Assari Mohammad Javad, Rezaee Abbas, Jonidi Jafari Ahmad, Bahrami Abdolrahman
Department of Occupational Health Engineering, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
J Res Health Sci. 2013 May 29;13(1):37-42.
The objective of this work was developing a simple and stable time-based on-line setup for assessing the potential of mercury (Hg) vapor adsorption of the commercial sorbents used in air sampling and control operation followed by cold vapor atomic absorption spectrometry (CVAAS).
A special designed separation chamber was used where reduction of the injected Hg (II) solution took place. Purge gas passes through this chamber resulting to a prompt release of mercury vapor, purging into the adsorbent that regulated at the desired adsorption temperature. After sorbent saturation, in order to study the adsorption parameters of sorbents (activated carbon and bone char) such as breakthrough time (BTT), and adsorptive capacity, mercury gas stream was passed through the sorbents, directly transport to the CVAAS.
Preliminary experiments concerning the reductant solution showed that SnCl2 offers higher stability than NaBH4. Around the loading range 0.125-2.5 ml min⁻¹ of 100 µg l⁻¹ Hg(II) solution, a linear calibration curve with the equation peak area=0.134; loading flow=-0.017 and a correlation coefficient r=0.996 was obtained, and the detection limit was improved up to c(L)=1 µg l⁻¹. The relative standard deviation of five measurements of lowest flow loading of Hg (II) was RSD=2.8%. The significant differences were observed in the breakthrough time and mercury adsorptive capacity between activated carbon and bone char (P=0.010).
This novel setup is suitable for an on-line study of elemental mercury adsorption, determination of breakthrough time and adsorption capacity, and because of its stable performance during all experiments; it can be applied to the time based studies.
本研究的目的是开发一种简单且稳定的基于时间的在线装置，用于评估空气采样和控制操作中使用的商用吸附剂对汞（Hg）蒸气的吸附潜力，随后采用冷蒸气原子吸收光谱法（CVAAS）进行检测。
使用一个特别设计的分离室，在此室内注入的汞（II）溶液会发生还原反应。吹扫气体通过该室，促使汞蒸气迅速释放，然后吹扫到在所需吸附温度下调节好的吸附剂上。吸附剂饱和后，为研究吸附剂（活性炭和骨炭）的吸附参数，如穿透时间（BTT）和吸附容量，汞气流通过吸附剂，直接传输至CVAAS。
关于还原剂溶液的初步实验表明，SnCl₂ 比 NaBH₄ 具有更高的稳定性。在 100 μg l⁻¹ Hg（II）溶液的加载范围为 0.125 - 2.5 ml min⁻¹ 时，获得了一条线性校准曲线，方程为峰面积 = 0.134；加载流量 = -0.017，相关系数 r = 0.996，检测限提高至 c(L) = 1 μg l⁻¹。Hg（II）最低流量加载的五次测量的相对标准偏差为 RSD = 2.8%。活性炭和骨炭在穿透时间和汞吸附容量方面存在显著差异（P = 0.010）。
这种新型装置适用于元素汞吸附的在线研究、穿透时间和吸附容量的测定，并且由于其在所有实验过程中的稳定性能，可应用于基于时间的研究。
