砷中毒商业V2O5-WO3/TiO2催化剂再生研究

Study on Regeneration of Commercial V2O5-WO3/TiO2 Catalyst for Arsenic Poisoning

采用FeCl3和2,4,6-三巯基三嗪(TMT)溶液分别清洗再生砷(As)中毒商业V2O5-WO3/TiO2催化剂,通过BET、XRD、XRF、in situ DRIFTS以及H2-TPR等表征方法对清洗再生前后催化剂理化性质进行分析.研究发现,清洗后催化剂脱硝活性有极大地恢复,20 mg·mL-1 FeCl3和0.5%TMT溶液再生30 min时最佳As去除率分别为83.67%和94.57%.清洗后,阻塞在催化剂微孔和中孔中的AsOx被清除,因此再生后催化剂比表面积和孔体积均有所增大而平均孔径略有减小.同时,FeCl3和2,4,6-TMT溶液清洗再生后催化剂表面Bronsted和Lewis酸强度均有所增加,这可能是再生催化剂催化性能提高的主要原因.

FeCl3 and 2,4,6-trimercaptotriazine(TMT)solutions were used to clean and regenerate arsenic(As)poisoned commercial V2O5-WO3/TiO2 catalysts.A comparative study of physico-chemical properties between poisoned and regenerated catalysts was carried out by Brunauer-Emmette-Teller(BET),X-ray diffraction(XRD),X-ray fluorescence(XRF),in situ infrared spectrometry(in situ IR),and temperature programmed reduction of H2(H2-TPR).It was found that the catalyst’s denitration activity was greatly restored after cleaning.Regeneration by 20 mg·mL-1 FeCl3 and 0.5%TMT solution for 30 min exhibited best As removal ratio of 83.67%and 94.57%,respectively.The micropores and mesopores which blocked by As oxides were cleaned,thus the specific surface area,pore volume increased and the average pore diameter decreased.Meanwhile,the Br?nsted and Lewis acid strengths of the catalyst surface increased after FeCl3 and 2,4,6-TMT solution cleaning and regeneration,which might be the main reason for the improvement of catalytic performance over the regenerated catalysts.