The Determination and Treatment of Waste Water with Chromium
Liu Xia Hu Yingxi Li Yanyun Wang Xin Chen Yan (Chemical Engineering Department, Beijing Institute of Petro Chemical Technology, Beijing 102600)
The methods are studied for treatment an iodometric microdetermination of chromium in waste water. Cr(III) can be reduced from Cr(VI) with Fe(NH 4) 2(SO 4) 2·6H 2O as reductant then be removed mostly with the co precipitation. The proposed method can be used to treat the waste water with Cr(VI). The microgram amount of chromium system can be determined by iodometric complification method. The method offers 9 fold amplification for Cr(III). The method is based on oxidation of Cr(III) with an excess of periodate, masking the unreacted periodate with molybdate and subsequent iodomertric determination of the liberated iodate. Cr(VI) can be determined by this method after prior reduction to Cr(III) with saturated sodium sulphite in sulphuric acid. When the amount of chromium is less than 340 μg,the average recovery obtained is 99.7%.