Performances of biological aerated filter employing hollow fiber membrane segments of surface-improved poly （sulfone） as biofilm carriers

Using the surface of poly （sulfone） hollow fiber membrane segments as grafted layer, the hydrophilic acrylamide chain was grafted on by UV-photoinduced grafting polymerization. The gained improvement of surface wettability for the modified membrane was tested by measuring the contact-angle as well as FTIR spectra. Then correlation between the hydrophilic ability of support material and the biofilm adherence ability was demonstrated by comparing the pollutant removal rates from urban wastewater via two identical lab-scale up-flow biological aerated filters, one employed the surface wettability modified poly （sulfone） hollow fiber membrane segment as biofilm carder and the other employed unmodified membrane segment as biofilm carder. The experimental results showed that under the conditions of influent flux 5 L/h, hydraulic retention time 9 h and gas to liquid ratio （G/L） 10： 1, the removal rates of chemical oxygen demand （COD） and ammonium nitrogen （NH4^＋-N） for the modified packing filter and the unmodified packing filter was averaged at 83.64% and 96.25%, respectively, with the former filter being 5%-20% more than the latter. The effluent concentration of COD, NH4^＋-N and turbidity for the modified packing filter was 25.25 mg/L, 2 mg/L and 8 NTU, respectively. Moreover, the ammonium nitrogen removal performance of the filter packing the modified PSF was compared with the other bioreactor packing of an efficient floating medium. The biomass test indicated that the modified membrane matrixes provided better specific adhesion （3310-5653 mg TSS/L support）, which gave a mean of 1000 mg TSS/L more than the unmodified membrane did. In addition, the phenomenon of simultaneous denitrification on the inner surface of the support and nitrification on the outer surface was found in this work.     

Di（2-ethylhexyl）phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater

Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconutoil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 × 10-9 to 8.9 × 10-9 mol/(m2·s) within the Cu(II) concentration range 7.8×10-4-78.6×10-4 mol/L at pH of 4.0 in the feed and 12.4 × 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10-9 mol/(m2·s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10-4 mol/L D2EHPA (membrane) in 0.5 (m pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II). rane. It     

Improved VOC bioremediation using a fluidized bed peat bioreactor

A gas–solid fluidized bed bioreactor was successfully used to treat air contaminated with a volatile organic compound (VOC). A bioreactor containing both a fluidized and packed bed of moist peat granules removed ethanol, a representative VOC, from an air stream. The fluidized bed operation mode of the bioreactor outperformed the packed bed mode. The maximum elimination capacity (EC) of ethanol in the fluidized mode was 1520 g m⁻³ h⁻¹, with removal efficiencies ranging between 45 and 100%, at loadings up to 3400 g m⁻³ h⁻¹. Maximum EC was 530 g m⁻³ h⁻¹ in the packed bed mode. Removal efficiency in the fluidized bioreactor was best at the lowest velocity, where the bubbling bed fluidization regime predominated. As gas velocity increased, the size and amount of large bubbles (slugs) increased and removal efficiency decreased while elimination capacity increased.     

矿难救生球系统在瓦斯爆炸冲击波作用下的动态响应

介绍矿难救生球系统(简称球)的原理及结构,构建巷道空间和球的分析模型,运用数值分析的方法,分别选择3种球体材料和3种球体厚度进行计算,对该系统在瓦斯爆炸冲击波作用下的动态响应进行研讨,分析冲击波作用下球表面的变形、等效应力、等效塑性应变以及球体材料、厚度等因素对球动态响应的影响。结果表明:运用数值分析的方法,可以为救生球系统设计建立一个仿真的实验环境,为优化系统设计、提高设计效率提供参考数据。     

非稳态微生物污染物在建筑群内迁移的数值模拟

随着城市化进程的加快和城市中心人口密度的激增,微生物污染问题成为人们关注的热点.本文利用病毒群体动力学演化模型研究非稳态微生物污染的产生过程,并将模型结果作为非稳态污染源的源强引入污染物对流扩散方程.假设没有继发性感染,研究致病性微生物污染源对建筑群环境的影响,得到了建筑群表面及周围污染物浓度随时间的变化规律.假定致病感染浓度,得到了微生物污染源的影响范围,这为控制污染物扩散和建立致病微生物污染预警系统提供了理论指导.     

用硅橡胶平板复合膜分离苯酚时总传质系数的影响因素

用硅橡胶平板复合膜处理高浓度含酚废水,测定了体系的总传质系数（Kov）,分析了温度、盐离子强度、跨膜压差（△p）、膜厚度对Kov的影响。实验结果表明：Kov随温度的升高而呈线性增加,传质通量与温度的关系符合Arrhenius方程;当△p〈0．1MPa时,Kov与压力无关;当△p〉0．1MPa时,压差升高可提高传质系数,但会导致膜的致密化;离子强度改变了苯酚在相间的分配系数,进而影响传质过程;膜厚度降低能有效提高膜的Kov;在膜活性皮层厚度4μm、pH12．5～13．0、温度323．15K、废水流量1205mL／min、废水中苯酚质量浓度7．78g/L、无压差和离子强度的条件下,运行8h后,Kov为16．1×10^-7m／s。     

液膜法处理硫普罗宁废水的研究

采用W／O型乳状液膜法提取水溶液中的硫普罗宁,考察了载体、温度、硫普罗宁浓度以及油内比、试剂比、乳水比对提取率的影响,并得出了液膜法提取硫普罗宁的最佳乳液配方：油内比＝1：1,乳水比＝1：2,试剂比＝6－8,载体浓度＝5％,温度20℃,转速＝240－250r.min^-1,其提取率高达90％。     

鼎湖山主要森林类型土壤pH值动态变化

鼎湖山主要森林类型土壤pH值都较低,但从1994年以来土壤酸化都得到了控制,pH值比较稳定。针叶林土壤pH值比混交林高,季风常绿阔叶林pH值最低。     

镧施用下黄潮土酶活性的动态变化

通过模拟试验研究了镧施用下黄潮土酶活性的动态变化。土壤脱氢酶、碱性磷酸酶、脲酶及蔗糖酶活性均随培养时间延长而降低。镧强烈抑制土壤脱氢酶活性 ,在 3 0mg/kg时达到显著水平 (P <0 0 5 ) ,最大抑制率达到 3 9%。镧对土壤碱性磷酸酶活性也有抑制 ,最大抑制率为 1 5 %。镧对土壤脲酶活性影响不明显。镧对土壤蔗糖酶活性表现出不同程度的刺激作用 ,最大刺激率达到 1 5 %。土壤脱氢酶活性是评价稀土元素环境效应的敏感指标。     

地震次生火灾动态危险性分析方法研究

提出了一个城市地震次生火灾动态危险性分析与预估的一般模型。根据地震次生火灾发生具有离散性和随机性的特点,采用泊松过程模型作为地震次生火灾发生的初始估计模型。在此基础上,按照时、场域分离的原则和贝叶斯估计原理,发展了地震次生火灾动态危险性分析与模型,建议了动态危险性分析方法,经实例验证,本文所建议的模型与方法是合理可信的。