SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Yongjun Sun,Shengbao Zhou,Wenquan Sun,Sichen Zhu,Huaili Zheng
In order to effectively remove the dissolved heavy metals and the heavy metals on the colloidal particles during the flocculation process, a novel dual-functional chitosan flocculant CMCTS-g-P(AM-CA) is prepared by ultraviolet light-initiated graft polymerization using CMCTS, AM, and ammonium dithiocarbamate. The main influencing factors of monomer concentration, monomer ratio, pH value, photoinitiator concentration, and illumination time are investigated on the basis of intrinsic viscosity, grafting rate, and grafting efficiency of CMCTS-g-P(AM-CA). Characterization results provided empirical evidence for existence of chelating groups. In addition, CMCTS-g-P(AM-CA) was applied to treat the simulated heavy metals and electroplating wastewater. The effect of CMCTS-g-P(AM-CA) dosage, pH value, and reaction G value on flocculation efficiency was also explored. After the two-stage flocculation, the residual concentration of Ni(II), COD, and turbidity of actual electroplating wastewater decreased to 0.96 mg/L, 93.00 mg/L, and 1.71 NTU after flocculation tests at optimal condition, respectively. Finally, the “3E” triangular evaluation model is established and applied to evaluate the flocculation performance of CMCTS-g-P(AM-CA) on the actual heavy metal wastewater further, thereby proving its excellent chelation flocculation performance.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
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IF 3.573
Zhijun Guo,Guoliang Zhang,Lei Wang,Ping Li,Chunshan Li
To meet the increasing demand for methyl methacrylate, a series of Fe modified Cs–P/γ-Al2O3 catalysts were developed through the impregnation method and tested for the aldol condensation of methyl propionate with formaldehyde in a fixed-bed reactor. Through various characterization studies, the physicochemical properties of the catalysts were systematically studied, especially the relationship between the number of the acid sites and catalytic activity. The number of medium acid sites was increased effectively by the addition of Fe, and the catalytic selectivity was improved consequently. Moreover, the reaction conditions were also optimized, and the life span of the optimized catalyst was evaluated. The Cs–P–0.1Fe/γ-Al2O3 showed excellent reusability during a 260 h lifetime experiment.
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CHEMOSPHERE
·
2020
·
IF 5.778
Huan Jiang,Chenyuan Dang,Wen Liu,Ting Wang
Degradation of phenols with different substituent groups (including –OCH 3 , –CHO, –NHCOCH 3 , –NO 2 , and −Cl) at boron-doped diamond (BDD) anodes has been studied previously based on the removal efficiency and •OH detection. Innovatively, formations of CO 2 gas and various inorganic ions were examined to probe the mineralization process combined with quantitative structure-activity relationship (QSAR) analysis. As results, all phenols were efficiently degraded within 8 h with high COD removal efficiency. Three primary intermediates (hydroquinone, 1,4-benzoquinone and catechol) were identified during electrochemical oxidation and degradation pathway was proposed. More importantly, CO 2 transformation efficiency ranked as: no N or Cl contained phenols ( p -CHO, p -OCH 3 and Ph) > N-contained phenols ( p -NHCOCH 3 and p -NO 2 ) > Cl-contained phenols ( p -Cl and o,p -Cl). Carbon mass balance study suggested formation of inorganic carbon (H 2 CO 3 , CO 3 2− and HCO 3 − ) and CO 2 after organic carbon elimination. Inorganic nitrogen species (NH 4 + , NO 3 − and NO 2 − ) and chlorine species (Cl − , ClO 3 − and ClO 4 − ) were also formed after N- and Cl-contained phenols mineralization, while no volatile nitrogen species were detected. The phenols with electron-withdrawing substituents were easier to be oxidized than those with electron-donating substituents. QSAR analysis indicated that the reaction rate constant ( k 1 ) for phenols degradation was highly related to Hammett constant (∑ σ o , m , p ) and energy gap ( E LUMO - E HOMO ) of the compound ( R 2 = 0.908), which were key parameters on evaluating the effect of structural moieties on electronic character and the chemical stability upon radical attack for a specific compound. This study presents clear evidence on mineralization mechanisms of phenols degradation at BDD anodes.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Mengran Lou,Ruiying Wang,Lili Yang,Dianzeng Jia,Zhipeng Sun,Luxiang Wang,Yong Guo,Xingchao Wang,Jie Zhang,Hongli Shi
Direct formic acid fuel cells have great application potential in the energy field, but their commercialization is hindered by the CO poisoning and low performance of Pd-based anode catalysts. In this study, novel composite catalysts composed of Pd, organic-inorganic hybrid imidazole ionic liquid polyoxometalates, and N,P-codoped coal-based carbon fibers with good dispersion and smaller Pd nanoparticles were synthesized successfully. Physical and electrochemical characterizations revealed that the as-prepared Pd-based composite catalysts have excellent CO poisoning resistance and enhanced electrocatalytic activity in formic acid electrooxidation. Notably, the CO oxidation onset potential of a catalyst modified by imidazole ionic liquid polyoxometalate with long alkyl chain was 0.1 V lower than that of the unmodified catalyst. The mass activity of the as-prepared Pd catalyst in formic acid oxidation was 754.1 mA mg −1 Pd . It is expected that organic-inorganic hybrid polyoxometalates can be further applied to fuel cell catalysts.
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Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 11
·5750-5757
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IF 11.301
Liang Sun,Zhicheng Shi,Huanlei Wang,Kun Zhang,Davoud Dastan,Kai Sun,Runhua Fan
Polymer dielectric composites are of great interest as film capacitors that are widely used in pulsed power systems. For a long time, huge efforts have been devoted to achieving energy densities as high as possible to satisfy the miniaturization and high integration of electronic devices. However, the discharge efficiency which is particularly crucial to practical applications has gained little attention. With the target of achieving concurrently improved energy density and efficiency, a class of rationally designed bilayer composites consisting of a pure polyetherimide layer and a BaTiO3/P(VDF-HFP) composite layer were prepared. Interestingly, the bilayer composites exhibit ultrahigh discharge efficiencies η (>95%) under external electric fields up to 400 kV mm−1 which are much higher than most of the so far reported results (η < 80%). Meanwhile, a low loss (tan δ < 0.05 @ 10 kHz) comparable to that of the pure polyetherimide is obtained. In addition, the bilayer composites show impressive improvements in breakdown strengths Eb, i.e., 285%, 363%, 366% and 567% for composites with 5 vol%, 10 vol%, 20 vol% and 40 vol% BaTiO3, compared to their single layer counterparts, resulting in obviously improved energy densities Ud. In particular, the bilayer composite with 10 vol% BaTiO3 displays the most prominent comprehensive energy storage performance, i.e., η ∼ 96.8% @ 450 kV mm−1, Ud ∼ 6 J cm−3 @ 450 kV mm−1, tan δ ∼ 0.025 @ 10 kHz, and Eb ∼ 483.18 kV mm−1. The ultrahigh discharge efficiencies and high energy densities, along with low loss and breakdown strengths, make these bilayer composites ideal candidates for high-performance dielectric energy-storage capacitors.
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Nano-Micro Letters
·
2020
·Vol. 12
·期 1
·1-13
·
IF 12.264
Pan Zhengbin,Han Ershuan,Zheng Jingui,Lu Jing,Wang Xiaolin,Yin Yanbin,Waterhouse Geoffrey I. N.,Wang Xiuguo,Li Peiqiang
Flower-like CeO 2 nanoparticles enhance the performance of CuO nanoparticle/Cu.
The system benefits from the heterojunction between p-type CuO and n-type CeO 2 .
The selective reduction of CO 2 to methanol on the target catalyst is studied.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Jingjing Li,Zhiyu Wang,Xiaodong Tang,Xiaojie Lei
The olefin alkylation of thiophenic sulfur (OATS) in model fluid catalytic cracking gasoline was carried out using the temperature-responsive catalyst which was prepared by mixing the temperature-responsive ionic liquid (TRIL) and p-toluenesulfonic acid (PTSA) with the mass ratio 1:10 (10% TRIL–PTSA). The liquid–liquid biphasic system was formed during the OATS and returned to the liquid–solid state automatically after completion of the reaction at cooling temperature, which enhanced the mass transfer efficiency and separation ability of oil and the catalyst. As for 10% TRIL–PTSA, the acid strength was adjusted properly by TRIL, and the anionic cluster of [−SO3(−SO3H)x]– was also found by Fourier transform infrared, 1H NMR, and thermogravimetric–differential scanning calorimetry, which displayed a better catalyst performance over PTSA. Moreover, the effects of various factors were fully discussed, including the reaction temperature, reaction time, and catalyst dosage. Under optimal conditions, the conversion of thiophene (T) can reach 100% and it can remain unchanged during 10 recycles. Furthermore, apparent reaction kinetics for OATS was discussed. It suggested that the alkylation of T conformed to the pseudo-first-order kinetic characteristic, and the apparent activation energy was 47.6 kJ/mol. Finally, the synergistic catalysis mechanism was proposed.
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ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Weiju Hao,Hao Huang,Ziliang Chen,Lincai Wang,Xiaohua Ma,Mingxian Huang,Xin Ou,Yanhui Guo
Precisely controlling the morphology of electrocatalyst which is critical to its activity and stability remains a key challenge toward efficient overall water splitting. Herein, a distinct temperature-dependent structure modulation effect of electroless plating technique is reported and consequently several bifunctional electrocatalysts with various structures are developed. The optimized bifunctional electrode with cobalt-phosphorus-boron nanoflowers growing on the carbon cloth demands overpotentials of only 91 mV and 294 mV to achieve a current density of 50 mA cm −2 for the hydrogen evolution reaction and oxygen evolution reaction in 1.0 M potassium hydroxide at 25 °C. Moreover, an overall water-splitting device assembled by this electrode can also work at high temperature of 60 °C with excellent long term durability and achieve a current density of 20 mA cm −2 at a cell voltage of around 1.39 V. This work uncovers some structure design principles of highly active electrocatalyst and provides a versatile strategy for structure modulation of the electrocatalyst for pratctical water electrolysis.
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Nanoscale Advances
·
2020
·Vol. 2
·期 8
·3334-3340
·
IF 0
Jieyu Xu,Lin Ge,Yajun Zhou,Guangyu Jiang,Liang Li,Yunheng Li,Yongsheng Li
Heteroatom doping has been proved to be an effective strategy to optimize the activity of hydrogen evolution reaction (HER) catalysts. Herein, we report N, P, S multi-doped Mo2C/C composites exhibiting highly efficient HER performance in acidic solution, which are facilely fabricated via annealing of N, P, S-containing MoOx–polyaniline (MoOx–PANI) hybrid precursors. The optimized N, P, S multi-doped Mo2C/C catalyst with a moderate P dopant level (NPS-Mo2C/C-0.5) exhibits excellent performance with an overpotential of 53 mV to achieve a current density of 20 mA cm−2, a Tafel slope of 72 mV dec−1 and good stability in acidic electrolytes. Based on the study of XPS, EPR and 31P MAS NMR, the excellent electrocatalytic performance could be attributed to the effective electronic configuration modulation of both Mo2C nanorods and the carbon matrix, derived from stronger synergistic N, P, S multi-doping coupling effects. This work provides a promising methodology for the design and fabrication of multi-doped transition metal based electrocatalysts via electronic structure engineering.
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TRANSITION METAL CHEMISTRY
·
2020
·Vol. 46
·期 1
·37-47
·
IF 1.366
Guo Leilei,Wang Quanxiu,Shi Qingqing,Guan Ruolin,Zhao Liping,Yang Hanmin
In this study, the shape-controlled synthesis of ruthenium (Ru) nanostructures was examined using microwave irradiation. Dendritic Ru nanostructures, with an average diameter of about 34.7 nm, were successfully synthesized when ruthenium chloride (RuCl 3 ) was reduced using a reducing agent of benzyl alcohol, in the presence of polyvinylpyrrolidone (PVP) under microwave irradiation for 360 s. By examining selected parameters affecting the shape-controlled synthesis of dendritic Ru nanostructures, i.e., the concentration of the RuCl 3 precursor, different reducing agents, molecular weight of PVP and the molar ratio of RuCl 3 /PVP, were identified as key factors affecting the successful synthesis of dendritic Ru nanostructures. The catalytic performance of obtained dendritic Ru nanostructures was evaluated for hydrogenation of p-chloronitrobenzene (p-CNB). High selectivity to p-chloroaniline (p-CAN) of about 99.58% was obtained using dendritic Ru nanostructure catalysts at 80 °C under 1 MPa hydrogen pressure, having a 72.81% conversion rate of p-CNB. The selectivity to p-CAN with a dendritic Ru nanostructure catalyst is notably higher than that of conventional 5% ruthenium/carbon catalysts (62.12%). Here in we demonstrate that synthesized dendritic Ru nanostructures present a promising catalytic performance in the hydrogenation of p-CNB, having potential applicability to a wide range of catalytic reactions.
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RSC Advances
·
2019
·Vol. 9
·期 72
·42335-42342
·
IF 3.049
Bo Huang,Xinxin Luo,Qichao Zou,Suxiao Wang,Jinzhi Zhang
We reported an innovative transparent, elastic and flexible conductive composite materials P(SSNa-BA-St)/PEDOT/graphene which were prepared by using P(SSNa-BA-St) latex as template for PEDOT polymerization and graphene doping. This P(SSNa-BA-St)/PEDOT/graphene film exhibited highly transparent, good water resistance, low moisture adsorption, highly elastic and highly conductive properties, which can serve as a practical approach to fabricate the flexible, conductive and transparent films for wearable and implantable electronic devices, and photovoltaic cells.
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WATER ENVIRONMENT RESEARCH
·
2019
·Vol. 92
·期 5
·713-721
·
IF 1.24
Yunhai Zhang,Shuangxi Zhou,Xin Su,Jimin Xu,Guangze Nie,Yongjun Zhang,Yide He,Shuili Yu
A p-type TiO 2 with Ti vacancies (D-TiO 2 ) was synthesized by a facile solvothermal treatment, and Ag/TiO 2 with different Ag loading amount was prepared through a photo-reduction deposition method. The samples were characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The adsorption and photocatalytic characteristics of tetrabromobisphenol A (TBBPA) on D-TiO 2 and Ag/TiO 2 were investigated. The adsorption of TBBPA on Ag/TiO 2 was significantly enhanced and was five times greater than that of pure TiO 2 . The increase in pH significantly inhibited the adsorption of TBBPA. The 2%-Ag/TiO 2 nearly completely degraded TBBPA in 10 min under UV–Vis light (λ > 360 nm), and the apparent reaction rate constant ( k app ) reached 0.63 min −1 . The significantly enhanced UV–Vis light catalytic properties of the Ag/TiO 2 in comparison with that of TiO 2 were attributed to the increased adsorption capacity and electron transfer ability of the Ag/TiO 2 . Free radical trap experiments results showed that holes and superoxide radicals play a major role in the catalytic degradation of TBBPA by Ag/TiO 2 . Moreover, the Ag/TiO 2 catalyst exhibits high stability during TBBPA degradation even after three cycles. Practitioner points Ti-defected TiO 2 and Ag/TiO 2 were synthesized using a solvothermal and photo-reduction deposition, respectively. Ag/TiO 2 exhibited outstanding adsorption and photocatalytic activity for TBBPA removal under UV–Vis light. Holes and superoxide radicals play a major role in the photocatalytic degradation of TBBPA.
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