Nano fibrillated cellulose-based foam by Pickering emulsion: Preparation,characterizations, and application as dye adsorbent

An ecofriendly and biodegradable porous structure was prepared from drying aqueous foams based on nano fibrillated cellulose (NFC), extracted from softwood pulp by subcritical water/CO₂ treatment (SC-NFC). The primary aim of this work was to use the modified SC-NFC as stabilizer for a water-based Pickering emulsion which upon drying, yielded porous cellulosic materials, a good dye adsorbent. In order to exploit the carboxymethylated SC-NFC (CMSC-NFC, with a degree of substitution of 0.35 and a charge density of 649 μeqv/g) as a stabilizer for water-based Pickering emulsion in subsequent step, an optimized quantity of octyl amine (30 mg/g of SC-NFC) was added to make them partially hydrophobic. A series of dry foam structures were prepared by varying the concentrations of treated CMSC-NFCs and 4 wt% was found to be the optimum concentration to yield foam with high porosity (99%) and low density (0.038 g/cc) along with high compression strength (0.24 MPa), superior to the conventionally extracted NFC. The foams were applied to capture as high as 98% of methylene blue dyes, making them a potential green candidate for treating industrial effluent. In addition, the dye adsorption kinetics and isotherms were found to be well suited with second order kinetics and Langmuir isotherm models.     

Facile self-assembly approach to construct a novel MXene-decorated nano-sized phase change material emulsion for thermal energy storage

In recent years, phase change material emulsions (PCMEs) with enhanced energy storage capacities and good flow characteristics have drawn significant attention. However, due to the thermodynamically unstable nature and tiny particle confinement, the nanomaterial modification strategies at PCM/water interface to improve stabilities and reduce supercooling of nano-sized PCMEs (NPCMEs) are very limited and challenging. Herein, we report a facile strategy for constructing MXene-decorated NPCME with good stability, little supercooling, and high thermal conductivity by self-assembly of MXene nanosheets at PCM/water interface. The concentrations of MXene have great influences on the average droplet diameters, stabilities, and thermophysical properties of the NPCMEs. The results show that the PCMs have been well dispersed into the water in the form of quasi-spherical droplets, with average droplet diameters of 242–805 nm. The thermal conductivity of 10 wt% n-tetradecane/water NPCME containing 9 mg ml^-1 MXene is 0.693 W m^-1·K^-1, achieving an enhancement by 15.5%, as compared to that of water. Besides, the MXene-decorated paraffin/water NPCMEs exhibit little supercooling and enhanced heat storage capacities. More importantly, this facile self-assembly strategy opens a new platform for preparing high-performance NPCMEs, which can be used as novel heat transfer fluids for thermal energy storage systems.     

Enhancement of super-hydrophilic/underwater super-oleophobic performance of ceramic membrane with TiO2 nanowire array prepared via low temperature oxidation

A gradient porous ceramic membrane with surface super-hydrophilic and underwater super-oleophobic performance was prepared by combining hydrogel directional freezing method and low temperature oxidation process. The effects of solid contents and sintering temperature on the ceramic membrane matrix were examined. The reaction time and synthesis temperature on the TiO₂ nanowire array were also evaluated. In addition, the related effects on pore size distribution, permeation flux, contact angle, and oil-in-water emulsion separation were systematically investigated. The ceramic membrane matrix pore size changed from 0.5 μm to 25 μm gradually, indicating the gradient structure controlled by the growth of ice. The super-hydrophilic and underwater super-oleophobic performance of ceramic membrane surface was obtained with surface modification by TiO₂ nanowire array, and the surface water contact angle and underwater oil contact angle were less than 5° and over 158°, respectively. The bonding strength between TiO₂ nanowire and ceramic membrane matrix was high enough to withstand ultrasonic waves. The ceramic membrane modified with TiO₂ nanowire array was used for 1000 ppm diesel oil-in-water emulsion separation, and the stable separation efficiency and flux were about 97% and 100–200 L/(m² h bar) even after 10 filtration cycles.     

两种混合单元混合机理的数值模拟

为了研究SV型和SX型混合单元在全静态乳化器的混合机理,使用群体平衡模型对乳化器内部流场进行模拟分析。结果表明,SV型与SX型混合单元的混合机理是油相与水相材料通过混合单元时其空间流动方向改变,在流场内形成大量的漩涡,从而达到乳化的目的;通过比较流体在经过SV型和SX型混合单元后的水相索特平均直径(d_(32)),得出SV型混合单元的乳化效果更强,但同时消耗更多的能量,压降更大。     

Double emulsion (W/O/W) gel stabilised by polyglycerol polyricinoleate and calcium caseinate as mangiferin carrier: insights on formulation and stability properties

Mangiferin (MGF) is a phenolic compound isolated from mango, but its poor solubility significantly limits its use. In this study, MGF was embedded into the inner aqueous phase of W₁/O/W₂ emulsions. Firstly, the dissolution method of MGF was determined. MGF remained stable in solution with pH 13 at 30 min, and its solubility reached 10 mg mL⁻¹. When the pH of MGF solutions was adjusted from pH 13 to pH 6, MGF did not immediately crystallise, providing sufficient time to construct the MGF-loaded W₁/O/W₂ emulsions. Subsequently, the MGF-loaded W₁/O/W₂ emulsions were constructed using polyglycerol polyricinoleate (PGPR) and calcium caseinate (CAS). The formation and stability of the W₁/O/W₂ emulsions were investigated. The MGF-loaded W₁/O/W₂ emulsions stabilised with 1% PGPR and 1% – 3% CAS exhibited a low viscosity, limited loading capacity, and poor stability. Conversely, the MGF-loaded W₁/O/W₂ emulsions stabilised by 3%PGPR–3%CAS exhibited optimal loading capacity (encapsulation efficiency = 95.31% and loading efficiency = 0.91%) and stability, which was attributed to the fact that high viscosity and gel state retarded the migration of inner aqueous phase. These results indicated that the W₁/O/W₂ emulsions stabilised by PGPR and CAS may be a potential alternative for encapsulating mangiferin.     

聚苯乙烯磺酸钠掺杂正渗透膜的制备及其性能

通过两步无皂乳液聚合法，改变第二步对苯乙烯磺酸钠的加入量，制备表面携带磺酸根基团量不同的纳米粒子（PSS），并将其应用于正渗透（FO）膜的制备。采用红外光谱仪（FTIR）和光电子能谱仪（XPS）表征粒子组成，通过扫描电子显微镜（SEM）表征膜的表面和断面形貌，测定膜孔隙率和亲水性，考察表面磺酸根量不同的聚合物粒子对膜结构性能的影响。结果表明，PSS的引入能提高膜的孔隙率，改善膜的亲水性，且随着粒子表面携带的磺酸根基团量增多，膜的孔隙率与亲水性也随之提高。这是因为PSS粒子可以支撑内部孔道，且表面携带的亲水基团-SO3Na可以提高膜的亲水性，影响活性层的形成。所制备的FO膜性能也得到相应改善，水通量达到了61.1L/(m²·h)，为纯聚砜膜的2.8倍，盐截留率达到93.2%，J_s/J_v值仅为0.31g/L，性能得到极大提升。     

磷酸酯化苯丙共聚物乳液的合成及防锈性能

以甲基丙烯酸（MAA）为亲水单体、甲基丙烯酸羟丙酯（HPMA）为交联单体、苯乙烯（St）和甲基丙烯酸甲酯（MMA）为硬单体、丙烯酸丁酯（BA）为软单体、2-羟乙基甲基丙烯酸酯磷酸酯（PM-2）为功能单体、十二硫醇为链段调节剂，采用半连续种子乳液聚合法，制备了具有核壳结构的磷酸化苯丙防锈乳液（PM-2-SP）。讨论了PM-2用量对PM-2-SP乳液稳定性，胶膜耐水性及漆膜防锈性能的影响。利用激光粒径散射仪（DLS）及透射电镜（TEM）对PM-2-SP乳液的乳胶粒的大小及形貌进行了表征，通过原子力显微镜(AFM)对胶膜表面进行观测，采用盐水喷雾试验机对漆膜的防腐性进行测试。结果表明：当PM-2用量为4%（以总单体质量为基准，下同）时，PM-2-SP乳液粒径为135.7nm，PDI为0.150，且具有核壳结构，稳定性能较好；同时胶膜表面光滑、致密，且有优异的耐水性能；漆膜相比纯苯丙腐蚀电位上升率为47.16%，可达到-0.391V，腐蚀电流下降率为94.76%，可达到1.95E-7（A?cm2），耐盐雾时间达到144h。     

Performance and exhaust emissions of a diesel engine using diesel nanoemulsions as alternative fuels

The aim of this paper is to investigate the effect of water-in-diesel fuel nanoemulsions on diesel engine performance and exhaust emissions of a single cylinder diesel engine at different engine loads. Emulsified diesel fuel was prepared by mixing diesel fuel with surfactant in the percentage of 4, 6, 8 and 10 wt% of the emulsion total weight. Emulsified diesel oils with varying content of water and surfactant concentrations were prepared via the batch method technique. Different concentrations of water as 5, 6 and 7 wt% was gradually added. Effect of water content and surfactant concentration on engine performance parameters and exhaust emissions were investigated. From the obtained results, specific fuel consumptions for water diesel emulsions were reduced by 8% compared to pure diesel fuel at 4 wt% surfactant concentration, 7 wt% water content and engine load of 1 kW. Furthermore, the lowest HC, CO and NOx emissions value of 66, 48 and 32%, respectively were obtained in case of using 6 wt% of surfactant concentration, 7% water content and engine load of 1 kW. The prepared emulsified diesel fuel achieved a higher engine performance and lower exhaust emissions compared to neat diesel fuel.     

Pickering乳液在油基钻井液中的应用

Pickering乳液以其较高的聚并稳定性、多样性、可调控性、低成本、低毒性和生物兼容性等优势，广泛应用于生物医学、食品和化妆品等领域。近年来，Pickering乳液在石油行业的应用备受关注。分析了Pickering乳液的稳定机理与其相较于传统乳液的优势；探究了影响Pickering乳液稳定性的诸多因素及调控方式；最后综述了近年来国内外Pickering乳液在钻井和驱油方面的应用，并对Pickering乳液在石油行业中的发展前景进行了展望。