Effects of fluoride on the removal of cadmium and phosphate by aluminum coagulation

This study focuses on the effects of p H and fluoride at different molar ratios of fluoride to Al(R F:Al) on the removal of cadmium(Cd~(2+)) and phosphate by Al coagulation. Fluoride at R F:Al≥ 3:1 inhibits the removal of Cd over wide Al dose ranges from 5 to 10 mg/L as Al. The removal of phosphate decreases significantly at high R F:Al of 10:1 whereas at lowered R F:Al(i.e., ≤ 6:1), an adverse effect is observed only at insufficient Al doses below 2 mg/L. Fluoride shows inhibitive effects towards the removal of Cd at p H 7 and 8 and that of phosphate at p H 6. Fluoride decreases the ζ-potential in both systems, and the decreasing extent is positively correlated to the elevated R F:Al. The Al fluoride interactions include the formation of Al–F complexes and the adsorption of fluoride onto Al(OH)_3 precipitates, i.e., the formation of Al(OH)n F m. Al–F complex formation inhibits Al hydrolysis and increases residual Al levels, and a more significant increase was observed at lower p H. Al–F complexes at high R F:Al complicate the coagulation behavior of Al towards both negative and positive ionic species. Moreover, fluoride at low R F:Al shows little effect on Al coagulation behavior towards Cd~(2+)and phosphate, and the spent defluoridation adsorbent,i.e., aluminum(Al) hydro(oxide) with adsorbed fluoride at R F:Al of below 0.1:1, may be reclaimed as a coagulant after being dissolved.     

污水中溶解游离氨基酸和结合氨基酸测定方法研究

采用邻苯二甲醛作为柱前衍生化试剂，结合反相高效液相色谱，对污水中溶解游离氨基酸（dissolvedfreeami．nOacid，DFAA）进行定性和定量分析，探讨了污水样品有无前处理对DFAA分析的影响，并采用气相酸水解方法对污水中总溶解氨基酸（dissolvedtotalaminoacid，DTAA）进行了分析。结果表明，污水经过pH调节和N，流清洗后，可以明显去除氨和挥发性胺的干扰，色谱峰更加清晰；前处理后的水样经RP—HPLC分析，能够快速检测出14种氨基酸，各氨基酸在一定线性范围内呈现良好的线性关系，相应的线性相关系数（R^2）均大于0．99，加标回收率为92％～102％。污水处理厂进水和出水中氨基酸主要以溶解结合氨基酸（dissolvedcombinedaminoacid，DCAA）为主，与进水相比，出水中DFAA含量减少了0．22μmol／L，DTAA由5．68μmol／L降至3．08μmol／L。     

不同垃圾渗滤液组合处理工艺中DOM的变化特征

为了快速表征垃圾渗滤液处理过程中有机物的特性变化,分别采用紫外光谱和三维荧光光谱对2种垃圾渗滤液处理工艺不同单元溶解性有机物(DOM)的变化进行了系统分析。结果表明,二级RO和厌氧+好氧+MBR+NF+RO工艺对渗滤液COD和NH3-N的去除率分别为98.7%、99.0%和98.8%、98.6%。随着处理过程的进行,2个处理工艺中DOM的SUVA254、E253/E203分别由0.74、0.33和0.46、0.12下降至0.015、0.014和0.010、0.012,有机物的芳香性和不饱和性下降,脂肪链芳香烃化合物开始增加。不同处理阶段渗透液DOM三维荧光光谱表明,随着处理过程的进行,类富里酸和类蛋白物质的含量逐渐下降,芳构化程度开始降低。其中二级RO系统对渗滤液中类富里酸物质的去除效果较好,而厌氧-好氧-MBR-NF-RO工艺中,类酪氨酸物质主要通过微生物降解去除,NF和RO膜对类富里酸和类腐殖酸物质的截留效果较好。     

角联风路的自动识别

分析风路的稳定性，是保障矿井安全的基础，而角联风路的识别是分析风路稳定性的基础，本文论述了角联风路的自动识别的数学模型以及在解决矿井安全方面的应用问题，用此自动识别的数学模型及其实用方法对辽宁铁法矿务局大明一矿的角联风路进行判别。     

天津市环境空气质量监测点位优化技术

概述了城市建成区面积扩大后，环境空气质量监测点位增设优化技术，本技术应用于天津市位点位优化工作，取得了较好的应用效果。     

低浓度有机磷萃取剂P204促进普通小球藻(Chlore11a vulgaris)生长的研究

本文以普通小球藻为实验对象,研究了有机磷萃取剂P204在低浓度（相似文献   

腐殖酸与钙离子共存下ZVI界面沉积过程

为精准分析环境介质在零价铁（ZVI）界面沉积过程和沉积层特性，采用喷涂方法制备ZVI负载芯片，应用耗散式石英晶体微天平（QCMD）研究了腐殖酸（HA）与钙离子（Ca（Ⅱ））在ZVI界面沉积吸附过程的差异，并探讨了Ca（Ⅱ）浓度与HA/Ca（Ⅱ）投加顺序对沉积过程的影响机理.结果表明，在反应体系中先通入HA相较先通入Ca（Ⅱ），ZVI表面形成的沉积层质量更高、沉积层结构更稳定；HA沉积后可促进Ca（Ⅱ）沉积，然而Ca（Ⅱ）先沉积后HA沉积量较少，很大程度上与吸附层外层结构组成差异相关.此外，发现随着Ca（Ⅱ）浓度从10mg/L升高至200mg/L，Ca（Ⅱ）沉积速率加快，界面沉积量增多.QCMD耗散变化研究发现，当Ca（Ⅱ）浓度从10mg/L提高至100mg/L，沉积层耗散变化值（ΔD）逐渐下降，沉积层转变为刚性结构；Ca（Ⅱ）浓度继续加大到200mg/L，ΔD升高趋势，沉积层构象呈现疏松态.应用QCMD可实时监测ZVI钝化层形成的动态变化过程，提供了ZVI界面吸附层变化特征等关键信息.     

部分固体废弃物作外加碳源的研究进展

目前污水处理面临脱氮除磷效率低下的问题,其原因是污水中有机物含量高但可生物降解有机物含量不足,而可生物降解有机物是脱氮除磷微生物的重要碳源。部分固体废弃物具有有机物含量高、价廉易得、易生物降解等特点,因此将固体废弃物作为外加碳源提高污水的脱氮除磷效果具有良好的前景。通过对污泥、农业废物、水产养殖废物、厨余垃圾等固体废弃物的特点及其水解液作碳源的研究现状进行分析,指出了目前固体废弃物作碳源存在的问题及未来的研究方向,为学者后期研究奠定基础。     

Removal of elemental mercury with Mn/Mo/Ru/Al2O3 membrane catalytic system

In this work, a catalytic membrane using Mn/Mo/Ru/Al₂O₃ as the catalyst was employed to remove elemental mercury (Hg⁰) from flue gas at low temperature. Compared with traditional catalytic oxidation (TCO) mode, Mn/Al₂O₃ membrane catalytic system had much higher removal efficiency of Hg⁰. After the incorporation of Mo and Ru, the production of Cl₂ from the Deacon reaction and the retainability for oxidants over Mn/Al₂O₃ membrane were greatly enhanced. As a result, the oxidization of Hg⁰ over Mn/Al₂O₃ membrane was obviously promoted due to incorporation of Mo and Ru. In the presence of 8 ppmv HCl, the removal efficiency of Hg⁰ by Mn/Mo/Ru/Al₂O₃ membrane reached 95% at 423 K. The influence of NO and SO₂ on Hg⁰ removal were insignificant even if 200 ppmv NO and 1000 ppmv SO₂ were used. Moreover, compared with the TCO mode, the Mn/Mo/Ru/Al₂O₃ membrane catalytic system could remarkably reduce the demanded amount of oxidants for Hg⁰ removal. Therefore, the Mn/Mo/Ru/Al₂O₃ membrane catalytic system may be a promising technology for the control of Hg⁰ emission.