Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Mengni Ge,Zhuohui Jia,Quanguo Jiang,Guobing Ying,Yan Yang,Shaoyu Wu,Takashi Goto,Jianfeng Zhang
The development of highly-permeable reverse osmosis membranes has yet been pursued as a basis for efficient water purification/desalination. In this study, graphitic carbon nitride (g-C 3 N 4 ) nanomaterials with three structures, including one-dimensional (1D) g-C 3 N 4 nanorods , two-dimensional (2D) g-C 3 N 4 nanosheets and one/two-dimensional (1D/2D) g-C 3 N 4 nanohybrids were dispersed into polyamide layer for preparation of thin-film nanocomposite (TFN) membranes. The effects of different structures of g-C 3 N 4 nanomaterials on the microstructure and performance of membranes were investigated. Compared with polyamide membrane, 1D/2D nanohybrids incorporated TFN membrane had more open and larger nodular structures with abundant water channels. The surface roughness was decreased, the negativity and hydrophilicity were improved. The water permeability of resultant TFN membrane increased to 3.63 L·m −2 ·h −1 ·bar −1 for 2000 ppm NaCl brackish solution, 3.4 times that of PA membrane, with a high rejection of about 99.0 %. Even for 32,000 ppm NaCl solution, almost the same as the concentration of seawater, the water permeability of TFN membrane still maintained at 1.73 L·m −2 ·h −1 ·bar −1 , 1.4 times that of PA membrane. Meanwhile, antifouling performance of membranes was systematically analyzed under organic foulant, inorganic foulant and mixed organic-inorganic foulants, which proved the excellent antifouling performance of resultant TFN membranes. In a word, the 1D/2D nanohybrids incorporated TFN membrane exhibited superior permeability and antifouling performance to 1D nanorods or 2D nanosheets incorporated ones, confirming the effectiveness of 1D/2D g-C 3 N 4 nanohybrids for modification of reverse osmosis membrane and promising for more applications.
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Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Xiaoyu Yang,Boming Tang,Xuejuan Cao
Continuous photocatalysis is achieved by using light-storing assisted photocatalytic composites, but little is known about the interactions between photocatalysts and long afterglow materials. g-C 3 N 4 /Sr 2 MgSi 2 O 7 :(Eu,Dy) with a sustained reaction activity was prepared by pyrolysis polymerization, and its optical-photocatalysis behaviors were studied. It was found that the light absorption ability and NO removal effect were improved, but the luminescence-afterglow performance became worse. The interface model of g-C 3 N 4 /Sr 2 MgSi 2 O 7 :(Eu,Dy) was constructed for the first time. On the basis of experimental analyses, its electronic structure and carrier transfer paths were studied by First-principles calculations, and reasons behind the changes in macro performance were revealed. The results showed that Eu 4 f electrons are difficult to return to the Eu 5d orbits after being captured by C 2p orbits, leading to the reduction of light energy radiation; the built-in electric field and energy band offsets between g-C 3 N 4 and Sr 2 MgSi 2 O 7 :(Eu,Dy) promote the transfer of photoinduced carriers, which follows a traditional type-II mechanism, resulting in enhanced photocatalytic activity and decreased luminescence-afterglow performance. This paper reveals the relationship between optical-photocatalysis behaviors and the electronic structure of g-C 3 N 4 /Sr 2 MgSi 2 O 7 :(Eu,Dy). It provides a reference for designing and optimizing light-storing assisted photocatalytic composites.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Min Zhang,Yiguo Jiang,Xiuquan Xu,Xiaofeng Yu,Wenyan Shen,Miaomiao Luo,Luyao Ding,Haiwen Chen
The reinforced light-harvesting capability, suppressed photocarrier recombination and increased specific surface area represented a possibility of excellent photocatalytic performance for graphitic carbon nitride (g-C 3 N 4 )-based photocatalysts . Herein, the porous 1,3,5-Trihydroxybenzene substituted g-C 3 N 4 (denoted as PTBCN) composites with superior visible-light-driven photocatalytic properties were rationally constructed via a two-step reaction combination of freeze-drying and thermal-polymerization. The optimal PTBCN-2 achieved the maximum photocatalytic Rhodamine B (Rh B) degradation and H 2 O 2 evolution rate constants, nearly 6.56 and 3.17 times higher than that of bare g-C 3 N 4 . The outstanding performances of PTBCN-2 were probably attributed to the extended specific surface area, robust visible light response, adjusted electronic band structure , accelerated separation and transfer of photocarriers as well as good hydrophilicity. As a result, the above integrated merits were directly responsible for the huge superoxide anion ( • O 2 − ) generation, which dominated the efficient photocatalytic reactions. This work provided a new idea to design and construct high efficiency porous aromatic ring substituted g-C 3 N 4 -related photocatalysts for organic pollutants degradation and H 2 O 2 production.
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Catalysts
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2022
·Vol. 12
·期 7
·774
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IF 4.501
Wei Qian,Wangtong Hu,Zhifei Jiang,Yongyi Wu,Zihuan Li,Zenghui Diao,Mingyu Li
In recent years, with the large-scale use of antibiotics, the pollution of antibiotics in the environment has become increasingly serious and has attracted widespread attention. In this study, a novel CDs/g-C3N4/BiPO4(CDBPC) composite was successfully synthesized by a hydrothermal method for the removal of the antibiotic tetracycline hydrochloride (TC) in water. The experimental results showed that the synthesized photocatalyst was crystalline rods and cotton balls, accompanied by overlapping layered nanosheet structures, and the specific surface area was as high as 518.50 m2/g. This photocatalyst contains g-C3N4and bismuth phosphate (BiPO4) phases, as well as abundant surface functional groups such as C=N, C-O, and P-O. When the optimal conditions were pH 4, CDBPC dosage of 1 g/L, and TC concentration of 10 mg/L, the degradation rate of TC reached 75.50%. Active species capture experiments showed that the main active species in this photocatalytic system were holes (h+), hydroxyl radicals, and superoxide anion radicals. The reaction mechanism for the removal of TC by CDBPC was also proposed. The removal of TC was mainly achieved by the synergy between the adsorption of CDBPC and the oxidation of both holes and hydroxyl radicals. In this system, TC was adsorbed on the surface of CDBPC, and then the adsorbed TC was degraded into small molecular products by an attack with holes and hydroxyl radicals and finally mineralized into carbon dioxide and water. This study indicated that this novel photocatalyst CDBPC has a huge potential for antibiotic removal, which provides a new strategy for antibiotic treatment of wastewater.Keywords:carbon dots;photocatalysis;graphitic carbon nitride;bismuth phosphate;tetracycline hydrochloride
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Catalysis Science & Technology
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2022
·Vol. 12
·期 16
·5178-5188
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IF 6.177
Zegang Qiu,Xiaoxia He,Zhiqin Li,Qichen Guan,Liang Ding,Yanan Zhu,Yueling Cao
The development of non-noble metal catalysts with high efficiency for the hydrodeoxygenation (HDO) of bio-oil is of great importance for the utilization of lignin biomass resources. As a crucial lignin-based platform chemical, vanillin is a promising candidate for the production of fine chemicals and polymers. Here, a promising non-noble Co–Zn/NPC catalyst (NPC: nitrogen-doped porous carbon materials) for the HDO of vanillin was prepared by pyrolysis of Co–Zn zeolite imidazolate framework/graphitic carbon nitride (Co–Zn-ZIF/g-C3N4) composites. Full vanillin conversion with 99% MMP (2-methoxy-4-methylphenol) selectivity could be achieved at 100 °C and 1 MPa H2 over 4Co–1Zn/NPC. Characterization results indicate that the presence of g-C3N4 promotes the formation of mesopores, which is beneficial for fast mass transfer. Additionally, the introduction of Zn downsizes the size of Co nanoparticles, and lowers the electron density around the Co atoms in Co–Zn/NPC catalysts, which can accelerate the hydrogenation of vanillin. More importantly, the Zn introduced in the catalyst may function as a basic site to facilitate the conversion of the intermediate HMP (4-hydroxy-3-methoxybenzyl alcohol) into MMP, thus enhancing the MMP selectivity. Moreover, Co–Zn/NPC presents excellent stability in the HDO reaction of vanillin. This work provides some useful insights into the design of novel non-noble metal catalysts with high efficiency for HDO of bio-oil.
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Journal of Physical Chemistry C
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2022
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IF 4.177
Kang Hu,Ping Liu,Ziqing Zhang,Ji Bian,Guowei Wang,Hongjun Wu,Hui Xu,Liqiang Jing
g-C3N4 is a promising photocatalyst for CO2 conversion owing to its outstanding reduction potential. However, its shallow valence band position and sluggish water oxidation reaction restrict the overall CO2 photoreduction process. Herein, g-C3N4 nanosheets are first doped with B through thermal treatment of mixed NaBH4 and subsequently modified with highly dispersed Ru-oxo clusters by using tailored chitosan oligomers. The optimal Ru-oxo modified B-doped g-C3N4 exhibits an exceptional photocatalytic CO2 conversion rate with 22-fold improvement compared with pristine CN. Based on the results of electron paramagnetic resonance, atmosphere-controlled surface photovoltage spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc., it is confirmed that the improved photoactivities are attributed to the downward shift of the valence band to obtain the strong driving force for water oxidation along with extension of the visible light response region by B doping and to the capture of photogenerated holes to enhance charge separation and then to accelerate the water oxidation process from the modified Ru-oxo clusters.
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Journal of Environmental Chemical Engineering
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2022
·
IF 7.968
Chen Li,Tianyi Sun,Guohui Yi,Dashuai Zhang,Yan Zhang,Xiaoxue Lin,Jinrui Liu,Zaifeng Shi,Qiang Lin
A highly efficient visible light-driven photocatalytic membrane composed of Ag/CNQDs/g-C 3 N 4 and PVDF membranes was successfully prepared by vacuum filter crosslinking. This new type of photocatalytic membrane possessed both excellent photocatalytic degradation performance and photocatalytic self-cleaning properties. The Ag/CNQDs/g-C 3 N 4 photocatalyst coating amount of 10 mg had the highest photocatalytic degradation of norfloxacin (NOR), and the quasi-first-order kinetic constant ( k ) value was 0.0138 min −1 . Moreover, the mechanism of the photocatalytic reaction was also discussed. In addition, bovine serum albumin (BSA) as the simulated pollutant was applied to evaluate the self-cleaning property of the Ag/CNQDs/g-C 3 N 4 -PVDF composite membrane. After contamination with BSA, the water flux of the composite membrane decreased from 3880 L (m 2 h) −1 to 800 L (m 2 h) −1 . Then, the maximum pure water flux of the Ag/CNQDs/g-C 3 N 4 -PVDF photocatalytic composite membrane recovered 87% (3360 L (m 2 h) −1 ) within 90 min of visible light irradiation, indicating that the Ag/CNQDs/g-C 3 N 4 -PVDF photocatalytic composite membrane had excellent self-cleaning properties.
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CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Desen Zhou,Jun Zhang,Zhenxing Jin,Tingmin Di,Tielin Wang
Photocatalytic CO 2 reduction has been considered as a potential way to solve the energy problem and the greenhouse effect. In this work, layered g-C 3 N 4 /rGO/NiAl-LDHs heterojunctions were prepared by using a hydrothermal method, the optimized composite exhibited enhanced photocatalytic CO 2 reduction to CO (2.6 μmol h −1 g −1 ) and CH 4 (20 μmol h −1 g −1 ) activity, which was 3.7 and 14.2 times higher than that of pure g-C 3 N 4 , respectively. According to the experimental and density functional theory calculation (DFT) results, it is believed that with the large contact interface and excellent electron mobility rGO could act as an electron transfer bridge to facilitate the rapid charge migration and separation between g-C 3 N 4 and NiAl-LDHs. Thus, driven by the internal electric field, interfacial band edge bending, as well as the type II heterostructure, the activity of g-C 3 N 4 /rGO/NiAl-LDHs could be greatly enhanced. This work provides a possible way to rational design and fabrication of rGO-assisted composite systems with type II, Schottky, S-scheme, P-N and other heterojunctions.
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CHEMOSPHERE
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2022
·
IF 8.943
Xiaohui Zhan,Yue Zhao,Yanping Sun,Chen Lei,He Wang,Huixiang Shi
In this study, with thiourea and 3-aminopyridazine as precursors, the graphite-phase carbon nitride (ACN-x) with nitrogen defects and sponge structure is prepared via the introduction of the benzene-like ring structure of pyridazine replacing a “melem” group through hydrothermal procedure combined with calcination. It is made possible by the attraction of three hydrogen bond receptors for 3-aminopyrazine to lone pair electrons on the “melem” molecule. The remarkable extensively photocatalytic activity can be attributed to three effects of the introduction of 3-aminopyridazine: (i)formation of nitrogen defects between adjacent tri-s-triazine groups; (ii)formation of effective charge transfer channels within the tri-s-triazine group; (iii)the spongy structure exposed abundant amino groups(-NH 3 ) at edge sites, combining with the internal amino group and as hole stabilizer to prolong the excited state life of photocatalyst. The photogenerated carrier migration and separation efficiency improved effectively through the tuning synergy. As a result, ACN-x exhibits excellent photocatalytic activity, with hydrogen production efficiency of up to 11331.74 μmol g −1 h −1 , which is approximately 94.5 times that of the pristine g-C 3 N 4 (119.88 μmol g −1 h −1 ). The degradation constants of TC and RhB are 0.0498min −1 and 0.129min −1 , which are 3.32 and 6.35 times of the pristine g-C 3 N 4 , respectively. The TC degradation in different initial concentrations, pH, dissolved organic matter concentrations, and water sources is conducted to prove the environmental adaptability of the ACN-x system. The mechanism of the system indicates that ·O 2 − plays an important role, and the ·OH and h + play a minor role in the TC photocatalytic degradation . Finally, the TC degradation possible pathway is proposed.
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高影响因子
Journal of Environmental Chemical Engineering
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2022
·
IF 7.968
Ling-Hui Kong,Yan Wu,Rong-Fang Shen,Wen-Jie Zhang,Zhen-Yue Dong,Wen-Ting Ge,Xiao-Jing Guo,Xi Yan,Yan Chen,Wan-Zhong Lang
Herein, N-doped porous carbon (NPC) and g-C 3 N 4 were combined as peroxymonosulfate (PMS) activator, showing excellent catalytic performance for the degradation of rhodamine B (RhB), methyl orange (MO) and tetracycline (TC). A synergistic effect was proved to exist between NPC and g-C 3 N 4 in the as-prepared catalyst (g-C 3 N 4 @NPC). The radical quenching study, electron paramagnetic resonance (EPR) measurement, LSV measurements and electrochemical EIS were performed to examine RhB degradation mechanism. The main degradation intermediates of RhB were identified by LC-MS, and the possible degradation pathways were proposed. The effects of pH, temperature and natural substances on RhB degradation were investigated. Cycling experiments and the degradation of RhB in tap water and river water showed that the g-C 3 N 4 @NPC/PMS system had practical prospects for environmental remediation.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Wenyuan Ye,Jinjie Chen,Na Kong,Qingyuan Fang,Mingqiu Hong,Yuxiang Sun,Yifan Li,Patricia Luis,Bart Van der Bruggen,Shengqiong Fang,Shuaifei Zhao,Jiuyang Lin,Shungui Zhou
Conventional membrane processes, e.g., microfiltration and ultrafiltration, suffer from severe permeation flux decline and fouling during the oily wastewater treatment. The superhydrophilic surface decoration provides an important and effective strategy to address this challenge. Herein, a surperhydrophilic/underwater superoleophobic nanocomposite surface with the photocatalytic properties was constructed via one-step facile vacuum-assisted filtration of a g-C 3 N 4 nanosheet/SiO 2 nanoparticle dispersion onto a microfiltration membrane substrate. Specifically, with the intercalation of 20 mg∙L −1 SiO 2 nanoparticles into the g-C 3 N 4 nanosheets, the g-C 3 N 4 /SiO 2 composite membrane showed the superhydrophilic/underwater superoleophobic properties with an underwater oil contact angle of 170.0 ± 0.3°. Such a g-C 3 N 4 /SiO 2 composite membrane yielded a permeation flux of >1290 LMH·bar −1 with an oil rejection of >99.91% during the vacuum filtration of oil-in-water emulsions. The g-C 3 N 4 /SiO 2 composite membrane significantly outperformed the pristine microfiltration substrate that had severe fouling caused by oil blockage. Additionally, the g-C 3 N 4 /SiO 2 composite membrane not only effectively retained the E. coli bacteria through size exclusion effect, but also promoted the inactivation of bacteria via visible-light photocatalysis. Therefore, our membrane has a great promise in practical oily wastewater treatment due to its excellent separation performance and biofouling resistance.
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ACS Omega
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2022
·
IF 4.132
Lina Zhang,Ying Zhang,Baikang Zhu,Jian Guo,Dongguang Wang,Zhongqi Cao,Lihui Chen,Luhui Wang,Chunyang Zhai,Hengcong Tao
Electrochemical CO2 reduction has been acknowledged as a hopeful tactic to alleviate environmental and global energy crises. Herein, we designed an Fe@C/g-C3N4 heterogeneous nanocomposite material by a simple one-pot method, which we applied to the electrocatalytic CO2 reduction reaction (ECR). Our optimized 20 mg-Fe@C/g-C3N4-1100 catalyst displays excellent performance for the ECR and a maximum Faradaic efficiency (FE) of 88% with a low overpotential of −0.38 V vs. RHE. The Tafel slope reveals that the first electron transfer, which involves a surface-adsorbed *COOH intermediate, is the rate-determining step for 20 mg-Fe@C/C3N4-1100 during the ECR. More precisely, the coordinating capability of the g-C3N4 framework and Fe@C species as a highly active site promote the intermediate product transmission. These results indicate that the combination of temperature adjustment and precursor optimization is key to facilitating the ECR of an iron-based catalyst.
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高影响因子
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