羟基铝柱撑膨润土负载纳米铁还原Cr(Ⅵ)

Reduction of Chromium(Ⅵ) by Nanoscale Zero-Valent Iron Supported on Al-Pillared Bentonite

用具有良好吸附能力的羟基铝柱撑膨润土作载体,通过FeSO4与NaBH4反应制得羟基铝柱撑膨润土负载的纳米铁(nanoscale zero-valent iron supported on Al-pillared bentonite,NZVI/Al-PILC).用X射线衍射(X-ray diffraction,XRD)(、Brunauer-Emmett-Teller,BET)法对NZVI/Al-PILC进行了结构表征.以Cr(Ⅵ)为目标污染物,考察了NZVI/Al-PILC与Cr(Ⅵ)反应过程中,介质pH、不同起始浓度的Cr(Ⅵ)对其去除率的影响,并与相同铁含量的纳米铁(nanoscale zero-valent iron,NZVI)进行了比较.结果表明,在相同实验条件下,Cr(Ⅵ)与NZVI/Al-PILC反应120 min后去除率接近100%,不仅高于相同铁含量NZVI对Cr(Ⅵ)去除率(63.0%),而且也明显优于相同铁含量的NZVI和相同含土量的羟基铝柱撑膨润土对Cr(Ⅵ)去除率的加和(75.4%).

In the presence of Al-pillared bentonite with good sorption capacity, nanoscale zero-valent iron supported on Al-pillared bentonite （NZVI/Al-PILC） was prepared with NaBH4 and FeSO4 aqueous solution. The structure of NZVI/Al-PILC was characterized by X-ray diffraction （XRD） and Brunauer-Emmett-Teller （BET）. The effects of pH values and initial chromium（ Ⅵ ） concentrations on its removal rate by NZVI/ Al-PILC were investigated, and were compared with those of unsupported nanoscale zero-valent iron （NZVI） containing the same iron mount of NZVI/Al-PILC. The results indicate that in the same experimental condition, the chromium（ Ⅵ ） removal by NZVI/Al-PILC reached 100% after 120 min. The removal is not only much higher than that （63.0%） of the NZVI containing same iron mount, but also superior to the sum of removal （75.4%） by NZVI containing the same iron amount and the Al-pillared bentonite containing the same clay amount with NZVI/Al- PILC.