锰氧化物负载聚苯胺选择性氧化硫化物的效能及机理

Efficiency and mechanism of sulfide selective oxidation by manganese oxides supported polyaniline

目前关于含硫废水处理技术的研究已取得有效进展,但难以在去除含硫污染物的同时实现硫资源的回收利用。为此,通过化学浸渍法制得了锰氧化物负载聚苯胺(Mn_(x)O_(y)-PANI)催化剂。XRD、FTIR、XPS和SEM表征结果表明,Mn_(x)O_(y)已成功负载于PANI载体。以空气为氧化剂,探究了该催化剂对含硫废水(以Na_(2)S为模拟污染物)的选择性氧化性能。结果表明:Mn_(x)O_(y)-PANI催化剂表现出优异的Na_(2)S选择氧化性;当催化剂用量为0.2 g∙L^(−1)、Na_(2)S初始质量浓度为100 mg∙L^(−1)时,240 min内S^(2−)可被完全氧化为单质硫(S_(0))。Mn_(x)O_(y)-PANI反应后的XPS、XRD、Raman表征结果证明,S 0在催化剂上稳定存在。此外,考察了催化剂投加量、Na_(2)S初始浓度、反应温度、初始pH和不同反应气氛对催化氧化Na_(2)S的影响。循环实验结果表明,Mn_(x)O_(y)-PANI具有较好的稳定性。最后,提出了选择性氧化的可能反应机理,为含硫废水的治理和回收提供参考。

An effective progress has been made for sulfide wastewater treatment technology development,but the recovery of sulfur resources is hard to be achieved while alleviating environmental pollution.Here a manganese oxides supported polyaniline material(Mn_(x)O_(y)-PANI)was prepared by a chemical impregnation method.XRD,FTIR,XPS and SEM results indicated that manganese oxides were successfully loaded on the polyaniline substrate.When air was taken as the oxidant,effect of catalyst on sulfide wastewater(Na_(2)S as simulated contaminant)selective oxidation was investigated.The results demonstrated that Mn_(x)O_(y)-PANI catalyst had an excellent catalytic activity and selectivity on Na_(2)S oxidation.When the catalyst dosage was 0.2 g∙L^(-1)and the initial Na_(2)S concentration was 100 mg∙L−1,S^(2−)could be completely oxidized to element sulfur(S 0)within 240 minutes.S_(0)existence on catalyst was confirmed by XPS,XRD and Raman detection of used Mn_(x)O_(y)-PANI.Besides,the influences of catalyst dosage,reaction temperature,initial Na_(2)S concentration,initial pH and different reaction atmospheres on the catalytic oxidation of Na_(2)S were studied.Cycling experiments suggested that Mn_(x)O_(y)-PANI had a superior stability.Finally,the possible mechanism of selective oxidation was proposed,providing a new insight into the treatment and recovery technology of sulfide wastewater.