关键词:
Two-dimensional nanochannel membrane;Montmorillonite;Separation of Li + and Mg 2+;Porous nanochannel
摘要:
Recent innovations have created various two-dimensional membranes to break the Li+/Mg2+ selectivity limit of traditional separation membranes. However, the simultaneous achievement of ultrafast transport and high selectivity is still below the theoretical prediction. Herein, for overcoming these shortcomings, the twodimensional montmorillonite membrane (2D MMT membrane) consisting of sulfonated polyvinyl alcohol (SPVA), ethylene glycol (EG), and polyacrylamide (PAM) is proposed based on the design of porous 2D nano channels. It is found that the SPVA can effectively improve the membrane stability, but will densify the channel, and prevent ion transport. When the appropriate EG is included in the membrane component, the transport rate of Li+ can be increased from 0.29 mol h-1 m- 2 to 0.56 mol h-1 m- 2. However, because the transport of Mg2+ needs to overcome the high dehydration energy barrier, the JMg2+ changes little, hence increases in SLi+Mg2+ from 4.1 to 7.3. In addition, the selectivity regulation of PAM can be further integrated, and the permselectivity of the membrane is improved to 9.2 due to the strong selective coordination of amide groups to Mg2+. This novel strategy provides a valuable reference for developing high-performance 2D MMT membranes, which can also promote the application of 2D membranes in the Li+/Mg2+ separation.
摘要:
Manganese dioxides (MnO2) and biochar materials are both desirable candidates for environmental remediation of toxic organic pollutants (TOPs) in water due to wide availability and environmental-friendly. In practical application, however, MnO2 suffers from low redox activity owing to deprotonation, while biochar is subject to limited removal capacity. Herein, a difunctional engineering sulfuric acid-pretreated biochar supporting MnO2 composite (MBC-A) was firstly synthesized and optimized to remove various TOPs from aqueous solution. Specifically, sulfuric acid not only served as an active agent to improve the specific surface area of biochar for improvement of adsorption capacity and more MnO2 loading, but also facilitated the introduction of sulfonic acid groups (-SO3H) as an internal proton reservoir to inhibit inactivation of MnO2 due to deprotonation in alkaline. Thanks to adsorption and oxidation, MBC-A showed excellent removal capacity (214.9 mg/g) and fast reaction kinetics (360 min) for tetracycline (TC), exceeding precursor and other materials reported in literature. Importantly, the effective operation pH range of MBC-A was broadened to 1-13 with the help of buffering capacity of -SO3H groups. The dominant driving force of adsorption were pi-pi interaction and hydrogen bond; while reactive oxidative species were mainly ascribed to singlet oxygen (O-1(2)), hydroxyl radical (center dot OH) and reactive Mn3+. The possible reactive sites and pathway were investigated by combining experimental results with density functional theory (DFT) calculation. Further, the results of multiple cyclic runs, removal in real river water and toxicity assessment demonstrated well reusability, high environmental security, and excellent practical applicability of MBC-A.
摘要:
In this study, a new procedure of two-step direct immersion single-drop microextraction (TS-DI-SDME) was firstly developed for the sequential separation and enrichment of Tl(III) and Tl(I) before graphite furnace atomic absorption spectrometry detection. At pH 6.0, Tl(III) selectively reacts with 1-(2-Pyridylazo)− 2-naphthol to form the complexes which can be extracted into one organic drop, while Tl(I) remained in the solution. Then, another organic drop containing dicyclohexano-18-crown-6 was immersed in the sample solution after the extraction of Tl(III) for the enrichment of Tl(I) at the same pH value. Main parameters affecting the separation and enrichment of Tl species were investigated. Under optimized conditions, limits of quantification (LODs) were 6.3 ng L−1 and 8.3 ng L−1 for Tl(III) and Tl(I), respectively. Repeatability and reproducibility were assessed by calculating relative standard deviations (RSDs), which were less than 5.1% and 6.7% for Tl(III) and Tl(I), respectively. Preconcentration factors of 300-fold were achieved for Tl species. This method was used successfully for the determination of Tl(III) and Tl(I) in food samples. To validate this procedure, a certified reference material of milk powder was analyzed with the satisfactory results. This method may avoid the problems of tedious operations, sample contamination and analysis errors in redox speciation strategies.
作者:
Min Tu;Yin Li;Junli Chang;Guangyuan He;Yaqiong Wang
期刊:
Foods,2023年12(5) ISSN:2304-8158
通讯作者:
Chang, J.;Li, Y.
作者机构:
[Yin Li; Junli Chang; Guangyuan He] The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science & Technology, Wuhan 430074, China;These authors contributed equally to this work.;Hubei Technical Engineering Research Center for Chemical Utilization and Engineering Development of Agricultural and Byproduct Resources, School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China;[Min Tu] Hubei Technical Engineering Research Center for Chemical Utilization and Engineering Development of Agricultural and Byproduct Resources, School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China<&wdkj&>These authors contributed equally to this work.;[Yaqiong Wang] The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science & Technology, Wuhan 430074, China<&wdkj&>These authors contributed equally to this work.
通讯机构:
[Yin Li; Junli Chang] T;The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science & Technology, Wuhan 430074, China
摘要:
Cereal crops are of great importance in the development of human civilization and fall into two groups, major crops and minor crops [...]
通讯机构:
[Zhandong Ren; Yuchan Zhu] S;School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, 430023, PR China<&wdkj&>School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, 430023, PR China
摘要:
The research and development of high-efficiency low-temperature disinfection technology in all aspects of coldchain food has begun to receive attention. This paper aims to develop low temperature acidic electrolyzed water (LT-AEW) disinfectant. The anti-freezing temperature, disinfection efficiency and practical application effect were evaluated in detail. The results had shown that the freezing point of AEW can be reduced to -18 degrees C by adding 25% CaCl2, 20% NaCl, 30% ethylene glycol (EG) and 35% propylene glycol (PG). At the low temperature (-1, -10 and -18 degrees C), the bactericidal efficiencies of all EG-acidic electrolyzed waters (EG-AEWs) with different EG contents were close. The reason is that although the low temperature environment will reduce the sterilization efficiency of EG-AEW, the addition of EG can promote the increase of HClO content in EG-AEW, thus increasing the sterilization efficiency. As long as the HClO content reached 35.2, 50.8 and 64.3 mg L-1, the killing logarithm (KL) value had achieved 4.50, 4.49 and 5.07 log10(CFU mL-1). Finally, the KL values of EGAEW against Escherichia coli on the corrugated board and stainless-steel board both exceeded 3 log10(CFU mL-1) at the low temperature, which indicates that EG-AEW can be applied in food cold chain.
通讯机构:
[Fui, H ] W;Wuhan Polytech Univ, Sch Chem & Environm Engn, Wuhan 430023, Hubei, Peoples R China.
摘要:
Layered double hydroxides (LDHs) have been extensively investigated as promising peroxymonosulfate (PMS) activators for the degradation of organic pollutants. However, bulk LDHs synthesized using conventional methods possess a closely stacked layered structure, which seriously blocks active sites and yields low intrinsic activity. In this study, we exfoliated bulk CoAl-LDHs to fabricate CoAl-LDH nanosheets by alkali-etching and Ostwald ripening via a simple hydrothermal process in a KOH solution. The exfoliated LDHs possessed the typical nanosheet structure with more exposed active sites for PMS activation, and hence, boosted the degradation of the pollutants. CoAl-1 exhibited an outstanding catalytic performance as the PMS activator for rhodamine B (RhB) degradation with the apparent rate constant of 0.1687 min(-1), which was about 3.63 and 5.02 times higher than that of commercial nano-Co3O4 and bulk CoAl-LDH, respectively. The maximum RhB degradation of 93.1% was achieved at the optimal reaction conditions: catalyst dose 0.1 g L-1, PMS concentration 0.3 mM, pH 7, and temperature 298 K. Further analysis of RhB degradation mechanism illustrated that singlet oxygen (O-1(2)) dominated RhB degradation in the CoAl-1/PMS system, while (OH)-O-center dot, O-center dot(2)-, and (SO4-)-S-center dot may mainly serve as the intermediates for the generation of O-1(2) and were indirectly involved in the degradation. This study provides a promising strategy for developing two-dimensional LDH nanosheets for wastewater remediation.
通讯机构:
[Xu, Y ] W;Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan, Peoples R China.
关键词:
anti-bacterial;coatings;membranes
摘要:
This study aims to develop Ultraviolet-cured (UV-cured) antimicrobial coatings by dispersing epoxy resin F51–quaternary ammonium salt (QAS) as antimicrobial agents in UV-cured emulsions. The molecular structures of these F51–QAS coatings were analyzed using infrared spectroscopy. Thermogravimetric analysis was performed to evaluate the thermal stability of the antimicrobial coatings. Contact angle testing was conducted to investigate the hygroscopic wettability of the coatings. Mechanical properties such as pencil hardness, adhesion strength, flexibility and impact resistance were evaluated. Antimicrobial rate experiments were conducted to examine the antimicrobial properties of the coatings. The antimicrobial properties were examined through rate experiments against Escherichia coli and Staphylococcus aureus. The results showed that when the F51–QAS content was at 2.7%, the UV-cured antimicrobial coatings exhibited excellent overall performance with a 100% antimicrobial rate.
摘要:
Gold recovery from secondary resources involves tremendous environmental and economic implications. In this work, four nucleobase (guanine, xanthine, hypoxanthine and adenine) modified cellulose microspheres were synthesized via radiation method for Au(III) capture from actual gold slag solution. The adsorption rapidly achieved equilibrium within 4 h. It was discovered that the pseudo-second-order and Langmuir model provided a superior match for the Au(III) adsorption process on adsorbents. At the optimal pH, the four adsorbents exhibited the outstanding adsorption capacities for Au(III) with a range of 307.69-510.20 mg/g. Furthermore, cellulose microspheres bearing nucleobase were able to selectively adsorb trace Au(III) with recovery efficiencies of 62 %- 70 % from gold slag leaching solution. In addition, the column separation approach was utilized to better assess the applicability of adsorbents, proving that cellulose microspheres bearing nucleobase exhibited great benefits and prospects in industrial applications. The N-containing groups on adsorbents captured Au(III) by ion ex-change, chelation and oxidation-reduction. The low-cost nucleobase-bearing adsorbents offer a new prospect for nucleobase in environmental remediation and water treatment.
摘要:
The magnetic CuFeO2 anchored on nitrogen-doped porous carbon (CuFeO2/NC) hybrid catalysts were further synthesized via hydrothermal reaction without the addition of a chemical reductant. The systematic CuFeO2/NC with larger specific surface areas (SSAs) and abundant active sites exhibited strong adsorption ability and great catalytic performance towards activating peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. It was noted that 18 mg/L SMX was completely removed after 40 min of pre-adsorption and 30 min of oxidative degradation in CuFeO2/NC and PMS system. The degradation rate constant (k) was calculated by fitting as 0.166 min-1, being about 7.9 times that in the CuFeO2 and PMS system (0.021 min-1). The SO4 & BULL;-,& BULL;OH, and 1O2 as the dominant reactive oxygen species (ROSs) contributed to sulfamethoxazole degradation. The N species, active oxygen and the redox cycles of Cu(II)/Cu(I) and Fe(III)/Fe(II) were confirmed to play a vital role in the activation of PMS for the generation of ROSs. Based on the LC-MS analysis, the possible degradation routes of SMX in the PMS activation system by CuFeO2/NC were proposed.
摘要:
Particle size might affect the inhibition behaviors of gold nanoparticles (AuNPs) on enzyme activity by influencing the density of binding sites (ρ), the association constant (K(a)), the steric hindrance of enzymes by AuNPs, the binding orientations of the enzyme on AuNPs, as well as the structural changes of enzymes. In previous studies, the effects of the above-mentioned factors, which could not be ignored in the applications of enzymatic electrochemistry, were often overshadowed by the effects of surface area. In order to study the size effect on the inhibition types and inhibitory ability of enzymes by AuNPs, we investigated the inhibition behaviors of chymotrypsin (ChT) by AuNPs with three different sizes (D1-AuNCs, D3-AuNPs, and D6-AuNPs) under the same surface area concentration. The results showed that both of the inhibition types and the inhibition ability varied with the particle size of AuNPs. D1-AuNCs inhibited ChT noncompetitively, while D3/D6-AuNPs inhibited ChT competitively. Contrary to the common sense, D6-AuNPs showed a weaker inhibitory ability than D3-AuNPs. By means of zeta potential, agarose gel electrophoresis, isothermal titration calorimetry, synchronous fluorescence spectroscopy, and circular dichroism, the mechanism of the weak inhibitory ability of D6-AuNPs was found to be the standing binding orientation caused by the small curvature. This work had certain guiding significance for the biosafety of AuNPs, the development of nanoinhibitors, as well as the applications of AuNPs in enzymatic electrochemistry.
作者机构:
[Shen Y.-Q.; 张智勇; 宋垚; 王新杰; 兰庚; 吴胜莉] Department of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan, 430023, China;[汪相如] School of Electronic Science and Engineering, University of Electronic Science and Technology, Chengdu, 611730, China
通讯机构:
[Zhang, Z.-Y.] D;Department of Chemistry and Environmental Engineering, China
摘要:
Formulation and shaping of heterogeneous catalysts are vital in the successful industrial application. Here micro-sized vanadium chromium composite oxides catalysts with the spherical shape were prepared via spray drying with colloidal silica as a binder material. The physicochemical properties of catalysts with different Cr/V molar ratios were characterized by XRD, XPS, FT-IR, TPR, and particle size distribution analysis. It was revealed that the addition of Cr inhibited the formation of the crystalline phase V2O5 and decreased the reduction temperature of pentavalent vanadium species, and also resulted in the formation of monoclinic CrVO4 and a highly dispersed state of vanadia species. VCrO/SiO2 particles with various Cr/V atomic ratio were studied as catalysts for p-chlorotoluene ammoxidation to p-chlorobenzonitrile, in which the catalyst with Cr/V ratio of 1 exhibited the best catalytic performance. When the Cr/V ratio was less than 1, mixed phases of orthorhombic CrVO4 and monoclinic Cr2V4O13 were formed and resulted in a low catalytic activity. With the increase of Cr/V ratio, the content of monoclinic CrVO4 in the catalysts increased, resulting in the catalytic activity of the catalysts improved. However, too large an amount of Cr led to the formation of highly oxidizing hexagonal-Cr2O3 phase, which reduced the selectivity of the catalytic reaction. [GRAPHICS] .
通讯机构:
[Liu, JS ] W;Wuhan Polytech Univ, Sch Civil Engn & Architecture, 68 Xuefu S Rd, Wuhan 430023, Hubei, Peoples R China.;Wuhan Polytech Univ, Pilot Scale Platform Marine Engn Struct Protect Ma, 68 Xuefu S Rd, Wuhan 430023, Hubei, Peoples R China.
关键词:
geopolymer;steel slag;flue gas desulfurization gypsum;grouting material;mechanical properties
摘要:
In this paper, the performance of steel slag (SS) and flue gas desulfurization (FGD) gypsum modified metakaolin-based geopolymer (MGP) was studied for the purpose of industrial solid waste reuse, and a new geopolymer grouting material was obtained. The setting time, fluidity, bulk density, and compressive strength of MGP containing different mass contents of solid waste materials were studied through a series of tests. In addition, the microstructure mechanism of MGP was analyzed using scanning electron microscopy and Fourier transformation infrared spectroscope. The results show that the setting time of MGP increases with the increase of SS content, whereas the setting time decreases with the increase of FGD content. The addition of SS or FGD slightly reduces the fluidity of MGP. Adding an appropriate amount of SS to MGP can significantly improve the later compressive strength of the specimen, whereas adding an appropriate amount of FGD can improve the compressive strength of the specimen, especially the early compressive strength. When the SS content was 4 %, the hardened MGP exhibited the best properties in compressive strength and bulk density. The formation of amorphous geopolymer gel products in MGP matrix was promoted by the addition of SS and FGD. These results will be beneficial to the production of new environmentally friendly and low-cost MGP grouting materials, which can improve the comprehensive utilization level of SS and FGD and achieve the purpose of protecting the ecological environment.