CNT-Fe/Zn催化剂的制备及其催化臭氧氧化降解DBP

Preparation of CNT-Fe/Zn catalyst and its catalytic ozonation for DBP degradation

本研究采用浸渍-煅烧法制备了负载锌(CNT-Zn)、铁(CNT-Fe)和锌铁共掺杂(CNT-Fe/Zn)的碳纳米管催化剂,考察了不同pH值下3种催化剂催化臭氧氧化水中DBP的效果.结果表明,CNT-Fe/Zn具有最佳催化性能,在宽pH值范围内比单独臭氧降解DBP的去除率提升22%~52%.在DBP初始浓度4mg/L、初始pH值为4、臭氧用量20mg/L、催化剂投加量50mg/L的条件下,30min内DBP去除率可达72.41%.利用SEM、XRD和XPS等多种手段对该催化剂进行了表征,CNT-Fe/Zn表面的含氧基团是主要活性位点,CNT-Fe/Zn的加入促进了羟基自由基的产生,在酸性条件下生成的过氧化氢进一步提高了DBP的去除率.催化剂循环实验表明,CNT-Fe/Zn催化剂具有优异的催化稳定性和重复利用性.

Dibutyl phthalate(DBP),an endocrine disruptor,has been frequently detected in surface water,soil,and groundwater in recent years,posing potential risks to both ecological environments and human health.Catalytic ozonation has been proven effective for DBP removal,albeit its efficacy is significantly influenced by pH level.In this study,carbon nanotube-based catalysts were prepared through an impregnation-calcination method,including zinc-loaded(CNT-Zn),iron-loaded(CNT-Fe),and zinc-iron co-doped(CNT-Fe/Zn)catalysts,whose performances in catalytic ozonation of DBP in water were examined at varying pH levels.The results demonstrate that CNT-Fe/Zn exhibited optimal catalytic performance with a removal rate increase by 22%~52%compared to sole ozone degradation of DBP over a wide pH range.Even after five consecutive uses,CNT-Fe/Zn maintained high catalytic activity and low metal leaching rates.Under conditions of an initial DBP concentration of 4mg/L,initial pH of 4,ozone dosage of 20mg/L,and catalyst addition of 50mg/L,the DBP removal rate was up to 72.4%within 30minutes.The catalyst was characterized to reveal oxygen-containing groups on the surface of CNT-Fe/Zn as the primary active sites.In general,the CNT-Fe/Zn can facilitate the generation of hydroxyl radicals and further enhance DBP removal by forming hydrogen peroxide under acidic conditions,and its robust stability and reusability have been also confirmed by catalysis cycling experiments.