scholarly journals Enzyme-Loaded Mesoporous Silica Particles with Tuning Wettability as a Pickering Catalyst for Enhancing Biocatalysis

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Tao Meng ◽  
Ruixue Bai ◽  
Weihao Wang ◽  
Xin Yang ◽  
Ting Guo ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Enzymatic Reaction ◽  
Interfacial Area ◽  
Mass Transfer Process ◽  
Pickering Emulsion ◽  
Contact Angles ◽  
Silica Particles ◽  
Emulsion System ◽  
Pickering Emulsions ◽  
Two Phase

Pickering emulsion systems have created new opportunities for two-phase biocatalysis, however their catalytic performance is often hindered by biphasic mass transfer process relying on the interfacial area. In this study, lipase-immobilized mesoporous silica particles (LMSPs) are employed as both Pickering stabilizers and biocatalysts. A series of alkyl silanes with the different carbon length are used to modify LMSPs to obtain suitable wettability and enlarge the interfacial area of Pickering emulsion. The results show the water/paraffin oil Pickering emulsions stabilized by 8 carbon atoms silane grafted LMSPs (LMSPs_C8) with a three-phase contact angles of 95° get the relatively large interfacial area. Moreover, the conversion of enzymatic reaction catalyzed by LMSPs_C8 Pickering emulsion system is 3.4 times higher than that unmodified LMSPs with the reaction time of 10 min. Additionally, the effective recycling of LMSPs is achieved by simple low-speed centrifugation. As evidenced by a 6-cycles reaction of remaining 75% of relative enzymatic activity, the protection of 350–450 nm mesoporous silica particles can alleviate the inactivation of enzyme from the shear stress and make a benefit to form stabile Pickering emulsion. Therefore, the biphasic reactions in the Pickering emulsion system can be effectively enhanced through changing interfacial area only by the means of adjusting the wettability of biocatalysts.

Preparation of a synergistically stabilized oil-in-water paraffin Pickering emulsion for potential application in wood treatment

Holzforschung ◽  
2018 ◽  
Vol 72 (6) ◽  
pp. 489-497 ◽  
Author(s):  
Jun Jiang ◽  
Jinzhen Cao ◽  
Wang Wang ◽  
Haiying Shen
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Size Distribution ◽  
Droplet Size ◽  
Surface Hardness ◽  
Pickering Emulsion ◽  
Silica Particles ◽  
Morphological Properties ◽  
Pickering Emulsions ◽  
Oil In Water

AbstractPickering emulsions (emulsions stabilized by solid-state additives) are attractive as they have strong similarities with traditional surfactant-based emulsions. In this study, an oil-in-water (O/W) paraffin Pickering emulsion system with satisfying stability and small droplet size distribution was developed by hydrophilic silica particles and traditional surfactants as mixed emulsifiers. The droplet morphology and size distribution were observed by optical microscopy and a laser particle analyzer. The emulsion stability was improved and the droplet size was reduced after addition of a suitable amount of silica particles. The silica concentration of 1% showed the optimal effect among all the levels observed (0.1, 0.5, 1 and 2%). Wood was impregnated with the prepared emulsion, and the chemical and morphological properties of the product were investigated by Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) combined with energy-dispersed X-ray analysis (SEM-EDXA). Moreover, the hydrophobicity, thermal properties, surface hardness, axial compression strength (CS) and dynamic mechanical properties were tested. The silica was evenly distributed in the wood cell wall and thus there was a synergistic positive effect from the paraffin and silica in the cell wall leading to better hydrophobicity, improved surface hardness and mechanical properties including the thermal stability.

scholarly journals Enhancing reaction rate in a Pickering emulsion system with natural magnetotactic bacteria as nanoscale magnetic stirring bars

2018 ◽  
Vol 9 (9) ◽  
pp. 2575-2580 ◽  
Author(s):  
Xin Zhou ◽  
Changyou Chen ◽  
Changyan Cao ◽  
Tao Song ◽  
Hengquan Yang ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Magnetotactic Bacteria ◽  
Pickering Emulsion ◽  
Emulsion System ◽  
Pickering Emulsions ◽  
Magnetic Stirring

The reaction rate of Pickering emulsions was greatly enhanced with natural magnetotactic bacteria as nanoscale magnetic stirring bars.

Direct Measurement of Contact Angles of Silica Particles in Relation to Double Inversion of Pickering Emulsions

Langmuir ◽  
2013 ◽  
Vol 29 (16) ◽  
pp. 4923-4927 ◽  
Author(s):  
Bernard Paul Binks ◽  
Lucio Isa ◽  
Andrew Terhemen Tyowua
Keyword(s):  
Direct Measurement ◽  
Contact Angles ◽  
Silica Particles ◽  
Pickering Emulsions

scholarly journals NanoTraPPED—A New Method for Determining the Surface Energy of Nanoparticles via Pickering Emulsion Polymerization

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3200
Author(s):  
Andrei Honciuc ◽  
Oana-Iuliana Negru
Keyword(s):  
Surface Energy ◽  
Functional Groups ◽  
Pickering Emulsion ◽  
Contact Angles ◽  
New Method ◽  
Pickering Emulsions ◽  
Surface Functional Groups ◽  
Emulsion Droplets ◽  
Pickering Emulsion Polymerization ◽  
Physicochemical State

Surface energy with its polar and disperse components describes the physicochemical state of nanoparticles’ (NPs) surfaces, and can be a valuable parameter for predicting their bulk behavior in powders. Here, we introduce a new method, namely, Nanoparticles Trapped on Polymerized Pickering Emulsion Droplets (NanoTraPPED), for measuring the surface energy of a series of silica NPs bearing various surface functional groups. The method consists in creating Pickering emulsions from vinyl bearing monomers, immiscible with water, whereas NPs of interest have a stabilizing role, and in the process, become trapped at the monomer/water interface of emulsion droplets. The Pickering emulsion is polymerized, and polymer microspheres (colloidosomes) decorated with NPs are obtained. NanoTraPPED relies on measuring contact angles from the immersion depth of nanoparticles at the interface of various polymer colloidosomes with the electron microscope. The contact angle values are used as input for the Owens-Wendt-Rabel-Kaelble (OWRK) model, to quantitatively determine the total surface energy with water γNP/water, air γNP, and the corresponding polar and dispersive interaction components of NPs carrying -NH2, -SH, -OH, -CN and -C8 surface functional groups, ranking these according to their polarity. Our findings were confirmed independently by calculating the interfacial desorption energies of NPs from contact angles.

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

Interfacial biocatalysis in bacteria-stabilized Pickering emulsions for microbial transformation of hydrophobic chemicals

2021 ◽  
Author(s):  
Haisheng Xie ◽  
Wenyu Zhao ◽  
Daniel Chikere Ali ◽  
Xuehong Zhang ◽  
Zhilong Wang
Keyword(s):  
Microbial Transformation ◽  
Pickering Emulsion ◽  
Pickering Emulsions

The Pickering emulsion interface is an exceptional habitat for bacteria to grow by simultaneously utilizing hydrophobic and hydrophilic chemicals.

A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
David Heinze ◽  
Thomas Schulenberg ◽  
Lars Behnke
Keyword(s):  
Direct Contact ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Interfacial Area ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Two Fluid Model ◽  
Contact Condensation ◽  
Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

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