纳米Pd/Fe双金属对2,4-二氯酚的脱氯机理及动力学

采用纳米Pd Fe双金属对2,4 二氯酚(2,4 DCP)进行了催化还原脱氯处理.结果表明,纳米Pd Fe双金属具有较高的比表面积和反应活性,对2,4 DCP具有较好的脱氯效率.当纳米Pd Fe用量在6g·L-1时,2,4 DCP脱氯率达到90%以上;脱氯效率与pH值、温度、钯化率、Pd Fe投加量等因素有关.2,4 DCP在脱氯过程中先生成邻氯酚和对氯酚,而后继续脱氯生成苯酚,或由2,4 DCP直接降解成苯酚.2,4 DCP降解符合拟一级反应动力学.2,4 DCP催化还原脱氯反应的活化能为139 7kJ·mol-1.

Dechlorination mechanism and kinetic of 2,4-DCP by nanoscale Pd/Fe system

Nanoscale Pd/Fe bimetallic catalysts were synthesized via chemical deposition and used to decompose 2,4-DCP. Nanoscale particles were characterized by high surface area to volume ratios and high reactivity. Batch experiments demonstrated that the nanoscale Pd/Fe particles could effectively dechlorinate 2,4-DCP at relatively low metal to solution ratio (6g·L^-1), Dechlorination efficiency reached 90% at Pd weight ratio (Pd to Fe) 0.11%. Dechlorination was affected by reaction temperature, pH, Pd ratio and the addition of nanoscale Pd/Fe.2-CP and 4 CP represent stable partially dechlorination intermediates, and then phenol. Some 2,4-DCP was dechlorinated to phenol indirectly. The dechlorination was believed to take place on the surface of the nanoscale Pd/Fe bimetallic particles via a pseudo-first order reaction,the activation energy was found to be 139.7kJ·mol-1.