Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, USA.
Water Res. 2013 Jul 1;47(11):3706-15. doi: 10.1016/j.watres.2013.04.024. Epub 2013 Apr 24.
In this work, we developed and tested a new class of supported Pd catalysts by immobilizing CMC (carboxymethyl cellulose) stabilized Pd nanoparticles onto alumina support. The alumina supported Pd nanoparticles were able to facilitate rapid and complete hydrodechlorination of TCE (trichloroethylene) without intermediate by-products detected. With a Pd mass loading of 0.33 wt% of the alumina mass, the observed pseudo first order reaction rate constant, k(obs), for the catalyst was increased from 28 to 109 L/min/g when CMC concentration was raised from 0.005 to 0.15 wt%. The activity increase was in accord with an increase of the Pd dispersion (measured via CO chemisorption) from 30.4% to 45.1%. Compared to the commercial alumina supported Pd, which has a lower Pd dispersion of 21%, our CMC-stabilized Pd nanoparticles offered more than 7 times greater activity. Pre-calcination treatment of the supported catalyst resulted in minor drop in activity, yet greatly reduced bleeding (<6%) of the Pd nanoparticles from the support during multiple cycles of applications. The presence of DOM (dissolved organic matter) at up to 10 mg/L as TOC had negligible effect on the catalytic activity. The alumina supported CMC-stabilized Pd nanoparticles may serve as a class of more effective catalysts for water treatment uses.
在这项工作中，我们通过将 CMC（羧甲基纤维素）稳定的钯纳米颗粒固定在氧化铝载体上，开发并测试了一类新型负载型 Pd 催化剂。负载在氧化铝上的钯纳米颗粒能够促进 TCE（三氯乙烯）的快速完全加氢脱氯，而没有检测到中间副产物。当 CMC 浓度从 0.005wt%增加到 0.15wt%时，负载型 Pd 的质量负载为氧化铝质量的 0.33wt%，观察到的假一级反应速率常数 k(obs)从 28L/min/g 增加到 109L/min/g。活性的增加与 Pd 分散度（通过 CO 化学吸附测量）从 30.4%增加到 45.1%一致。与 Pd 分散度较低（21%）的商业氧化铝负载 Pd 相比，我们的 CMC 稳定的钯纳米颗粒的活性提高了 7 倍以上。负载型催化剂的预煅烧处理导致活性略有下降，但在多次应用循环中，Pd 纳米颗粒从载体上的渗滤（<6%）大大减少。高达 10mg/L TOC 的 DOM（溶解有机物质）的存在对催化活性几乎没有影响。负载型 CMC 稳定的钯纳米颗粒可用作水处理的一类更有效的催化剂。
