摘要
建立了chelex-100螯合树脂分离技术与石墨炉原子吸收联用测定水体中Tl(Ⅰ)与Tl(Ⅲ)的方法,分别考察了光化学氧化中pH值、H2O2投加量、光照强度对Tl(Ⅰ)的氧化效果。方法的Tl(Ⅰ)与Tl(Ⅲ)检出量均为0.5μg/L。两者共存时各自加标回收率大于95%。结果表明,在偏酸性环境(pH=3.0),投加适量30%H2O2,光照强度大有利于Tl(Ⅰ)的氧化。当pH=2.91,投加30%H2O2为5 mL,UV照射10min后,Tl(Ⅰ)的转化率达90%。研究表明,光化学氧化可有效转化水体中不易被物理化学法去除的Tl(Ⅰ)和容易被物理吸附、化学沉淀方法去除的Tl(Ⅲ)。
This paper is engaged in the study of valence status transformation between Tl（Ⅰ） and Tl（Ⅲ） in UV-H2O2 system.For this purpose,we have tried a simplified,quick-effective chelex-100 resin-column separating technique and adopted the graphite furnace atomic absorption spectrometer to determining Tl（Ⅰ） and Tl（Ⅲ） in the UV-H2O2 reaction.For this purpose,we have done experiments by pumping a water sample with its pH of 110 by using a small plug of the Na-form of chelex,that is,a 100 resin at a flow rate of 0.5-10 mL/min.And then,we have carried out a batch pH and flowing rate experiments in hoping to find the effect of pH and the flow rate on the separation and adsorption process.And,finally,we have gained the optimal separating effect of Tl（Ⅲ） from Tl（Ⅰ） through testing various pH values and flow rates by adjusting the sample pH to about 1.0 and removing Tl（Ⅲ） from the sample onto a chelex-100 resin the column at a flow rate of 8 mL/min.The maximal separating limit for the method was 0.5 μg/L.The recovery rate of the two thallium forms in the synthetic solutions can be as high as 95%.Besides,we have also investigated the effect of the pH value,the quantity of 30% H2O2 to be added,the light intensity on the Tl（Ⅰ） oxidation under UV＋ H2O2.The results of our experiments show that the low pH（≈3.0）,the moderate quantity of H2O2 added,the strong light intensity are all in favor of Tl（Ⅰ） oxidation.In case of pH=5.01,with about 40% Tl（Ⅰ） in the water sample after 50 min of irradiation,only less than 5% Tl（Ⅰ） remained in the water sample after 25 min of irradiation if the added quantity of 30% H2O2 was 4 mL.In addition,If the distance between the surface of solution and the light source is 10 cm,pH=2.91,the amount of 30% H2O2 4 mL,the conversion rate of Tl（Ⅰ） in the solution after 10 min of UV irradiation should reach about 98%.Thus,Tl（Ⅰ）,for its not being easy to be removed by the physical-chemical methods in solution,can be effectively transformed into Tl（Ⅲ） by photo-chemical oxidation in water sample.And Tl（Ⅲ） is easily separated through physical adsorption,or chemical precipitation.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2012年第2期72-75,共4页
Journal of Safety and Environment
基金
国家水体污染控制与治理科技重大专项东江项目(2008ZX07211-003)
