CHEMICAL GEOLOGY
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2020
·
IF 3.363
Jing-Jing Fan,Jie Li,Qiang Wang,Le Zhang,Jing Zhang,Xiang-Lan Zeng,Lin Ma,Zi-Long Wang
Recent advances in analytical techniques have achieved high-precision (2σ ≤ 0.06‰) determinations of Mo isotopic ratios in silicate rocks but few such data are as yet available, especially for low-Mo (<50 ppb) rocks such as leucogranites . Here we present two low-blank, double-spike, high-yield, ion-exchange chromatographic methods (single- and two-column) for precise determination of Mo isotopic ratios in low-Mo rock samples (10–500 ppb) using multicollector–inductively coupled plasma–mass spectrometry (MC–ICP–MS). The two-column technique involved AG 1-X8 anion-exchange (100–200 mesh) and BPHA chelatin resins, with the latter also used in the single-column procedure. Two USGS reference materials (basalt BIR-1a and diabase W-2a) were analyzed for quality-control purposes. Their δ 98/95 Mo values determined using the two methods are consistent within uncertainties, and with those determined by previously published methods. We provide the first Mo isotopic data for the reference materials of dunite DTS-2b (USGS), GPt-3 (NRCG) and peridotite WPR-1 (CCRMP). δ 98/95 Mo values for DTS-2b and WPR-1 by using two-column procedure are in good agreement with those obtained by single-column separation. Repeated analyses of these standards indicate a long-term external reproducibility of better than ±0.05‰. However, the δ 98/95 Mo values of GPt-3 show poor reproducibility due to either the sample heterogeneity or existing undigested minerals (e.g., spinel). The methods were applied to leucogranites with low Mo contents of 10–74 ppb from the Himalaya orogen and southern Lhasa terrane of Tibet . The isotopic analyses yielded δ 98/95 Mo values of −0.2‰ to 0.34‰ and −0.41‰ to −0.68‰ (against NIST SRM 3134), respectively, within the range of values for igneous crust. Their contrasting Mo isotopic compositions may indicate compositional diversity in their sources or differences in magma evolution .
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WATER RESEARCH
·
2020
·
IF 9.13
Shiqing Zhou,Ling Li,Yangtao Wu,Shumin Zhu,Ningyuan Zhu,Lingjun Bu,Dionysios D. Dionysiou
The presence of nitrite (NO 2 − ) is inevitable with concentrations of several mg L −1 in some typical water bodies. In this study, UV at wavelength of 365 nm was investigated to degrade contaminants of emerging concern (CECs) in the presence of NO 2 − at environmentally relevant concentrations (0.1–5.0 mg L −1 ). Six selected CECs with different structures were efficiently removed because of the generation of reactive nitrogen species (RNS) and hydroxyl radical (HO • ) from photolysis of NO 2 − . Contributions of UV 365 photolysis, RNS, and HO • to CEC degradation in UV 365 /NO 2 − system were calculated, and RNS were found to be the predominant species that are responsible for CEC degradation. The second major contributor is HO • for the degradation of selected CECs except for the case of sulfadiazine. Impacts of water matrix components (including dissolved oxygen, solution pH, and natural organic matter) on CEC degradation in UV 365 /NO 2 − system were evaluated. Furthermore, evolution profiles of CECs and NO 2 − in UV 365 /NO 2 − system were tracked when actual water samples were used as background, and a simultaneous removal of CECs and NO 2 − was observed. Transformation products of bisphenol A and carbamazepine were proposed according to the results of HPLC/MS and quantum chemistry calculations. Nitration induced by RNS and hydroxylation induced by HO • are main reactions occurred during CEC degradation in UV 365 /NO 2 − system. Overall, UV 365 is a potential technology to remove CECs and NO 2 − in aquatic environment when residual NO 2 − is present. Our present study also provides possibility for the application of sunlight to remediate water co-polluted by CECs and NO 2 − .
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JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Xiang Li,Yan Jia,Minghua Zhou,Xianfa Su,Jianhui Sun
In this study, the Fe, N co-doped biochar (Fe-N-BC) was prepared by pyrolyzing wheat straw, urea and iron salts and used to activate persulfate (peroxydisulfate, PS) for organic contaminant degradation. Iron oxide doping not only introduced magnetism into the biochar for easy separation, but also influenced its catalytic ability for PS activation. In the Fe-N-BC/PS system, almost all acid orange (AO7) was removed within 90 min with an apparent rate constant ( k obs ) of 0.114 min −1 , which was almost 37 times larger than that of pure N-BC (0.003 min −1 ). Factors influencing the removal of AO7 were investigated, including PS concentration, catalyst dosage, and initial pH. The Fe-N-BC/PS system had high removal efficiencies for various organic contaminants and showed high resistance to inorganic anions in aquatic environments. The radical quenching studies, electron paramagnetic resonance (EPR) measurements, and electrochemical analyses verified that the mechanism of AO7 degradation in the Fe-N-BC/PS system included both radical and non-radical pathways involving the generation of OH, SO 4 − , O 2 − , 1 O 2 , and electron transfer. Additionally, persistent free radicals (PFRs) on the catalysts also related to their catalytic efficiencies. These results demonstrated that the Fe-N-BC/PS system had the potential for wastewater treatment applications.
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FIBERS AND POLYMERS
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2020
·Vol. 21
·期 4
·762-774
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IF 1.797
Tan Zhenjiang,Gao Ming,Dai Jiangdong,Ge Wenna,Zhu Wenjing,Yan Yongsheng
Here, novel magnetic imprinted porous foams (MIFs) were prepared by Pickering oil-in-water high internal phase emulsion polymerization, using renewable cellulose nanocrystals (CNCs) derived from cotton source as the stabilizer, and surfactant Tween 85 and iron oxide magnetic nanoparticles as additive in aqueous phase, for selective adsorption of 4-nitrophenol (4-NP). Interconnected porous foam structure was formed and optimized by controlling the addition amount of solid stabilizer CNCs, Tween 85, and oil phase volume, the optimum value of which was 7.5 wt%, 5.0 wt%, and 85 %, respectively. The as-synthesized imprinted material had the good thermal stability and magnetic responsivity. The adsorption equilibrium data was fitted well by the Langmuir isothermal model with a maximum adsorption capacity of 287.5 µmol/g. Pseudo-second-order kinetics model could better describe the kinetics data. MIFs showed excellent selective ability for 4-NP as compared with these structural analogues. Besides, Thomas model explained the dynamic breakthrough curves better. The regeneration ability of MIFs was also satisfying after several reuse.
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ACS Applied Nano Materials
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2020
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IF 0
Yun Shan,Hong-Lin Zhang,Yuan Zhu,Ying Wang,Huaju Song,Chuanguo Shi
An electrochemiluminescent immunosensor is constructed for the detection of diethylstilbestro (DES) on the basis of amplified quenching of electrochemiluminescence (ECL) from CdTe nanocrystal (NC)/reduced graphene oxide (rGO) composite films by antibody (Ab) against DES-modified SiO2 nanoparticles (Ab@SiO2). In this immunosensing system, CdTe NC/rGO composite films act as solid supporters for both DES and ECL emitters, which generate a 100-fold stronger ECL emission than CdTe NC films because the presence of rGO can lower the potential barrier, facilitate charge transfer, suppress nonradiative Auger recombination, and make the electron trap states fill more efficiently. On the composite films, the immobilized ovalbumin-modified DES (OVA-DES) competes with free target DES to bind Ab@SiO2. As a result, the number of formed OVA-DES-Ab@SiO2 immunocomplexes is inversely related to that of target DES. Using an ECL quenching maximum at blank as a calculation benchmark, the ECL intensity increment of the immunosensor and the concentration of target DES show a linear range of 0.002–2 ng/mL (R2 = 0.996) with a detection limit of 0.001 ng/mL (signal/noise = 3). This immunosensor, of good selectivity and stability, was used to detect beef samples, with recoveries at a scope of 93.2%–105.0%.
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MACROMOLECULES
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2020
·
IF 5.918
Jia-Wei Long,Li Chen,Bo-Wen Liu,Xiao-Hui Shi,Xue-Bao Lin,Ying-Ming Li,Yu-Zhong Wang
The construction of novel semiaromatic polyamides (SaPAs) combining all advantages of aliphatic and aromatic polyamides is of particular importance in both academia and industrial circles. To study the effect of different pendent groups on the comprehensive properties of SaPAs, three kinds of SaPAs with different pendent groups were designed and prepared by the aromatic nucleophilic substitution polycondensation, named as P-PAH (dimethyl-), P-PEPH (methylphenyl-), and P-DPMPH (diphenyl-). All of these polyamides exhibited a relatively high molecular weight with narrow molecular weight distribution. It was found that the chain conformation of P-PEPH was significantly different from those of P-PAH and P-DPMPH due to the formation of the helical structures caused by the asymmetric methyl and phenyl pendent groups, which was testified by computational simulation. Meanwhile, SaPAs with phenyl pendent groups (P-PEPH and P-DPMPH) exhibited an interaction between molecular chains due to π–π stacking, as proved by wide-angle X-ray diffraction (WAXD) results. With an increase in the content of the phenyl pendent groups, their glass-transition temperatures (Tg) increased gradually from 135.6 to 156.5 °C and the initial decomposition temperatures (T5%) also increased. Rheological investigations and solubility tests showed that these polyamides were suitable for processing either in melt or in solution. The expected mechanical properties of P-PEPH were also obtained due to the unique chain conformation and π–π stacking. Taking these advantages, this kind of novel SaPAs exhibited potential availability in versatile applications.
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ENVIRONMENTAL RESEARCH
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2019
·
IF 5.026
Peng Mei,Huihui Wang,Han Guo,Ning Zhang,Sailun Ji,Yapeng Ma,Jiaqi Xu,Ying Li,Hamed Alsulami,Mohammed Sh Alhodaly,Tasawar Hayat,Yubing Sun
A new photocatalyst of TiO 2 /C 3 N 4 composite (TiO 2 /g-C 3 N 4 ) was synthesized by the hydrothermal method. The characterization showed that TiO 2 /g-C 3 N 4 extended absorption light range and enhanced generation efficiency of photo-induced electron. Under the simulated solar irradiation, the photodegradation rate of bisphenol A (BPA) by TiO 2 /g-C 3 N 4 was twice as fast as that of g-C 3 N 4 . Furthermore, TiO 2 /g-C 3 N 4 presented the good stability and excellent selectivity for BPA degradation. The high degradation rate of BPA by TiO 2 /g-C 3 N 4 was demonstrated to be superoxide radical (·O 2 − ) and singlet oxygen ( 1 O 2 ) by radical quenching experiment, which was further evidenced by EPR, XPS, DRS and PL analysis. These findings revealed that TiO 2 /g-C 3 N 4 can be used as a potential photocatalyst for removing organic pollutants in actual environmental remediation.
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COMPOSITES SCIENCE AND TECHNOLOGY
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2020
·
IF 7.094
Mufang Li,Xu Zhao,Yingying Li,Wen Wang,Weibing Zhong,Mengying Luo,Ying Lu,Ke Liu,Qiongzhen Liu,Yuedan Wang,Dong Wang
The rapid development of optoelectronic devices puts forward higher requirements for flexible transparent films with good mechanical and thermal properties. To further improve the mechanical, thermal and optical properties of the PVA-co-PE nanofiber reinforced epoxy composite film, cellulose nanocrystals (CNCs) was selected as modifier to enhance the interfacial adhesion between the reinforced nanofibers and matrix. Benefiting from excellent hydrophily, high strength , transparency and ultra-low thermal expansion coefficient (CTE) of CNCs, dramatic improvements in tensile strength , transparency and thermal stability of CNCs/PVA-co-PE/epoxy composites were observed over pure PVA-co-PE nanofiber/epoxy film. Typically, when the CNCs concentration was 3%, the transparency of CNCs/PVA-co-PE/epoxy film increased from 83.4% to 90.4%, the tensile strength increased from 11.4 MPa to 16.4 MPa, the CTE dropped from 33 to 10 ppm/K. Furthermore, as the reinforcement for matrix and the carrier for functional materials , the CNCs/PVA-co-PE nanofiber membrane was used to prepare the patterned photochromic and thermochromic films encapsulated with epoxy, indicating the potential application of CNCs/PVA-co-PE/epoxy composites in the light emitting devices .
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Atian Xie,Jiuyun Cui,Jin Yang,Yangyang Chen,Jihui Lang,Chunxiang Li,Yongsheng Yan,Jiangdong Dai
Herein, a graphene oxide/MIL-88A(Fe) (GO/M88A) membrane was prepared for the first time by a facile vacuum filtration method. The intercalation of photo-Fenton catalytic M88A into GO nanosheets can not only regulate 2D nanochannels, but also endow the membrane with photo-Fenton catalytic activity. Accordingly, the GO/M88A membrane showed an enhanced separation efficiency and flux (more than 6 times that of GO membrane) based on synergistic separation/photo-Fenton processes. Importantly, the GO/M88A membrane maintained high separation efficiency (97.87 %) and almost constant flux even after 12 cycles of MB separation. The GO/M88A membrane can also be used to treat real textile wastewaters. Moreover, the membrane was directly used as catalyst for photo-Fenton catalytic degradation of contaminants with high degradation efficiency for MB (98.81 %) and BPA (97.27 %). Therefore, the results indicate that this novel GO/M88A membrane has excellent separation performance, stability and photo-Fenton activity and can be used as a potential membrane for water purification and environmental protection applications.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Liying Wu,Junming Hong,Qian Zhang,Bor-Yann Chen,Ji Wang,Zhengyu Dong
This first-attempt study explored interactive function of oxygen vacancies, transition metals, and surface hydroxyl groups for persulfate (PS) activation, at different pH conditions. Oxygen vacancy-rich Fe 2 Co 1 -LDHs was fabricated via calcination in hydrogen atmosphere. The Fe 2 Co 1 -LDH possessed the maximal concentration of oxygen vacancies and abundant hydroxyl groups for effective functioning according to the characterization through X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The BPA-degrading efficiency in the LDHs/PS system indicated that Fe 2 Co 1 -LDH exhibited the most promising activated performance since oxygen vacancies could improve the catalytic efficiency to enhance electron transport phenomena between the Fe and Co. N 2 experiments proved that the presence of oxygen vacancies could promote the production of 1 O 2 and O 2 − . Phosphate and pH effect experiments showed the Fe 2 Co 1 -LDH/PS system stably maintained operation performance over a wide pH range for bisphenol A (BPA) removal with the effect of surface hydroxyl groups. Practical samples had little effect on the removal of BPA. According to the quenching experiments and EPR technology, SO 4 − was the main active radicals in acid and neutral conditions and apparently the OH played the crucial role at alkaline pHs. Two different major reaction routes at different pH levels in the Fe 2 Co 1 -LDH/PS system for mechanisms of BPA degradation were proposed herein. The Chemical intermediates of BPA degradation were identified by gas chromatography-mass spectrophotometry (GC–MS) analysis, and degradation pathways were proposed for system optimization.
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JOURNAL OF CHROMATOGRAPHY A
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2019
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IF 3.858
Lili Lian,Xinhao Jiang,Junjiao Guan,Zhifu Qiu,Xiyue Wang,Dawei Lou
The migration of bisphenols (BPs) can take place from plastic packaging materials into freshly cooked takeaway food, especially at high temperatures. In this study, cetyltrimethylammonium bromide - intercalated zinc oxide (ZnO@CTAB) was developed and used to extract the migration of BPs (bisphenol A and bisphenol AF) from disposable plastic materials to contained food simulates. Several experimental parameters that influence extraction efficiency were investigated. Under optimal conditions, a sensitive dispersive solid-phase extraction method based on ZnO@CTAB was proposed for the analysis of BPs coupled with ultra-high performance liquid chromatography and time-of-flight mass spectrometry. The method exhibited good linearity of calibration, high recovery (97.63–109.33%), low limits of detection 0.027–0.030 μg L −1 , and acceptable precisions. The developed method was used to carry out a migration test from two disposable plastic bags and a disposable plastic container, using distilled water at 100 °C as a hot liquid food simulant. The migration concentrations of bisphenol AF was found to be 0.42 μg L −1 and 0.86 μg L −1 for the two types of disposable plastic bags, and the concentration of bisphenol A was 0.49 μg L −1 for disposable plastic container. The proposed method was also applied to investigate the migration of BPAF from the disposable plastic bags to different food simulants, revealing that the release of BPAF levels depended on the polarity of the liquid food components.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Bao-Cheng Huang,Gui-Xiang Huang,Jun Jiang,Wu-Jun Liu,Han-Qing Yu
Carbon-based materials are recognized as promising candidates for pollutant degradation because of their environmental benignity. Massive and cost-effective production and efficient recovery of carbon-based catalysts are crucial to apply this technology. However, various nanostructured carbons with different dimensions are usually utilized as precursors while not considering their complex preparation procedures and the high costs of ingredients. Moreover, catalyst separation and recovery are not given sufficient attention. In this work, a calcium salt-assisted pyrolysis strategy is proposed to tune the catalytic site formation of carbon-based catalysts. Results show that blending equal amounts of Ca2+ (calcium chloride) and organic precursors could greatly improve the catalytic activity of the carbonated product to activate peroxymonosulfate for pollutant degradation. In addition, the proposed synthetic strategy is universal to most of the readily accessed and cost-effective organic precursors. Singlet oxygen is identified as the main reactive oxidant for pollutant removal in the catalytic reaction. By cross-linking calcium ions and alginate as a hydrogel to immobilize the catalyst, the carbon material could be readily recovered. Furthermore, a long-term continuous-flow reactor test is conducted to validate the effectiveness of applying the immobilized catalyst to treat a synthetic wastewater with 0.5 mM bisphenol A. As a result, a green synthesis and immobilization strategy for persulfate catalysts is successfully established, and the prepared catalyst might be applied for wastewater treatment through using calcium salt in two purposes.
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