WATER RESEARCH
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2019
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IF 7.913
Yao Ma,Yuan Feng,Yulin Feng,Gaoming Liao,Yue Sun,Jie Ma
Controlled release materials (CRMs) are emerging oxidant delivery techniques for in-situ chemical oxidation (ISCO) for groundwater remediation . Successful implementation of CRM relies on good understandings of the kinetics and mechanism of controlled release of reactive agents. In this study, batch experiments and model simulations were conducted to explore the impacts of CRM properties (composition and size) and environmental conditions (temperature, pH, water volume and anions) on KMnO 4 release from KMnO 4 -paraffin controlled release beads. Experimental results indicated that higher KMnO 4 : paraffin mass ratio resulted in shorter release longevities and higher release rate. Larger bead resulted in lower release rate, longer release longevity, and more KMnO 4 released. Higher incubation temperature resulted in higher release rate and shorter release longevity, but did not affect the total mass of KMnO 4 released. Acidic pH decreased the total mass of KMnO 4 released while alkaline pH did not affect KMnO 4 release. The presence of SO 4 2− , CO 3 2− , Cl − and Br − had negligible impacts on KMnO 4 release. A dissolution-diffusion conceptual model was developed. The above experimental observation and the associated controlled release mechanisms can be qualitatively explained by the conceptual model. A more detailed two-film boundary mathematical model was developed to simulate KMnO 4 release process. Comparison of modeling results with experimental data suggest that the new mathematical model gave a good quantitatively predication. Overall, this study shows that properly designed CRM can sustain release for years, thus representing a cost-effective and low-maintenance groundwater remediation technology . Both CRM properties and environmental conditions significantly affect the release kinetics and longevity, therefore these factors should be considered in the design and maintenance of CRM-based ISCO system.
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Environmental Science-Nano
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2019
·Vol. 6
·期 12
·3699-3711
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IF 7.704
Wenjing Ma,Mengjie Zhang,Yuansheng Li,Mengmeng Kang,Chaobo Huang,Guodong Fu
One of the most pervasive environmental issues is water contaminated with various oils. Developing an efficient and novel functional membrane for oil/water separation is urgently needed. Herein, a flexible, durable and magnetic pH-responsive F3O4/MA–TiO2/PI electrospun nanofibrous membrane (ENM) was fabricated via an electrospinning and green dip-coating route. Combining the rough hierarchical structure and pH-responsive wettability, the as-prepared hybrid membrane can controllably separate a range of not only heavy oil/water but also light oil/water mixtures by only adjusting the pH of the aqueous medium. Both separations exhibit a large flux and outstanding efficiency for the tested oil/water mixtures even after 20 reuse cycles due to the hierarchical structure and flexibility of the membrane. In addition, the flexibility and magnetism of the membrane make it easily removed with a magnet after the separation of the oil/water mixtures. More importantly, the as-prepared membrane not only has excellent stability towards high temperature, corrosive organic solvent/salt solution immersion, and UV irradiation but also shows great resistance to mechanical abrasion and ultrasonic treatment, and the preparation method is facile, environmentally friendly, and cost-effective. Thus, such a membrane may offer exciting opportunities in the application of oily wastewater treatment and on-demand oil/water separation.
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Materials Research Express
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2018
·Vol. 5
·期 6
·065602
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IF 1.151
Qilei Wu,Huihui Jin,Wei Chen,Siqi Huo,Xi Chen,Xiaogang Su,Hang Wang,Jun Wang
Rational construction of profitable microstructure in carbon-based electromagnetic composites is becoming a promising strategy to reinforce their microwave absorption performance. Herein, a N-doped highly porous carbon composite derived from thermal decomposition of Zn-based MOF (ZIF-8) has been synthesized for microwave absorption applications. The maximum reflection loss (RL) of −39.7 dB could be achieved with a thickness of 4 mm and the effective absorption bandwidth was from 7.9 GHz to 12.2 GHz covered X band (8–12 GHz). By comparing the porous carbon composites derived from conventional ZIF-8, it can be validated that porous structure, degree of graphitization and graphitic-N level is the key factors to improve the microwave absorption performance by increasing dielectric loss ability. The results demonstrated that the ZIF-8 derived graphitized nitrogen-doped porous carbon composites had great potential for microwave absorption performance, which may open up a new avenue to promote the electromagnetic applications of MOF-derived carbon composites.
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APPLIED ENERGY
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2018
·
IF 7.9
Yafei Zhao,Weixiao Kong,Zunlong Jin,Ye Fu,Wencai Wang,Yatao Zhang,Jindun Liu,Bing Zhang
With the rapid depletion of fossil fuels and the associated environmental issues, solar energy is identified as one of the most promising pollution-free and renewable resource. Herein, we prepared a novel Ag-Paraffin@Halloysite microsphere with the integrated abilities of storing solar energy and catalytic function by self-assembly method. The results show that Ag-Paraffin@Halloysite microsphere has a core-shell structure with paraffin as core and halloysite as shell, and Ag nanoparticles are dispersed uniformly on the surface of the microspheres. The high thermal storage capability, encapsulation ratio and encapsulation efficiency of Ag-Paraffin@Halloysite indicate that it can be used as an ideal heat storage material. Compared with pure paraffin, Ag-Paraffin@Halloysite has higher thermal conductivity, excellent thermal storage capacity, and faster transient thermal response. After heat storage, Ag-Paraffin@Halloysite shows much better catalytic activity (95.3% of conversion in 6 min) compared with the one without heat storage (71.1% of conversion in 6 min) for catalytic reduction of 4-nitrophenol. This result suggests its potential to be used as a self-heating catalyst for storing/releasing thermal energy during catalytic reactions. This work may offer a general and innovative approach to couple phase change materials with catalyst and open up a new avenue for utilization of solar energy in the fields of chemistry and chemical engineering.
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Qinxian Ye,Peng Tao,Chao Chang,Linye Zhou,Xiaoliang Zeng,Chengyi Song,Wen Shang,Jianbo Wu,Tao Deng
The heat packs that are based on solid–liquid transition of phase-changing materials (PCMs) have been pursued as a promising way to provide heating for human body comfort and thermotherapy owning to their large heat storage capacity and near-constant heat-release temperature. Current heat packs, however, suffer from leakage, slow charging, and poor heat-release performance due to the flow of liquid PCMs and their low thermal conductivity. Here, we report a strategy for preparing high-performance PCM-based solar thermal heat packs through impregnating organic PCMs within carbon-coated copper foams (CCFs). The porous structure and hydrophobic surface of CCF help to effectively confine the melted liquid PCM within the composite heat pack without leakage. The carbon coating layer efficiently converts the incident solar light into heat, which is rapidly transferred along the three-dimensional thermal conductive network of CCF and stored within the PCM. In the discharging process, the CCF network facilitates the extraction of the heat stored within the PCM. In contrast to neat PCM pack within which only a small portion of PCM that is in contact with human skin contributes to thermal comfort, all PCMs within the CCF-based composite heat pack concertedly release the stored heat. Such release significantly increases the extractable thermal energy and prolongs the usable healing duration for thermotherapy.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Ying Chu,Liming Qin,Liang Zhen,Qinmin Pan
Smart miniaturized aquatic devices have many important applications, but their locomotion at different interfaces remains a challenge. Here, we report a smart miniaturized submarine moving at various air/liquid or oil/water interfaces. The microsubmarine is fabricated by a CO2-responsive superhydrophobic copper mesh and is driven by the Marangoni effect. The microsubmarine can not only transfer among different interfaces reversibly but also move horizontally at the interfaces freely. The unique locomotion of the device is attributed to a CO2-triggered switch between superhydrophobicity and underwater superoleophobicity. Moreover, the microsubmarine exhibits good stability and excellent oil repellence at the oil/water interface. Our study provides a strategy for fabricating smart aquatic devices that have potential applications in environment monitoring, water purification, channel-free microfluidics, and so on.
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CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Yong Liu,Mingji Su,Yanbo Fu,Pingping Zhao,Meng Xia,Yuhong Zhang,Benqiao He,Peixin He
Constructing high-performance materials that combine high separation efficiency, corrosive environments tolerance and self-healing ability are highly attractive for the next generation oil/water separation materials, but it is still a grand challenge. Here, we report a supramolecular hydrogel network of acrylamide and acrylic acid copolymers (P (AM-co-AA)) and chitosan (CS), sequentially cross-linked by amino-functionalized silica (APTES-SiO 2 ) nanoparticles. The as-prepared APTES-SiO 2 /P (AM-co-AA)/CS composite hydrogels demonstrate outstanding ductility up to 1360% elongation, and good self-healing ability, combined with excellent under-water superoleophobicity with an oil contact angle above 164°. Most importantly, the underwater superoleophobic properties can be well maintained in various extremely harsh environments, such as acid, alkali and salt solution, providing great potential for oil/water separation in these corrosive environments. Indeed, the hydrogel-coated mesh displays oil/water selectivity above 98.7% at higher water flux.
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Science Advances
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2018
·Vol. 4
·期 9
·
IF 11.511
Jie Wang,Wei Gao,Han Zhang,Minhan Zou,Yongping Chen,Yuanjin Zhao
Surface materials with specific wettability play important roles in a wide variety of areas from science to industry. We present a novel paraffin-infused porous graphene film (PIPGF) with programmable wettability. Because of graphene’s photothermal property, the paraffin in the PIPGF was in transition between liquid and solid in response to near-infrared (NIR) light irradiation. Thus, we imparted the film with a dynamic and reversible transition between a slippery and a rough surface as the remotely tunable wettability. In addition, with the integration of NIR masks, the paraffin could melt at corresponding patterns on the PIPGF, which formed special flow pathways for the slipping droplets. Therefore, the PIPGF could provide programmable wettability pathways for the spatiotemporal droplet manipulation by flexibly changing the NIR masks. We demonstrated these programmable wettability pathways to not only simplify liquid handling in the microplates and droplet microarrays technology but also to provide distinctly microfluidic microreactors for different purposes, such as practical blood grouping diagnosis. These features indicated that the photocontrollable PIPGF would be amenable to a variety of applications, such as microfluidic systems, laboratory-on-a-chip settings, and droplet manipulations.
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Food Analytical Methods
·
2018
·Vol. 12
·期 3
·644-651
·
IF 2.245
Luo Dan,Zhao Xiaoshuang,Zheng Yiliang,Ma Yaolu,Cun Fei,Ye Jiannong,Chu Qingcui
A gold nanoparticle/reduced graphene oxide composite electrode (AuNP/rGO) was fabricated for the determination of the main bioamines and their precursor amino acids in beer based on a miniaturized capillary electrophoresis with amperometric detection system (mini-CE-AD). The surface morphology and structure of the synthetic AuNP/rGO material were observed by scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffraction, and Fourier transform infrared spectroscopy. The analytical performance of the composite electrode was verified by cyclic voltammetry and mini-CE-AD approaches. Four target analytes were separated within 7 min in 50 mM Na 2 B 4 O 7 -NaOH buffer (pH 9.35) at a separation voltage of 3 kV. This developed method has been applied to the beer samples, and acceptable recovery could be obtained ranging from 84.5 to 108%. The assay results indicated that this AuNP/rGO composite electrode has the advantages of simple preparation, low working potential (+ 0.65 V vs. SCE), good sensitivity (0.13~0.87 μM), and satisfactory reproducibility. This proposed method provides an alternative for rapid analysis of food safety.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
·
IF 2.829
Yuan Lu,Xiudi Xiao,Jiamei Mo,Changmeng Huan,Shuai Qi,Yongjun Zhan,Yanqing Zhu,Gang Xu
Inspired by the phase change materials (PCMs) based microcapsules, green phase change nanofibers mats with core-sheath structure based on paraffin wax emulsion (PWE) and polyvinyl alcohol (PVA) for thermal energy storage (TES) is obtained by coaxial electrospinning approach. The PWE could be encapsulated by PVA, simultaneously addressing the leakage issue effectively. In addition, the melting enthalpy (Δ H m ) increased from 3.16 J/g to 48.35 J/g as the core speed rate (R core ) increased from 0.1 to 2.0 μl/min, indicating higher R core can induce higher PWE encapsulation efficiency. Finally, the core-sheath structure PWE@PVA nanofibers mats have high Δ H m of 48.25 J/g and freezing enthalpy (Δ H c ) of -47.75 J/g. Furthermore, only slightly decreasing tendency on the enthalpy can be observed after 500 heating-cooling cycles, demonstrating good TES stability and practicability of the as-prepared PWE@PVA nanofibers mats. Hence, this study offers new idea for the fabrication method of green PCMs.
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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2018
·
IF 4.514
Peijiang Liu,Zhengjun Yao,Vincent Ming Hong Ng,Jintang Zhou,Ling Bing Kong,Kan Yue
Although two dimensional (2D) materials have already been studied as promising microwave absorption materials due to fascinating layered structure, it is hard to achieve both thin coating and excellent absorbing capability. Herein, 2D hierarchical composites of nano-sized Fe 3 O 4 particles on MXenes (TiO 2 /Ti 3 C 2 T x /Fe 3 O 4 ) with different [TiO 2 /Ti 3 C 2 T x ]/[Fe 3 O 4 ] ratios were synthesized by using a moderate chemical hydrothermal reaction. Scanning electron microscope and transmission electron microscope techniques indicated that the surfaces of MXenes were densely covered with Fe 3 O 4 nanoparticles of ∼4.9 nm in diameter and TiO 2 particles. By tuning the ratio of [TiO 2 /Ti 3 C 2 T x ]/[Fe 3 O 4 ], microwave absorption capabilities in terms of the maximum reflection loss ( R L ) value and absorber thickness could be readily optimized. Specifically, the sample TiO 2 /Ti 3 C 2 T x /Fe 3 O 4 -5 exhibited a remarkable absorption performance, with a maximum reflectivity of −57.3 dB at 10.1 GHz and a band range below −10 dB to over 9.1–11.1 GHz at a thickness of 1.9 mm. Therefore, our 2D MXene composites are expected to be promising candidates as ultrathin and lightweight absorbing materials.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Yuan Lu,Xiudi Xiao,Yongjun Zhan,Changmeng Huan,Shuai Qi,Haoliang Cheng,Gang Xu
Paraffin wax (PW) is widely used for smart thermoregulation materials due to its good thermal performance. However, the leakage and low thermal conductivity of PW hinder its application in the heat storage field. Accordingly, developing effective methods to address these issues is of great importance. In this study, we explored a facile approach to obtain PW-loaded core-sheath structured flexible nanofibers films via coaxial electrospinning technique. The PW as the core layer was successfully encapsulated by the sheath-layer poly(methyl methacrylate). The diameter of the fiber core increased from 395 to 848 nm as the core solution speed rate increased from 0.1 to 0.5 mL/h. In addition, it can be seen that higher core solution speed rate could lead to higher PW encapsulation efficiency according to the transmission electron microscopy results. The core-sheath nanofiber films, moreover, possessed the highest latent heat of 58.25 J/g and solidifying enthalpy of –56.49 J/g. In addition, we found that after 200 thermal cycles, there was little change in latent heat, which demonstrated that it is beneficial for the PW-loaded core-sheath structure to overcome the leakage issue and enhance thermal stability properties for the thermoregulation film.
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