SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Tongtong Wang,Jiyong Zheng,Jinjun Cai,Qiangqiang Liu,Xianxia Zhang
To improve the performance of graphitic carbon nitride (g-C 3 N 4 ), a hotly researched metal-free photocatalyst, for better application in the efficient removal of organic pollutants, adsorption synergistically enhanced photocatalysis mechanism was thoroughly explored. Based on KOH pore-forming activated biochar (ACB) and K + doped g-C 3 N 4 (K-gC 3 N 4 ), the novel activated biochar-based K-gC 3 N 4 composite (ACB-K-gC 3 N 4 ) was synthesized via the innovative ultrasonic-milling method. Rhodamine B (RhB), tetracycline (TC), norfloxacin (NOR), and chloramphenicol (CAP) were selected as target pollutants, and the effects of environmental factors, recycling and actual wastewater tests, disinfection effects, and various enhancement strategies were investigated. The results showed that K-gC 3 N 4 was successfully composited with ACB by various characterizations, where the loading mass ratio of 1:2 exhibited the best performance. ACB-K-gC 3 N 4 possessed a larger specific surface area, richer functional groups, suitable band gap (2.29 eV), and broader visible light absorption (~716 nm) than K-gC 3 N 4 . ACB-K-gC 3 N 4 presented effective removal efficiency over K-gC 3 N 4 for four pollutants, in which the removal efficiency of RhB reached 93.26%, and the degradation rate constant of 0.0119 min −1 was four times higher than K-gC 3 N 4 (0.0029 min −1 ). Moreover, ACB-K-gC 3 N 4 was superior to K-gC 3 N 4 in disinfecting S. aureus and E. coli , with a sterilization rate of exceeding 90% for 12 h. The photodegradation activity was dominated by · O 2 − , h + , and · OH, and the mechanisms involved in the three stages. This was attributed to the unique structure and surface properties (defects and persistent free radicals) of ACB, as evidenced by improved adsorption stage and transfer of degradation intermediates, facilitated the generation of active species, accelerated migration of photogenerated electrons, and inhibited photogenerated carriers recombination by the heterojunction . The good reusability and stability, enhancement strategies (blowing air and heating), and satisfactory feasibility for actual wastewater allow ACB-K-gC 3 N 4 possible to promote high-concentration wastewater treatment and disinfection.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
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2021
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IF 3.882
Binyao Liu,Xiaoqin Nie,Yi Tang,Shan Yang,Liang Bian,Faqin Dong,Huichao He,Yong Zhou,Kun Liu
The thermal-condensation method is widely used for the synthesis of K-doped g-C3N4 photocatalysts, but the presence of organic byproducts in the resultant products is often overlooked in previous reports. Here, we demonstrated the universal presence of organic byproducts in K-doped g-C3N4 synthesized by typical thermal condensation of KOH/melamine, KOH/dicyandiamide, or KOH/urea. Taking the K-doped g-C3N4 photocatalysis for the degradation of dimethyl phthalate as an example, the negative influence of the organic byproducts on K-doped g-C3N4 photocatalysis was confirmed. Specifically, the organic byproducts can be gradually dissolved into the photocatalytic system of K-doped g-C3N4 as new and stable pollutants. Based on the solubility investigations on the byproducts in several solvents, hot-water washing was demonstrated to be a relatively effective approach to remove the organic byproducts from K-doped g-C3N4. The formation of organic byproducts during the synthesis of K-doped g-C3N4 could be ascribed to the fact that the presence of K salts in melamine, dicyandiamide, or urea molecules results in their insufficient thermal condensation into expected g-C3N4. The present work provides objective information about the K-doped g-C3N4 photocatalysts and reminds researchers about the influence of the organic byproducts on the applications of the other impurity-doped g-C3N4 photocatalysts.
研究领域:
材料化学
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环境催化
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光催化
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纳米材料
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污染物降解
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
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2020
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IF 3.085
Junnan Qu,Yi Du,Yibing Feng,Jianyong Wang,Bo He,Minxing Du,Yang Liu,Nan Jiang
A visible-light-responsive hybrid photocatalyst , K-doped g-C 3 N 4 /BiOBr, has been synthesized by K-doped g-C 3 N 4 (K–CN) and BiOBr. The property of photocatalysts was characterized by XRD , FT-IR, TEM, SEM , DRS , PL , EIS and HPLC. The photocatalytic activity of K-doped g-C 3 N 4 /BiOBr was evaluated by degradation of Rhodamine B (RhB) and tetracycline hydrochloride under visible-light irradiation. The K-doped g-C 3 N 4 /BiOBr hybrid photocatalyst which contains K–CN with mass fraction of 20% (20K–CN/BiOBr) shows the best degradation efficiency of RhB. The degradation efficiency of RhB (20 mg/L) can be achieved to 99% and the degradation efficiency of tetracycline hydrochloride by BiOBr decreased with the increase of K-doped g-C 3 N 4 doping. The results of photocurrent and EIS assumed that the tight coupling between K–CN and BiOBr can enhance the separating efficiency of photo-generated carrier. In addition, the capture experiment proof that h + is the primary active substance in the system of reaction and ·OH is the auxiliary active substance. After five degradation experiments, the efficiency of the degradation of Rhodamine B by the sample can still reach 90%, which proves that the samples are stable. A new and efficient method is provided in this work to solve the pollution of organic dyes and antibiotics.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）