ChemElectroChem
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2018
·Vol. 6
·期 4
·1014-1018
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IF 4.446
Rong Zhang,Haoran Guo,Li Yang,Yuan Wang,Zhiguo Niu,Hong Huang,Hongyu Chen,Li Xia,Tingshuai Li,Xifeng Shi,Xuping Sun,Baihai Li,Qian Liu
Graphical Hollow VO 2 microspheres can operate efficiently and stably to give an NH 3 yield of 14.85 μg h −1 mg −1 cat and a Faradaic efficiency of 3.97 % at −0.7 V (vs. the reversible hydrogen electrode) in 0.1 M Na 2 SO 4 , rivaling the performances of most reported aqueous-based electrocatalysts. Density functional theory calculations provide further insight into the catalytic mechanism involved. Electrochemical N 2 fixation has gained much attention as an environmentally friendly and sustainable process for NH 3 production at ambient conditions. Its efficiency depends greatly on identifying highly active electrocatalysts with good stability. In this work, we propose the use of VO 2 hollow microspheres as a robust non-precious metal catalyst for the N 2 reduction reaction (NRR). The catalyst operates efficiently and stably at neutral pH to high Faradaic efficiency (3.97 %) and NH 3 yield (14.85 μg h −1 mg −1 cat. ) under an applied potential of −0.7 V (vs. the reversible hydrogen electrode). Note that this catalyst also presents a high selectivity for NH 3 synthesis without N 2 H 4 generation. Density functional theory reveals that the energetically favorable pathway for NRR is *N 2 →*NNH→*NHNH→*NHNH 2 →*NH 2 NH 2 →*NH 2 +NH 3 →*NH 3 +NH 3 →2NH 3 , where the first hydrogenation step to form *NNH is the potential-determining step.
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Journal of Environmental Chemical Engineering
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2019
·
IF 0
Hao Chen,Xialei Wang,Xilei Lyu,Ling Xu,Juncheng Wang,Xiuyang Lu
Recovering heavy metals from a hyperaccumulator is of significant interest; however, such metals are typically extracted in the liquid phase, which increases the cost of recovery. In this work, hydrothermal processing is used to extract Cd, Cu, Pb and Zn from enriched Sedum alfredii Hance in order to separate the heavy metals into the solid phase for easy recovery and the simultaneous production of bio–oil. The results show that almost all enriched Cd, Cu, Pb and Zn (87.8% Ce, 87.5% Cu, 90.2% Pd and 87.2% Zn) are concentrated in the solid phase at only 320 °C (30 min), which also contains considerable carbohydrates. Interestingly, the additives/H 2 O 2 do not affect the removal of metals during the hydrothermal process. The yield of bio-oil is 21.5% (38.1 MJ/kg of calorific value) and is obtained with almost no heavy metals. Finally, we use different ratios of metals ions to reducing sugars as well as the non-hyper accumulating ecotype Sedum alfredii Hance to study the behavior of metals’ recovery. It is showed that the heavy metals are recovered in the solid phase due to reducing substances in the biomass that convert metal ions to the metallic state.
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CHEMOSPHERE
·
2019
·
IF 5.108
Ling Gan,Yifan Wu,Haiou Song,Chang Lu,Shupeng Zhang,Aimin Li
Self-doped TiO 2 nanotube arrays (DNTA) were prepared for the electrooxidation of resistant organics. The anatase TiO 2 NTAs had an improved carrier density and conductivity from Ti 3+ doping, and the oxygen-evolution potential remained at a high value of 2.48 V versus the standard hydrogen electrode, and thus, achieved a highly enhanced removal efficiency of phenol. The second anodization could stabilize Ti 3+ and improve the performance by removing surface TiO 2 particles. Improper preparation parameters (i.e., a short anodization time, a high calcination temperature and cathodization current density) harmed the electrooxidation activity. Although boron-doped diamond (BDD) anodes performed best in removing phenol, DNTA exhibited a higher mineralization of phenol than Pt/Ti and BDD at 120 min because intermediates were oxidized once they are produced with DNTA. Mechanism investigations using reagents such as tert-butanol, oxalic acid , terephthalic acid, and coumarin showed that the DNTA mineralization resulted mainly from surface-bound OH, and the DNTA produced more than twice the amount of OH compared with BDD. The free OH on the BDD electrode was more conducive to initial substrate oxidation, whereas the adsorbed OH on the DNTA electrode mineralized the organics in situ. The preferential removal of p -substituted phenols on DNTA was attributed mainly to their electromigration and the aromatic intermediates that are hydrophobic were beneficial to mineralization.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Ping Hu,Yan Chen,Xi Yan,Wan-Zhong Lang,Ya-Jun Guo
VOX-SiO2 catalysts have been synthesized by the one-pot method using different vanadium precursors, namely, ammonium metavanadate (NH4VO3; VO3–, V5+), vanadium acetylacetonate [V(acac)3; organic complex, V3+], and vanadyl sulfate (VOSO4; VO2+, V4+). The influence of different vanadium precursors on the structure–performance relationship of these catalysts is studied on the propane dehydrogenation (PDH) reaction. The catalysts derived from VO3– attain a mesoporous structure with fairly high specific surface area and large pore volume, while those prepared with V(acac)3 or VOSO4 display a microporous structure. It is noted that VOX-SiO2 catalysts derived from NH4VO3 present a better catalytic performance, and low-polymerized VOX species display better intrinsic activity compared with isolated species. This study may contribute to the selection of vanadium precursors for the one-pot synthesis.
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ACS Sustainable Chemistry & Engineering
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2019
·
IF 6.97
Jiaying Cui,Nengwu Zhu,Deliang Luo,Yao Li,Pingxiao Wu,Zhi Dang,Xuan Hu
In this study, oxalic acid showed better performance than inorganic acid in the indium leaching system from waste liquid crystal displays. The In3+ leaching efficiency with the powder dosage of 50 g/L came up to 100% within 45 min, using 0.5 M oxalic acid and stewing at 70 °C. Ultrasonic cavitation can improve the powder dosage. Combined with the substance analysis using ICP, XPS, SEM, and XRD, In2O3 dissolution depended on the distributive H+ concentration. Metal hydrolysis was a general negative phenomenon for ions loss in an acid leaching system. According to the Arrhenius model, the apparent activation energy for the indium leaching reaction was 43.622 kJ/mol, indicating that the indium leaching rate was mainly affected by the ion diffusion process through the solid–liquid interface and the chemical reaction process. Oxalic acid can maintain an appropriate H+ concentration to reduce the acid consumption from nontarget substances to relieve the powder surface corrosion for reuse and to inhibit metal hydrolysis, and its C2O42– ions also could precipitate some metal impurities such as Ca2+ and Sr2+ in the leachate.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2018
·
IF 5.091
Feihao Shi,Haoru Shan,Di Li,Xia Yin,Jianyong Yu,Bin Ding
Fenton or Fenton-like technique, as one of the advanced oxidation processes, plays a significant role in the removal of non-easily degradable organic pollutants; however, most of such catalysts are fragile with poor structural integrity under large deformation, thereby restricting their wide applications. Herein, soft copper ferrite nanostructures functionalized silica nanofibrous membranes (CuFe 2 O 4 @SNM) were fabricated through a novel strategy with the combination of in-situ dopamine polymerization, ion adsorption, and cohesive precipitation method. Benefiting from the high metallic ion adsorption capacity of polydopamine together with the rapid co-precipitation of adsorbed ions on fiber surface in alkaline solution, the membranes possessed homogenously distributed nanostructured CuFe 2 O 4 , large specific surface area, and high pore volume, which are a benefit for the improvement of Fenton-like catalytic activity towards organic pollutants decomposition. The resultant soft CuFe 2 O 4 @SNM provided favorable catalytic performance towards organic pollutants with a relatively high degradation degree of 96% in 20 min, a fast removal rate of 0.148 min −1 , and outstanding recyclability. The successful preparation of such fascinating ceramic nanofibrous membranes would provide a reference for further exploitation of new type Fenton or Fenton-like catalysts with outstanding softness towards wastewater purification.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2018
·
IF 3.927
Hao Ling,Sen Liu,Hongxia Gao,Zhiwu Liang
In order to study the effect of heat-stable salts (HSSs) on the CO 2 absorption performance of amine solution, the CO 2 absorption/desorption rates and cyclic CO 2 capacity of 30 wt% (monoethanolamine) MEA solutions in the presence of various acidic degradation products were comprehensively investigated systematically by an improved rate-based screening method. In addition, the initial pH values and CO 2 equilibrium solubility were also evaluated. These acidic degradation products considered were formic acid , acetic acid, propionic acid , butyric acid , glycolic acid, oxalic acid , lactic acid, malonic acid and bicine. The experimental results indicated that the carboxylic acids with different chemical structures can reduce the initial pH values, equilibrium solubility of CO 2 , absorption rate and cyclic CO 2 solubility, but promote the CO 2 desorption rate of aqueous MEA solution. Furthermore, a countermeasure was proposed to maintain absorption performance and reduce the energy requirement of solvent regeneration for an MEA amine-treating unit. The obtained results can provide a guidance for developing corresponding countermeasure for heat-stable salts control and removal in the CO 2 absorption-stripping process using amine solutions.
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Small
·
2019
·Vol. 15
·期 34
·1901828
·
IF 10.856
Shixun Wang,Xinyu Shen,Yu Zhang,Xingwei Zhuang,Dingke Xue,Xiangtong Zhang,Jinlei Wu,Jinyang Zhu,Zhifeng Shi,Stephen V. Kershaw,William W. Yu,Andrey L. Rogach
All-inorganic cesium lead halide perovskite nanocrystals (NCs) have demonstrated excellent optical properties and an encouraging potential for optoelectronic applications; however, mixed-halide perovskites, especially CsPb(Cl/Br) 3 NCs, still show lower photoluminescence quantum yields (PL QY) than the corresponding single-halide materials. Herein, anhydrous oxalic acid is used to post-treat CsPb(Cl/Br) 3 NCs in order to initially remove surface defects and halide vacancies, and thus, to improve their PL QY from 11% to 89% for the emission of 451 nm. Furthermore, due to the continuous chelating reaction with the oxalate ion, chloride anions from the mixed-halide CsPb(Cl/Br) 3 perovskite NCs could be extracted, and green emitting CsPbBr 3 NCs with PL QY of 85% at 511 nm emission are obtained. Besides being useful to improve the emission of CsPb(Cl/Br) 3 NCs, the oxalic acid treatment strategy introduced here provides a further tool to adjust the distribution of halide anions in mixed-halide perovskites without using any halide additives.
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ADVANCED FUNCTIONAL MATERIALS
·
2019
·Vol. 29
·期 13
·1808234
·
IF 15.621
Qiuxia Fu,Yang Si,Cheng Duan,Zishuo Yan,Lifang Liu,Jianyong Yu,Bin Ding
Chromatographic media with synchronously large protein adsorption capacity and high processing flux are highly desired in protein separation; however, the creation of such materials still faces enormous challenges. Herein, a robust strategy to develop highly carboxylated monolithic media by combining nanofibrous aerogels' forming technique and an in situ modification approach is reported. The obtained ion-exchange nanofibrous aerogels (IENFAs) exhibit a unique cellular structure consisting of flexible ceramic nanofibers and a functional polymer wrapping layer, endowing them with outstanding underwater superelasticity and compressive fatigue resistance (nearly no plastic deformation after 1000 compressive cycles). Benefiting from the interconnected nanofibrous cellular structure, good hydrophilicity, high carboxylation, and excellent mechanical properties, the IENFAs exhibit synchronously promoted static (2.9 × 10 3 mg g −1 ) and dynamic (1.7 × 10 3 mg g −1 ) lysozyme adsorption capacities and improved buffer flux (2.17 × 10 4 L m −2 h −1 , gravity driven), which are superior to these reported nanofibrous materials and commercial ion-exchange membranes. The IENFAs also possess outstanding performance stability, easy operation, and excellent regenerability. Moreover, the IENFA-packed column could directly and continuously separate lysozyme from egg white solely driven by gravity, highlighting their excellent practical application performance. This work may provide a new avenue to design and develop next-generation high-performance chromatographic media for bioseparation.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Jiayi Chen,Xinyan Xiao,Yi Wang,Zhihao Ye
A novel Ag nanoparticles (NPs) decorated WO 3 nanoplates/g-C 3 N 4 (CN) nanosheets 2D/2D heterostructure was successfully synthesized by a solvent evaporation and in situ calcination method. The as-prepared WO 3 /Ag/CN ternary composite exhibited remarkably enhanced photocatalytic activity towards rhodamine B (RhB) and tetracycline (TC) degradation compared with WO 3 , CN, Ag/WO 3 , Ag/CN and WO 3 /CN under visible light irradiation. The enhanced photocatalytic activity could be attributed to the efficient separation of photogenerated charge carriers, the strong redox ability and enhancement of visible-light absorption derived from the construction of Z-scheme 2D/2D heterostructure. Ag NPs not only possess the surface plasmon resonance (SPR) effect, but also act as an electron mediator in Z-scheme heterostructure. The UV–vis absorption spectra analysis indicated that the loading of Ag NPs can enhance the visible-light adsorption. And the decreased photoluminescence and the increased photocurrent demonstrated the high separation rate of photoinduced charge carriers owing to the successful heterojunction construction. Furthermore, the possible degradation pathways of RhB and TC were proposed according to HPLC-MS analysis. The results of radical trapping experiments indicated that O 2 − and OH were the primary active species during the photocatalytic degradation process.
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MICROCHEMICAL JOURNAL
·
2018
·
IF 2.746
Zheng-Meng Jiang,Lan-Jin Wang,Zhao Gao,Bo Zhuang,Qiang Yin,E-Hu Liu
Deep eutectic solvents (DESs) have attracted increasing attention as eco-friendly and efficient alternatives to conventional organic solvents. In this study, five herbal medicines (HMs) including Caulis sinomenii , Coptis chinensis , Stephania tetrandra , Tetradium ruticarpum , and Sophora flavescens were selected for the first time to comprehensively evaluate the potential and effectiveness of DESs on the extraction of Morphinane, Protoberberine, Bisbenzylisoquinoline, Indole and Quinolizidine alkaloids , respectively. A total of 75 types of binary or ternary DESs with different polarity, viscosity, pH, and solubilization abilities were tailored to screen a suitable DESs for extraction of morphinane alkaloids from Caulis sinomenii , and the extraction conditions were optimized using response surface methodology (RSM) and artificial neural network hybridized with genetic algorithm (ANN-GA) for the first time. The results demonstrated that DESs were excellent solvents for extraction of alkaloids with superior efficiency to conventional extraction solvents. Moreover, both ANOVA and sensitivity analysis demonstrated that the most critical parameter for alkaloids extraction was water content in DESs. This study reveals the potential of eco-friendly DESs for applications involving the efficient extraction of bioactive alkaloids from natural sources.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2018
·
IF 2.831
Mengzhe Guo,Dantong Liu,Qian Sha,Houfa Geng,Jun Liang,Daoquan Tang
The epigenetic modification of DNA or RNA may have relationship with the development of diabetic nephropathy (DN). We designed to develop a liquid chromatography mass spectrometry (LC–MS) coupled with mobile phase additive sensitization method for the analysis of the dissociative epigenetic modified nucleosides in serum of patients from different periods of DN with the health comparison. Serum samples were collected from 43 healthy volunteers and 156 patients, which divided into four groups. A succinic acid enhanced LC–MS/MS strategy was developed for the quantitative analysis of seven nucleosides in serum samples. The signal intensity of seven nucleosides increased three to seven times, respectively. A series of statistical analysis were carried out to demonstrate the dynamic changes of modified nucleosides in four groups. This method showed good specific, accuracy, and stability. The results were calibrated and presented through the formation of m 6 A/C, I/C, 5-mdC/C, 5-mC/C, pseU/U to eliminate the individual and age differences. The m 6 A/C, I/C, and pseU/U were found having the dynamic changes in four groups ( p < 0.05). And these five modified nucleosides can also used as one parameter to distinguish these four groups by ROC and LDA analysis. Additionally, they were found to be connected with several clinical biochemical indexes through multiple linear regression analysis. Our LC–MS/MS method assay successfully quantifies the modified nucleosides in serum. And three modified nucleosides can act as the potential biomarkers to describe the development of DN and help to evaluate the diagnosis, treatment, and prognosis of DN in clinical.
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