Influence of Arsenate Adsorption to Ferrihydrite, Goethite, and Boehmite on the Kinetics of Arsenate Reduction by Shewanella putrefaciens strain CN-32
Influence of Arsenate Adsorption to Ferrihydrite, Goethite, and Boehmite on the Kinetics of Arsenate Reduction by Shewanella putrefaciens strain CN-32
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DOI：
10.1021/es201503g
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发表时间：
2011-09-15
影响因子：
11.4
通讯作者：
Kretzschmar, Ruben
中科院分区：
文献类型：
--
作者：
Huang, Jen-How;Voegelin, Andreas;Kretzschmar, Ruben
在低As(10mM)和低乳酸(25mM)条件下，研究了腐败希瓦氏杆菌CN-32菌株在0.2、2和20g L-1铁水铁矿、针铁矿或白铁矿悬浮液中还原As(V)的动力学。实验数据与基于独立测定的As(V)解吸、As(III)吸附和微生物还原溶解As(V)的吸附等温线和速率的模型预测进行了比较。选择低乳酸浓度是为了防止Fe(III)的显著还原，但仍允许As(V)的完全还原。溶解As(V)的还原遵循一级动力学，半衰期为3h。添加矿物吸附剂可显著降低还原速率(32-154h As(V)半衰期)。这种影响的大小随着吸附剂浓度和吸附容量(针铁矿、薄水铝石和氢氧化铁)的增加而增大。该模型始终低估了添加腐生菌后的溶解As(V)浓度和微生物As(V)的还原速率(类似于5×10(9)cell mL(-1))，这表明腐生菌细胞附着在氧化物矿物表面促进了As(V)的解吸，从而促进了As(V)的还原。因此，As(V)在矿物表面的吸附和细菌诱导的解吸之间的相互作用可能是控制还原土壤和沉积物中As还原和释放的动力学的关键。
The kinetics of As(V) reduction by Shewanella putrefaciens strain CN-32 was investigated in suspensions of 0.2, 2, or 20 g L-1 ferrihydrite, goethite, or boelunite at low As (10 mu M) and lactate (25 mu M) concentrations. Experimental data were compared with model predictions based on independently determined sorption isotherms and rates of As(V) desorption, As(III) adsorption, and microbial reduction of dissolved As(V), respectively. The low lactate concentration was chosen to prevent significant Fe(III) reduction, but still allowing complete As(V) reduction. Reduction of dissolved As(V) followed first-order kinetics with a 3 h half-life of As(V). Addition of mineral sorbents resulted in pronounced decreases in reduction rates (32-1540 h As(V) half-life). The magnitude of this effect increased with increasing sorbent concentration and sorption capacity (goethite < boehmite < ferrihydrite). The model consistently underestimated the concentrations of dissolved As(V) and the rates of microbial As(V) reduction after addition of S. putrefaciens (similar to 5 x 10(9) cells mL(-1)), suggesting that attachment of S. putrefaciens cells to oxide mineral surfaces promoted As(V) desorption and thereby facilitated As(V) reduction. The interplay between As(V) sorption to mineral surfaces and bacterially induced desorption may thus be critical in controlling the kinetics of As reduction and release in reducing soils and sediments.