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Tao Hu-Chun Li Shuo Zhang Li-Juan Chen Yi-Zhen Deng Li-Ping 《Environmental geochemistry and health》2019,41(1):297-308
Environmental Geochemistry and Health - Using sodium alginate hydrogel as skeleton, in combination with chitosan and magnetic Fe3O4, a new type of magnetic chitosan/sodium alginate gel bead (MCSB)... 相似文献
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Peng-Song Li Wei-Min Wu Debra H. Phillips David B. Watson Shelly Kelly Bing Li Tonia Mehlhorn Kenneth Lowe Jennifer Earles Hu-Chun Tao Tong Zhang Craig S. Criddle 《环境科学学报(英文版)》2019,31(11):156-167
This study evaluated uranium sequestration performance in iron-rich(30 g/kg) sediment via bioreduction followed by reoxidation. Field tests(1383 days) at Oak Ridge, Tennessee demonstrated that uranium contents in sediments increased after bioreduced sediments were re-exposed to nitrate and oxygen in contaminated groundwater. Bioreduction of contaminated sediments(1200 mg/kg U) with ethanol in microcosm reduced aqueous U from 0.37 to 0.023 mg/L. Aliquots of the bioreduced sediment were reoxidized with O_2, H_2O_2,and NaNO_3, respectively, over 285 days, resulting in aqueous U of 0.024, 1.58 and 14.4 mg/L at pH 6.30, 6.63 and 7.62, respectively. The source-and the three reoxidized sediments showed different desorption and adsorption behaviors of U, but all fit a Freundlich model.The adsorption capacities increased sharply at pH 4.5 to 5.5, plateaued at pH 5.5 to 7.0, then decreased sharply as pH increased from 7.0 to 8.0. The O_2-reoxidized sediment retained a lower desorption efficiency at pH over 6.0. The NO_3~--reoxidized sediment exhibited higher adsorption capacity at pH 5.5 to 6.0. The pH-dependent adsorption onto Fe(Ⅲ) oxides and formation of U coated particles and precipitates resulted in U sequestration, and bioreduction followed by reoxidation can enhance the U sequestration in sediment. 相似文献
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Environmental Geochemistry and Health - 相似文献
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刘淑春 《湖南环境生物职业技术学院学报》2002,8(1):58-60
本文阐述了高等学校实行物资竞标采购制度的必要性,概述了物资竞标采购过程中必须遵循的原则,介绍了物资竞标采购的基本程序,同时对改进物资竞标工作提出了两点问题.对改进高等学校及事业单位的物资采购工作有一定的 启示和借鉴意义. 相似文献
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