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This paper intends to describe a simple and rapid analytical method for polarographic determination of native azo dye-Variamine Blue B Salt. In 0.1 N hydrochloric acid media, the half wave of 0.001 M solution of Variamine Blue B Salt is found at a potential of -0.65 volts (vs. S.C.E.), Increasing pH and concentration of the solution causes a shift of E 1/2 to more negative potential. The height of wave rises as concentration of the solution increases but it drops as pH increases. The presence of... This paper intends to describe a simple and rapid analytical method for polarographic determination of native azo dye-Variamine Blue B Salt. In 0.1 N hydrochloric acid media, the half wave of 0.001 M solution of Variamine Blue B Salt is found at a potential of -0.65 volts (vs. S.C.E.), Increasing pH and concentration of the solution causes a shift of E 1/2 to more negative potential. The height of wave rises as concentration of the solution increases but it drops as pH increases. The presence of sodium sulfate or zinc sulfate as deluent in the dyestuff does not affect the polarographic wave. This method is applicable for the quantitative analysis of this dyestuff. 重氮鹽类的含量測定,在印染工业方面有其重要的意义和作用。作者試用极谱法分析印染工业上常用的国产偶氮染料——凡拉明藍B鹽,以求得一个簡單迅速的分析方法。以0.1N鹽酸为底液,0.001 M凡拉明藍B鹽在-0.65伏特左右产生一波。它的半波电位与波高随溶液酸度和濃度的改变而异。溶液pH值增高,半波电位負值增加,波高降低。溶液濃度愈高,半波电位負值愈大,波高愈增。应用标定曲綫法可以测定凡拉明藍B鹽的含量。硫酸鈉或硫酸鋅作为填充剂时,对凡拉明藍B鹽的极譜曲綫及波高无多大影响。重氮鹽在高温易于分解,因此操作过程宜在低溫进行。 Using acetic, sulfuric, hydrochloric, phosphoric and perchloric acid as acidifying agent, gelation time of monostlicic acid of different concentration at various pH was determined. All the log t--pH curves were of N-Shape. The pH value at the minimum point of each curve shifted upward and to- ward the left as concentration of silicic acid decreased. With acetic acid as acidifying agent, the gelation curve had the same tendency when concentra- tion of silicic acid changed, but with a strong... Using acetic, sulfuric, hydrochloric, phosphoric and perchloric acid as acidifying agent, gelation time of monostlicic acid of different concentration at various pH was determined. All the log t--pH curves were of N-Shape. The pH value at the minimum point of each curve shifted upward and to- ward the left as concentration of silicic acid decreased. With acetic acid as acidifying agent, the gelation curve had the same tendency when concentra- tion of silicic acid changed, but with a strong acid, as hydrochloric or sulfuric, no such shift was observed at the maximum point. When log t of the minimum points of each set of gelation time curves were plotted against the corresponding log T_(?), straight lines were always obtained. However, the slope of the lines was about -3 instead of -2 as required by the theoretical equation. This is found to be due to the effect of the salt formed in the process of acidification of sodium monosilicate. When the concentration of sodium monosilicate used was kept constant and different amounts of a salt corresponding to the acid used as acidifying agent were added, the gelation curves obtained indicated that, in case when either hydrochloric acid or sulfuric acid was used as acidifying agent, the added salt had a little pro- motion effect at the maximum point but did not change the pH value. However, with the minimum points of all the curves and the maximum of that of acetic acid as acidifying agent, they all shifted downward and rightward. When log t was plotted against log T_s, straight line was also obtained, with a slope of about -1, indicating that getlation time of monosi- licic acid is inversely proportional to the first power of the concentration of salt. When the concentration of salt was kept constant and that of silicic acid varied, pH of the maximum points of all gelation curves no matter which acid was used as acidifying agent remained constant, while that of the minimum points changed but a little. And in all cases, when log t was plotted against log T_(?), a straight line was always obtained, the slope of which was -2, indicating experimental results were in complete accord with our theoretical expression. When the effect of added salt is included, the expression should be modified slightly and takes the following form: log t=log C'--(2+n')log T_A--log (1+β_1[H~+]+β_2[H~+]~2+β_3[H~+]~3)~2/β_2β_3 [H~+]~3 --log(β_1/β_2+[H~+]~2). 以乙酸、硫酸、盐酸、磷酸及高氯酸为胶凝剂,测定了不同浓度单硅酸在不同pH的胶凝时间,得到了一系列硅酸浓度与胶凝时间的曲线。曲线皆为N形。所有曲线的最低点和乙酸曲线的最高点的pH值,皆随硅酸浓度的减少而向左上方移动,但盐酸和硫酸曲线最高点pH值无明显变化。各组曲线最低点的log t和相应的log T_A昔为直綫关系,但直线斜率昔等于-3,而不是表达式中的-2。这是由於酸化过程所产生的盐的效应。在单硅酸浓度恒定时,加入不同量与所用胶凝剂相当的盐,从所得的胶凝曲綫表明,盐对发盐酸及硫酸为胶凝剂的曲线最高点略有促进作用,而不改变pH值。但所有曲线最低点及乙酸曲线最高点,昔随各种盐浓度的增加而向右下方移动。每组曲线最低点的log t和log T_s皆为直线关系,直线斜率在-1左右,表示盐浓度与胶凝时间的一次方成反此。在固定盐浓度,改变单硅酸浓度的实验中,所有盐酸、硫酸、硝酸、乙酸及磷酸的各套胶凝曲线的最高点pH值皆不改变,而最低点的pH值只微有不同,每组曲线的不论最低点或最高点,它们的log t和log T_A皆有直线关系,其直綫的斜率都在-2左右,和表达式的要求完全符合。故包括盐效应的硅酸聚合而成凝胶的表达式改进为: A new method of dearsenization polluted water by means of magnesium salts from seawater is developed-dearsenization by Magnesium Salts. This method has the advantages of high efficiency and low cast, so it suit coastal industries for their sewage disposal. The influence of arsenic content, the valency state of arsenic, magnesium salt content, the ratio between magnesium and arsenic and the nature of the medium upon dearsenization has been examined. The most favorable condition for dearsenization were.... A new method of dearsenization polluted water by means of magnesium salts from seawater is developed-dearsenization by Magnesium Salts. This method has the advantages of high efficiency and low cast, so it suit coastal industries for their sewage disposal. The influence of arsenic content, the valency state of arsenic, magnesium salt content, the ratio between magnesium and arsenic and the nature of the medium upon dearsenization has been examined. The most favorable condition for dearsenization were. found to be pH 9.5-10.5, Mg: As 8-12. Polluted water containing arsenic as high as 600 mg/l can be dearsenized with the efficiency of more than 99%. Trivalent arsenic appears to be dearsenized less easily than pentavalent arsenic. In order to decrease the amount of magnesium salt used and improve the efficiency of dearsenization, technological processes of stepwise dearsenization by magnesium saits, dearsenization by magnesium salts after the trivalent arsenic being oxidized and the removal of the residual arsenic by magnesium salts containing Fe or phosphate were studied. Conditions for dearsenizing polluted water containing about 200 mg As/l to an arsenic content conforming that of the national standard (0. 5 mg As/l) were obtained. An enlarged experiment on a 5 lsample was also made with the same satisfa- ctory resoult. Aiming at minimizing environmental pollution by way of "disposing of wastes by wastes", experiments using the waste residue discharged from soda plants-to the sea-caustic mud-to take the place of lime in dearsen- ization have also been carried out. Results prove that caustic mud not only can satisfactory take the place of lime, but also lowers the cost and increases the efficiency of dearsenization. Instead of magnesium salts from seawater, the by-product from salt- works, solid bitterm, has also been used. Satisfactory results of dearsenization have also been obtained.Thus, it is made possible for the inland plants, where sea-water is hardly avaliable, to dearsenize arsenic-containing wastewater by magnesium salts. 本试验研究了一种利用价廉易得的海水中的镁盐来脱除污水中无机砷的新方法──镁盐脱砷法。试验结果表明;脱砷比较彻底,成本也较低廉,很适于临海工厂使用。 试验考查了污水中砷含量、砷的价态、镁砷比以及介质条件等因素对脱砷效果的影响。找出了在pH为 9.5-10.5,镁砷比为8-12时脱砷效果最好。三价砷比五价砷较难脱除。利用分段镁盐脱砷、氧化镁盐脱砷及混合镁盐脱砷均可降低镁盐用量和提高脱砷效率。同时,还进行了五升规模的扩大试验。 试验还考查了利用碱厂废渣苛化泥代替石灰及利用盐场副产的卤块代替海水提供镁盐来进行脱砷,也获得了同样良好的脱砷效果。
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