The prediction of the oxidation rate of elemental sulfur （S^0） is a critical step in sulfur （S） fertilizer strategy to supply plant-available sulfur. An incubation experiment was conducted to determine the rate an...The prediction of the oxidation rate of elemental sulfur （S^0） is a critical step in sulfur （S） fertilizer strategy to supply plant-available sulfur. An incubation experiment was conducted to determine the rate and amount of S^0 oxidation in relation to the contribution of Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria. After 84 days, 16.3% and 22.4% of the total S^0 applied to the soil were oxidized at 20 and 30 ℃, respectively. The oxidation of So proved to be a two-step process with a rapid oxidation during the first 28 days and a slow oxidation from then on. The highest oxidation rate of 12.8 μg S cm ^-2 d^-1 was measured during the first two weeks at 30 ℃. At 20 ℃ the highest oxidation rate of 10.2 μg S cm^-2 d^-1 was obtained from two to four weeks after start of the experiment. On an average the soil pH declined by 3.6 and 4.0 units after two weeks of experiment. At the same time the electric conductivity increased nine times. With the oxidation of S^0 the population of Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria increased. The corresponding values for Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria increased from 2.9 × 10^5 and 1.4 × 10^5 g^-1 soil at the start of the experiment to 4 × 10^8 and 5.6 × 10^8 g^-1 soil 14 days after S^0 application, respectively. No Thiobacillus spp. was present eight weeks after S^0 application. The results suggested that oxidation of residual S^0 completely relied oll aerobic heterotrophic S-oxidizing bacteria.展开更多
借助吸附测定、动电测定和浮选试验研究了T t 菌与闪锌矿和方铅矿的作用。试验表明 ,吸附在方铅矿和闪锌矿表面上的T t 菌的数量与 pH无关。但是 ,细菌细胞在方铅矿上的吸附量比在闪锌矿上的吸附量高 1个数量级 ,T t 菌在方铅矿和闪锌...借助吸附测定、动电测定和浮选试验研究了T t 菌与闪锌矿和方铅矿的作用。试验表明 ,吸附在方铅矿和闪锌矿表面上的T t 菌的数量与 pH无关。但是 ,细菌细胞在方铅矿上的吸附量比在闪锌矿上的吸附量高 1个数量级 ,T t 菌在方铅矿和闪锌矿上的吸附等温线表现为兰格缪尔特性。电泳测定表明 ,方铅矿和闪锌矿的等电点位于pH 2附近 ,T t 菌的等电点位于pH3附近。与T t 菌作用后 ,矿物的等电点向高pH偏移 ,这表明细菌在矿物表面上特效吸附。电泳迁移率测定还查明 ,随细菌细胞作用时间的增长 ,电泳迁移率负值减小。在与矿物作用不同时间的细胞的电泳迁移率也具有类似的变化规律。与闪锌矿作用后的细胞的电泳迁移率比与方铅矿作用后的细胞电泳迁移率负值要小些。在与T t 菌作用 1h不影响闪锌矿的浮选回收率 ,而与T t 菌作用 1h后在pH 5～ 11范围内 ,方铅矿的浮选几乎完全被抑制。方铅矿和闪锌矿人工混合样浮选分离试验表明 ,在T t 菌存在时可以从方铅矿中优先浮选闪锌矿。展开更多
基金Project supported by the Norwegian Education Loan Fund (Lnekassen) for the Scholarship, Norway (No. 2025120)the Research Council of Norway (No. 969338440MVA)
文摘The prediction of the oxidation rate of elemental sulfur （S^0） is a critical step in sulfur （S） fertilizer strategy to supply plant-available sulfur. An incubation experiment was conducted to determine the rate and amount of S^0 oxidation in relation to the contribution of Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria. After 84 days, 16.3% and 22.4% of the total S^0 applied to the soil were oxidized at 20 and 30 ℃, respectively. The oxidation of So proved to be a two-step process with a rapid oxidation during the first 28 days and a slow oxidation from then on. The highest oxidation rate of 12.8 μg S cm ^-2 d^-1 was measured during the first two weeks at 30 ℃. At 20 ℃ the highest oxidation rate of 10.2 μg S cm^-2 d^-1 was obtained from two to four weeks after start of the experiment. On an average the soil pH declined by 3.6 and 4.0 units after two weeks of experiment. At the same time the electric conductivity increased nine times. With the oxidation of S^0 the population of Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria increased. The corresponding values for Thiobacillus spp. and aerobic heterotrophic S-oxidizing bacteria increased from 2.9 × 10^5 and 1.4 × 10^5 g^-1 soil at the start of the experiment to 4 × 10^8 and 5.6 × 10^8 g^-1 soil 14 days after S^0 application, respectively. No Thiobacillus spp. was present eight weeks after S^0 application. The results suggested that oxidation of residual S^0 completely relied oll aerobic heterotrophic S-oxidizing bacteria.
文摘借助吸附测定、动电测定和浮选试验研究了T t 菌与闪锌矿和方铅矿的作用。试验表明 ,吸附在方铅矿和闪锌矿表面上的T t 菌的数量与 pH无关。但是 ,细菌细胞在方铅矿上的吸附量比在闪锌矿上的吸附量高 1个数量级 ,T t 菌在方铅矿和闪锌矿上的吸附等温线表现为兰格缪尔特性。电泳测定表明 ,方铅矿和闪锌矿的等电点位于pH 2附近 ,T t 菌的等电点位于pH3附近。与T t 菌作用后 ,矿物的等电点向高pH偏移 ,这表明细菌在矿物表面上特效吸附。电泳迁移率测定还查明 ,随细菌细胞作用时间的增长 ,电泳迁移率负值减小。在与矿物作用不同时间的细胞的电泳迁移率也具有类似的变化规律。与闪锌矿作用后的细胞的电泳迁移率比与方铅矿作用后的细胞电泳迁移率负值要小些。在与T t 菌作用 1h不影响闪锌矿的浮选回收率 ,而与T t 菌作用 1h后在pH 5～ 11范围内 ,方铅矿的浮选几乎完全被抑制。方铅矿和闪锌矿人工混合样浮选分离试验表明 ,在T t 菌存在时可以从方铅矿中优先浮选闪锌矿。
