造纸废水化学需氧量的双波长紫外光谱法测定

摘要

以两种造纸废水为研究对象,探讨了采用紫外光谱法直接测定废水COD的可行性.研究发现,两种废水虽然来源不同,但其紫外最大吸收波长均为272 nm,并且废水在272 nm下的吸光度与COD具有良好的相关性.以546 nm的可见光作为参比波长可以消除水样悬浮物对紫外吸光度的干扰,提高相关性曲线的准确性.与标准测试方法的比较表明,双波长光谱法的测量精密度和准确性符合HJ/T 377-2007《化学需氧量(CODCr)水质在线自动监测仪》的要求,可以用于废水COD的快速测定.%This paper deals with the feasibility of direct COD (chemical oxygen demand) determination for paper-making wastewater via ultraviolet spectroscopy, with two kinds of papermaking wastewater being used in the experiments. The results show that (1) the two kinds of papermaking wastewater both possess the maximum UV absorption wavelength of 272nm although they are of different sources; ( 2 ) there is a good correlation between the UV ab-sorbance at 272nm and the COD; and (3) by using 546nm as a reference wavelength, the interference of suspended solids in the wastewater with the UV absorbance is eliminated and the correlation curve becomes more accurate. Moreover, as compared with the standard testing method of COD, the proposed dual-wavelength method is of high precision and accuracy that well meet the requirements of Standard HJ/T 377-2007 Water Quality On-Line Automatic Monitor of Chemical Oxygen Demand (CODCr) , which means that it is feasible in the rapid determination of COD for papermaking wastewater.