零价铁（ZVI）去除Cu2+的特性及机制研究

研究了零价铁去除水溶液中铜离子的影响因素及动力学特性,并利用X射线衍射(XRD)分析对反应机制进行了探讨.结果表明,当溶液中Cu2+的浓度为300 mg/L,零价铁的用量为1 g/L时,Cu2+的去除率99%.Cu2+的去除速度很快,且反应前30min零价铁去除Cu2+的过程可以用一级反应动力学方程模拟.零价铁去除Cu2+的机制主要基于氧化还原反应,Cu2+的还原产物主要为Cu和Cu2O.     

不同环境条件下黑土对四溴双酚A的吸附动力学特征

采集吉林省松源农田的黑土样品,研究四溴双酚A在黑土中的吸附动力学特征,并探讨了pH值、离子强度(CaCl_2)、温度等不同环境条件对吸附动力学的影响。结果表明,四溴双酚A在黑土中的吸附过程可以分为快速吸附阶段(0~4 h)和慢速吸附阶段(4~48h),并于48 h达到吸附平衡。黑土对四溴双酚A的吸附符合拉格朗日准二级动力学方程和内扩散模型,表明该吸附过程以化学吸附为主,而吸附过程的限速步骤为颗粒间扩散。pH值等环境条件对吸附有明显影响,当pH值在6~9时,随pH值降低,黑土对四溴双酚A的吸附速率加快且平衡吸附量增加;离子强度(CaCl_2)为0.001 mol/L、0.01 mol/L、0.1 mol/L时,离子强度增大,黑土对四溴双酚A的吸附速率加快但平衡吸附量减小;温度为15℃、25℃、35℃时,随着温度升高,黑土对四溴双酚A的吸附速率加快且平衡吸附量增加。     

氯菊酯在不同质地土壤中的光降解动力学规律

为了研究氯菊酯在土壤中的光降解规律,更好地为其在自然环境中的降解提供理论依据,探讨了氯菊酯在不同质地土壤中,不同条件下的光降解动力学规律。结果表明:氯菊酯降解符合准一级动力学规律,氯菊酯的降解受土壤质地的影响较大,在不同土壤中降解率为:壤质砂土砂质壤土壤质黏土,日光比紫外光照射下腐殖酸对氯菊酯的降解影响明显,随着腐殖酸浓度的增加,它对氯菊酯的降解作用先促进后抑制。     

Kinetic study of phytotoxicity induced by foliar lead uptake for vegetables exposed to fine particles and implications for sustainable urban agriculture

At the global scale, foliar metal transfer occurs for consumed vegetables cultivated in numerous urban or industrial areas with a polluted atmosphere. However, the kinetics of metal uptake, translocation and involved phytotoxicity was never jointly studied with vegetables exposed to micronic and sub-micronic particles (PM). Different leafy vegetables (lettuces and cabbages) cultivated in RHIZOtest® devices were, therefore, exposed in a greenhouse for 5, 10 and 15 days to various PbO PM doses. The kinetics of transfer and phytotoxicity was assessed in relation to lead concentration and exposure duration. A significant Pb accumulation in leaves (up to 7392 mg/kg dry weight (DW) in lettuce) with translocation to roots was observed. Lead foliar exposure resulted in significant phytotoxicity, lipid composition change, a decrease of plant shoot growth (up to 68.2% in lettuce) and net photosynthesis (up to 58% in lettuce). The phytotoxicity results indicated plant adaptation to Pb and a higher sensitivity of lettuce in comparison with cabbage. Air quality needs, therefore, to be considered for the health and quality of vegetables grown in polluted areas, such as certain megacities (in China, Pakistan, Europe, etc.) and furthermore, to assess the health risks associated with their consumption.     

Using a novel adsorbent macrocyclic compound cucurbit[8]uril for Pb removal from aqueous solution

In this study, cucurbit[8]uril (CB[8]) was utilized as a kind of new adsorbent to remove Pb^2 + ions from aqueous solution. With the solution pH increased from 2 to 6, the removal efficiency of adsorption increased from 55.6% to 74.5%correspondingly. The uptake of Pb^2 + increased rapidly in the initial 30 min, and then the adsorption rate became slower. The Pseudo-second order model could be used to interpret the adsorption kinetics satisfactorily; and the rate determining step in Pb^2 + adsorption onto CB[8] was the external mass transfer step. Equilibrium isotherm study reveals that the Langmuir model gave a better fitting result than Freundlich model. The maximum adsorption capacity calculated by the Langmuir model was 152.67 mg/g for 298 K, 149.70 mg/g for 313 K and 136.42 mg/g for 323 K, respectively. The adsorption is a spontaneous process of exothermic nature. The effect of the adsorbent dosage and the influences of solution pH and co-existing cations were also investigated. The CB[8] was synthesized and characterized by ¹H NMR, IR, ESI-MS spectra, SEM-EDAX, Zeta-potential and BET-analysis. The adsorption mechanism was due to the coordination between CB[8] molecule and Pb^2 + ions.     

超声辅助生物淋滤废旧Zn-C电池锌锰溶出的研究

以氧化硫硫杆菌(A.thiooxidans)为淋滤菌株对废旧Zn-C电池电极材料中的Zn、Mn进行了生物浸提,比较研究了化学浸提、生物淋滤和不同超声辅助方法生物淋滤体系下的Zn、Mn的溶出效率及溶出动力学.结果表明:不同超声辅助方法中,超声+生物淋滤体系Zn、Mn溶出最优,Zn、Mn的最大溶出率分别为94.2%和65.5%,并提高了溶释速率.此外,对于Mn的溶出,化学淋滤体系符合边界层扩散控制模型,生物淋滤和超声+生物淋滤体系符合收缩核Stoke's regime模型,而Zn的溶出均符合化学反应控制模型.     

稻壳沸石的合成及其对磷酸盐的吸附/脱附动力学

以稻壳为原料采用煅烧-水热合成法制备了合成沸石,运用XRD和SEM表征了合成沸石的特性,通过静态实验,研究了合成沸石对磷酸盐的吸附和脱附机理。结果表明:12 h后产物发现了Na P沸石的特征峰和亚晶结构,延长水热合成晶化的时间有利于沸石晶核的形成。沸石对磷酸盐的吸附机理符合伪二级模型,实测值与伪二级吸附动力学模型的拟合值相差在1.1%以内。颗粒内扩散速率是由膜扩散和内扩散共同控制,颗粒内扩散速率常数kp随初始浓度的增加而减小。升温有利于磷酸盐的脱附,MNa OH/P>8.0时(MNa OH/P为Na OH物质的量与吸附的磷酸盐物质的量之比),磷酸盐的脱附率可达82.9%。伪二级脱附动力学模型的拟合结果优于伪一级,拟合值与实测值相差在1.7%以内。     

灭幼脲(Ⅲ)在模拟大气条件下光解动力学的初步研究

本文初步研究灭幼脲(Ⅲ)在模拟大气条件下的光化学行为,测定定在不同气体气流环境中灭幼脲(Ⅲ)的反应速率。结果表明,灭幼脲(Ⅲ)在氮气及空气中的光解反应表现为动力学一级形式,而在氧气中则近似为二级反应。     

序列间歇式活性污泥法处理毛纺厂废水的研究

采用序列间歇式活性污泥法处理毛纺厂废水。试验结果表明,经4h曝气处理,进水COD为190～650mg/L时,出水COD始终低于100mg/L,去除率大多在80％～90％之间,色度去除率大多在50％以上,出水COD和色度均达到行业排放标准。还对较低COD浓度下序列间歇式活性污泥法的COD降解过程进行了研究,推导出一级反应动力学关系式Sr＝So（1－10￣^-k1^t）,并以试验数据进行了拟合,求解出动力学常数k1和So。     

The kinetics of reductive dehalogenation of a set of halogenated aliphatic hydrocarbons in anaerobic sediment slurries

Disappearance rate constants are reported for the reductive transformation of 17 halogenated aliphatic hydrocarbons in anaerobic sediment-water samples. Statistical experimental design in combination with multivariate chemical characterization of their chemical properties was used to select the compounds. Degradation followed pseudo first-order kinetics through at least two half-lives for 15 of the 17 compounds. Of all the compounds investigated, 1,2,3-trichloropropane and dichloromethane were unique in that they were dehalogenated according to zero-order kinetics. Reductive dehalogenation was the sole transformation reaction taking place.