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以实际刊发为准
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XIE Kun, CHENG Qian, LIU Changlong, YIN Qingguo, HE Jiawei, CAO Weijia
2024,41(7), DOI:
Abstract:
Oilfield chemicals play a crucial role in drilling and completion, fracturing and acidizing, profile control and water plugging, emulsification and viscosity reduction, oil/water separation, etc. However, the harsh reservoir environment such as low permeability, high temperature, high salinity, extreme pH, and changes of temperature or pH has brought severe challenges to the research of polymers and surfactants. The traditional methods of adding groups to resist temperature and salinity, such as sulfonic acid groups, or increasing the relative molecular mass of oil displacement agents can no longer meet the oilfield needs. In this paper, the principles, properties, and potential applications of stimuli-responsive materials were introduced, which can respond to environmental changes, such as temperature-sensitive, pH-sensitive, magnetic-responsive, CO2-sensitive, and salinity-sensitive. Finally, the development prospect of stimuli-responsive materials in oil and gas production is summarized.
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HE Dan-dan, ZHANG Ze-yu, Juanli Liu, SUN Wen-xiao, ZHANG Wen-bo, ZHANG Hong
2024,41(7), DOI:
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With the rapid development of economic globalization, the amount of sludge discharged from municipal wastewater treatment is increasing, and the annual production of municipal sludge is expected to exceed 90 million tons by 2025 in China. The pathogenic microorganisms, organic matter and heavy metals contained in municipal sludge can cause serious harm to the environment and human health. Due to its large specific surface area, excellent pore structure and rich oxygen-containing groups, sludge-derived biochar materials are widely used in wastewater treatment, achieving the dual purpose of solid waste reuse and pollution removal. In addition, a win-win situation of ecology and development by treating waste with waste can be obtained. So the preparation and modification methods of sludge biochar is systematically summarized, its application to heavy metals, dyes, inorganic salts, antibiotics and phenols in wastewater and its adsorption mechanism are also reviewed in the paper. And the future development and the problems to overcome are also prospected, Green low-carbon resource treatment system will be tried to form.
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DING Heyu, LIU Huijing, LEI Xuebo
2024,41(7), DOI:
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With the continuous progress of industrialization, environmental pollution has become an increasingly prominent problem. The development of sensors and arrays specifically designed to detect different types of pollutants is significant for the management of environmental pollution and the protection of people"s health. In recent years, fluorescent molecule probes with high detection sensitivity and fast response have gradually become important tools for pollutant detection. Fluorescent sensing films prepared by fixing them on flexible substrates through physical or chemical methods are devices with huge potential for the detection of trace amounts of substances. They have series of advantages including simple operation, easy carrying, adjustable size, and non-polluting to the test system, especially it will greatly promote research on intelligent wearable materials, which have attracted widespread attention in recent years. This article mainly reviews the research status of flexible sensing films and devices based on fluorescent probe technology for the detection of common gaseous and liquid environmental pollutants in recent years. Moreover, some existing problems and future prospects in this field are summarized and discussed.
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LI Haike, ZHANG Huan, WANG Xiaolei, WANG Huicai
2024,41(7), DOI:
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The consumption of lithium resources in China accounts for 40% of the global consumption, but its production capacity can only meet 20% of the industrial demand, and 80% of lithium needs to be imported. Therefore, it is urgent to study a new generation of lithium extraction technology. Nanofiltration (NF) membrane has the ability of selective ion separation, showing outstanding potential in the selective separation of Mg2+ and Li+. Commercial NF membrane is negatively charged, which is influenced by Donnan effect and electrostatic attraction, and its separation ability for positively charged ions is limited. In recent years, it has been found that positively charged NF membrane can effectively separate Mg2+ and Li+ with similar hydrate ion radii. Firstly, the ion transport theory and selective screening mechanism in NF membrane are introduced. Secondly, the research status and shortcomings of commercial NF membrane in the field of lithium extraction from salt lakes are summarized. Then, the influence of preparation methods of positively charged NF membrane (including the selection of amine monomer, doping of nano-materials, introduction of interlayer and surface grafting, etc.) on improving the selective separation performance of Mg2+ and Li+ was analyzed. Finally, the challenges and prospects of positively charged NF membrane in practical engineering applications are summarized.
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WANG Yingfeng, LI Kaizhun, YIN Maoli, LI Wei
2024,41(7), DOI:
Abstract:
The appearance of drug-resistant bacteria has led to a sharp increase in clinical incidence and mortality, significantly impacting human life and medical systems. In order to address the problem of drug-resistant bacteria mutations and the prolonged process of antibiotics investigation, the invention of new antibiotic methods is required. As a novel technique for antibacterial purposes, Photothermal therapy (PTT) utilizes solar energy to generate thermal energy, raising the temperature in the local area and eliminating the bacteria. Due to the unique antibacterial mechanism, PTT Reduces the risk of drug-resistant bacteria emerging, thus providing a special advantage in the field of antibacterial. The fabrication and preparation of various photothermal nanomaterials are essential for PTT applications. In this review, the latest research on the design and synthesis of various photothermal agents (PTAs) is discussed and summarized. The development and applications of PTAs are discussed simultaneously. Finally, the existing problems and the challenges of developing a PTT antibacterial application are discussed and assessed. This review aims to provide reference experience for the design and synthesis of PTAs materials with efficient antibacterial properties.
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TANG Jian-wei, WANG Xu, LIU Yong, WANG Bao-ming, YOU Shao-wei, LIU Peng-fei
2024,41(7), DOI:
Abstract:
Building energy consumption, industrial energy consumption and traffic energy consumption are the main ways of energy consumption. Among them, building energy consumption accounts for about 40 % of energy consumption. The continuous rise of building energy consumption will increase carbon emissions and accelerate the consumption of fossil energy. Therefore, improving the thermal insulation and energy saving performance of building materials has gradually become a research hotspot in the field of building materials. Heat storage technology can not only reduce building energy consumption, but also reduce environmental pollution. Phase change energy storage material has excellent heat storage and release capacity. It is an important technical means to realize thermal energy storage and temperature control, and has broad application prospects in the field of building energy conservation. In this paper, the research progress of gypsum-based composite phase change energy storage materials is reviewed. According to the difference of gypsum-based phase change materials, gypsum-based organic phase change materials and gypsum-based composite phase change materials are analyzed and summarized. The methods and mechanisms of preparing gypsum-based composite phase change energy storage materials, such as impregnation method, porous material adsorption method and microcapsule method, and the factors affecting gypsum-based phase change energy storage materials are introduced. Finally, the research direction of gypsum-based phase change energy storage materials is prospected.
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XUE Fei, LIU Mengli, LIAO Min, LI Zhen, XIA Chungu, WANG Jinbang
2024,41(7), DOI:
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The catalytic oxidation of primary alcohols to carboxyl compounds is an extremely important transformation process in organic synthesis, with a wide range of application scenarios. For heterogeneous catalytic oxidation systems, the preparation of efficient catalysts has always been a hot and difficult research topic. This article provides a comprehensive review of recent literature on the preparation of carboxyl compounds by heterogeneous catalytic oxidation of primary alcohols. The development status and trends of heterogeneous catalysts for the oxidation of primary alcohols were systematically evaluated in terms of single metal and bimetallic active components, as well as the utilization of supports. Furthermore, the prospects and challenges of heterogeneous catalysis in industrial applications were discussed.
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LI Liang-rong, AI Sheng, YANG Xiao-zhe, Zhang Liang-Dong, YANG Qing-qing, RAO Zechang
2024,41(7), DOI:
Abstract:
Carbon capture is an effective way to promote the low-carbon application of fossil energy under " double carbon ".Solid amine adsorbent is an important means to realize carbon capture, utilization and storage. Among them, carrier modification and amine type optimization are the hot research strategies of solid amine adsorbents. The mechanism, technical difficulties and carbon capture effects of the optimization strategies of solid amine adsorbents at home and abroad are reviewed and commented. The effects of silicon-based, porous carbon and organic framework carrier optimization strategies on improving CO2 selectivity, adsorption capacity and stability are emphatically described and compared. The future research directions and application prospects of solid amine adsorbents in efficient and stable capture, biomass adsorption and carbon utilization and storage are prospected.
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2024,41(7), DOI:
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This article provides a comprehensive review of the synthesis routes and applications of vinylidene (—CH==CH—)-bearing hyfrofluoroolefins (v-HFOs). Currently, among the major routes for synthesizing v-HFOs, such as fluorine-chlorine exchange, isomerization, dehydrohalogenation, selective hydrogenation, hydrodechlorination, and telomerization, the fluorine-chlorine exchange route stands out due to its readily available starting materials and the ease of achieving large-scale production, making it the optimal synthesis route for v-HFOs. Due to the unique molecular structure of v-HFOs, they exhibit excellent heat transfer properties, environmental friendliness, foamability, and etching performance, which are primarily used as refrigerants, heat pump working fluids, cleaning agents, blowing agents, and etching agents. In particular, trans-v-HFOs ((E)-v-HFOs) demonstrate outstanding electrical insulating properties, combined with their excellent heat transfer and cleaning performances, have led to their application in new scenarios such as immersion liquid cooling and charged cleaning. The future development trends of v-HFOs are discussed, including the development of efficient fluorination catalysts, environmentally friendly and green synthetic routes, as well as exploring new applications for v-HFOs.
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Pan Lang, JU Guang-xu, ZAHNG Xin-yue, WU Chuan-liang, KE Shao-wen, LIU Ya-xing, YIN Xue-qiong
2024,41(7), DOI:
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With the increase of global temperature, ultraviolet radiation intensity and chemical pollutants, the bleaching problem of marine coral reefs is becoming increasingly serious. It is of great significance to develop new coral reef repair materials. The Montipora digitara coral reef (CR) was selected as the research object. On the basis of comprehensive analysis of chemical composition, physical morphology and mechanical properties on CR, white cement was used as the matrix to simulate the chemical composition and physical structure of the coral reef, by adding foaming agent (LG-2258), calcium carbonate, calcium bicarbonate and chitosan (CS) to prepare Coral reef biomimetic materials. The structure and properties of natural coral reefs and bioinspired materials were measured by SEM, FTIR, EDS, ICP-OES and universal testing machine. The results showed that the biomimetic materials had similar pore structure, mechanical properties and chemical composition with the natural coral reefs. After six months of cultivation on the surface of biomimetic materials, coral plants got 10.36 mm increase on height, and the polyps could attach to the surface of the biomimetic material and form new coral tissue.
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WANG Yaozhi, YU Danfeng, WEN Wu, QIAN Qin, WU Xu
2024,41(7), DOI:
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Low surface energy coatings have attracted wide attention due to their excellent anti-fouling and self-cleaning abilities. However, existing coatings are prone to degradation by microorganisms such as bacteria and fungi, leading to a decrease in their anti-fouling effectiveness. Therefore, the construction of anti-fouling and antibacterial coatings is of significant importance. Based on the electrophoretic deposition process, depositing vinyl silicone oil modified polyacrylate and curing agent onto conductive substrates. After further loaded with nano silver antibacterial agents, the coatings were crosslinking curing, resulting in coatings with both anti-bacterial adhesion and bactericidal functions. The morphology and structure of the coatings were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). The results showed that the coating surface had excellent oil and dirt resistance, as well as the ability to resist bacteria and blood adhesion, The Anti-bacterial adhesion rate of the coating against E. coli and S.aureus exceeds 99.9%. Even after exposure to extreme conditions such as strong acid, strong alkali, and 3000 cycles of friction, the coating surface still has excellent anti-liquid adhesion effect.
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WU Yanan, WANG Xuan, TANG Bingtao, ZHANG Yuang
2024,41(7), DOI:
Abstract:
Based on the good compatibility of long-chain alkyl groups, three eutectic phase change materials (IS-LC, OC-LC and OC-LC-HD) were prepared by melt blending with eicosane (IS), octadecane (OC), lauric acid (LC) and hexadecanol (HD). The optimum mass ratio of eutectic points was calculated by Schr?der formula, and was determined as m(IS):m(LC) = 0.61:0.39, m(OC):m(LC) = 0.74:0.26 and m(OC):m(LC): m(HD) = 0.61:0.21:0.18, combing the results of step-cooling curve and differential scanning calorimeter (DSC) analysis. The eutectic temperatures are 30.2, 25.4, 22.6 ℃, respectively, which are consist with the theoretical calculation results. The chemical structure, crystallization behavior, heat storage capacity, and thermal stability of eutectic phase change materials were characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), thermogravimetric analyzer (TGA) and DSC. The results show that three eutectic phase change materials are combined by physical interaction without chemical reaction. The phase transition temperatures are between 18~32 ℃ and lower than any single component. The phase transition enthalpy values are greater than 180 J/g, The eutectic phase change materials has good thermal stability and cycle stability.
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LI Xiao, ZHANG Hui, WANG Zhixin, GUO Lei, TONG Cuizhi, MAO Ai-qin
2024,41(7), DOI:
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The nanoscale strategy is represented to further improve the rate performance of (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 high-entropy oxide (HEO) as anode material for lithium-ion batteries. Herein, spinel-structured (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 HEO nanocrystalline powder was successfully synthesized by hydro-thermal synthesis using metal nitrate as metal source, urea as precipitant and dodecyl trimethyl ammonium bromide (DTAB) as surfactant. The research shows that by introducing surfactant DTAB in the hydrothermal process, the as-synthesized (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4 HEO possesses smaller crystalline size, higher uniform dispersion, larger specific surface area and more uniform pore distribution than that without adding surfactant. This unique structural feature makes the as-synthesized electrode material have pronounced pseudo-capacitive behavior, which greatly improves the reversible specific capacity and rate performance of LIBs. The surfactant-induced electrode exhibited a higher initial specific capacity (1308 mA·h/g), significantly enhanced initial coulomb efficiency (82.5%), higher reversible capacity of 1263 mA·h/g at 0.2 A/g after 25 cycles, and outstanding rate performance accompanied with excellent cycling stability (more than eighth the reversible specific capacity of 1053 mA·h/g at 3 A/g after 150 cycles).
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Chen Jian-jun, YI Fan, QIU Pei-hua, CHEN Jia-li, LUO Jia-jin, Qiu Tao-jie, MENG Kun-ming, LEI Hui-bin
2024,41(7), DOI:
Abstract:
A superhydrophobic coating with the structure of "concave and convex gully" structure like the foot of water strider was prepared on the surface coated with epoxy/gutta-percha varnish using palygorskite powder as the functional pigment and the mixture of epoxy resin and gutta-percha as the film-forming material. The surface morphology and structure were characterized by means of scanning electron microscope (SEM), infrared spectroscopy (FTIR), X-ray diffraction spectrum (XRD). The water contact angle, water rolling angle, self-cleaning property, wettability, wear resistance and water resistance of C3 coating (mass fraction of palygorskite powder was 25%) were tested. The results showed that the surface of C3 coating had obvious "concave and convex gully" structure, the average static and dynamic water contact angle were 153.1° and 152.6°respectively, and the water rolling angle was 8.8°, which had excellent self-cleaning performance. In addition, the C3 coating also showed excellent wettability resistance to mud slurry, methyl orange solution and methylene blue solution, and all the contact angles were above 150°. The C3 coating had good substrate applicability, and showed super hydrophobic properties on the surface of concrete, fabric, paper and plastic. After 50 times of cyclic polishing of A4 paper with a load of 100 g, the water contact angle was still as high as 151.9°, with good wear resistance. After soaking for 18 and 24 h, the water contact angle of C3 coating were 152.2° and 144.5°, respectively.
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ZHAO Zhigang, JIN Dan, HUANG Huidan, LI Guiwen, SHAN Zhenwei
2024,41(7), DOI:
Abstract:
Burdock fructooligosaccharide (BFO) was carboxymethylated by aqueous method to prepare modified products (CM-BFO) with different degrees of carboxymethyl substitution (DS). The relationship between reaction conditions and DS and the interaction of various factors were investigated by single factor and response tests. The structures of BFO and CM-BFO were characterized by GC,FTIR, 1HNMR, and 13CNMR. RAW264.7 cells were used as a model to test the immune activity of CM-BFO with different DS in vitro. The results showed that 0.5 g of BFO was alkalized with 30 mL of 20% NaOH aqueous solution for 1 h, 30 mL of 2.5% chloroacetic acid aqueous solution was used as carboxymethylation reagent, the reaction temperature was 65 ℃, the reaction time was 3.3 h, and the highest ds of BFO carboxymethylation was 1.06 under the optimal conditions; Both BFO and CM-BFO could enhance the immune activity of RAW264.7 cells. The immune activity of three kinds of CM-BFO with DS of 0.82, 0.93 and 0.96 was significantly increased compared with BFO, while the CM-BFO with the lowest (0.73) and highest DS (1.06) was slightly increased. The immune activity of CM-BFO increased first and then decreased with the increase of DS in a certain range.
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WANG Yilong, WANG Ping, ZHANG Meng, YI Xia, WEI Yanan, ZHU Jie
2024,41(7), DOI:
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Nitrogen-doped graphene (NDGR) with amphiphilic surface was efficiently prepared by introducing nitrogen-containing groups on graphene by cold plasma surface modification. By adjusting plasma gas source, discharge power, discharge time and working pressure, the process was optimized. As-prepared NDGR was characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), organic elemental analysis (OEA), transmission electron microscopy (TEM) and water contact angles (WCA). Platinum nano-catalysts supported by NDGR (Pt/NDGR) were evaluated for selective hydrogenation of cinnamaldehyde and crotonaldehyde in water. The results showed that a nitrogen-doped graphene NDGR(O2-NH3) with the excellent surface properties was obtained by a two-step plasma grafting method, that is, using oxygen (O2) as plasma gas source to activate the graphene surface and then using ammonia (NH3) as plasma gas source to graft nitrogen-containing groups on the surface. Compared with graphene supported Pt catalyst (Pt/GR), Pt/NDGR(O2-NH3) prepared under the optimum conditions (discharge power 140 w, working pressure 200 Pa, discharge time 6 min) showed excellent catalytic performance in the aqueous hydrogenation of cinnamaldehyde (CAL) and crotonaldehyde (CRAL). Under the reaction conditions of 80 oC and 3 MPa, CAL conversion over Pt/NDGR(O2-NH3) reached 98% within 4 h, and the selectivity to unsaturated alcohol cinnamyl alcohol (COL) remained high (about 84%). In aqueous hydrogenation of CRAL, the apparent rate constant kapp over Pt/NDGR(O2-NH3) was 0.53 h-1, much higher than that of Pt/GR (0.37 h-1). The selectivity to CROL also remained high (about 40%) at nearly complete reaction. The high catalytic performance of Pt/NDGR(O2-NH3) was attributed to the enhanced properties of graphene surface after grafting a small number of nitrogen-containing groups on it, including the increased anchoring sites for Pt nano-particles, high adsorption performance to substrates and metal-support interaction.
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CHEN Hong, ZHONG Zhaoping, ZHOU Junwui
2024,41(7), DOI:
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CeO2 modification was carried out on V-W-Ti catalyst, and the denitration performance of the catalyst was tested with different levels of CeO2 addition. The results showed that the addition of CeO2 could improve the medium and low temperature activities of the catalyst significantly, but too much loading would reduce the high temperature activity of the catalyst. Overall, V-W-Ti catalyst containing 1% of CeO2 in the mass of the catalyst showed the best performance. Its denitrification activity was better than that of the unmodified catalyst across the entire temperature range. Under reaction conditions of 260 ℃ and GHSV of 60000 h-1, its NOx removal efficiency increased from 79.01% to 99.19%. In an atmosphere containing H2O and SO2, its NOx removal efficiency increased from 58.33% to 74.55%. The catalyst with different CeO2 additions were characterized by XRD, N2 adsorption-desorption, XPS, NH3 temperature programmed desorption (NH3-TPD), and FTIR, which showed that the CeO2 addition increased the proportion of adsorbed oxygen and Br?nsted acidic sites on the catalyst surface , but it also decreased the proportion of V4+ and Lewis acidic sites on the surface, so CeO2 addition has different effects on the denitrification activity of V-W-Ti catalyst at low and high temperatures. DFT calculation results show that Ce doping reduces the formation energy for the oxygen vacancy on the catalyst surface, changes the acidity of the catalyst surface and enhances the adsorption of SO2 on the catalyst.
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LIU Jingjin, ZHAO Hua, LI Huipeng, CAI Tianfeng
2024,41(7), DOI:
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Supramolecular self-assembly and chemical precipitation methods were used to prepare P-doped three-dimensional graphitic phase carbon nitride (g-C3N4) MNP-x using melamine and cyanuric acid as raw materials and ammonium phosphate as a P-dopant (x denotes the added mass of ammonium phosphate when the melamine is 0.01 mol, the same below), and characterisation of MNP-x was performed by XRD, FTIR, XPS, SEM, UV-Vis and photoluminescence (PL), etc. The photocatalytic degradation of the dye rhodamine B (RhB) reaction was applied to evaluate the photocatalytic performance of MNP-x. A free radical trapping agent was used to verify the reactive groups that play a role in the photocatalytic reaction and to speculate the reaction mechanism. The results showed that MNP-0.08 prepared under optimal conditions, compared to the undoped P-doped g-C3N4(MN), SEM showed that the MNP-0.08 morphology changed from a one-dimensional tubular to a three-dimensional bouquet; XPS confirmed that the P atoms replaced some of the C atoms doped into the g-C3N4 structural unit; PL showed that MNP-0.08 improved the electron-hole pair (e-,h+) separation; UV-Vis showed that MNP-0.08 changed the energy band structure, the valence band (VB) from 1.96 eV to 2.00 eV, and the conduction band (CB) from 0.7 eV to 0.75 eV,,and the energy band gap value (Eg) from 2.66 eV to 2.75 eV; it was verified that -O2- as the main reactive group makes the MNP-0.08 photocatalytic degradation of RhB was improved with a reaction rate constant (k) of 0.02816 min-1, which was 2.95 times higher than that of MN (k=0.00955 min-1); the synergistic effects of the change in energy band structure, P as an electron-rich centre to promote carrier separation, and P doping to induce a high charge transfer and localize excited electrons made MNP possess a much higher photocatalytic performance than MN with higher photocatalytic performance.
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CHEN Congjin, HUANG Libin, FAN Hui, ZHANG Qiangxu, LIAO Jinge, Chen Zixia
2024,41(7), DOI:
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The composite catalyst MnFe2O4-CR was prepared by hydrothermal method by loading MnFe2O4 on biomass gasification carbon residue (CR), characterized by SEM, XRD, XPS, BET and VSM, and utilized to activate permonosulfate (PMS) to degrade tetracycline hydrochloride (TC). The effects of different reaction systems, the mass ratio of MnFe2O4 to CR, dosage of PMS, dosage of catalyst, temperature, pH value, anion(HCO3–、H2PO4–、Cl–、NO3–) and humic acid (HA) on the degradation efficiency of TC in MnFe2O4-CR/PMS system were investigated. The stability and recyclability of MnFe2O4-CR were also investigated. The possible degradation mechanism of TC in MnFe2O4-CR/PMS system was investigated by free radical quencher experiments. The results showed that: When the mass ratio of MnFe2O4 to carbon residue is 1:2, the catalytic effect of MnFe2O4-CR is good. At 30 ℃, 30 mg MnFe2O4-CR catalyzes, 40 mg PMS, and the degradation efficiency of TC in TC solution with natural pH of 100 mL and 50 mg/L reaches 91.32% within 90 min. MnFe2O4-CR catalyst can be recovered by its magnetic properties. After 5 cycles, the degradation efficiency of TC degraded by PMS can still reach 82.90%, indicating that MnFe2O4-CR has good stability and reusability. Free radical quenching experiments show that SO4??, ?OH, 1O2 and O2?? are the main reactive oxygen species for TC degradation in MnFe2O4-CR/PMS system, and the corresponding catalytic degradation mechanism is proposed.
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LI Jing, LUO Can, LI Changchun, ZHENG Cao
2024,41(7), DOI:
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The effects of combined treatment of ultrasound and basic amino acids (BAA) on the structural and functional properties of soy isolate protein (SPI) were studied, and correlation analyses were investigated. The results showed that combined treatment was more effective in improving the emulsification and solubility of SPI than that of BAA treatment alone. The ζ-potential result showed that the synergistic effect of ultrasound and BAA enhanced the ζ-potential of SPI compared to BAA treatment alone, which improved the electrostatic repulsion between the protein molecules. The surface hydrophobicity and fluorescence spectrum results showed that more hydrophobic groups were exposed to the polar environment, which promote the hydrophilic-hydrophobic groups balance. The free sulfhydryl groups and total sulfhydryl results illustrated that combined treatment was more effective in increasing the content of free sulfhydryl groups and decreasing total sulfhydryl content. The results of secondary structure content showed that the combined treatment was more conducive to the transformation of SPI to ordered molecular structure. SDS-PAGE results showed that neither ultrasound nor BAA treatment could change the structure of SPI subunits. Correlation studies showed that surface hydrophobicity was positively correlated with solubility (0.960) and emulsification (0.861). The ζ-potential was highly significantly negatively correlated with solubility (-0.974).
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LIU Jiongna, ZHANG Dan, JIANG Yuxin, FAN Fangyu
2024,41(7), DOI:
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Walnut protein (WalPI) and galactooligosaccharides (GOS) were used as materials for the preparation of WalPI-GOS composite nanoparticles by pH-cycling combined with the ultrasound method and mixed with tea oil to prepare Pickering emulsion. The structure and particle size distribution of WalPI-GOS were characterized by FTIR and particle size analysis. The free sulfhydryl content, thermal stability, and surface hydrophobicity (H0) of WalPI-GOS were determined by fluorescence absorption spectroscopy, DSC, and endogenous fluorescence spectroscopy. The particle size, microstructure, and rheological properties of Pickering emulsion were determined. To investigate the changes in the WalPI-GOS particle and Pickering emulsion properties when the mass ratio of WalPI and GOS was varied from 10:0 to 10:5. The result showed that the WalPI-GOS and Pickering emulsion had the best properties when the mass ratio of WalPI and GOS was 10:4. The particle size, Zeta potential, emulsifying activity index (EAI) and emulsion stability index (ESI) of the WalPI-GOS were 82.08 nm, -52.37 mV, 31.12 m2/g, and 4346.35 min, respectively, which showed good emulsification and stability. Part of the hydrophobic groups of WalPI were embedded inside the WalPI-GOS molecule, which reduced the H0 of the WalPI-GOS (840.81 a.u.) and increased the free sulfhydryl content (8.78 μmol/g) and melting temperature (93.74 °C) of the WalPI-GOS. The complexation of WalPI and GOS changed the secondary and tertiary structure of WalPI to form a secondary structure dominated by β-folding. WalPI and GOS form a compact network structure by hydrogen bonding, electrostatic interaction, and hydrophobic interaction. The particle size of the Pickering emulsion was only 5.24 ?m with uniform droplet distribution, which formed an elastic gel network structure. The Pickering emulsion exhibited the highest apparent viscosity of 1.06 Pa·s at a shear rate of 0.1 s-1. The high cross-linking density between WalPI and GOS enhanced the gel network structure of the Pickering emulsion.
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XueYu, TAN Yanyan, ZHANG Daohai, LUO Zu, QIN Shuhao, WU Xiao
2024,41(7), DOI:
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To regulate the pore structure and performance of polyvinylidene fluoride (PVDF) membranes, a series of PVDF/EAA composite ultrafiltration membranes were prepared by immersion precipitation phase conversion method using EAA (polyvinyl acrylic acid) as an additive and PEG400 as a porogenic agent. The effects of different EAA content and different porogenic agent PEG400 on the performance of the composite membranes were investigated by scanning electron microscopy, infrared, water contact angle, viscosity characterization, porosity, pure water flux, bovine serum protein (BSA) retention, The effects of different EAA content and different porogenic agent PEG400 content on the performance of the composite membrane were investigated using scanning electron microscopy, infrared, water contact angle, viscosity characterization, porosity, pure water flux, bovine serum protein (BSA) retention rate, flux recovery rate and contamination rate. The results showed that the addition of EAA improved the hydrophilicity of the membrane surface, and the addition of porogenic agent PEG400 improved the affinity between the casting solution and the solidification bath, accelerated the membrane formation rate, and thus formed more pores on the membrane surface, in which the pure water flux and BSA retention rate of E-3 membrane reached 271.57 L.m?2.h?1 and 64.83%, respectively. -The flux recovery rate and total contamination rate were 75.97% and 46.51%, which were 19.37% and 26.92% higher and lower, respectively, compared with the pure PVDF membrane. In contrast, the porosity of the P-3 membrane was 53.33% and the average pore size was 4.55 nm, which improved the porosity and average pore size of the P-0 membrane without a porogenic agent by about 33.33% and 88.02%, respectively; therefore, the method of EAA as additive and PEG400 as porogenic agent mentioned in this study could significantly improve the structure and permeation performance of PVDF membrane.
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DING Shuaishuai, CHENG Xianglin, QI Ziyi, WANG Xiaoping
2024,41(7), DOI:
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The core-shell acrylate emulsion was prepared with methyl methacrylate (MMA), styrene (St) and butyl acrylate (BA) as the main monomers and silane coupling agent as the modified monomers. The structure was designed and the influence of crosslinked monomer on the properties of emulsion was investigated in the study. The results showed that the stability and film formation of the emulsion were better when the amount of styrene is 15%(based on the total mass of all monomers, the same below), the theoretical glass temperature of the core layer and the shell layer were -10 ℃ and 30 ℃, and the amount of the core layer cross-linked monomer vinyltriethoxysilane (A-151) and the shell layer cross-linked monomer gamma-methacryloxy propyl trimethoxysilane (A-174) is 3% and 2%, respectively. Compared with the homogeneous particle structure without crosslinked monomer, the maximum thermal adhesion temperature of the core-shell structure polymer is increased by 90 ℃, the water absorption rate is reduced by 10.8%, and the thermal decomposition temperature (mass loss of 5%) is increased by 38 ℃, alleviating the high-temperature adhesion problem of ink coatings and improving the water and heat resistance of the coating film.
