含新结合相DGT的构筑及其在富营养水体中磷原位测定中的应用
发布时间：2018-11-02 19:18
【摘要】：磷酸根离子的准确测定对于水体富营养化和水环境污染的防治与治理有着重要的意义。由于待监测环境中待测物质的浓度低、组成成分繁杂、干扰物多、会随环境条件转变,传统监测技术需进行繁琐的前处理,方可进行检测实验。样品预处理工艺需要复杂的手工操作,工作强度大,操作时间长,重现性差,给最终的测量分析带来很大的误差。故研究原位被动采样新技术以降低传统测定方法中样品预处理过程引入的误差具有重要的意义。薄膜梯度扩散技术(Diffusive Gradients in Thin Films Technique,DGT)是以Fick第一扩散定律为基础的新型监测技术,其近年来被广泛应用于水体、沉积物及土壤中磷含量的原位监测。本文选用新型结合相——含碳酸镧和CaAl-LDH的聚丙烯酰胺凝胶膜,研究DGT放置时间、初始磷浓度、pH、离子强度以及温度对其富集磷酸根离子能力的影响,最后在实际水体中,探究其应用性能,结果如下:(1)选用碳酸镧聚丙烯酰胺凝胶膜用作DGT结合相。在环境条件为pH=7.00,温度T=25℃,磷初始浓度为5μg/mL时,碳酸镧-DGT对磷的最大吸附容量为68.73μg,有效吸附容量为12.82μg;洗脱液是5 mL,2 mol/L的H2SO4,洗脱效率为92.35%;当pH在3.21-6.90,离子强度在10-6-0.1 mol/L范围内时,碳酸镧-DGT检测磷酸根离子结果变化不显著;温度在5-35℃范围内,碳酸镧-DGT对磷的富集量随着温度的升高而增加。磷初始浓度为0.10-5.04μg/m L时,碳酸镧-DGT测定值与磷钼蓝比色法测定值相吻合;存储时间为0.5-10个月,碳酸镧-DGT对磷的富集能力波动变化不显著。方法对磷的检出限为98.12 ng/L。将碳酸镧-DGT和传统Ferrihydrite-DGT在模拟水样、易海及巢湖中进行实地监测实验,比较实验结果得,碳酸镧-DGT可以更好的监测不同水环境中的磷。(2)CaAl-LDH的聚丙烯酰胺凝胶膜作为DGT的结合相。该CaAl-LDH采用乙醇辅助液相共沉淀法制备而成。洗脱液为5 mL,2.0 mol/L的NaOH,洗脱效率为76.0%;在温度T=25℃,pH=7.00,离子强度NaNO3=0.01 mol/L,磷初始浓度为5μg/m L,放置时间为15-360 min的条件下,CaAl-LDH-DGT所测得的实际磷吸附量与计算公式所得吸附磷量相一致;当初始磷浓度在0.1-5μg/mL时,CaAl-LDH-DGT测定磷浓度值与磷钼蓝比色法测定磷浓度值相基本一致;当pH在3.12-7.79,离子强度在10-6-0.1 mol/L范围内时,CaAl-LDH-DGT检测磷结果变化不显著;在10-30℃下,CaAl-LDH-DGT对磷的富集量随着温度的升高而增加,方法对磷的检出限为81.71ng/L。CaAl-LDH-DGT和传统的Ferrihydrite-DGT应用于模拟水样、易海、巢湖水中的对比研究结果可知,CaAl-LDH-DGT更能准确测定不同水体中的磷浓度。
[Abstract]:The accurate determination of phosphate ion is of great significance for the prevention and control of water eutrophication and water environmental pollution. Because the concentration of the substances to be tested in the environment is low, the composition is complex and the interference is many, it will change with the environmental conditions, so the traditional monitoring technology needs tedious pretreatment before the detection experiments can be carried out. The sample pretreatment process needs complicated manual operation, high working intensity, long operating time and poor reproducibility, which brings great error to the final measurement and analysis. Therefore, it is of great significance to study the new technique of in situ passive sampling to reduce the error in the process of sample pretreatment. Thin film gradient diffusion (Diffusive Gradients in Thin Films Technique,DGT) is a new monitoring technique based on the first diffusion law of Fick. It has been widely used in the in-situ monitoring of phosphorus content in water, sediment and soil in recent years. In this paper, polyacrylamide gel membrane containing lanthanum carbonate and CaAl-LDH was used to study the effects of DGT storage time, initial phosphorus concentration, pH, ion strength and temperature on the ability of phosphate ion enrichment. The results are as follows: (1) Lanthanum carbonate polyacrylamide gel film is used as DGT binding phase. The maximum adsorption capacity of lanthanum carbonate-DGT for phosphorus was 68.73 渭 g and the effective adsorption capacity was 12.82 渭 g when the initial concentration of phosphorus was 5 渭 g/mL and the temperature of pH=7.00, was 25 鈩，
本文编号：2306717
[Abstract]:The accurate determination of phosphate ion is of great significance for the prevention and control of water eutrophication and water environmental pollution. Because the concentration of the substances to be tested in the environment is low, the composition is complex and the interference is many, it will change with the environmental conditions, so the traditional monitoring technology needs tedious pretreatment before the detection experiments can be carried out. The sample pretreatment process needs complicated manual operation, high working intensity, long operating time and poor reproducibility, which brings great error to the final measurement and analysis. Therefore, it is of great significance to study the new technique of in situ passive sampling to reduce the error in the process of sample pretreatment. Thin film gradient diffusion (Diffusive Gradients in Thin Films Technique,DGT) is a new monitoring technique based on the first diffusion law of Fick. It has been widely used in the in-situ monitoring of phosphorus content in water, sediment and soil in recent years. In this paper, polyacrylamide gel membrane containing lanthanum carbonate and CaAl-LDH was used to study the effects of DGT storage time, initial phosphorus concentration, pH, ion strength and temperature on the ability of phosphate ion enrichment. The results are as follows: (1) Lanthanum carbonate polyacrylamide gel film is used as DGT binding phase. The maximum adsorption capacity of lanthanum carbonate-DGT for phosphorus was 68.73 渭 g and the effective adsorption capacity was 12.82 渭 g when the initial concentration of phosphorus was 5 渭 g/mL and the temperature of pH=7.00, was 25 鈩，
本文编号：2306717
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