库仑滴定法测定煤中全硫影响因素的探讨

从煤样的粒度和均匀性、载气流量、电解液的使用、电解池和电极片的处理、库仑法测硫仪的校正等方面,对应用库仑法测定煤中全硫应注意的问题及因为进行分析,提出相应的控制措施,以确保测定结果的准确性.     

Al(Ⅲ)盐水解聚合过程中聚合铝含量的定量计算

依据Al(Ⅲ)盐强制水解聚合过程的电位滴定实验结果,利用铝盐水解聚合电位滴定曲线上的3个临界特征点,同时利用Origin软件自备的Boltzmann方程对滴定曲线拟合,给出了通过电位滴定实验计算聚合铝含量的定量公式。此公式能方便地计算出铝盐强制水解聚合溶液中的聚合铝含量。模式计算结果与Al-Ferron逐时络合比色法的测试结果线性拟合较好。     

Coulometric determination of sulfur speciation in natural waters

Ｃｏｕｌｏｍｅｔｒｉｃｄｅｔｅｒｍｉｎａｔｉｏｎｏｆｓｕｌｆｕｒｓｐｅｃｉａｔｉｏｎｉｎｎａｔｕｒａｌｗａｔｅｒｓ￥ＬｉＹｕｘｉａｎ；ＺｅｎｇＹｕ；ＹａｎＨｕｉｙｕ（ＲｅｓｅａｒｃｈＣｅｎｔｅｒｆｏｒＥｃｏ－ＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃｅｓ...     

水杉锯末对三价铬离子的吸附机理研究

用酸碱电势滴定法和静态实验对木屑表面的带电状况﹑Cr3+的吸附规律及其吸附反应焓进行了研究,并用X射线光电子能谱对吸附Cr3+前后的木屑表面元素进行了测定。结果表明木屑的等电点(pHzpc)为3.2,pH大于时表面带负电;木屑表面的羧基离子是带电的主要官能团,也是吸附Cr3+的主要基团;羧基与Cr3+之间为1∶1的配位吸附。     

微回流比色测定仪与滴定法测定水中COD值的方法对比

简单介绍了微回流法和滴定法测定水中COD浓度值的原理及方法,着重对两种方法的测定结果进行了对比,并通过统计验证,证明两种方法无显著性差异.     

以炼铝灰渣为原料制备絮凝剂及其应用

通过正交实验确定:10g一次铝灰渣和100mL浓度为4mol/L的盐酸在100℃搅拌浸取(转速为140r/min)2h,具有最佳的溶出效果,对制备的絮凝剂进行pH值调节可使之达到最佳的污水处理效果.     

化学需氧量测定中分光光度法与滴定法的比较

文章对水样化学需氧量（COD）测定方法中的密闭催化消解-分光光度法和回流消解-滴定法进行了比较。与回流消解-滴定法相比，分光光度法测定标准水样COD结果稍为偏高，但对于废水样品，2种方法的测定结果呈良好线性相关（b=1．024，R^2=0．990），整体上没有显著性差异。密闭催化消解-分光光度法有快速、节能、环保等优点，值得在环境监测工作中推广应用。     

Determining short chain fatty acids in sewage sludge hydrolysate：A comparison of three analytical methods and investigation of sample storage effects

In anaerobic digestion, the production of short-chain fatty acids （SCFAs） can be beneficial or harmful to the overall process, depending on the concentration of accumulated acids. Therefore, the accurate determination of the SCFA concentration in both fresh and stored sludge hydrolysates is important. To select a suitable method for monitoring SCFAs during the anaerobic digestion of sewage sludge, the accuracy of three available analytical methods, including 5 pH point acid titration （TITRA5）, gas chromatography （GC）, and spectrophotometry, were compared in the present study. The results revealed that TITRA5 and GC displayed better agreement in the achieved measurements and higher precision and accuracy than the spectrophotometric assay, as supported by the application of different statistical models. TITRA5 excelled in titrating unfiltered hydrolysate while simultaneously measuring the alkalinity, whereas the GC method provided detailed information on the contribution of different fatty acids to the total acidity. In contrast, the spectrophotometric assay suffered from many forms of interference, depending on the sample＇s matrix. SCFA production followed the pattern of enzymatic reactions and fitted the Michaelis-Menten model. In addition to promoting TITRA5 as an accurate and robust analytical tool for routine SCFA analyses, this comparative study also demonstrated the possibility of storing hydrolysate samples at different temperatures and durations without altering the SCFA measurements.     

环境水样中氯化物测定方法探讨

文章目的：分析用硝酸银滴定法测定水中氯化物,滴定终点溶液颜色的变化特征,总结其规律,以便分析者做为参考。方法：以环境监测标准中推荐的硝酸银滴定法GB11896-89进行实验测定。结果：当看到溶液为明显的砖红色时,早已过了等当点和滴定终点了,当溶液为比较明显的灰黄色时,虽然已经过了等当点了,但却是滴定终点,用其点计算可以得到准确的结果。结论：在水样滴定的全过程中,不要找溶液成什么明显的砖红色时即为终点,而要找溶液成为较明显的灰黄色时,即为水样滴定终点,用这个点进行计算往往可以得到满意的结果。     

Determination of the dissociation constants of polyepoxysuccinic acid

The dissociation constants of polyepoxysuccinic acid (PESA) were investigated in this study. Based on the potentiometric titration and the BEST program, the dissociation constants of PESA were determined. Considering the complexity of the dissociation of PESA in aqueous solution, several models were constructed to simulate the dissociation process of PESA. By comparison, the dissociation constants of PESA were obtained with model 4. The species distribution of PESA in aqueous solution as a function of pH was also presented according to the experimental and calculation results. It showed that the H₂L model with five basic structure units to describe the dissociation of PESA was reasonable, and the relevant constants had less error and better matching between the experimental and calculation data. The corresponding values of pK _ai were 4.68 and 4.92, respectively, for H₂L at 35°C with ionic strength of 0.1 mol/L.