Photocatalytic activation of sulfite by nitrogen vacancy modified graphitic carbon nitride for efficient degradation of carbamazepine
Photocatalytic activation of sulfite by nitrogen vacancy modified graphitic carbon nitride for efficient degradation of carbamazepine
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氮空位改性石墨氮化碳光催化活化亚硫酸盐高效降解卡马西平
DOI：
10.1016/j.apcatb.2018.09.007
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发表时间：
2019-02-01
影响因子：
22.1
通讯作者：
Tang, Heqing
中科院分区：
文献类型：
--
作者：
Cao, Jin;Nie, Wenshan;Tang, Heqing
以三聚氰胺为原料，在氮气保护下制备了具有丰富氮空位的石墨碳氮化物（NV-g-C3 N4），并将其用于构建可见光下亚硫酸盐活化体系降解卡马西平。在Na_2SO_3（20 mmol L ~（-1））存在下，NV-g-C_3N_4（1 g L ~（-1））使卡马西平（42 μ mol L ~（-1））光降解的表观速率常数增加到0.0187 min ~（-1），与常规g-C_3N_4（Bulkg-C_3 N_4）相比，增加幅度为270%。NV-g-C3 N4对卡马西平光降解的促进作用归因于氮空位对光生电子的有效捕获，抑制了光生载流子的复合.因此，更多的空穴聚集在价带，可用于激活亚硫酸根阴离子，产生亚硫酸根自由基。亚硫酸根自由基被确定为主要的反应物种在所研究的光催化体系降解卡马西平。通过GC-和LC-MS对中间产物的鉴定，阐明了亚硫酸根在NV-g-C3 N4/Na 2SO 3体系中对卡马西平的降解途径。
Graphitic carbon nitride with plentiful nitrogen vacancies (NV-g-C3N4) was prepared through a treatment of melamine under a N-2 flow, and used for constructing a system of sulfite activation under visible light toward the degradation of carbamazepine. In the presence of Na2SO3 (20 mmol L-1), the use of NV-g-C3N4 (1 g L-1) increased the apparent rate constant for the photodegradation of carbamazepine (42 mu mol L-1) to 0.0187 min(-1), with an increasing magnitude of 270% in comparison with that obtained by using the conventional g-C3N4 (Bulkg-C3N4). The enhanced photodegradation of carbamazepine by NV-g-C3N4 was found to be attributed to the efficient trap of photo-generated electrons by nitrogen vacancies, which inhibited the recombination of photo-generated carriers. Therefore, more holes aggregating in the valence band were available for the activation of sulfite anions to produce sulfite radicals. Sulfite radicals were identified as the major reactive species in the investigated photocatalytic system for the degradation of carbamazepine. The degradation pathway of carbamazepine induced by sulfite radicals in the NV-g-C3N4/Na2SO3 system was clarified on the basis of the identification of intermediates by GC- and LC-MS. The photocatalytic activation of sulfite by metal free NV-g-C3N4 may be a useful technique for purifying waste-water containing organic pollutants.