Determination of haloacetic acids concentrations in hospital effluent after chlorination by ion chromatography

The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids(HAAs),a calss of disinfection by-products formed as a result of chlorination of hospital wastewater. The monitored HAAs included monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid and trichloroacetic acid. The method employed a sodium hydroxide eluent at a flow rate of 0.8 ml/min, electrolytically generated gradients, and suppressed conductivity detection. To analyze the HAAs in real hospital wastewater samples, C18 pretreatment cartridge was utilized to reduce samples' turbidity. Preconcentration with SPE and matrix elimination with treatment cartridges were investigated and were found to be able to obtain acceptable detection limits. Linearity, repeatability and detection limits of the above method were evaluated. The detection limits of monobromoacetic acid and dibromoacetic acid were 2.61 μg/L and 1.30 μg/L respectively, and the other three are ranging from 0.48 to 0.82 μg/L under 25-fold preconcentration. When the above optimization procedure was applied to three hospital wastewater samples with different treatment processes in Tianjin, it was found that the dichloroacetic acid is the major compound, and the growth ratios of the HAAs after disinfection by sodium hypochlorite were 91.28%, 63.61% and 79.50%, respectively.     

Application of multiwalled carbon nanotubes treated by potassium permanganate for determination of trace cadmium prior to flame atomic absorption spectrometry

In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes (MWCNTs) and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry.The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing.Parameters influencing the recoveries of target analytes were optimized.Under optimal conditions,the target analyte exhibited a good linearity (R~2=0.9992) over the concentration range 0.5-50 ng/ml.The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively.The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%.All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.     

塿土中可给态镍浸提方法的研究

在前人工作的基础上,应用主成分分析、逐步回归分析和通径分析的方法,提出了(土娄)土中可给态镍的浸提方法及影响可给态镍的土壤性质.结果表明,DTPA浸提法可作为(土娄)土中可给态镍的浸提方法,铁锰氧化物结合态镍是(土娄)土可给镍的主要来源.碳酸盐结合态镍和有机质结合态镍是(土娄)土可给镍的潜在来源.它们在调控可给态镍的储量上起着重要作用.影响(土娄)土可给态镍最重要的土壤性质是pH和E_h7.     

排污收费制度执行程序探讨

论述了我国现行的排污收费制度的执行程序,指出了实践中存在的一些问题,并对完善执法程序、提高监理部门的法律地位等,提出了建议和措施。     

图文化操作规程在海上气田生产作业中的应用

为了避免因人的误操作造成的安全事故,东方1-1气田创新推行图文化操作规程。本文介绍了图文化操作规程制订的步骤与方法,论述了图文化操作规程的主要内容,并概括了图文化操作规程的优势和在东方气田生产作业中的实施效果。实施效果表明:通过在东方气田实施图文化操作规程,不仅解决了传统的操作规程均采用纯文字陈述形式,存在不直观、不利于记忆、不易自学等问题,而且气田没有发生一起因人的误操作而造成的安全事件和事故,有效地控制了风险,可见图文化操作规程可有效地规避海上气田生产作业中的风险。     

电波暗室场地电压驻波比标准测试法介绍和分析

场地电压驻波比(SVSWR)测试方法作为一种新的电磁兼容电波暗室评估方法,可以很好地解决归一化场地衰减(NSA)测试法中天线不能均匀有效地照射在暗室内的所有墙壁上的问题.介绍了CISPR16-1-4:2007标准中对电波暗室在1 GHz以上的场地电压驻波比的规定,详细说明了电波暗室场地电压驻波比的测试原理、目的和使用天...     

添加剂和水洗对焚烧飞灰烧结过程中重金属迁移特性的影响

研究了添加剂（粘土和粉煤灰）、水洗预处理对焚烧飞灰烧结过程重金属（Cd、Cu、Zn、Pb、Cr、Ni）迁移特性的影响.水洗时间为8、 16、 24 h.烧结实验条件为成型压力3 kN,烧结温度1 100℃,烧结时间4 h.结果表明,在飞灰中粘土添加比例增加到70%时,重金属Cd的固化率从16.96%升高到28.42%,Pb的固化率从10.58%升高到37.02%, Cu的固化率从46.38%上升到55.14%,Zn的固化率从42.14%上升到64.47%,Ni和Cr的固化率总体上呈现下降的趋势.总体上添加粘土对焚烧飞灰烧结过程中重金属的固定效果有限.当粉煤灰在烧结前样品中的比例增加时,Cd的固化率从16.96%下降到4.67%,Cu的固化率从46.86%上升到81.43%.粉煤灰的加入对于Zn和Pb的影响不大,对于Ni和Cr的影响规律也不明显.水洗预处理可以把Cd、Cu和Pb的固化率提高到80%以上.焚烧飞灰烧结体TCLP浸出测试表明,添加粘土和粉煤灰以及水洗预处理后,焚烧飞灰烧结试体的重金属浸出浓度普遍较低.     

半渗透膜采样技术监测城市污水处理流程中的难降解有毒有机污染物

应用新型半透膜采样技术（ＳＰＭＤ）,监测某城市污水处理流程中８个点污水中两类难降解有毒有机污染物多氯联苯（ＰＣＢ）和多环芳烃（ＰＡＨ）,同时同地采集水样,气相色谱质谱联机,选择性离子扫描方式对各ＰＣＢ异构体和ＰＡＨ定性定量。与水样液液萃取相比,ＳＰＭＤ采样技术显著提高了分析的准确度。根据测定的采样器中污染物浓度,推算采样期间该点污水中的平均浓度,与瞬间水样分析结果符合程度较好。半透膜采样方法可用于污水处理工艺流程中多氯联苯和多环芳烃污染物的定性和半定量监测     

均权计算及其程序化实现

许多情况下 ,人们最关心一些变化量的总体情况怎么样 ,这就用到均权计算 ,均权计算一些量能更好的反映统计范围的实际情况。文章以环境监测中地表水 2 4项监测结果按水量均权计算年均值为例 ,把均权计算程序化 ,解决了年均值的代表性问题     

做好工作危害分析保证操作安全

介绍了工作危害分析方法,列举实例进行分析,并提出了将控制措施融入操作程序中的思路.