ULTRASONICS SONOCHEMISTRY
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2020
·
IF 6.513
Nannan Geng,Wei Chen,Hang Xu,Mingmei Ding,Tao Lin,Qiangshun Wu,Lei Zhang
In this work, as a new strategy, ultrasound/H 2 O 2 /MOF system was firstly applied by environmental-benign Fe-MOFs (MIL-53, MIL-88B and MIL-101) for tetracycline hydrochloride removal. The synthetic Fe-MOFs were characterized by XRD, FTIR, SEM, XPS, N 2 sorption-desorption isotherms and CO-FTIR. MIL-88B demonstrated the best catalytic performance because of its highest amount of Lewis acid sites. Influencing factors, contrast experiment, and corresponding dynamics were carried out to obtain the best experimental conditions and reaction system. Under optimal conditions ([Tetracycline hydrochloride] = 10 mg/L, [MIL-88B] = 0.3 g/L, [H 2 O 2 ] = 44 mM, [ultrasound power] = 60 W, and pH = 5.0), the-first-order kinetic rate constant k was calculated to be 0.226 min −1 , higher than the simple combination of the ultrasound system (0.004) and MIL-88B/H 2 O 2 system (0.163), indicating the importance of synergistic effect between ultrasound and Fenton reaction. EPR test and quenching experiment proved that ·OH is mainly responsible for tetracycline hydrochloride removal. The major reaction path is the adsorption and decomposition of H 2 O 2 by coordinative unsaturated iron sites on Fe-MOF, but it is not the only path. The direct decomposition of H 2 O 2 and the cavitation effect caused by ultrasound also contribute to the generation of OH.
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高影响因子
Nanomaterials
·
2020
·Vol. 10
·期 9
·1655
·
IF 4.324
Yuqiong Shi,Yuxuan Wang,Jinhua Zhu,Wei Liu,Md. Zaved H. Khan,Xiuhua Liu
MIL-based molecularly imprinted polymer (MIP) nanocomposites were successfully synthesized through a simple and versatile stirring auxiliary encapsulation method. MIP as a carrier has been applied to the highly efficient selective recognition and sustained release of doxorubicin hydrochloride (DOX). The adsorption mechanism and release behavior of[email protected]in vitro were also discussed. Adsorption studies showed that MIP using DOX as template had specific selectivity to DOX, and its optimal drug loading efficiency reached 97.99%. The adsorption isotherm accorded with Freundlich models. The cumulative release curve showed that at the conditions of pH 5.5 and 7.4, the nanomaterials have a slow-release effect on the release of DOX. In addition, the cytotoxicity and bioactivity of MIP nanoparticles on HepG2 and HL-7702 cell lines measured by MTT assay also proved their low toxicity and biological activity. The cell activity of HepG2 and HL-7702 incubated with MIP for 24 h was 69.9% and 76.07%, respectively. These results collectively illustrated that the MIP nano-materials synthesized in this study can be efficiently employed to the drug delivery systems.Keywords:MIP;nanocomposites;drug delivery;DOX;controlled release
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Yuanming Deng,Xi Zou,Zairan Liu,Jinzhi Wang,Zhong Wang,Jiaoning Tang
Here we present a simple method to prepare a highly efficient three components nanocomposites via thermal degradation of layered double metal hydroxides (LDHs)@polyvinyl alcohol (PVA) composites. Co 7 Fe 3 /CoFe 2 O 4 @C obtained from this method is applied to activate peroxymonosulfate (PMS) to degrade polluted organics and showed excellent performance. The best removal RhB efficiency of Co 7 Fe 3 /CoFe 2 O 4 @C (Co/Fe = 1:1) is near 100% within 10 min and the lowest ions elution (∼0.05 mg/L) under pH = 7, which is also better than the performance of the precursor Co–Fe LDH. Through further cycling experiments and degradation of p -nitrophenol, the stability and catalytic performance of the catalyst were verified. Finally, free radical scavenging experiments prove ·OH and SO 4 · - radicals participating in the reaction, which are the key factors for degradation. Based on the above, the derivation of the mechanism of Co 7 Fe 3 /CoFe 2 O 4 @C (Co/Fe = 1:1) catalyzing PMS to degrade polluted organics was proposed, and we consider this catalyst has great application prospect.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
·
IF 7.489
Zhengfeng Shen,Feifei Li,Jiangrui Lu,Zhidan Wang,Rui Li,Xiaochao Zhang,Changming Zhang,Yawen Wang,Yunfang Wang,Zhiping Lv,Jianxin Liu,Caimei Fan
Photocatalytic nitrogen fixation has been considered to be a safe, green, eco-friendly, and sustainable technology. However, photoinduced activation of inert dinitrogen is an important factor hindering the development of this technology. Herein, in-situ Fe 3+ doped flower-like BiOCl with highly active sites exposure was prepared by a solvent thermal method, which has excellent performance of N 2 photofixation. Compared with virgin BiOCl with no nitrogen fixation activity, Fe-BiOCl reached 30 μmol·L −1 ·h −1 ammonia evolution rate under simulated sunlight without any sacrificial reagent. Characterization results demonstrated that the enhancement of N 2 photofixation capacity was mainly attributed to the in-situ doped Fe 3+ in BiOCl, the doped Fe 3+ not only acts as a reaction center for N 2 activation also as an “electron transfer bridge” trapping and migrating electrons from BiOCl to N 2 molecules. Furthermore, the transformation of crystal facets from virgin BiOCl (0 0 1) to Fe-BiOCl (1 1 0) and (1 0 2) is more conducive for the exposure and accessibility of iron reactive sites. This work developed a potential strategy by in-situ introducing Fe 3+ active sites in BiOCl semiconductor substrate, which establishes a good basis for the application of semiconductor catalysts in nitrogen fixation.
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高影响因子
Metals
·
2020
·Vol. 10
·期 12
·1574
·
IF 2.117
Ruochen Shen,Chaohui Pu,Xiaoou Xu,Youpeng Xu,Zhilin Li,Zhu Wu
The research aims to study the effect of adding mischmetal (Mm) to the TiFe0.86Mn0.07Co0.07alloy on its hydrogen storage performance and cyclic stability. The results show that TiFe0.86Mn0.07Co0.07+ x% Mm (x = 0,4,6,8) alloys can be easily activated. The hydrogen absorption capacity of TiFe0.86Mn0.07Co0.07+ 4% Mm reaches 1.76 wt% (mass fraction) at 298 K. With the increase of Mm addition, the hydrogen storage capacity decreases slightly. Furthermore, after 40 absorption and desorption cycles in hydrogen containing 250 ppm O2, the alloy still has 36% of its initial hydrogen storage capacity, and the alloy can recover 93% of its hydrogen storage capacity through heat treatment.Keywords:TiFe hydrogen storage alloys;life test;impure hydrogen gas;cyclic stability
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Catalysts
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2020
·Vol. 10
·期 12
·1379
·
IF 3.52
He Liu,Shiguang Fan,Xu Gong,Jian Wang,Aijun Guo,Kun Chen,Zongxian Wang
Partial hydrogenation of anthracene under CO-H2O, N2-H2O, and H2-H2O over Fe-based catalysts was studied at 400 °C and 10 MPa. Results show that the Fe-based catalysts display obvious catalytic activity for anthracene hydrogenation under CO-H2O instead of hydrogenation under N2-H2O and H2-H2O. The activity follows in the order of Fe(NO3)3·9H2O > Fe naphthenate > FeSO4·7H2O. Even though the amount of molecular hydrogen remains higher than that of in situ hydrogen, the anthracene conversion with in situ hydrogen is remarkably higher. It demonstrates that the in situ hydrogen is more active than molecular hydrogen for PAH hydrogenation. To further reveal the exact fate of these Fe-based catalysts, the decomposed products under CO-H2O, N2-H2O and H2-H2O were characterized by TG, XRD, and TEM. Results indicate that the Fe3O4species play a key role in hydrogenation of anthracene under CO and H2O. Higher catalytic activity for Fe(NO3)3·9H2O is due to its complete decomposition at 350 °C to acquire higher concentration of active Fe3O4species. The possible form of in situ hydrogen during this process is also discussed. Given that heavy oil contains abundant polyaromatics, these results are meaningful for enhancing hydrogen shuttling to heavy oil by producing natural hydrogen donors and, thus, benefiting the high-efficient upgrading.Keywords:PAH hydrogenation;in situ hydrogen;water gas shift reaction;natural hydrogen donors
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Weike Zhao,Bo Zhou
In recent years, multi-walled carbon nanotubes (CNTs), which are emerging nanocatalysts, have received much attention in advanced oxidation processes. CNTs were introduced into H 2 O 2 /Fe(III) Fenton-like process to enhance the degradation of bisphenol A (BPA) in this study. The results of the study suggests that CNTs could effectively promote electron transfer from H 2 O 2 to Fe(III) and directly reduce Fe(III) to Fe(II) to accelerate Fe(III)/Fe(II) cycles, in which carbonyl groups and structural defects of CNTs were identified as the major active sites via SEM, Raman, XRD, FTIR and XPS analyses. It was revealed that hydroxyl radical (·OH) majorly contributed to the degradation of BPA, and the generation efficiency of ·OH was significantly increased by 3.2 times with the addition of CNTs. Also, nine intermediate products were identified, and the possible degradation pathways of BPA were proposed through the density functional theory (DFT) calculations and HPLC-MS/MS analysis. The ecotoxicity evaluation of BPA demonstrates that the oxidative degradation of BPA in CNTs/H 2 O 2 /Fe(III) system could effectively reduce its environmental risk. The critical experimental parameters including the dosage of Fe(III), H 2 O 2 , CNTs, initial pH and various anions (Cl − , HCO 3 – , SO 4 2− ) were investigated, and the reusability experiments indicate that CNTs maintained high stability and reusability during the reaction.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2020
·
IF 6.551
Xiong Jia,Yujie He,Philippe F.-X. Corvini,Rong Ji
Humic substances are reactive during redox alteration. However, the role of this reactivity in the transformation of organic compounds and in carbon cycling in the environment is still unclear. Here, we used 14 C-radioactive tracer to study abiotic transformation and humification of catechol, a representative of naturally occurring monomeric phenols and phenolic pollutants, in suspensions of humic acids (HAs) at original and H 2 /Pd-reduced redox states with flux of air (HA org -Air and HA red -Air, respectively) or N 2 (HA org -N 2 and HA red -N 2 , respectively) for 20 min in absence and presence of Cu(II) and Fe(II). Both HA org and HA red can transform catechol in the absence of O 2 to 19% and 25% of the initially applied amount, respectively. The transformation of catechol strongly increased when air was introduced, amounting to 75% in HA red -Air treatment and 43% in HA org -Air treatment, owing to the generation of reactive oxygen species . Considerable amounts of catecholic carbons were incorporated into HAs (26% for HA red -Air and 19% for HA org -Air), constituting humification of catechol. The presence of Cu(II) strongly inhibited the overall transformation and humification of catechol, although it significantly increased humification at the start of incubation. The presence of Fe(II) overall enhanced both the transformation and humification. The results provide first insights into the impacts of redox alteration of humic substances together with the presence of metal ions with variable valences on the fate of phenolic compounds in the environment. This study points out that redox alteration-induced abiotic transformation may be one important process for dissipation of phenolic pollutants and humification of phenolic carbons in environments rich in HAs and subject to redox fluctuation.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2020
·
IF 16.683
Kai Zhao,Zisheng Zhang,Yalan Feng,Shuanglong Lin,Hong Li,Xin Gao
The development of efficient strategies to promote spatial charge separation is a promising way for the improvement of photocatalytic performance. Herein, a novel surface oxygen vacancy (OVs) modified Bi 2 MoO 6 /MIL-88B(Fe) heterostructure (BMO/M88) was exemplified by a facile two steps solvothermal method to demonstrate synergistic promotion of bulk & interface charge separation. Due to the existence of OVs and the construction of heterostructure, the Bi 2 MoO 6 /MIL-88B(Fe) composites exhibited significant enhancement of visible-light responsive range and possessed more efficient bulk & interface charge separation. This novel Bi 2 MoO 6 /MIL-88B(Fe) composites exhibited high visible light photocatalytic performance toward dye pollutant rhodamine B (RhB) and model colorless pollutant bisphenol A (BPA) photodegradation , and the possible Type II heterojunction mechanism of photocatalysis process was investigated. This work not only provides a novel pathway for design of MOFs-based heterojunction with surface OVs defect modification but also offers a strategy for significantly enhanced bulk & interface charge carriers separation.
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高影响因子
PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2020
·Vol. 45
·期 3
·368-373
·
IF 1.544
Naimeng Song,Li Yang,Pingan Liu
In this study, the ultrasonic spray drying technology was applied to prepare composite microspheres of catalyst (Ta−Fe, Ph−Fe) and AP. The surface morphology of the two composite microspheres was characterized by scanning electron microscopy (SEM). Their particle size distribution characteristics were tested by a nano laser particle size analyzer. The results showed that the spray drying technology can uniformly compound the AP and the catalyst into spherical particles. The thermal decomposition process of Ta(Ph)-Fe/AP composite microspheres were tested by differential scanning calorimetry (DSC). The DSC data demonstrated that Ta(Ph)-Fe/AP composite microsphere had a very good catalytic effect and significantly promoted the thermal decomposition process of AP. In addition, the catalytic mechanism was discussed by calculating the change in activation energy. Compared with the raw AP, the activation energies of the Ta−Fe/AP and Ph−Fe/AP composite microspheres were reduced by 18.5 kJ/mol and 28.1 kJ/mol, respectively.
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Nanoscale Research Letters
·
2020
·Vol. 15
·期 1
·1-14
·
IF 3.578
Guo Chaozhong,Li Yanrong,Li Zhaoxu,Liu Yao,Si Yujun,Luo Zhongli
Designing appropriate methods to effectively enhance nitrogen-doping efficiency and active-site density is essential to boost the oxygen reduction reaction (ORR) activity of non-platinum Fe/N/C-type electrocatalysts. Here, we propose a facile and effective strategy to design a mesopore-structured Fe/N/C catalyst for the ORR with ultrahigh BET surface area and outstanding conductivity via nanochannels of molecular sieve-confined pyrolysis of Fe 2+ ions coordinated with 2,4,6-tri(2-pyridyl)-1,3,5-triazine complexes as a novel precursor with the stable coordination effect. Combining the nanochannel-confined effect with the stable coordination effect can synergistically improve the thermal stability and stabilize the nitrogen-enriched active sites, and help to control the loss of active N atoms during pyrolysis process and to further obtain a high active-site density for enhancing the ORR activity. The as-prepared Fe/N/C electrocatalyst has exhibited excellent catalytic activity with an onset potential of ~ 0.841 V (versus RHE) closely approaching the Pt/C catalyst and high long-term stability in alkaline electrolyte. Besides, low-hydrogen peroxide yield (< 6.5%) and high electron transfer number (3.88–3.94) can be found on this catalyst, indicating that it is a valuable substitute for traditional Pt/C catalysts. This work paves a new way to design high-performance Fe/N/C electrocatalysts and deepens the understanding of active site and ORR catalysis mechanism.
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MATERIALS & DESIGN
·
2020
·
IF 6.289
Yiqun Zhang,Yaqiang Dong,Bang Zhou,Qiang Chi,Liang Chang,Mengji Gong,Jianjun Huang,Yan Pan,Aina He,Jiawei Li,Xinmin Wang
In this work, dense and pinhole-free poly-para-xylylene (PPX) with high thermal stability, high insulating property and high lubricity has been designed as coating layer for Fe-based amorphous powder. Three ultra-thin PPX layers have been successfully deposited on the surface of FeSiBPNbCr amorphous powder via chemical vapor deposition (CVD) polymerization. The micromorphology and chemical structure of the PPX layer on the powder surface, as well as the conversion mechanisms, has been investigated systematically. Several methods have been used to estimate the amount and thickness of PPX layers. The corresponding amorphous powder cores (AMPCs) were also prepared. With the increasing thickness of the PPX layer, the saturation magnetization ( M s ) of the powder decreased slightly but the magnetic flux density ( B s ) of the AMPCs kept at a similar level thanked to the enhanced green density. In addition, the DC bias performance was improved and core loss ( P cv ) was reduced. Compare with other coating materials like epoxy and silicon resin, the PPX layer provided better insulation and higher lubricity for the AMPCs, thus reduced the P cv and improved the DC bias performance. The AMPCs coated by PPX-3 exhibited excellent comprehensive soft magnetic properties, which were promising for high-power and high-frequency applications.
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