利用CDM-PSS-DGT装置累积测量水中的Ni2+和Co2+

研究了CDM-PSS-DGT装置对Ni~(2 )和Co~(2 )的累积和测量.测定了Ni~(2 )和Co~(2 )与聚乙烯苯磺酸(PSS)的条件配位稳定常数以及Ni~(2 )和Co~(2 )在扩散层中的扩散系数.考察了酸度、离子强度以及碱金属和碱土金属对CDM-PSS-DGT装置累积水中Ni~(2 )和Co~(2 )的影响.在pH 4-9范围内,酸度对Ni~(2 )和Co~(2 )的累积容量影响不大;离子强度对Ni~(2 )和Co~(2 )的累积容量有较强的影响,随着离子强度的不断增大,CDM-PSS- DGT装置对Ni~(2 )和Co~(2 )的累积容量逐渐下降;碱金属、碱土金属与Ni~(2 )和Co~(2 )共存时,CDM-PSS-DGT装置对Ni~(2 )和Co~(2 )优先累积.经测定Ni~(2 )和Co~(2 )与结合相PSS的条件配位稳定常数(lg K)分别为8.04和8.07.配制水中CDM-PSS-DGT装置能准确地对Ni~(2 )和Co~(2 )进行测量,Ni~(2 )和Co~(2 )的测量回收率分别为:93.84%和91.82%,RSD%分别为:3.53%和4.89%.

THE MEASUREMENT OF CDM-PSS-DGT DEVICE FOR Ni2+ AND Co2+ IN WATER

In situ accumulation of Ni~(2 )and Co~(2 )was studied with the diffusive gradients in thin-films(DGT) technique.The effect of pH,ionic strength and the alkali,alkaline earth metals on the binding capacity of CDM-PSS-DGT device were investigated.The CDM-PSS-DGT device had a substantial binding capacity at pH 4-9.The binding capacity of CDM-PSS-DGT device decreased with the enhancement of ionic strength in bulk solution.It showed that the noted interference of the alkali,alkaline earth metals for the accumulation of Ni~(2 ) and Co~(2 )was not found in the bulk solution.The conditional complex constants of PSS with Ni~(2 )and Co~(2 ) have been measured(lg K(Ni~(2 ))= 8.04,lg K(Co~(2 ))=8.07).Validation was undertaken for Ni~(2 )and Co~(2 )in synthetic solution(Recovery=93.84% RSD=3.53% for Ni~(2 );Recovery=91.82 %,RSD4.89% for Co~(2 )).The CDM-PSS-DGT device shows good prospect for the in-situ accumulation of Ni~(2 )and Co~(2 )in natural waters.