Rivero-Huguet Mario, Marshall William D
Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne-de-Bellevue, Qc, Canada.
J Hazard Mater. 2009 Sep 30;169(1-3):1081-7. doi: 10.1016/j.jhazmat.2009.04.062. Epub 2009 Apr 22.
A variety of micron-scale mixed metallic particles (Pd/Fe, Ag/Fe, Cu/Fe, Zn/Fe, Co/Fe, Mg/Fe, Ni/Fe, Al/Fe, Si/Fe, Pd/Cu and Pd/Zn; and Pd/Cu/Fe, Pd/Zn/Fe and Zn/Cu/Fe) and selected nano-sized bimetallic analogs (Pd/Fe, Cu/Fe and Pd/Cu) were evaluated for reducting activity with Cr(VI) in a surfactant preparation (Tween 20) under a variety of reaction conditions. Relative to the reactivity of the zero-valent iron, the tested bimetallic mixtures (Pd/Fe>Pd/Zn>Ag/Fe>Ni/Fe>Zn/Fe>Pd/Cu>Cu/Fe) appreciably increased the pseudo-first-order rate constant. The Zn/Cu/Fe represented a cost-effective preparation providing comparable or improved kinetic parameters relative to the more expensive palladized bimetallic mixtures. The Pd/Fe, Cu/Fe and Pd/Cu nano-sized particles proved to be more reactive (up to 100-fold) for the reductive remediation of Cr(VI). The results were comparable when working with nano-sized Cu and Fe particles, suggesting that the cementation of a noble metal serves not only as a reaction catalyst but also provides protection to the metallic surface, impeding its rapid inactivation.
在各种反应条件下，对多种微米级混合金属颗粒（钯/铁、银/铁、铜/铁、锌/铁、钴/铁、镁/铁、镍/铁、铝/铁、硅/铁、钯/铜和钯/锌；以及钯/铜/铁、钯/锌/铁和锌/铜/铁）和选定的纳米级双金属类似物（钯/铁、铜/铁和钯/铜）在表面活性剂制剂（吐温20）中还原六价铬的活性进行了评估。相对于零价铁的反应活性，测试的双金属混合物（钯/铁>钯/锌>银/铁>镍/铁>锌/铁>钯/铜>铜/铁）显著提高了伪一级反应速率常数。锌/铜/铁是一种具有成本效益的制剂，相对于更昂贵的含钯双金属混合物，其动力学参数相当或有所改善。钯/铁、铜/铁和钯/铜纳米颗粒被证明对六价铬的还原修复反应性更高（高达100倍）。使用纳米级铜和铁颗粒时结果相当，这表明贵金属的胶结不仅作为反应催化剂，还能保护金属表面，阻止其快速失活。
