen. extent found strongly depend on nature oxidants Fe(II). When same were added aged products (mainly TcO 2 •nH O), decreased significantly relative fresh products. Increasing also resulted reoxidation. results attributed effect aggregation that effectively retained solid vulnerability Overall, our implied bioreduced minerals could play an important maintaining long-term stability