应用量子化学参数预测多氯有机物的分配性质

应用量子化学AM1算法求得多氯有机物的量化参数，以此来构建定量结构－性质相关（QSPR）模型。该模型能较好地预测多氯有机物的正辛醇／水分配系数（Kow)和沉积物吸附系数（Koc).Kow和Koc平均误差分别为0．31和0．33个对数单位。模型的稳健性检验结果表明：模型中自变量不存在相关关系；残差呈正态分布；对Koc来说，PCB和PCDD／F在构建模型中起核心作用，剔除该类化合物导致模型相关系数明显下降，农药类及氯硝基苯类化合物的存在降低了模型的精度。     

黄河水体沉积物对水胺硫磷和辛硫磷的吸附

以黄河水及沉积物为研究对象 ,探讨了有机磷农药水胺硫磷和辛硫磷在黄河水体中的迁移规律 ,同时还研究了 pH值和离子强度等因素对迁移规律的影响。结果表明 ,沉积物对水胺硫磷和辛硫磷均有一定程度的吸附 ,且对辛硫磷的吸附量大于水胺硫磷 ,即辛硫磷在黄河水体中的迁移性小于水胺硫磷 ;其吸附等温线呈线性 ,是分配作用的结果。降低pH值和增加离子强度均使沉积物对水胺硫磷和辛硫磷吸附量减小。     

小清河水中沉积物与铅离子吸附等温线的研究

运用界面分极离子/配位子交换原理和方法研究了小清河水中沉积物对Pb^2 的交换吸附等温线以及赖氨酸对吸附作用的影响。研究结果得出等温线具有1个“拐点”2个“平台”。用分级离子交换等温式求出平衡常数k1和k2,当低浓度的氨基酸存在时,对铅与沉积物的交换吸附起促进作用。     

Behavior of the herbicide dimepiperate with homoionic clays in aqueous solution

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Characteristics of the natural organic matter sorption affects of organic contaminants

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阳离子改型蛭石的铵离子交换平衡特性

对经Na^＋，Ca^2＋、Mg^2＋等不同离子处理的改型蛭石在不同pH和温度条件下进行了铵离子交换性能的研究。结果表明，交换反应均在前60min速率最快，约120min就趋向于平衡：铵离子交换总量均随pH变化而波动，在pH=7点上取最大值，且全交换容量按镁型蛭石、钙型蛭石，钠型蛭石顺序依次增大，每100g蛭石分别为59.32，71.89、92.85mmol；改型蛭石对NH^＋4等温交换吸附与Langmuir方程相符。表明改型蛭石对NH^＋4的吸附主要是单分子层的化学吸附。     

模拟酸化下水稻土微团聚体Cu2+吸附与解吸的影响

采用低能量超声波分散和冷冻机干燥法提取太湖地区水稻土(黄泥土)微团聚体颗粒,用平衡液吸附法和CaCl2与HCl溶液的连续解吸法研究了它们在pH2～6范围内pH对Cu2 的静电吸附和专性吸附的影响。结果表明,不同粒径的微团聚体颗粒对Cu2 的吸附等温线可都用Freundlich模型来描述。Cu2 吸附量大小以下序递减,粘粒级、砂粒级、粉砂级、粗粉砂级;吸附量受其中游离氧化铁、氧化铝和有机质含量的控制。吸附量随pH升高而增加。低pH条件下利于静电吸附,吸附过程H 减少使平衡液pH上升;高pH条件下主要是专性吸附所控制,释放H 使平衡液pH下降。     

活性炭纤维对定型机油烟废气吸附性能研究

采用动态吸附实验装置研究了粘胶基活性碳纤维的耐温性能以及预处理、采样流速、进气浓度对粘胶基活性碳纤维吸附定型机油烟废气平衡吸附量的影响,实验结果表明粘胶基活性碳纤维耐温性能良好,同时经去离子水煮沸2小时的粘胶基活性碳纤维平衡吸附量最大,采样流速增大平衡吸附量减少,但吸附速率变大,采用一级动力学模型较好地反映了吸附过程,Langmuir、Freundlich方程适合拟合低浓度下的吸附等温线,DR方程则较吻合高浓度下的吸附。     

黄河包头段不同粒径沉积物分形校正下重金属的吸附研究

推导了分粒级的表面分形维数计算公式,根据推导公式计算了分粒级沉积物的分维值.应用已有的表面分形分维计算公式分别计算了黄河包头段沉积物整体的表面分形分维(1.91)及＜63 μm粒级的分维值(1.36),揭示出黄河水环境的磨蚀和分选2个原因引起黄河包头段沉积物低的分维值.用分形校正吸附模型、Freundlich和Langmuir吸附模型对黄河包头段重金属分粒级沉积物吸附进行了拟合,表明分形校正吸附模型具有较好的适用性,同时揭示分形校正吸附模型与MEA理论结合能更好的对热力学吸附结果进行描述;由吸附结果分析得出4种重金属因粒径引起的吸附量变化程度序列为Cu＞Pb＞Zn≈Cd,初始浓度高的吸附量曲线变化较初始浓度低的曲线变化明显,同时指出Cu、Pb的吸附主要与矿物组成有关,而Zn、Cd的吸附则与吸附剂沉积物空间几何性质(或沉积物表面物理特征)有关.     

Effects of lipids on the sorption of hydrophobic organic compounds on geosorbents: a case study using phenanthrene

The impact of the lipid fraction of natural geosorbents on the sorption of a polycyclic aromatic hydrocarbon was assessed using several experiments. In the first set of experiments phenanthrene was sorbed on a coastal sediment as well as on its humin and humic acid fractions before and after lipid extraction. Before lipid extraction, sorption shows dominantly partitioning characteristics. However, the extraction of lipids from sediment and humin drastically increases, by up to one order of magnitude, their sorption affinity for phenanthrene at low sorbate concentrations, resulting in increased isotherm nonlinearity. This effect is less pronounced for humic acids. One mechanism proposed for the increasing sorption is that lipids, despite their very low relative abundance in the sediments, can compete with phenanthrene for specific high affinity sorption sites (e.g., matrix pores and adsorption sites). This competition is not surprising considering the similar hydrophobic nature of lipids and phenanthrene. Lipids, or any non-polar molecules, could also act like plasticizers by swelling rigid domains and disrupting high affinity sites. In both cases, the removal of lipids (and extraction solvents) makes those sites available for phenanthrene. These provide alternative explanations to the previously proposed “solvent conditioning effect” believed to occur when geosorbents are treated with non-polar solvents modifying the matrix structure, an effect yet to be proven at molecular scale. To further investigate the impact of lipids on sorption, other independent experiments were performed. In a second experiment, re-addition of lipids to the extracted sediment restored the sorption isotherm linearity observed in the native material supporting the absence of irreversible extraction artifacts. However, high addition of lipids (i.e., after saturation of high affinity sites) seems to also enlarge the low affinity partitioning domain. These results are consistent with dual-mode, hole-filling, sorption models involving diffusion. In the final set of experiments, solid-state ¹⁹F-NMR using F-labeled lipids sorbed onto the sediments confirmed that lipids may be in different domains (mobile or rigid) that interact or not with phenanthrene. The possible effects of lipid removal on sorption have been overlooked and should be considered when geosorbents are pretreated.