氮掺杂介孔碳催化过硫酸盐氧化降解盐酸四环素

Oxidative degradation of tetracycline hydrochloride by persulfate catalyzed by nitrogen-doped mesoporous carbon

以白酒糟为碳源、纳米SiO_(2)为模板剂,通过调控三聚氰胺添加量一步法制备了系列氮掺杂介孔碳(NMCs)。采用N;吸附/脱附、XPS、XRD、FT-IR、Raman等手段对NMCs的结构与表面性质进行表征,并将NMCs用于催化过硫酸盐(PS)处理盐酸四环素(TC)废水。结果表明,三聚氰胺投加量的不同,对NMCs的孔结构影响不大,孔径集中分布在3.8 nm附近,比表面积在138~184 m^(2)/g之间;NMCs催化降解TC的活性随着三聚氰胺投加量的增大而增强,其增强与表面吡啶氮和石墨氮2种含氮官能团密切相关。NMCs活化PS降解TC符合准二级动力学,反应活化能为20.29 k J/mol;当三聚氰胺添加量为白酒糟质量的14.5%时,其催化活性最好。在反应温度为25℃,催化剂投加量为0.4 g/L,PS投加量为0.4 g/L和较宽的pH范围(4.0~11.0)条件下,50 mg/L的TC溶液在反应60 min后,降解率可达82.9%。自由基掩蔽结果表明,表面自由基反应起主要作用。催化剂循环使用4次后,通过高温再生,催化活性可恢复至原来的86.9%。

A series of nitrogen-doped mesoporous carbons(NMCs)were prepared by using liquor grains as carbon source,nano-silica as template and different amount of melamine as nitrogen source. N2 adsorption/desorption,XPS,XRD,FT-IR and Raman were used to characterize the structure and surface properties of NMCs,and NMCs were used to catalyze persulfate(PS)oxidation for treating tetracycline hydrochloride(TC)wastewater. The results showed that the difference in the amount of melamine had little effect on the pore structure of NMCs. The pore size was concentrated around 3.8 nm,and the specific surface area was 138-184 m^(2)/g. The activity of NMCs increased with the increase of melamine,and this enhancement was closely related to the surface pyridine nitrogen and graphitic nitrogen. The reaction of PS activation to degrade TC met with the pseudo-second-order kinetic model,and the activation energy was 20.29 kJ/mol. When the added amount of melamine was 14.5%,its catalytic activity was the best. Under the conditions of 25 ℃,0.4 g/L catalyst,0.4 g/L PS,and wide pH range(4.0-11.0),the degradation efficiency of TC(50 mg/L)reached 82.9% after 60 min of reaction. The results of free radical masking indicated that surface free radical reactions played a major role. After 4 th cycles,the catalytic activity recovered to 86.9% by high-temperature regeneration.