The formation of a new horseradish peroxidase binding rare earth

The charge distribution, the isolation, purification, and characterization of horseradish peroxidase (HRP) were investigated. A new HRP protein binding La (La-HRP) was found for the first time in vivo. The molecular weight of the La-HRP protein is about 43,833 Da. The activity index (Rz) of the La-HRP protein (Rz = 2.4) is lower than that of HRP (Rz = 3.1). The La-HRP protein is absorbed in the plasma membrane of the plant and animal, leading to the change in the function of the cell membrane. Therefore, the La-HRP protein is harmful to living organisms.     

Characterization, dissolution and solubility of synthetic svabite [Ca5(AsO4)3F] at 25�C45��C

Svabite is a secondary arsenate mineral, calcium fluoride arsenate [Ca₅(AsO₄)₃F], in the apatite group of phosphates. Its dissolution and subsequent release of aqueous species play an important role in the cycling of arsenic and fluoride in the environment, but the thermodynamic and kinetic properties of svabite dissolution have never been investigated. In the present study, svabite was prepared by precipitation and characterized by various techniques, and then dissolution of synthetic svabite was studied at 25, 35 and 45°C in a series of batch experiments. In addition, the aqueous concentrations from the batch dissolution were used to calculate the solubility product and free energy of formation of svabite. The results of the X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy analyses indicated that the synthetic, microcrystalline svabite with apatite structure used in the experiments has not changed after dissolution. For the dissolution of svabite [Ca₅(AsO₄)₃F] in ultrapure water, F⁻ ions were initially found to dissolve preferentially when compared with calcium and arsenate. Preferential dissolution of arsenate when compared with that of calcium was also observed. Dissolution of svabite in aqueous medium appeared to be always non-stoichiometric at the beginning, but when a dissolution equilibrium or steady state was reached at 25 and 35°C, the solid dissolved almost stoichiometrically. The release of calcium, arsenic and fluoride to solution increased with decreasing temperature. The mean K _sp value was calculated for Ca₅(AsO₄)₃F of 10^−39.21 (10^−39.18 ~ 10^−39.24) at 25°C; the free energy of formation ΔG _f ^o [Ca₅(AsO₄)₃F] was −5210.46 kJ/mol.     

Application of continuous time random walk theory to nonequilibrium transport in soil

Continuous time random walk (CTRW) formulations have been demonstrated to provide a general and effective approach that quantifies the behavior of solute transport in heterogeneous media in field, laboratory, and numerical experiments. In this paper we first apply the CTRW approach to describe the sorbing solute transport in soils under chemical (or) and physical nonequilibrium conditions by curve-fitting. Results show that the theoretical solutions are in a good agreement with the experimental measurements. In case that CTRW parameters cannot be determined directly or easily, an alternative method is then proposed for estimating such parameters independently of the breakthrough curve data to be simulated. We conduct numerical experiments with artificial data sets generated by the HYDRUS-1D model for a wide range of pore water velocities (υ) and retardation factors (R) to investigate the relationship between CTRW parameters for a sorbing solute and these two quantities (υ, R) that can be directly measured in independent experiments. A series of best-fitting regression equations are then developed from the artificial data sets, which can be easily used as an estimation or prediction model to assess the transport of sorbing solutes under steady flow conditions through soil. Several literature data sets of pesticides are used to validate these relationships. The results show reasonable performance in most cases, thus indicating that our method could provide an alternative way to effectively predict sorbing solute transport in soils. While the regression relationships presented are obtained under certain flow and sorption conditions, the methodology of our study is general and may be extended to predict solute transport in soils under different flow and sorption conditions.     

影响灾后恢复期的因素分析——基于水灾灾民的调查

恢复力作为减灾建设的重要环节,探讨其影响因素,有助于提升承灾体适应变化及异常的能力.以恢复期为恢复性的刻画指标,通过问卷调查了539例灾民的水灾恢复期的主观识觉,运用列联表分析灾民受灾经历、个体属性与恢复期长短的关系.结果表明:灾后精神恢复期为5个月,物质恢复期约7.4个月;灾时心理越镇静精神恢复期越短,灾害损失越严重物质恢复期越长,而灾后救援没有发挥出明显改变恢复期的作用;个体属性中的家庭结构、受教育水平、收入水平等与恢复期没有明显相关.因此,拓展灾民可获救援渠道及能力,开展保险,有助于提升恢复力.     

中孔硅胶负载过氧乙酸深度脱除柴油硫化物

采用滴定吸附法将过氧乙酸组装于中孔硅胶中,通过红外光谱分析和N2吸附法对组装体进行了表征,研究了常温常压下,该组装体氧化、吸附、脱除柴油硫化物的活性.结果表明,该组装体具有优良的脱硫性能.柴油中硫化物与过氧乙酸在硅胶孔中发生氧化反应,氧化产物被吸附在硅胶上,使柴油的含硫量从1697μg/g降到14μg/g,符合美国环境保护署标准.     

棘孢曲霉（Aspergillus aculeatus）对Pb2＋和Cd2＋的吸附特征

为了研究棘孢曲霉（Aspergillus aculeatus）对溶液中Pb^2＋和Cd^2＋吸附过程的特征,分别从动力学、热力学和吸附等温线三方面进行了实验,同时还研究了pH、温度、时间、重金属离子起始浓度和吸附剂用量对吸附过程的影响。等温吸附过程可以用Langmuir方程来描述。在实验设定条件下,棘孢曲霉对Pb^2＋和Cd^2＋最大吸附量分别为71.2 mg/g和59.8 mg/g;动力学实验数据很好的符合二级     

废弃印刷线路板最佳分离参数的实验研究

为研究废弃印刷线路板的热解特性,确定金属和非金属分离的热解最佳参数,用差热-热重联用分析仪对FR-4型印刷线路板进行了热失重分析,并对影响废弃印刷线路板中金属和非金属分离效果的升温速率、颗粒尺寸、热解终温和保温时间等主要因素进行了实验研究。结果表明,FR-4型线路板在320~360℃区间热失重速率达到最大值;升温速率越高,热解起始温度、终止温度和失重峰温也越高,显著失重过程持续的时间越长;当热解终温相同时,升温速率对FR-4型线路板的热失重率影响很小。综合考虑FR-4型废弃印刷线路板中金属和非金属的分离效果、热解装置的设计、热解过程的能耗以及运行过程的控制等因素,最佳热解参数建议设定为升温速率为10℃/min,热解终温为500℃,保温时间取30 min为宜。     

铬(Ⅵ)-碘化钾-甲基紫-聚乙烯醇体系分光光度法测定废水中痕量铬

研究了铬(Ⅵ)-碘化钾-甲基紫-聚乙烯醇高灵敏显色体系测定铬(Ⅵ)的新方法。实验结果表明:在最大吸收波长540 nm处,铬(Ⅵ)质量浓度在0～0.8 mg/L范围内符合朗伯-比耳定律,表观摩尔吸光系数为6.59×10~4L/(mol·cm);采用该法测定铬(Ⅵ)标准试样与镀铬废水,测定结果与国家标准分析方法的结果相吻合,加标回收率为94.0%～103.0%;测定11次0.4 mg/L铬(Ⅵ),相对标准偏差为2.1%。     

油区盐碱土的治理研究

新疆油田公司油区地表土壤多为盐碱土。企业结合自身实际生产,采取多种措施,先后进行了油区绿化和清洁生产,并种植红柳,拉运戈壁土进行铺垫,提高员工环保意识。经过治理,站区内外扬尘明显减少,油区浮土明显减弱。2008年底企业通过油田公司的考核验收。     

Heavy metals in coastal wetland sediments of the Pearl River Estuary, China

Sediment quality in coastal wetlands of the Pearl River Estuary was concerned since the wetlands were used for land reclamation, aquaculture and wildlife protection, and meanwhile served as one of the main ultimate sinks for large amount of heavy metals discharged from the rapidly developing Pearl River Delta. Total concentrations of heavy metal, such as Zn, Ni, Cr, Cu, Pb, and Cd, and their chemical speciation were investigated. Results showed that the sediments were significantly contaminated by Cd, Zn and Ni with concentration ranges of 2.79-4.65, 239.4-345.7 and 24.8-122.1mg/kg, respectively. A major portion (34.6-46.8%) of Pb, Cd, and Zn was strongly associated with exchangeable fractions, while Cu, Ni and Cr were predominantly associated with organic fractions, residual, and Fe-Mn oxide. Cd and Zn would be the main potential risk and the sediment quality is no longer meeting the demand of the current wetland utilization strategies.