High Internal Phase Emulsion Monoliths Research Articles

Tubular catalytic polyHIPE reactor with deposited silver nanoplate nanoparticles

Continuously operating heterogeneous catalytic reactors are an important step towards more efficient and controllable processes compared to batch operation. Ideally, reactors should exhibit high permeability with the catalyst having a high surface area to volume ratio to minimize the required amount. An example of such catalyst morphology are nanoparticles with a plate-like morphology. In this work, the catalytic reactor was prepared by depositing plate-like silver nanoparticles on positively charged high internal phase emulsion monoliths by exploiting their negative zeta potential. The silver nanoplates had an edge length of 63 nm and a thickness of 13 nm with a sphericity factor of 0.548. The amount of deposited silver, determined from absorbance measurement and mass difference was 12.5 mg/ml and remained unaffected by the concentration of positively charged groups in the range between 69 and 110 mmol/l, demonstrating the robustness of the proposed approach. The permeability remained unchanged after silver deposition under flow due to the polymer microstructure. The reactor was found to be stable under various elution conditions, even after prolonged catalytic reduction of 4-nitrophenol. The specific catalytic activity of silver nanoplates was 428 min−1 g−1, which is an order of magnitude higher than that of silver nanoparticles with cuboctahedra shape and one of the highest reported. The proposed approach can be applied to various types of catalytic nanoparticles by exploiting a variety of possible interactions.

Preparation and Application of Polymerized High Internal Phase Emulsion Monoliths for the Preconcentration and Determination of Malachite Green and Leucomalachite Green in Water Samples

Polymerized high internal phase emulsion (polyHIPE) monoliths were prepared and applied as adsorbent materials for solid-phase extraction (SPE) of malachite green (MG) and leucomalachite green (LMG) from water samples. The polyHIPE monoliths were prepared by post-functionalization of monolithic surface with 6-aminocaproic acid (ACA) via ring opening reaction of epoxy groups in glycidyl methacrylate (GMA)-based polyHIPEs, and then applied to the preconcentration and determination of trace MG and LMG in environmental water samples by combing with high-performance liquid chromatography (HPLC). Taking MG and LMG as targets, main factors affecting SPE performance of the polyHIPE monoliths were investigated. Under the optimized conditions, the ACA-functionalized polyHIPE monoliths could effectively preconcentrate MG and LMG from 150 mL of water samples, and the recoveries of MG and LMG at three spiked levels were ranged from 84.8 to 97.4% with the relative standard deviations (RSDs) lower than 6%. The proposed method exhibited good linearity in the range of 2–200 ng mL–1, with low limits of detection of 17.0 and 8.7 pg mL–1 for MG and LMG, respectively. In addition, the prepared ACA-modified polyHIPE monolith showed good durability and stability, and it could be reused for 200 cycles without obvious losing the extraction performance.

Synthesis of Acrylonitrile Based High Internal Phase Emulsion Monoliths and their Application in Recovery of Heavy Metal Ions

Polymeric monoliths based on acrylonitrile-divinyl benzene were synthesized successfully by high internal phase emulsion (HIPE) polymerization. Highly porous polyHIPEs were prepared by variation in oil to water ratio as well as type and concentration of porogens. The porogens evaluated were toluene, chlorobenzene, heptane and chloroform. The effect of oil to water ratio and porogen type and concentrations on morphology and surface area of polyHIPEs were investigated. The polyHIPEs were modified to amidoxime functionality by treating base catalyzed reaction with hydroxylamine hydrochloride in presence of base. The treated and modified polymeric monoliths were characterized by FT-IR, SEM and surface area analysis. The modified porous polyHIPEs were tested for adsorption of Cr(VI) metal ions at various pH.

Development and validation of polymerized high internal phase emulsion monoliths coupled with HPLC and fluorescence detection for the determination of trace tetracycline antibiotics in environmental water samples.

A polymerized high internal phase emulsion monolith was used as a novel sorbent for solid-phase extraction coupled with high-performance liquid chromatography and fluorescence detection for the determination of oxytetracycline, tetracycline, doxycycline, and chlorotetracycline in environmental water samples. The polymerized high internal phase emulsion monolithic column was prepared by the in situ polymerization of the continuous phase of a high internal phase emulsion containing glycidyl methacrylate, styrene, and divinylbenzene in pipette tips, and then functionalized with iminodiacetic acid. The resulting monolith exhibited highly interconnected porosity and large surface areas, making it an excellent candidate as an solid-phase extraction sorbent for the enrichment of trace tetracycline antibiotics. Several factors affecting the extraction performance of polymerized high internal phase emulsion monoliths, including the pH of sample solution, the eluting solvents, the sample loading flow rate and volume, were investigated, respectively. Under the optimized conditions, the mean recoveries of oxytetracycline, tetracycline, doxycycline, and chlorotetracycline spiked in pond and farm wastewater samples ranged from 78.1 to 119.3% with relative standard deviation less than 15%. The detection limits (S/N = 3) of the proposed method were in the range of 51-137 pg/mL. This study demonstrated that the monolithic polymerized high internal phase emulsion would be promising solid-phase extraction sorbents in the extraction and proconcentration of trace analytes from complex samples.

Polymerized high internal phase emulsion monoliths for the chromatographic separation of engineered nanoparticles

ABSTRACTPolyHIPEs of ethylene glycol dimethacrylate (EGDMA) and styrene/divinylbenzene were prepared by polymerization of water‐in‐oil high internal phase emulsions (HIPEs) within high pressure liquid chromatography (HPLC) columns. The columns were incorporated into a HPLC system affixed to an inductively‐coupled plasma mass spectrometer, and their potential for the separation of engineered nanoparticles was investigated. Triplicate injections of 5 and 10 nm gold particles injected onto a poly(styrene‐co‐divinylbenzene) polyHIPE column produced an average difference in retention time of 135 s. On a poly(EGDMA) column, triplicate injections of dysprosium containing polystyrene particles of 52 and 155 nm produced a difference in retention time of 8 s. In both cases the smaller particles eluted from the column first. Comparison, using scanning electron microscopy, of the polyHIPE columns after the separations, against freestanding monoliths produced from the same HIPEs, revealed no apparent change in the internal porous structure of the polyHIPEs. © 2015 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 132, 41229.

Polymerised high internal phase ionic liquid-in-oil emulsions as potential separators for lithium ion batteries

In situ ionic liquid (IL) filled poly(merized) high internal phase emulsion monoliths and films were produced by polymerizing surfactant stabilized IL/monomer emulsion templates. The resulting in situ ionic liquid filled macroporous polymers have almost the ionic conductivity of the neat ionic liquid electrolyte. The effect of surfactant and lithium salt concentration, monomer to crosslinker ratio as well as internal phase volume ratio on the morphology and ionic conductivity were studied. It was found that the morphology of the resulting polyHIPEs affects significantly their ionic conductivity. PolyHIPEs with bigger pore throats have a higher ionic conductivity.