土壤腐殖酸SDS-凝胶分级及表观分子量的测定

用SDS-凝胶电泳技术对落叶林土壤提取出的腐殖酸进行分级,并应用凝胶层析分析技术测定腐殖酸各组分的连续分布特征及表观分子量,分子量分别为M=77678,M=49923,M=32085和M=16531.结果表明凝胶电泳和凝胶层析这两种技术可以相互补充,能更好地了解腐殖酸类大分子物质分子量的分布情况.     

太湖地区几种水稻土团聚体颗粒组中PAHs的分布及其环境意义

以太湖地区代表性的青紫泥、黄泥土、白土等3种水稻土为研究对象,采用低能量分离-分散法提取得到不同粒径的团聚体颗粒组,用HPLC测定了本土和分离得到的团聚体颗粒组中16种PAHs的含量.结果表明,供试水稻土不同粒径的团聚体颗粒组中PAHs含量分布存在差异,PAHs总含量以＜2μm粒径的团聚体颗粒组最高,其次是200～2000μm粒径的团聚体颗粒组,PAHs在这2个团聚体颗粒组有明显富集现象(富集系数为1.25～3.92);而20～200μm和2～20 μm粒径的团聚体颗粒组中PAHs含量小于本土,呈现亏缺现象(富集系数为0.64～0.88).考虑到不同粒径团聚体颗粒组的相对组成,水稻土中PAHs主要分布于20～200μm和200～2000μm 2个团聚体颗粒组中,而在＜2μm粒径的团聚体颗粒组中最少.PAHs在不同粒径的团聚体颗粒组中的含量分布与其总有机碳、腐殖质碳、胡敏酸碳的含量有关,并在很大程度上受芳构化疏水性有机物含量的控制.因此,水稻土不同粒径团聚体颗粒中有机碳及其组分的性质影响着这些团聚体颗粒组分对PAHs的吸持与固定.     

甲磺隆在土壤腐殖物质中结合残留的动态变化

土壤中14 C 甲磺隆的可提取态残留物随时间延长不断降低 ,而其结合态残留率第 2 8天达最高 .14 C 甲磺隆结合态残留物在土壤腐殖物质中的分布是 :富啡酸 胡敏素 >胡敏酸 .在处理最初 2 8天 ,富啡酸中14 C 甲磺隆结合态残留物不断增大 ,随后减少 ;胡敏素中的结合态残留量在 2 8— 2 2 4天变化不大 .14 C残留物在不同土壤之间的结合及其分布都是有差异的 ,与土壤pH值、粘粒矿物类型等都有密切关系     

Fabrication of Bi-Bi3O4Cl plasmon photocatalysts for removal of aqueous emerging contaminants under visible light

Photocatalytic oxidation of emerging contaminants (ECs) in water has recently gained extensive attentions. In this study, bismuth oxychloride-based plasmon photocatalysts (Bi-Bi₃O₄Cl) exhibiting high performance were successfully developed by reducing Bi³⁺ on the surface of Bi₃O₄Cl. Consequently, the photocatalysts were used to remove ECs from water. The effects of developmental process and Bi metal plasmon resonance on the photoelectric performances of Bi-Bi₃O₄Cl were investigated through a series of characterizations. The UV-vis diffuse reflection and photoluminescence spectra revealed that the light absorption range of the photocatalyst gradually increased and the electron recombination rate gradually decreased with the introduction of Bi metals. The optimal removal rates of ciprofloxacin and tetrabromobisphenol A by Bi-Bi₃O₄Cl were 93.8% and 96.4%; the respective reaction rate constants were 5.48 and 4.93 times higher than that of Bi₃O₄Cl. The mechanism study indicated that main reactants in the photocatalytic system were •O₂⁻ radicals and photogenerated holes, and the existence of oxygen vacancies and Bi metals promoted electron transfer in photocatalyst. In conclusion, this research produces a novel, green, highly efficient, and stable visible light photocatalyst for the removal of ECs from water.