紫外分光光度法测定精对苯二甲酸生产污水中的芳香酸

建立了用紫外分光光度法同时测定精对苯二甲酸生产污水中的对苯二甲酸、对甲基苯甲酸和苯甲酸3种主要芳香酸含量的方法。3种芳香酸的测定线性范围均为2~12m g/L,最低检测限均为0.5m g/L。讨论了实际污水中所含有机物对测定结果的干扰。实验结果表明,在吸收波长λ为225,250,255nm处,废水中含量较多的醋酸、醋酸甲酯等有机物不干扰测定结果;含量较少的对二甲苯、邻苯二甲酸等芳香化合物对测定结果也基本无干扰;该测定方法适合于采用稀盐酸或稀硫酸进行酸沉后污水中芳香酸含量的测定,不适合稀硝酸酸沉后芳香酸的测定。该方法具有简便、快速及准确度较高等特点,适合实际生产过程使用。

Determination of Three Aromatic Acids in Wastewater from Production of Terephthalic Acid by UV Spectrophotometry

A method was developed for quantitative determination of three aromatic acids in wastewater from production of high purity terephthalic acid(PTA)by UV spectrophotometry.The three aromatic acids are terephthalic acid(TA),p-methyl benzoic acid and benzoic acid.The linear ranges for determination of the three aromatic acids are all between 2 mg/L and 12 mg/L.Lower limit for detection of each acid is 0.5 mg/L.The effects of other organic compounds on the determination were investigated.Acetic acid and methyl acetate in the wastewater do not affect determination at adsorption wavelength 225,250,255 nm.Xylene and o-phthalic acid in the wastewater do also not interfere in the determination.The method is satisfactory when HCl or H2SO4 is used in acid precipitation,but is unsatisfactory when HNO3 is used instead.