SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Xiuyang Zou,Meisheng Li,Huifang Xiao,Shouyong Zhou,Chenglung Chen,Yijiang Zhao
The complex transport mechanism of water and ions in the membrane hinders the design of free standing membranes. The mechanism of the mass transport characteristics of traditional nanofiltration membranes is no longer applicable to free standing membranes due to the change of the driving force in the membrane. In this study, the vacuum filtration of the g-C 3 N 4 suspension was simulated to form a free standing membrane model for the first time by using the molecular dynamics (MD) simulations. In the nanochannels formed by the g-C 3 N 4 nanosheets , the water molecules rapidly penetrated across the free standing membrane due to ultra-low friction. On the other hand, the hydrated Na + and Mg 2+ ions needed energy to partially dehydrate and penetrate across the free standing membrane. Moreover, the MD simulations indicated that the speed of Mg 2+ ions penetrating across the g-C 3 N 4 nanochannels was lower than that of Na + ions. Combined with the computational works, salt retention experiments were conducted to demonstrate the correctness of the proposed model. Further, the developed membranes exhibited excellent non-swelling stability and antibacterial activity in aqueous solutions. The g-C 3 N 4 free standing membranes prepared in this study can effectively realize the separation of monovalent and divalent ions, accompanied with high permeability.
✓ 已验证
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2023
·
IF 4.1
Shixian Zhang,Xinshan Rong,Ting Sun,Ping Gao,Jun Liu,Xuchun Qiu,Xiangtong Zhou,Zhiren Wu
With the increasingly severe environmental problems the traditional high pollution and high energy consumption of nitrogen fixation industry is striving to develop new cleaner production technology. In this work, we designed and prepared the 3D porous g-C 3 N 4 with nitrogen vacancy (3DV N PCN) through a combination of alkali-assisted and supramolecular self-assembly methods. Subsequently, we synthesized, characterized and employed a Z -scheme 3DV N PCN/CoFe 2 O 4 photocatalyst with strong nitrogen adsorption and activation for nitrogen photofixation. The results show that the best photofixation nitrogen efficiency of the photocatalyst can reach 14.66 mmol/g/h within 120 min. This nitrogen fixation process carried out at room temperature, and only requires water and nitrogen as raw materials, which has the advantage of being energy efficient, environmental friendly and pollution-free.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2022
·
IF 12.92
Qing Yu,Shiyi Wang,Mengru Wang,Xiaoling Mou,Ronghe Lin,Yunjie Ding
Acetylene coupling with ethylene dichloride, which uses both coal and oil resources, is attractive for sustainable PVC manufacturing. Herein, highly active and stable carbon nitride-based catalysts were developed by a novel pre-oxidation-pyrolysis process, affording unprecedented dehydrochlorination activity with good durability. The best-performing system was further modified with different precious metals (Au, Pt, and Ru) to promote the hydrochlorination chemistry between the in-situ formed hydrogen chloride and acetylene co-feed. The presence of metal centers intensifies the hydrochlorination activity but weakens the dehydrochlorination ability due to competitive adsorption between the two reactants at the metal sites. Superior coupling performance was achieved over C 3 N 4 /AC and single-atom Au/C 3 N 4 /AC catalysts in cascade reactors. Our results strongly suggest that dehydrochlorination is an essential step in the coupling reaction, and the activation of acetylene and ethylene dichloride molecules requires different active sites that should be engineered in future work.
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Yali Song,Long Huang,Xiaojing Zhang,Hongzhong Zhang,Lan Wang,Huan Zhang,Yali Liu
A method combining g-C 3 N 4 and potassium peroxydisulfate (PDS) under simulated sunlight was put forward to effectively degrade sulfamethoxazole (SMX). The SMX removal efficiency was substantially improved compared with the processes involving only g-C 3 N 4 or PDS. The kinetic constants for the g-C 3 N 4, PDS and g-C 3 N 4 /PDS systems were 0.0023, 0.0239 and 0.068 min −1 , respectively. The g-C 3 N 4 /PDS process reached an SMX removal rate of 98.4 % after 60 min of simulated sunlight; in addition, the proposed system showed desirable efficiency for SMX degradation in two different actual water samples as well. The reaction mechanism was illustrated by trapping experiments, which showed that g-C 3 N 4 can promote S 2 O 8 2− to transfer SO 4 − , S 2 O 8 2− favored the generation of O 2 − , and O 2 − , SO 4 − and holes (h + ) were the main oxidative species for the SMX degradation in the combined reaction process under simulated sunlight. Then, to further explore this mechanism, the intermediates generated during the combined reaction process were analyzed by LC/MS and possible degradation pathways were proposed. The result showed that the breaking of the S N and C–S bonds, the hydroxylation of the benzene ring and the oxidation of the amino group were identified as the main pathways in the SMX degradation process by the g-C 3 N 4 /PDS system under simulated sunlight.
✓ 已验证
DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Chao Zhang,Jiandong Liu,Xiayun Huang,Daoyong Chen,Shiai Xu
Graphene-like g-C3N4 nanosheets (NSs) have been successfully synthesized with a modified polymerization process of melamine by cocondensation with volatile salts. Volatile ammonium salts such as urea–NH4Cl/(NH4)2SO4/(NH4)3PO4 were added with melamine to modulate the thermodynamic process during polymerization and optimize the structure formation in situ. The surface area, surface structure, and surface charge state of the obtained g-C3N4 NSs could be controlled by simply adjusting the mass ratio of the melamine/volatile ammonium salt. As a consequence, the g-C3N4 NSs exhibited much higher activity than bulk g-C3N4 for the photocatalytic degradation of target pollutants (rhodamine B, methylene blue, and methyl orange), and it also exhibited greater hydrogen evolution under visible light irradiation with an optimal melamine/volatile ammonium salt ratio. The as-prepared g-C3N4 NSs with melamine–urea–NH4Cl showed the highest visible light photocatalytic H2 production activity of 1853.8 μmol·h–1·g–1, which is 9.4 times higher than that of bulk g-C3N4 from melamine. The present study reveals that the synergistic effect of the enhanced surface area, surface structure, and surface charge state is the key for the enhancement of photocatalytic degradation and hydrogen evolution, which could be controlled by the proposed strategy. The result is a good explanation for the hypothesis that adding properly selected monomers can truly regulate the polymerization process of melamine, which is beneficial for obtaining g-C3N4 NSs without molecular self-assembly. Considering the inexpensive feedstocks used, a simple synthetic controlling method provides an opportunity for the rational design and synthesis, making it decidedly appealing for large-scale production of highly photocatalytic, visible-sensitizable, metal-free g-C3N4 photocatalysts.
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Mingyuan Guo,Yongning Ma,Zhanqing Liu,Donghua Wang,Yuhao Yang,Xiaolong Li,Enzhou Liu
Halogen doping is an effective approach to regulate the electronic structure and improve photocatalytic properties of g-C 3 N 4 . Here, a salt-assisted approach was employed to prepare layered porous halogen-doped g-C 3 N 4 . The effects of halogen electronegativity and pore morphology were discussed. Highly electronegative F-doped g-C 3 N 4 with smaller pore size and higher surface area displayed the enhanced absorption property on reactants. The H 2 production rate decreased and the RhB degradation significantly increased with increasing the electronegativity of layered porous g-C 3 N 4 , which was significantly different from the conventional halogen-doped g-C 3 N 4 prepared with halogenated acid and monolayer g-C 3 N 4 . The decreased H 2 evolution can be ascribed to the strong adsorption property, and the strong interactions between halide ions and H + were difficult to be disassociated. Additionally, the RhB degradation performance of halogen-doped g-C 3 N 4 significantly increased with increasing the electronegativity. The most active species that dominated the RhB degradation of F-doped g-C 3 N 4 are leaved holes (h + ), which are totally different from that of the pristine g-C 3 N 4 and Cl/Br-doped g-C 3 N 4 (superoxide radicals,·O 2 – ). This work helps us to well understand the role and importance of electronegativity and pore morphology on the H 2 generation and RhB degradation properties of layered porous g-C 3 N 4 .
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2021
·Vol. 9
·期 2
·302-309
·
IF 6.569
Jiayu Xin,Fei Li,Zhen Li,Jiaqi Zhao,Yu Wang
Single-atom dispersed carbon nitride photocatalysts have been extensively associated with clean energy conversion, storage and utilization. However, it is still a challenge to elucidate the relationship between the electronic structure of catalysts and their photocatalytic properties. In this work, single atom Ag/C3N4 catalysts have been prepared via pyrolyzing cyanuric acid, AgNO3 and melamine as precursors. We observe that their photocatalytic activity increases on increasing the concentration of Ag from 0.32% to 0.53%, and subsequently decreases on further increasing the concentration of Ag, which indicates that the concentration of Ag atoms can control the performance of single-atom catalysts. Deep investigations suggest that the concentration of Ag atoms can modulate the bottom of the conduction band (CB) and the maximum of the valence band (VB). The higher the bottom of the CB is, the better the performance of catalysts is. In contrast to bulk carbon nitride, the rate constants of the optimized single-atom photocatalyst Ag/C3N4 with 0.53% Ag for rhodamine B (RhB) and tetracycline (TC) degradation are enhanced approximately 165.3 and 24.9 times, respectively. Furthermore, the ESR spectrum shows that the superoxide radical plays a major role in the photocatalytic process. This work provides a new insight into the structure–property relationship and our strategy provides guidance for the synthesis of other single-atom photocatalysts.
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2020
·
IF 3.421
Menglong Sun,Qian Wang,Baiying Dai,Weihua Sun,Yaru Ni,Chunhua Lu,Jiahui Kou
A simple combination of thermal etching and liquid-phase ultrasonic stripping was deployed to prepare high-performance graphite carbon nitride (g-C3N4) nanosheets. Also, graphene oxide with plentiful active groups was used to combine g-C3N4 with a magnetically actuated artificial cilia array (MAACA) to generate a composite cilia array, which can ensure the facile recovery of g-C3N4. This strategy addresses the limitations of an adjustable band gap for easy response to visible light and circumvents the encumbered limitation of recyclability, thus addressing a chronic environmental problem by curbing waste. The underlying functional principle of the array used was analyzed and studied in greater detail. The photocatalytic hydrogen production efficiency of MAACA with 0.4 mg of g-C3N4 at a magnetic field driving frequency of 12.50 Hz was found to be ∼75.0% higher than that at a magnetic field driving frequency of 0 Hz.
✓ 已验证
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Ning Zhang,Chuanhui Huang,Ping Tong,Zunmei Feng,Xiaoping Wu,Lan Zhang
Volatile polycyclic aromatic hydrocarbons (PAHs) in water and soil are associated with status in the human body. Development of simple, efficient detection method is challenging due to the coating could be attacked by the abundance of water in the direct-immersion solid-phase microextraction. The stability of coating is essential to the analysis results. In this paper, a stable Ni-Zn MOF/g-C 3 N 4 (MG NFs) nanoflowers with cavity traps structure was firstly reported and acted as solid-phase microextraction (SPME) adsorbent for PAHs. Markedly enhanced moisture and acid stability of the MG NFs was obtained through the doping the hydrophobic graphitic carbon nitride (g-C 3 N 4 ) and metal ions into metal organic frameworks (MOFs). The aperture environment and ambient environment of MG NFs were changed by the doping of the Ni and the g-C 3 N 4, respectively. The moisture and acid stability of MG NFs were prominently increased under the dual protection. Compared to commonly used commercial coatings, the MG NFs own large surface area, unique nanoflowers structure and numerous open metal sites on the nanosheets, which demonstrated significant extraction superiority for PAHs. The MG NFs coated fiber was used for the SPME preconcentration of PAHs and couped with GC–MS for detecting PAHs. It presented low detection limits (0.1–3.0 ng L −1 ), wide linearity (0.3–5000.0 ng L −1 ) and good linearity (the correlation coefficient >0.9951). The inter-day and intra-day relative standard deviation (RSD) (n = 3) for three replicate extractions using one fiber was 3.8%–9.1%, and 3.5%–9.2%, respectively. The fiber-to-fiber reproducibility (n = 3) was 4.2–11.8%. The coupling method was successfully applied in the analysis of real water and soil samples with satisfactory recoveries of 82.9–109.2%, 84.2–106.4%, and the corresponding RSDs were 2.4–11.3%, 3.6–10.8%, respectively. The results indicated the effectiveness of NG NFs coated fiber in further practical application.
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Qiangbin Yang,Jibin An,Zhonghao Xu,Shuting Liang,Honghong Wang
Due to the carcinogenicity of atrazine, the effective removal of atrazine in water and soil has become the focus of attention. In the paper, the advanced oxidation technology based on sulfate radicals ( S O 4 · - ), which the visible light catalysis and nanocatalyst Co 3 O 4 /g-C 3 N 4 synergistically catalyzed to yield S O 4 · - , was constructed to efficiently degrade and remove atrazine. The Co 3 O 4 /g-C 3 N 4 was prepared through a simple solvothermal method, and its microstructure and composition were characterized by SEM and XRD. A series of experiments were carried out to degrade atrazine by Co 3 O 4 /g-C 3 N 4 activation of peroxymonosulfate under visible light, which revealed that the degradation efficiency reached to 78.5 percent in 35 min, CO 3 2− had a significant inhibitory effect on the degradation of atrazine in coexisting ions of NO 3 -, SO 4 2− , Cl- and CO 3 2− , the e -, ⋅OH, and S O 4 · - were mainly active species. Combined with density function theory calculations of Co 3 O 4 /g-C 3 N 4 , the high-efficiency degradation of atrazine was due to the synergetic enhancement between photocatalysis and Co 3 O 4 /g-C 3 N 4 catalyst in the constructed catalytic system.
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Chunyan Su,Yazhou Zhou,Lili Zhang,Xiaohui Yu,Shuai Gao,Xiujuan Sun,Chao Cheng,Qinqin Liu,Juan Yang
Graphitic carbon nitride (g-C 3 N 4 ) has been demonstrated to be a rising star among semiconductor materials for photocatalytic hydrogen (H 2 ) production. However, pristine g-C 3 N 4 usually suffers from inferior activity due to the inadequate visible light harvesting capacity and quick charge recombination. Herein, porous P doped g-C 3 N 4 nanosheets (PCNNSs) were fabricated via a simple thermal condensation of adenosine phosphate and urea followed by thermal exfoliation method. The synergetic effect of the porous structure and P dopant can provide abundant active sites for the photocatalytic reaction, which can enhance light absorption range extending from 450 nm to 700 nm attributed to the n→π* electronic transition, and improve hydrophilicity for easier water molecules adsorption via introducing hydroxyl groups. Furthermore, impurity level caused by the P dopant would change the excitation process and accelerate the charge separation efficiency. Therefore, the PCNNSs exhibited significantly elevated photocatalytic H 2 generation performance (9523.7 μmolg -1 h -1 ) under visible-light (λ > 420 nm) irradiation, which was about 20 times that of unmodified g-C 3 N 4 (458 μmol -1 h -1 ).
✓ 已验证
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2020
·
IF 2.65
Wei Yang,Xinyao Shan,Ying Chen,Yanhua Gao
In this paper, a novel heterojunction material was synthesized of C 3 N 4 via doping with π-deficient conjugated pyridine ring molecules (2,6-diaminopyridine) and BiOCl by ultrasound-assisted method. First, doping C 3 N 4 with 2,6-diaminopyridine can reduce the structural integrity and orderliness of C 3 N 4 , and reduce the number of structural fragments, Which makes C 3 N 4 have more reactive sites. And then BiOCl nanosheets were grown on the surface of the modified C 3 N 4 nanosheets to obtain a new heterojunction material composed of modified C 3 N 4 doped with π-deficient pyridine ring molecules and BiOCl by the co-precipitation method. At last, the degradation of methyl orange (MO) by BiOCl, C 3 N 4 , modified C 3 N 4 doped with 2,6-diaminopyridine, and a series of C 3 N 4 doped with 2,6-diaminopyridine and BiOCl composite heterojunction materials under visible light was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), ultraviolet visible diffuse reflection (UV–Vis DRS) and transient photocurrent densities, and electrochemical impedance spectroscopy (EIS) were used to analyze the structure, morphology, and photogenerated charge transfer characteristics of samples. The experimental results show that the new heterojunction composite materials has better photocatalytic activity compared with pure BiOCl, C 3 N 4 , and modified C 3 N 4 doped with 2,6-diaminopyridine. In addition, the degradation performance of methyl orange with different mass ratios of composite materials is also different. When the mass ratio of C 3 N 4 doped with 2,6-diaminopyridine to BiOCl is 1:2, The composite material exhibits the best photocatalytic performance, which may be related to the synergistic effect of the modified C 3 N 4 doped with 2,6-diaminopyridine and BiOCl. Based on the band structure and active species experiments, the reasons for the enhanced photocatalytic activity are discussed, and the possible degradation mechanisms are proposed. The research in this paper provides an effective new way to construct new heterojunction materials.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）