利用CDM-PSS-DGT装置累积测量水中的Ni2+和Co2+
THE MEASUREMENT OF CDM-PSS-DGT DEVICE FOR Ni2+AND Co2+IN WATER
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摘要: 研究了CDM-PSS-DGT装置对Ni2+和Co2+的累积和测量.测定了Ni2+和Co2+与聚乙烯苯磺酸(PSS)的条件配位稳定常数以及Ni2+和Co2+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Ni2+和Co2+的影响.在pH 4-9范围内,酸度对Ni2+和Co2+的累积容量影响不大;离子强度对Ni2+和Co2+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Ni2+和Co2+的累积容量逐渐下降;碱金属、碱土金属与Ni2+和Co2+共存时,CDM-PSS-DGT装置对Ni2+和Co2+优先累积.经测定Ni2+和Co2+与结合相PSS的条件配位稳定常数(lgK)分别为8.04和8.07.配制水中CDM-PSS-DGT装置能准确地对Ni2+和Co2+进行测量,Ni2+和Co2+的测量回收率分别为:93.84%和91.82%,RSD%分别为:3.53%和4.89%.Abstract: In situ accumulation of Ni2+and Co2+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 Ni2+ and Co2+was not found in the bulk solution.The conditional complex constants of PSS with Ni2+and Co2+ have been measured(lgK(Ni2+)= 8.04,lgK(Co2+)=8.07).Validation was undertaken for Ni2+and Co2+in synthetic solution(Recovery=93.84% RSD=3.53% for Ni2+;Recovery=91.82%,RSD4.89% for Co2+).The CDM-PSS-DGT device shows good prospect for the in-situ accumulation of Ni2+and Co2+in natural waters.
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Key words:
- diffusive gradients in thin-films /
- accumulation /
- measurement /
- Ni2+ /
- Co2+
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