三种波长测定COD比较兼论无汞对测定值的影响以及汞银的回收

综述密封高温快速测定COD在610 nm、420 nm和348 nm三种波长条件下的特点。前二者已定为国家标准方法,研究发现348nm灵敏度最高,可以测定超低量程的COD,其准确度4.5%、精密度5.2%,检出限1.6 mg/L,建议也将其定为国家标准方法。COD测定都加Hg^2＋掩蔽Cl^-,无汞法不加Hg^2＋,只加Ag＋或加Ag＋又加Cr^3＋;前者COD测定值偏高,后者的Cr^3＋使Cr（V1）/Cr^3＋电极电势下降,虽然有抑制Cl^-的氧化作用,但灵敏度下降,有机物氧化率下降,测定结果偏低较大。如果要求测定准确度高,无汞不行。测定废液中加入铁或铜,回收汞银。     

重铬酸钾法测定化学耗氧量消除氯离子干扰新掩蔽剂的研究

本文提出了一种以重铬酸钾为氧化剂,以硝酸银和硝酸铋为掩蔽剂消除氯离子干扰,测定化学耗氧量的新方法,并研究了消化过程中的各种条件,如硫酸浓度、消化时间等。采用硝酸银和硝酸铋联合掩蔽剂可以取代标准重铬酸钾法测定(COD)中使用的硫酸汞,从而避免汞对环境的污染,并使用这种新方法测定了多种类型的水样。结果表明,本法操作简便、快速灵敏、准确度高,并具有广泛的适应性。     

塞曼石墨炉原子吸收法中用钯消除氯化物干扰的机理

本文研究了塞曼石墨炉原子吸收法中采用钯消除环境水样基体氯化物干扰的机理。在最佳条件下,用10μg钯可消除5μg氯化钠基体对1.0ng铜的测定干扰。在10μg钯改进剂中加入5μg镁,可改善测定水样中铜的回收率。测定结果表明,铜的检出限(3σ)为5.0×10~(-11)g,回收率为97%～103%。     

蒸馏-中和法对高含量水样氨氮测定的优化

在环境监测中,氨氮的比色测定经常会遇到含量高的水样,遇到这种情况通常会少取水样,稀释后呈色测定。尤其对有颜色和浑浊的水样,去除盐类以及干扰物质就成为了一个重点,而经常使用的纳氏试剂比色法虽然操作简单、灵敏等优点,但水样带色或浑浊,就会影响氨氮的测定。为此分析就要对水样进行直接中和、蒸馏,为了能够做好预处理,准确分析具体水样的常量氨氮测定结果,提高其测试效率,找出测定过程中应该注意的问题,提出相应的防干扰和预处理措施,对此类水样进行方法的优化尤为重要。     

掩蔽剂对纳氏试剂分光光度法测定水中氨氮的影响研究

本文对钙镁离子在纳氏试剂法测定水中氨氮的干扰情况和酒石酸钾钠和六偏磷酸钠两种试剂的掩蔽效果进行了研究。结果表明:即使水中钙离子的浓度达到100mg/L对纳氏试剂显色的干扰影响不大,而镁离子对纳氏试剂显色的最低干扰浓度为20mg/L。酒石酸钾钠和六偏磷酸钠分别对钙、镁离子的掩蔽能力差异较大。酒石酸钾钠无法掩蔽钙离子,较高钙离子浓度反而产生浊度,影响氨氮测定,但能较好消除水样中镁离子的干扰;而六偏磷酸钠在消除钙、镁离子干扰方面都优于酒石酸钾钠。因此六偏磷酸钠作为掩蔽剂可用于实际水样氨氮的检测工作。     

钼酸铵分光光度法测定水中总磷方法的改进

在对水样消解进行简化和促进工作效率提升的目标下,本文改进了GB11893-89钼酸铵分光光度法测定水中总磷方法,对于试剂量和取样量予以大比例的减少。其中,用测定COD的带螺帽消解管来替换比色管,同时借助于COD消解器把温度控制到121度。根据钼酸盐分光光度方法,并对标准样品和实际水样总磷实行了测定,并证明了两种方法在结果上的一致性。     

纳氏试剂分光光度法测定氨氮

纳氏试剂分光光度法测定氨氮具有重大的意义,可适用于各式水样,与氮有关的水质指标较多。本文列出了一些金属离子的干扰和余氯的干扰,以及产生干扰的原因、消除干扰的方法、掩蔽原理。本文还分析了所加的试剂的作用原理及纯度的影响,还分析了酒石酸钾钠纯度的判断和两种提高纯度的方法 ,还列出了反应条件如温度、显色时间、体系PH值对实验的影响,提出了浓度较高的水样的两种稀释方法 ,它们各有优越性和局限性。并发现了实验过程中一些操作失误的补救工作。     

钠,钾离子对火焰法测定水样中锂,锶的干扰

本文针对水样中的锂、锶含量通常低于原子吸收火焰法的灵敏度这个特点，采用砂浴加热蒸发来浓缩水样，摸索了最佳检测条件。同时，由于浓缩后的地矿水样中的其它杂质离子浓度也相应增大，其中钾、钠离子对测定的干扰尤为突出：当溶液中单独含有钾离子或钠离子时，对测量锂、锶均有无规则干扰。实验结果表明：测定锂时，控制钠、钾离子浓度同时在２５００ｍｇ／Ｌ时，对锂的测定干扰最小，方法相对偏差为２５００ｍｇ／Ｌ时，对锂的测     

高锰酸盐指数测定方法改进前后的比对分析

高锰酸盐指数是水质监测中常规项目,在实际测定中对氯化物含量（Cl^-〉300mg／l、Cl^-〈300mg／1）时,采用酸性法、碱性法两种方法进行比对试验,是否改用更节约、更快捷的方法,且不影响监测结果,本文对此进行讨论。     

水体中镉对鱼类毒性及安全浓度的试验研究

采用COD比色管测定水样COD,石墨炉原子吸收光谱法测定水样中的镉含量,参照国标法进行镉对鱼类毒性试验。试验结果表明：镉对鲩鱼、鲫鱼、鲶鱼三类鱼的中毒剂量分别为0.005mg/L,0.0055mg/L、0.0065mg/L,安全浓度分别为0.005mg/L,0.007mg/L、0.008mg/L。     

光学镜面化学镀银中的敏化工艺研究

介绍了光学镜面化学镀银工艺的基本流程及对膜层质量影响较大的敏化工序的原理和工艺,并对该工序中的喷水量进行了理论计算和实验验证。对一块Φ365mm口径的次镜进行镀膜实验。实验结果表明,均匀喷雾35s左右能洗净敏化液中的Cl-,并使水解生成的Sn(OH)2胶体均匀残留于镜面,镀制的Ag膜层质量较好。膜层检测结果为:反射率为92%,厚度为60nm,对面形的影响:PV=λ/45,RMS=λ/250,满足该次镜的检测精度要求。     

Photoelectrocatalytic decontamination of oilfield produced wastewater containing refractory organic pollutants in the presence of high concentration of chloride ions

The feasibility study of the application of the photoelectrocatalytic decontamination of high saline produced water containing refractory organic pollutants was investigated in the slurry photoelectrocatalytic reactor with nanometer TiO2 particle prepared with sol-gel method using the acetic acid as hydrolytic catalyst. The efficiency of the photoelectrocatalytic decontamination of produced water was determined with both COD removal from the tested wastewater and the decrease of mutagenic activity evaluated by Ames tests. The experimental results showed that the photoelectrocatalysis is a quite efficient process for decontaminating the produced water, although there are high concentration of salt existed in oilfield wastewater. We found that the COD removal efficiencies by photoelectrocatalytic process are much higher than that of by photocatalytic or electrochemical oxidation individually in the photoelectrocatalytic reactor. The COD removal can be substantially improved by the added H2O2 and the generation of active chlorine from high concentration chlorides in the wastewater. The effects of various operating conditions, such as initial COD concentration, applied cell voltage, catalyst amount and initial pH value of solution, on the photoelectrocatalytic efficiencies, is also investigated in detail. The results showed that when the raw produced wastewater was diluted in a 1:1 (v/v) ratio, there is a highest COD removal efficiency. And the photoelectrocatalytic degradation of organic pollutants in saline water is much favored in acidic solution than that in neutral and/or alkaline solution.     

絮凝-微电解法处理DDNP废水实验研究

主要研究了絮凝-微电解法处理某化工厂的DDNP生产废水的工艺流程及处理效果。通过实验找出絮凝剂FeCl3的最佳用量,然后采用柱式装置通过微电解法处理DDNP废水,并考察了废水pH值、铁屑粒度、过柱流速等因素对处理效果的影响。对处理后废水的COD进行了测试,实验结果表明,通过最佳条件的选择对废水COD的去除率可以达到93．90％。     

焦化污水水质对生化A/O深度处理系统影响的试验研究

本文采用生化A/O法对焦化不同工序的污水进行深度处理试验,结果表明:化学需氧量(COD)是影响系统处理污水效果的关键水质指标。控制进水COD4500mg/L,可确保系统稳定运行和废水达标排放。     

稳定水质中COD与TOC的关系探讨

以本地区污水处理厂的稳定出水为研究对象,对水样的总有机碳（TOC）与化学需氧量（COD）进行测定,将得到的数值进行线性回归得到其关系式,并进行验证和分析。     

CMF系统处理生活污水厂二级出水

研究了连续微滤技术(CMF)在深度处理城市污水厂二级排放水中的应用前景,以某污水厂SBR(sequenting batch reactor)工艺二级出水为原水,着重考虑了CMF系统对水中OoD、SS、浊度等指标的去除效果,试验结果表明:CMF系统对水中COD有30%左右的去除率,出水浊度低于0.5 NTU.采用扫描电镜及能谱分析对膜污染物分析,得知膜表面的污染物以微生物和有机物为主.     

Anaerobic treatability of high oil and grease rendering wastewater

This study evaluated the use of a new biosurfactant, BOD-Balance, derived from cactus for the treatment of oil-and-grease-laden rendering wastewater anaerobically. Batch laboratory experimental results and preliminary full-scale data are presented. The biosurfactant affected a significant increase in the COD degradation rate for the raw wastewater. However, after reduction of the oil and grease (O&G) by dissolved air flotation, the biosurfactant did not exhibit any advantages. Modeling of the data indicated that various COD fractions, i.e. both soluble and particulate as well as total COD at various testing conditions conformed well to both zero-order and first-order models. The biosurfactant affected a 164-238 and 164-247% increase in COD and particulate COD biodegradation rate for the raw wastewater. The reduction of O&G concentration to <800 mg/l increased total and soluble COD degradation rates by 106%. Results from the full-scale mesophilic anaerobic digestion system indicated that the addition of the biosurfactant at doses of 130-200 mg/l decreased O&G concentrations from 66,300 to 10,200 mg/l over a 2-month-period.     

Peroxidation enhances the biogas production in the anaerobic digestion of biosolids

During the anaerobic digestion of wastewater treatment sludge, commonly called biosolids, an energy rich biogas is formed which is now considered as renewable energy source and widely used for the production of heat and/or electricity. Pre-treatment methods, which achieve a transformation of refractory COD into readily available and soluble BOD, have the potential to enhance the biogas-production. This paper studies several peroxidation techniques for this purpose: the well-known Fenton peroxidation and novel reactions involving peroxymonosulphate (POMS) and dimethyldioxirane (DMDO). The results of the treatments show a considerable increase of COD and BOD in the sludge water, and an increase of the BOD/COD ratio. The biogas production was moreover seen to increase significantly. A maximum increase of 75% was measured with Fenton, while the POMS treatment increased the biogas production by a factor of nearly 2, against an even higher 2.5 for the DMDO treatment. The methane content of the biogas remained between 65 and 70%, thus maintaining its heating value.     

F~-和Cl~-浓度对电沉积锌电化学过程的影响

目前,对电积锌过程中F~-、Cl~-的电化学过程研究较少。基于电化学原理,对含F~-、Cl~-的锌电解液体系电积锌时的极化曲线、循环伏安曲线、交流阻抗谱进行了测定。结果表明:电解液中存在F~-、Cl~-时,表现出去极化作用,Cl~-会使还原电位和氧化电位升高,F~-会抑制还原产物的析出,沉积过程中不伴随气体析出现象,且随着F~-、Cl~-浓度的增大,锌沉积越来越困难。     

光催化降解玫瑰红的机理研究

以玫瑰红作为研究机理的目标物，在紫外灯的照射和二氧化钛作催化剂的实验条件下，用重铬酸钾法测定化学需氧量，Apollo 9000型TOC测定仪测TOC，UV-VIS8500型紫外-可见分光光度计测定样品的色度，研究光催化降解机理。结果表明：玫瑰红染料的脱色过程与总有机碳TOC、化学需氧量COD的去除过程是不同步的。在玫瑰红的降解过程中，强氧化自由基首先进攻共轭结构．反应初期主要是脱色过程，TOC在没有很大的变化，生成了无色而又相对稳定的中间产物。反应后期是各芳烃中间产物的开环过程，最终完全降解为无机小分子。