查找使用阿拉丁产品的科研文献

Thermal properties and morphology of chitosan/gelatin composite shell microcapsule via multi-emulsion

Siyin Qin,Huabing Li,Chengzhi Hu

Microencapsulated phase-change materials (MEPCMs) possess promising application in storing energy and protecting environment of biomaterials. However, the MEPCMs have the difficulty of low encapsulation efficiency and irregular shape. In this study, biodegradable chitosan/gelatin co-emulsifier as composite shell was used to encapsulate n -tetradecanol through oil-in-water-in-oil (O/W/O) method, and then crosslinked with glutaraldehyde (GTA). The results reveal that the latent heat and encapsulation efficiency of the microcapsules reach 146.88 J g −1 and 70.94%, respectively. Besides, the prepared microcapsules exhibit great thermal stability and thermal cycling reliability during the phase change process.

Bioinspired roll-to-roll solar-thermal energy harvesting within form-stable flexible composite phase change materials

Chao Chang,Xiao Nie,Xiaoxiang Li,Peng Tao,Benwei Fu,Zhongyong Wang,Jiale Xu,Qinxian Ye,Jingyi Zhang,Chengyi Song,Wen Shang,Tao Deng

Converting solar energy into storable thermal energy within organic phase change materials has emerged as a promising way to overcome solar intermittency and continuously harness solar-thermal energy for many heating-related applications. The low thermal conductivity and leakage issue of the phase change materials, however, limit scalable solar-thermal energy storage and their practical applications. Inspired by the dynamic thermoregulation behavior of butterfly wings, here we demonstrate rapid roll-to-roll solar-thermal energy harvesting within flexible form-stable composite phase change materials. Instead of static charging the bulk materials, the thin composite sheets are exposed to solar radiation for rapid charging while being continuously rolled. Due to shortened heat-diffusion distance and rollability of the composites, it achieves fast uniform solar-thermal energy storage within the bulk storage media. The flexibility of charged composites also enables broad tuning of the discharging behavior, and offers the possibility to explore wearable thermotherapy and other flexible solar-thermal applications.

Eco-friendly, cost-effective, and durable guar gum/citric acid complex coating on mesh for oil/water separation

Ziru Ye,Kaibing Huang,Mei Xie,Han Yu,Fan Yang,Mingqi Gao,Ruina Wang,Lei Han,Fenxia Wu

Dynamic tuning of magnetic phase change composites for solar-thermal conversion and energy storage

Lei Shi,Yanwei Hu,Yijie Bai,Yurong He

Photo-thermal conversion and energy storage using phase change materials are now being applied in industrial processes and technologies, particularly for electronics and thermal systems. This method relies on adding high thermal conductivity fillers, such as nanoparticles, to enhance the phase change process. In the long term, dynamic tuning heat transfer provides a superior means of tuning control the heat transfer efficiency and speed. In this study, a nanofluid phase change material was prepared by adding magnetic nanoparticles, effectively combining the properties of high thermal conductivity and magnetism, in an attempt to develop a magnetically enhanced approach for dynamic tuning of photo-thermal conversion charging. Our results showed that the phase change efficiency of magnetic phase change material can be improved by magnetic field application. With the increasing magnetic strength, the photo-thermal storage efficiency was enhanced, and storage capacity was improved by more than 48%. Meanwhile the steady temperature of the magnetic phase change material increased, enhancing the open-circuit voltage in photo-thermoelectricity experiments. Thus, the proposed method demonstrated in this study achieved superior phase change heat transfer characteristics within a photo-thermal conversion process by dynamically controlling the magnetic field distribution, which should be especially useful for direct solar energy utilisation.

Hierarchically Porous PVA Aerogel for Leakage-Proof Phase Change Materials with Superior Energy Storage Capacity

Li Yang,Jie Yang,Li-Sheng Tang,Chang-Ping Feng,Lu Bai,Rui-Ying Bao,Zheng-Ying Liu,Ming-Bo Yang,Wei Yang

Organic phase change materials (PCMs) have been widely used in the thermal energy storage field, but melt leakage above the phase change temperature has greatly hindered their practical applications. Herein, poly(vinyl alcohol) (PVA) aerogels with hierarchically porous structure are fabricated and introduced into phase change matrices to obtain novel leakage-proof composite PCMs (CPCMs). The thermal storage efficiency of the working substance in the CPCMs reaches as high as 95.6%, maintaining a tremendously high energy storage density. More importantly, the CPCMs exhibit prominent shape stability when heated at 80 °C, higher than the phase change temperature, for 60 h. Finally, the leakage-proof CPCMs exhibit great application potential in the thermal management of electronic devices.

Facile Synthesis of Cobalt-Doped Porous Composites with Amorphous Carbon/Zn Shell for High-Performance Microwave Absorption

Qilei Wu,Huihui Jin,Bin Zhang,Siqi Huo,Shuang Yang,Xiaogang Su,Jun Wang

A facile method for the preparation of microwave absorbers with low density, high microwave absorptivity, and broad band is of paramount importance to the progress in practical application. Herein, commonly-used metal organic frameworks (MOFs) prepared just by mechanical stirring in methanol at room temperature were chosen as sacrificial templates to synthesize porous carbon composites with tunable dielectric and magnetic properties. With the replacement of Co atoms on the surface of zeolitic imidazolate framework-67 (ZIF-67) by Zn atoms, a Co-doped porous carbon composite with a low-dielectric amorphous carbon/Zn shell was constructed after annealing, leading to excellent impedance matching condition. Consequently, the as-obtained composite (Co/C@C-800) shows marvelous microwave absorption properties with an absorption capacity of −43.97 dB and a corresponding effective absorption bandwidth of 4.1 GHz, far exceeding that of the traditional porous carbon and composites directly derived from ZIF-67. The results provide a convenient way to modify MOFs for enhanced microwave absorption materials from the synergy of dielectric and magnetic losses.Keywords:MOFs-derived carbon composites;porous structure;impedance match;microwave absorption

Paraffin/chitosan composite phase change materials fabricated by piercing-solidifying method for thermal energy storage

Qi Honghua,Zhang Ting,Zhang Deyi,Wang Kunjie,Wang Yi

To study the effects of emulsifier content on the structure and thermal properties of encapsulated phase change materials (PCMs), four kinds of paraffin/chitosan (CS) macroencapsulated PCMs with different emulsifier contents were fabricated via the piercing–solidifying method. The effects of emulsifier content on macro-profile, micromorphology, thermal energy storage properties, and thermal durability of the as-prepared composite, as well as the structure of the optimal capsules, were investigated. The results show that the non-spherical degree, average diameter, and compressive strength decreased first and then increased with increase in emulsifier content, resulting in thermal energy storage capacity’s increase at first and then its decrease. The optimal macro-capsules, fabricated at the critical micelle concentration of the emulsifier, present a regular spherical surface and microencapsulated paraffin wax inside. The paraffin content is as high as 85%, with a phase change latent heat of 112.6 J g −1 for melting and 118.7 J g −1 for solidification. The melting enthalpy and weight loss ratio of the optimal paraffin/chitosan composite after 600 heating/cooling cycles only changed to 0.71% and 1.17%, respectively. These results not only suggest that the piercing–solidifying method can be employed to fabricate macro-capsules with high heat storage performance and excellent thermal stability but also reveal that paraffin/CS can be used in thermal management at low temperature.

Study of Janus Amphiphilic Graphene Oxide as a High-Performance Shale Inhibitor and Its Inhibition Mechanism

Lv Kaihe,Huang Pan,Zhou Zhishi,Wei Xin,Luo Qi,Huang Ziming,Yan Hui,Jia Han

Janus amphiphilic graphene oxide (JAGO), modified by dodecylamine on one side of graphene oxide (GO), was investigated for its novel use as a shale inhibitor. JAGO was synthesized by the Pickering emulsion template technology and was characterized by the Fourier-transform infrared spectra, UV-vis spectra, and transmission electron microscopy. Compared to KCl (5%), polyether diamine (2%), and pristine GO (0.2%), JAGO's highest shale recovery rate (75.2% at 80°C) and lowest swelling height of Mt-pellets (2.55 mm, 0.2%) demonstrated its excellent inhibitive property. Furthermore, JAGO acted as a perfect plugging agent and greatly reduced filtration loss. Based on the results of X-ray diffraction, contact angle measurements, and pressure transmission tests, we proposed that the 2D nano-sheet amphiphilic structure of JAGO, which enabled it to be effective both in chemical inhibition and physical plugging, was responsible for its remarkable inhibition performances.

A high-throughput system combining microfluidic hydrogel droplets with deep learning for screening the antisolvent-crystallization conditions of active pharmaceutical ingredients

Zhenning Su,Jinxu He,Peipei Zhou,Lu Huang,Jianhua Zhou

Crystallization of active pharmaceutical ingredients (APIs) is a crucial process in the pharmaceutical industry due to its great impact in drug efficacy. However, conventional approaches for screening the optimal crystallization conditions of APIs are usually time-consuming, labor-intensive and expensive. Recently, droplet microfluidic technology has offered an alternative strategy for high-throughput screening of crystallization conditions. Despite its many advantages such as low sample consumption, reduced operation time, increased throughput, etc., some challenges remain to be solved, such as instability of droplets in the long-term and tedious efforts required for extracting useful information from massive data. To solve these problems, a high-throughput system that combined microfluidic hydrogel droplets with deep learning was proposed for the first time to screen the antisolvent-crystallization conditions of APIs. In this system, stable hydrogel droplets containing different concentrations of indomethacin, its solvent and antisolvent were generated on a chip. Crystals of indomethacin with different morphologies were formed in hydrogel droplets, and their optical images were captured by a camera. Then, deep learning was applied to identify the hundreds of indomethacin crystal images and successfully classify the crystal morphologies in a short time; a ternary phase diagram was drawn by combining the experimental results with the recognition results of crystal morphologies, and was used to guide the scale-up preparations of indomethacin crystals as desired. This system, which integrated high throughput preparation, characterization and data analysis, is also useful for screening the crystallization conditions and processes of semiconductors, catalysts, agrochemicals, proteins and other specialty chemicals.

Comparison of an Emulsion- and Solution-Prepared Acrylamide/AMPS Copolymer for a Fluid Loss Agent in Drilling Fluid

Jingyuan Ma,Boru Xia,Peizhi Yu,Yuxiu An

Acrylamide polymers were widely used as oilfield chemical treatment agents because of their wide viscosity range and versatile functions. However, with the increased formation complexity, their shortcomings such as poor solubility and low resistance to temperature, salt, and calcium were gradually exposed. In this paper, acrylamide (AM)/2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) copolymers were synthesized by aqueous solution polymerization and inverse emulsion polymerization, respectively. The aqueous polymer (W-AM/AMPS) and the inverse emulsion polymer (E-AM/AMPS) were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and particle size analysis. The rheological properties, filtration properties, and sodium ion (Na+) and calcium ion (Ca2+) resistance were investigated. The results showed that E-AM/AMPS not only had a dissolution speed 4 times faster than that of W-AM/AMPS but also had superior shear-thinning performance both before and after aging. The filtration property of the bentonite system containing 2 wt % E-AM/AMPS was also better than that of the bentonite system containing 2 wt % W-AM/AMPS. In addition, E-AM/AMPS also exhibited extremely high tolerance for Na+ and Ca2+. The huge difference between rheological and filtration properties of E-AM/AMPS and W-AM/AMPS in drilling fluid can be attributed to the differences in the polymer microstructure caused by the two polymerization methods. Both FTIR and 1H NMR results showed that more hydrogen bonds were formed between E-AM/AMPS molecular groups and molecular chains, which led to a cross-linked network structure of E-AM/AMPS which was observed by TEM. It was this cross-linked network structure that made E-AM/AMPS have a high viscosity and allowed it to be better adsorbed on bentonite particles, thus exhibiting excellent rheological and filtration behavior. In addition, E-AM/AMPS powder had a high specific surface area so that it can be dissolved in water faster, greatly reducing the time and difficulty of configuring drilling fluid.

Preparation of a Sensor Based on Biomass Porous Carbon/Covalent-Organic Frame Composites for Pesticide Residues Detection

Liu Yali,Zhou Mingyue,Jin Chen,Zeng Jinxiang,Huang Chao,Song Qiuye,Song Yonggui

In this work, a covalent-organic framework with high carbon and nitrogen content microstructures (named COF-LZU1), assisted by 3D nitrogen-containing kenaf stem composites (represented as COF-LZU1/3D-KSCs), was constructed. Moreover, it was utilized for immobilizing acetylcholinesterase (AChE) for identifying trichlorfon, a commonly applied organophosphorus (OP) pesticide. The development of COF-LZU1/3D-KSC was affirmed by SEM, PXRD, and EDXS. The findings confirmed that COF-LZU1 microstructures were uniformly developed on 3D-KSC holes using a one-step synthesis approach, which can substantially enhance the effective surface area. Also, the COF-LZU1/3D-KSC composite contains not only the nitrogen element in COF-LZU1 but also the nitrogen element in 3D-KSC, which will greatly improve the biocompatibility of the material. The AChE/COF-LZU1/3D-KSC integrated electrode was fabricated by directly fixing a large amount of AChE on the composite. At the same time, the integrated electrode had good detection efficiency for trichlorfon. Improved stabilization, a wide-linear-range (0.2–19 ng/mL), and a lower detection limit (0.067 ng/mL) have been displayed by the sensor. Therefore, this sensor can be used as an important platform for the on-site detection of OP residue.

Biomimetic Durable Multifunctional Self-Cleaning Nanofibrous Membrane with Outstanding Oil/Water Separation, Photodegradation of Organic Contaminants, and Antibacterial Performances

Wenjing Ma,Yuansheng Li,Mengjie Zhang,Shuting Gao,Jiaxin Cui,Chaobo Huang,Guodong Fu

Wastewater pollution has always been one of the most severe worldwide environmental problems. In addition, in light of the frequent oil spills that have occurred in recent years, the treatment of oily wastewater is particularly important. In this work, a novel zeolitic imidazolate framework-8@thiolated graphene (ZIF-8@GSH) composites-based polyimide (PI) nanofibrous membrane was developed via a facile electrospinning and in situ hydrothermal synthesis approaches for effective purification of oily wastewater. The membrane showed superhydrophobicity/superoleophilicity and high separation efficiency (>99.9%) for a wide range of oil/water mixtures and water-in-oil emulsions. Besides, the membrane demonstrated excellent photocatalytic dye degradation, antibacterial, self-cleaning, and mechanochemical durable abilities, showing high potential in oily wastewater treatment and water remediation.