氯酸钾氧化分光光度法测定水体中总铬浓度.pdf

第26卷第4期
水资源保护
Vol 26 No 4
2010年7月
WATER RESOURCES PROTECTION
Jul.2010
DOI:10.3969/j.isa.10046933.2010.04.015
氯酸钾氧化分光光度法测定水体中总铬浓度
曹桂萍,壮亚峰,张金海,程辉
(常州工学院化工系,江苏常州213022
摘要:为了克服CB7466-87水质总铬的测定法中测定总铬浓度的不足之处,采用氯酸钾作为氧化剂建立
种新的测定方法。对国标法的消解预处理步骤进行了部分改进,简化操作过程,避免总铬成分的损失。在酸
性溶液中以二苯碳酰二胼(DPC)为显色剂测定总络时,研究显色剂配制方法、显色体系稳定性及饱和氯酸钾
溶液用量对测定的影响。结果表明:用乙醇代替丙酮配制显色剂对吸光度没有影响,显色液放置100min吸
光度无变化,0.5mL饱和氟酸钾溶液可满足氧化3价铬的要求,过量的氯酸钾无须另加还原试剂消除。该方
法测定总铬质量浓度的线性范国是0.02~1.0g/mL,相关系数r=0.999将新方法应用于测定几种水体
的总铬浓度,加标回收率为95.0%~102.0%,测定含络废水的平均浓度值与国标法无显著性差异。
关键词:总铬;消解;显色剂;氟酸钾
中图分类号:X830.2文献标识码:B文章编号:1004-6933(2010)04-0053-04
Determination of total chromium in water using potassium chlorate oxidation
spectrophotometry
CAO Gui-ping, ZHIANG Ya-feng, ZHANG Jin-tao, CHENG Hui
Department of Chemica Enginering Chanhw st e of Technology, Changzhou 213022, China
Abstract A novel method was set up for the determination of total chromium in water using potassium chlorate as an
oxidant to overcome the disadvantage of the national standard method(gb7466-87). The digestion pretreatment
proeure was mped n his met ma th that of e s ana method, which made for a simplified analysis
process and prevented the loss of total chromium. With 1, 5-diphenylcarbazide( DPC)as the color development reagent
used o e ermine he content of otal chromium in he acidic solution, the formation method of the color development
reagent, the stability of lor development ss em and he dosage of the aturaed solution of potassium chlorate used in
e oxidation process were studied. The results showed that the absorbency with alcohol as the solvent in the color
development reagent was the same as that with propanone as the solvent; absorbency of this colored development system
was constant over 100 minutes; and O5 ml of saturated potassium chlorate was enough to oxidize all of the Cr in the
ater, without the need to eliminate excessive o assium horae in the solution with other reductants. The linear range
of determinat on of otal chromium in this method was 0.02 to 1.0 g /ml, and the corelation coefficient was0.999
Using this method to determine the content of total chromium in several kinds of water, the recoveries were in the range
of 94. 70% to 102. 1%. The mean value of the waste water containing chromium was not significantly different from that
of the national standard method
Key words: total chromium; digestion; color development reagent; potassium chlorate
铬是重要的无机化工产品,被广泛应用于工业的废水中含有大量的铬,严重污染环境,对水生生
生产中。电镀、皮革、染料、橡胶、陶瓷等企业所排出物、农作物和生态系统产生极大影响。铬是严重
基金项目:国家自然科学基金(50871101)
作者简介:曹桂萍(1969一),女,山东徳州人,副教授,主要从事环境污染物监测技术的研究。E-mal: cage@cau.cmn
53