不同给水管材对管壁附着生物膜铅、镉的解吸动力学研究

Desorption kinetics of lead and cadmium on biofilm attached to pipe wall by different water supply pipes

给水管壁生物膜会吸附水中的重金属元素积累在管壁生物膜中,在受到扰动时释放回到水体,危害饮用水水质安全。试验以上海管网末梢水为实验对象,研究了PVC、铸铁和紫铜等三种管材上生物膜对铅、镉的解吸特性。结果表明,PVC、铸铁和紫铜附着生物膜对铅的解吸容量qe分别为:5.92211μmol·m^-2、128.3051μmol·m^-2和21.1808,解吸速率常数k分别为:0.001060 m^2·μmol^-1·min^-1、0.000041 m^2·μmol^-1·min^-1和0.000503 m^2·μmol^-1·min^-1,对于镉元素三种材质的解吸容量qe分别为:14.71519μmol·m^-2、18.50481μmol·m^-2和2.25225μmol·m^-2;解吸速率常数k分别为:0.000102 m^2·μmol^-1·min^-1、0.001070 m^2·μmol^-1·min^-1和0.000103 m^2·μmol^-1·min^-1。

The biofilm of the water supply pipe wall will adsorb heavy metal elements in the water and accumulate in the pipe wall biofilm,and will be released back to the water body when disturbed,which endangers the safety of drinking water quality.In the experiment,the peripheral water of Shanghai pipeline network was used as the experimental object,and the desorption characteristics of lead and cadmium on biofilms on three kinds of pipes such as PVC,cast iron and copper were studied.The results show that the lead desorption capacities qe of PVC,cast iron,and copper-attached biofilms are 5.92211 μmol · m^-2,128.3051 μmol · m^-2,and 21.1808,respectively,and the desorption rate constants k are:0.001060 m^2 · μmol^-1 · min^-1,0.000041 m^2 · μmol^-1 · min^-1,and 0.000503 m^2 · μmol^-1 · min^-1.The desorption capacities qe for the three materials of cadmium are:14.71519 μmol · m^-2,18.50481 μmol · m^-2 and 2.25225 μmol · m^-2;the desorption rate constants k are:0.000102 m^2 · μmol^-1 · min^-1,0.001070 m^2 · μmol^-1 · min^-1,and 0.000103 m^2 · μmol^-1 · min^-1.