TY - JOUR A1 - Simon, Franz-Georg A1 - Biermann, Vera A1 - Segebade, Christian A1 - Hedrich, Martina T1 - Behaviour of uranium in hydroxyapatite-bearing permeable reactive barriers: investigation using 237U as a radioindicator JF - The science of the total environment N2 - This study was undertaken to investigate the long-term performance of hydroxyapatite (HAP) as reactive material for the removal of uranium in passive groundwater remediation systems. 237U used as a radioindicator enabled tracking the movement of the contamination front through a test column without taking samples or dismantling the apparatus. The stoichiometric ratio between uranium and HAP was found to be 1:(487±19). Uranium removal by HAP is of pseudo first-order kinetics and the rate constant was measured to be (1.1±0.1)×10-3 s-1. HAP can sorb more than 2900 mg/kg uranium. Possible reaction pathways of uranium and HAP are discussed. The data obtained enable the calculation of ideal lifetime for permeable reactive barriers (PRB) using HAP for uranium removal neglecting hydrological factors that may impair the function of PRBs. KW - Uranium KW - Permeable reactive barriers KW - Radioindicator KW - Hydroxyapatite PY - 2004 DO - https://doi.org/10.1016/j.scitotenv.2004.01.005 SN - 0048-9697 VL - 326 IS - 1-3 SP - 249 EP - 256 PB - Elsevier CY - Amsterdam AN - OPUS4-3741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Franz-Georg A1 - Segebade, Christian A1 - Hedrich, Martina T1 - Behaviour of uranium in iron-bearing permeable reactive barriers: investigation with 237U as a radioindicator JF - The science of the total environment N2 - This study was undertaken to investigate the long-term performance of elemental iron as reactive material for the removal of uranium in passive groundwater remediation systems. By using 237U as a radioindicator it was possible to track the movement of the contamination front through a test column without taking samples or dismantling the apparatus. The stoichiometric ratio between uranium and iron was found to be 1:(1390±62). The reaction between iron and uranium is of pseudo first-order kinetics and the rate constant was measured to be (1.1±0.09)×10-3 s-1. These data enable the calculation of ideal lifetime for permeable reactive barriers (PRB) using iron for uranium removal neglecting hydrological factors that may impair the function of PRBs. KW - Uranium KW - Permeable reactive barriers KW - Radioindicator PY - 2003 DO - https://doi.org/10.1016/S0048-9697(02)00548-X SN - 0048-9697 VL - 307 SP - 231 EP - 238 PB - Elsevier CY - Amsterdam AN - OPUS4-2498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -