Pitoniak Erik, Wu Chang-Yu, Mazyck David W, Powers Kevin W, Sigmund Wolfgang
Department of Environmental Engineering Sciences, Particle Engineering Research Center, University of Florida, Gainesville, Florida 32611-6450, USA.
Environ Sci Technol. 2005 Mar 1;39(5):1269-74. doi: 10.1021/es049202b.
A novel nanocomposite that combines high-surface area silica with the photocatalytic properties of titania has been developed that allows for effective capture of elemental mercury vapor. The adsorption capability of the developed material has been found to improve after periods of photocatalytic oxidation. In this study, the mechanisms for adsorption enhancement were identified. BET nitrogen adsorption and mercury porosimetry were used to evaluate pore structure, and the results suggest that a decrease in contact angle was likely to be responsible for improved mercury capture over time. Contact angle measurements showed a significant change of more than 10 degrees, indicating greater attraction to mercury for the used pellets due to deposited mercuric oxide. ICP and TGA analyses showed that mercury was captured as both elemental mercury (Hg0) and mercuric oxide (HgO). In addition, it was shown that pellets used for nearly 500 h still showed greater than 90% removal efficiency and had an average capacity of 10 mg of Hg/g based on mass balance calculations, while some pellets had a capacity over 30 mg of Hg/g according to ICP and TGA analyses. Mercuric oxide doped pellets removed 100% of elemental mercury without pretreatment. The superior mercury removal efficiency combined with various advantages of the novel composite demonstrates its use as an effective alternative to conventional activated carbon injection technology.
一种将高比表面积二氧化硅与二氧化钛的光催化性能相结合的新型纳米复合材料已被开发出来，它能够有效捕获元素汞蒸气。研究发现，经过光催化氧化一段时间后，所开发材料的吸附能力有所提高。在本研究中，确定了吸附增强的机制。采用BET氮吸附和汞孔隙率测定法评估孔隙结构，结果表明接触角的减小可能是随着时间推移汞捕获量提高的原因。接触角测量显示有超过10度的显著变化，表明由于沉积的氧化汞，使用过的颗粒对汞的吸引力更大。电感耦合等离子体质谱（ICP）和热重分析（TGA）表明，汞以元素汞（Hg0）和氧化汞（HgO）两种形式被捕获。此外，研究表明，根据质量平衡计算，使用了近500小时的颗粒仍显示出大于90%的去除效率，平均容量为10毫克汞/克，而根据ICP和TGA分析，一些颗粒的容量超过30毫克汞/克。掺杂氧化汞的颗粒无需预处理就能去除100%的元素汞。这种新型复合材料卓越的汞去除效率及其各种优点表明，它可作为传统活性炭喷射技术的有效替代品。
