EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Li Zhao,Shulai Lu,Ming Chen,Yuchao Wang,Shicheng Zhao
Polymer agglomeration method is an efficient way to enlarge the particle size of polybutadiene latex (PBL). However, thus far, the particle size of polymer agglomerating agent and agglomerated PBL could not been accurately regulated, and there is a lack of investigation of agglomeration mechanism. Herein, an efficient way for regulating the particle size of the agglomerating agent and PBL was proposed. It was found that the particle size of agglomerating agents can be obtained in the range of 69 nm to 143 nm by adjusting the monomer content and the amount of α-methacrylic acid in the emulsion polymerization process. Then, the effects of different agglomeration parameters on the particle size of agglomerated PBL were investigated, including the amount, the α-MAA content and the particle size of agglomerating agent, agglomeration temperature and agglomeration time. The results indicated that the particle size of agglomerated PBL first increased and then decreased to a stable state with the increase of the amount of agglomerating agent. This phenomenon was quite different from the results of existing studies, which show that the particle size of agglomerated PBL gradually increases with the increase of the amount of agglomerating agent. According to the investigation of agglomeration process of PBL, the PBL agglomeration mechanism of dispersion-adsorption-coalescence-shrinkage was proposed. This study not only provides theoretical support for the PBL polymer agglomeration process, but also provides a practical way to increase acrylonitrile–butadiene–styrene (ABS) production efficiency.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Yang Liu,Chengxuan Wu,Xiaofang Lv,Hui Du,Qianli Ma,Chuanshuo Wang,Shidong Zhou,Bohui Shi,Shangfei Song,Jing Gong,Jimiao Duan
During deep-sea and ultra-deep-sea oil and gas exploitation, multiphase transmission lines are prone to be clogged by sediments produced by the various components in crude oils under extreme subsea conditions, such as hydrates, wax, resins, and asphaltenes. The pipelines face higher plugging risks when these deposits exist simultaneously. In order to elucidate the effects of wax and anti-agglomerants (AA) on hydrate growth and aggregation, microscopic morphology observation and cohesive force measurement of cyclopentane hydrate particles were conducted through a piece of equipment similar to the micromechanical force (MMF) apparatus. Results showed that in the low concentration of AA (0.05 wt%), hydrate particles experienced an approximately 10 % reduction in the profile area after converting water droplets to hydrate particles. Furthermore, the cohesive force between hydrate particles decreased from 8.57 ± 0.90 mN/m to 3.51 ± 0.43 mN/m as the AA concentration increased from 0.05 to 0.2 wt%. On the other hand, the presence of wax significantly altered the morphologies of hydrate particles. When wax coexisted with AA, the hydrate cohesive force was reduced by wax under low AA concentration (0.05 wt%) but increased under higher AA concentration. For a given concentration of AA, the hydrate cohesive force increased with the increasing wax content (from 0.1 to 0.3 wt%), indicating that wax crystals weakened the efficiency of AA, such as Span 80. Additionally, the effect of surface wetness of waxy hydrate particles on their cohesion was also investigated. The liquid bridge appeared between wet waxy hydrate particles, while the solid–solid contact existed between dry waxy hydrate particles. The cohesive force between dry waxy hydrate particles was smaller. Either liquid bridge or solid–solid contact that dominated hydrate cohesive force was affected by wax.
研究领域:
石油工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ULTRASONICS SONOCHEMISTRY
·
2019
·
IF 7.279
Yitao Li,Xingdong Shi,Zhi Zhang,Yazhou Peng
Ultrasonic treatment has attracted much attention because of its physical and chemical effects that are distinct from those of chemical agents. In particularly, high-frequency ultrasound is known as an effective method because the theoretical resonance frequency of the gas vesicles in Microcystis aeruginosa is in the high frequency range (>100 kHz), which causes gas vesicles collapse and changes the settleability of the algal cells. In this work, the effects of the ultrasonic frequency, acoustic power density and duration on enhancing coagulation to remove turbidity in algae-laden water were studied. In order to explain the mechanism, the morphology of algae cells, the changes in extracellular organic substances, the zeta potential and the formation of hydroxyl radicals were analyzed systematically. Finally, Zeta potentials and flocs morphology after adding PAC were investigated to verify the mechanism. The results showed that the frequency exhibited fewer effects than power and duration on coagulation. SEM images showed that there were more severe cellular damages at 430 and 740 kHz than other frequencies. Sonication could cause the collapse of gas vesicle inside the cell, which was due to the instantaneous high pressure generated by the ultrasonic cavitation instead of the resonance. Furthermore, sonication would result in an increase in proteins in extracellular organic matter (EOM) with continuous ultrasonic irradiation, indicating that a small amount of proteins could promote coagulation and that the accumulation of proteins would inhibit coagulation. Free radical content testing showed that the production of excessive free radicals was often accompanied by a deterioration of the coagulation. The proper mechanical effects were the main mechanism of ultrasonic enhanced coagulation. Thus, it was recommended that the appropriate ultrasonic condition was the one that resulted in a small amount of protein leakage and little generation of free radicals, which occurred at 740 kHz and 0.02 W/mL in approximately 5 min, and would significantly enhance the turbidity removal rate in algae-containing water from approximately 80–90%.
研究领域:
环境科学
·
水处理
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2015
·Vol. 15
·期 1
·600-605
·
IF 1.556
Jiang Ping,Li Duxin,Xiao Ya,Yang Xingxing,Liu Yuejun
The biodegradable microcapsules based on chitosan for a controlled delivery of clove oil were prepared by the single coagulation process. The effect of chitosan concentration, core to shell ratio, types of emulsifier, flocculating agent and hardening agent on the microcapsule diameter
and the particle size distribution of microcapsule were investigated. The optimized conditions for the preparation of microcapsules with well-defined structure and narrow dispersibility were under that (1) the concentration of chitosan was 1.0 wt%, (2) clove oil to chitosan ratio was 75:25,
(3) OP-10 and 10 wt% sodium sulfate were used as emulsifier and flocculating agent respectively, and (4) the concentration hardening agent glyoxal was 1 wt% based on the weight of chitosan. The uniform spherical structures with smooth surfaces with a particle size distribution of 1–15
μm were evidenced by SEM images of microcapsules. Core–shell, hetero-structures were confirmed by optical micrograph. The chemical component of the microcapsules was determined by FTIR. Thermal analysis showed the microcapsules were thermally stable below 150°C. It was
found that the pH value and temperature play important roles on the release rate of clove oil from the microcapsules. The release volume of clove oil from microcapsules at pH = 7, and pH = 10 were smaller than that at pH = 2. And the release volume of Clove oil from microcapsules at 60°C
was smaller than that at 20°C and 40°C, which showed a sustained and prolonged release.
研究领域:
食品科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
COMBUSTION AND FLAME
·
2020
·
IF 4.57
De-Yun Tang,Zhi-Min Fan,Guangcheng Yang,Yinglei Wang,Pei-Jin Liu,Qi-Long Yan
Aluminum (Al) has been widely used in solid composite propellants (SCPs) to increase the specific impulse. However, Al always subjects to coalescence , sintering to large agglomerations during combustion of SCPs resulting in larger two-phase flow losses. Herein, core-shell μ-Al@M(IO 3 ) x composites have designed and synthesized as a replacement for micron-sized Al (μ-Al) in the Al/AP/RDX/HTPB propellant with tunable combustion behavior. The results show the thermal reactivity and heat releases of SCP are largely enhanced by using these novel metal-based composites. With the inclusion of μ-Al@EGCG@Fe(IO 3 ) 3 (EGCG: Epigallocatechin gallate), the major exothermic peak is reduced by 29.1 °C compared to the reference propellant with a heat release increase up to 5475 J g −1 , exceeding that of the reference sample (86 J g −1 higher). The burn rates are increased with the inclusion of μ-Al@(MIO 3 ) x , while the pressure exponent is higher. The SCP-1 (0.3), SCP-2 (0.18) and SCP-4 (0.25) that have relatively low pressure exponent and high burn rates are good candidates for future applications. The major condensed combustion products (CCPs) of these SCPs are Al 2 O 3 , Al 2.81 O 3.56 N 0.44 , Al 4 C 3 , Al 2 OC, AlN and C 7 H 18 ClN. The agglomeration can be reduced with a minor inclusion of μ-Al@M(IO 3 ) x due to the enhanced interfacial reactions, and the average CCP sizes (0.5 μm for SCP-1 and SCP-4) are even smaller than that of initial μ-Al (1.2 μm).
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Yanyan Gong,Yang Bai,Dongye Zhao,Qilin Wang
Nanoplastics (NPs) pollution of aquatic systems is becoming an emerging environmental issue due to their stable structure, high mobility, and easy interactions with ambient contaminants. Effective removal technologies are urgently needed to mitigate their toxic effects. In this study, we systematically investigated the removal effectiveness and mechanisms of a commonly detected nanoplastics, carboxyl-modified polystyrene (PS-COOH) via coagulation and sedimentation processes using aluminum chloride (AlCl 3 ) as a coagulant. PS-COOH appeared as clearly defined and discrete spherical nanoparticles in water with a hydrodynamic diameter of 50 nm. The addition of 10 mg/L AlCl 3 compressed and even destroyed the negatively charged PS-COOH surface layer, decreased the energy barrier, and efficiently removed 96.6% of 50 mg/L PS-COOH. The dominant removal mechanisms included electrostatic adsorption and intermolecular interactions. Increasing the pH from 3.5 to 8.5 sharply enhanced the PS-COOH removal, whereas significant loss was observed at pH 10.0. High temperature (23 °C) favored the removal of PS-COOH compared to lower temperature (4 °C). High PS-COOH removal efficiency was observed over the salinity range of 0 − 35‰. The presence of positively charged Al 2 O 3 did not affect the PS-COOH removal, while negatively charged SiO 2 reduced the PS-COOH removal from 96.6% to 93.2%. Moreover, the coagulation and sedimentation process efficiently removed 90.2% of 50 mg/L PS-COOH in real surface water even though it was rich in inorganic ions and total organic carbon. The fast and efficient capture of PS-COOH by AlCl 3 via a simple coagulation and sedimentation process provides a new insight for the treatment of NPs from aqueous environment.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Bioscience
·
2024
·
IF 4.8
Pengkai Xie,Limin Cui,Mingdi Yu,Yulong Shao,Abdelaziz Elbarbary,Qingzhe Jin,Xingguo Wang,Jun Jin
Aerated emulsions find wide applications in the food industry, with partial coalescence playing a crucial role as the core of such products in whipping capabilities. Although tweens are the most traditional emulsifiers used in aerated emulsions, the microscopic mechanisms of how they work are still not fully understood. This study focused on elucidating the mechanisms of Tweens in fat crystallization, oil-water interface rheology, and fat globule interface membrane properties, clarifying their roles in partial coalescence and whipping capabilities. The fat crystals induced by Tween 20 (T20) faced difficulty in puncturing the interface membrane with a high elastic modulus (5.58 mN/m), which may constrain occurrence and progression of partial coalescence. Tween 60 (T60) and Tween 40 (T40) exhibited strong interactions with proteins, with the interface film formed by T60 having a high elasticity of up to 7.79 mN/m. However, the highest elasticity interface film formed by orogenic behavior from T60 was not conducive to the interaction between fat crystals and the interfacial proteins during the whipping process. T40 not only helps to stimulate fat crystallization and create interface films with appropriate elastic strength but also plays a role in enhancing foam quality as its concentration rises. This is supported by its rheological properties and microscopic structures. The interface membrane formed by Tween 80 (T80) was viscous, leading to a significant partial coalescence but poor foam quality. This study reveals the interaction mechanisms between fat crystallization, interface membrane, partial coalescence, and the structure of aerated emulsions regulated by Tweens.
研究领域:
食品科学
·
胶体化学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2023
·
IF 3.9
Ruijuan Wang,Chunliu Ma,Haitao Yan,Pu Wang,Shuyan Yu,Tongyan Zhang,Zhigang Yin
Co-encapsulated xanthoxylin (GX-50) and vitamin C (Vc) microcapsules (GX-50-Vc-M) were prepared by the combination of a water-in-oil-in-water (W1/O/W2) double emulsion with complex coacervation. The W1/O/W2 double emulsion was prepared by two-step emulsification, and it has a uniform particle size of 8.388 μm and high encapsulation efficiencies of GX-50 (85.95%) and Vc (67.35%) under optimized process conditions. Complex coacervation occurs at pHs 4.0–4.7, which has the highest encapsulation efficiency of GX-50 and Vc at pH 4.5. The complex coacervate with tannic acid solidifying (namely, wet microcapsules) has better mechanical properties and also enhances the ability of co-encapsulation of active ingredients. The resulting microcapsules by freeze-drying of wet microcapsules were characterized by UV–vis absorbance spectroscopy (UV–vis), Fourier infrared spectroscopy (FI-IR), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), X-ray diffraction (XRD), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging, and in vitro permeation measurements. Under optimal conditions, the encapsulation efficiency and drug loading of GX-50-Vc-M for GX-50 and Vc are, respectively, 78.38 ± 0.51 and 59.34 ± 0.56%, and 35.6 ± 0.68 and 29.8 ± 0.92%. A slight shift in the FTIR peak between single GX-50 or Vc and GX-50-Vc-M confirmed the successful co-encapsulation of GX-50 and Vc in microcapsules. GX-50-Vc-M has bridged irregular spherical aggregates, while GX-50 and Vc are, respectively, encapsulated in hydrophobic and hydrophilic cavities of microcapsules in an amorphous dissolved state. GX-50-Vc-M has the highest DPPH· radical scavenging rate of 62.51%, and the scavenging process of GX-50-Vc-M on DPPH· radicals is more in line with the pseudo-second-order kinetic equation model. Moreover, the in vitro permeation of GX-50 and Vc in GX-50-Vc-M can reach maximum values of 40 and 60%, respectively. This concludes that GX-50-Vc-M is a promising delivery system for the penetration of the antioxidant into the deeper layers of the skin for the antioxidant effect.
研究领域:
药剂学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2023
·
IF 4.8
Gaogui Jing,Xiangsong Meng,Jing Chen,Wei Sun,Przemyslaw Boguslaw Kowalczuk,Zhiyong Gao
Efficient treatment and purification of mineral processing wastewater (MPW) have not been sufficiently investigated in the past though they are of great importance for sustainable mineral processing. Herein, a unique electrocoagulation (EC) reactor with aluminium scraps as anode material was developed for the treatment of real industrial MPW containing residual flotation reagents (major contributor to chemical oxygen demand, COD) and suspended particles. It was found that the active coagulants produced from the dissolution of aluminium scraps can play a key role in the purification of MPW. Under the conditions of initial pH 9, current 1 A, and processing time 90 min, the removal rate of COD was 74% while the turbidity can be almost completely removed. The mechanism lies in that most of the flotation reagents was adsorbed on the surfaces of suspended mineral particles, namely, montmorillonite, quartz, garnet, chlorite and mica, and then precipitated with the mineral particles. This innovative technology of utilizing wasted aluminium scraps to treat MPW is in line with the green development.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
International Journal of Low-Carbon Technologies
·
2022
·
IF 3.071
Huo Xianliang,Xie Donghuan,Zhao Zimo,Wang Shujun,Meng Fanbin
Inorganic hydrated salts have many advantages over organic phase change materials (PCMs), such as higher thermal storage density, low cost, non-toxicity and non-flammability. In this research, microcapsules loaded with eutectic hydrated salt (EHS) as the core material was fabricated via coacervation method at room temperature, with ethyl cellulose/acrylonitrile butadiene styrene as the shell material. EHS consisted of sodium sulfate decahydrate and disodium hydrogen phosphate dodecahydrate with a mass ratio of 1:3 was prepared as the PCM with its phase change temperature of 29.3°C and phase change enthalpy of 218.58 J/g. The chemical structures and morphology were investigated by Fourier transform infrared spectroscopy and scanning electron microscope. Results indicates that the almost spherical microcapsules, with diameter around 60 μm, are of core–shell microstructures and good chemical compatibility of the core and shell material. Differential scanning calorimetry results shows that microcapsules possess a high latent heat (178.36 J/g) and excellent thermal stability and reliability, which are suitable for thermal energy storage and management in practical applications. More importantly, the simple and environmentally conscious way of this study may be extended to other promising inorganics@organics PCMs with different core–shell structured compositions.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Qirui Tian,Weiqing Zhou,Qiong Cai,Xiaoyun Pan,Guanghui Ma,Guoping Lian
Hypothesis Essential oils (EOs) are common additives in daily products by virtue of their olfactory, physicochemical, and biological characteristics . However, EOs are physicochemically unstable and susceptible to degradation or loss, leading to limited shelf life and inadequate efficacy. Herein we propose a new bi-layered encapsulation structure in combination with complex coacervation and self-coating of polydopamine (PDA) on membrane emulsified mono-dispersion of EOs droplets. Experiments A mono-dispersed EOs emulsion stabilized by nonionic surfactants was produced by membrane emulsification , wherein the EOs droplets were applied as soft templates to deposit a superficial PDA layer. Under alkaline conditions, gelatin (GE) was bound to the PDA layer and further applied as in situ coacervation sites for gum Arabic (GA). Structural identification and morphological observation proved the successful preparation of bi-layered EOs capsules. Findings Compared with traditional complex coacervation strategies, current novel bi-layered capsules showed significantly improved structural stability, thermal stability, providing better protection of EOs with sustained release properties. Moreover, the encapsulation efficiency and loading content were both proved higher for the bi-layered system. The first report on PDA-coating onto surfactants-absorbed macroemulsion droplets also provides an in-depth insight into applying PDA as versatile intermediate functional biomaterials.
研究领域:
食品科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Shiwei Xie,Chang Li,Hui Zhan,Wei Shao,Yuanxin Zhao,Peng Liu,Peng Liao
Fe-based replacement and precipitation are promising methods for removal of copper ethylenediaminetetraacetic acid (Cu(II)-EDTA) but are limited by the necessity of controlling pH and dissolved oxygen. The details of the decomplexation mechanism also remain unclear. The present work investigated an anoxic iron electrocoagulation process capable of automatically modulating anoxic conditions and solution pH during exposure to air and thus promoting the rapid and thorough decomplexation of Cu(II)-EDTA. Dissolved Fe (II), rather than Fe(II)-bearing minerals, was found to be primarily responsible for the reduction of Cu(II)-EDTA to Cu(I)-EDTA and for the subsequent replacement reaction to generate free Cu(I) ions within the initial pH range of 2–7. The Cu(I) was primarily precipitated as Cu 2 O on the surface of green rust and magnetite as the pH was increased. The aeration of these Fe-containing precipitates released free Cu(I) ions instead of chelated Cu into solution, allowing for recycling of the Cu. This release of Cu(I) was likely induced by the pH decrease during aeration. This study provides important insights regarding the reductive decomplexation of chelated Cu(II) and the recovery of Cu via anoxic iron electrocoagulation, which is a promising green approach to recycling Cu from wastewater.
研究领域:
环境科学
·
废水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）