Deep Eutectic Solvent-Functionalized Mesoporous Silica SBA-15-Based Mixed Matrix Polymeric Membranes for Mitigation of CO2

In this research, a novel DES (choline chloride + decanoic acid) was synthesized, and SBA-15 was functionalized by the DES to form a DES-SBA filler to fabricate MMMs. DES-SBA-based MMMs at 5%, 10%, 15%, and 20% were synthesized and evaluated. The DES-SBA-based MMMs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Gas permeation tests were applied to the pure and mixed gas samples, and the results of the permeability and selectivity (CO2/CH4, and CO2/N2) of the membranes are reported. DES modification of SBA-15 increased the efficiency of the synthesized MMMs in comparison with the pristine polysulfone membrane.

A Biofouling Resistant Zwitterionic Polysulfone Membrane Prepared by a Dual-Bath Procedure

This study introduces a zwitterionic material to modify polysulfone (PSf) membranes formed by a dual bath procedure, in view of reducing their fouling propensity. The zwitterionic copolymer, derived from a random polymer of styrene and 4-vinylpyrridine and referred to as zP(S-r-4VP), was incorporated to the PSf solution without any supplementary pore-forming additive to study the effect of the sole copolymer on membrane-structuring, chemical, and arising properties. XPS and mapping FT-IR provided evidence of the modification. Macrovoids appeared and then disappeared as the copolymer content increased in the range 1–4 wt%. The copolymer has hydrophilic units and its addition increases the casting solution viscosity. Both effects play an opposite role on transfers, and so on the growth of macrovoids. Biofouling tests demonstrated the efficiency of the copolymer to mitigate biofouling with a reduction in bacterial and blood cell attachment by more than 85%. Filtration tests revealed that the permeability increased by a twofold factor, the flux recovery ratio was augmented from 40% to 63% after water/BSA cycles, and irreversible fouling was reduced by 1/3. Although improvements are needed, these zwitterionic PSf membranes could be used in biomedical applications where resistance to biofouling by cells is a requirement.

Combining Diffusion, Convection and Absorption: A Pilot Study of Polymethylmethacrylate versus Polysulfone Membranes in the Removal of P-Cresyl Sulfate by Postdilution On-Line Hemodiafiltration

Dialytic clearance of p-cresyl sulfate (pCS) and other protein-bound toxins is limited by diffusive and convective therapies, and only a few studies have examined how to improve their removal by adsorptive membranes. This study tested the hypothesis that high-flux polymethylmethacrylate (PMMA) dialysis membranes with adsorptive capacity increase pCS removal compared to polysulfone membranes, in a postdilution on-line hemodiafiltration (OL-HDF) session. Thirty-five stable hemodialysis patients randomly completed a single study of 4 h OL-HDF with PMMA (BG2.1U, Toray®, Tokyo, Japan) and polysulfone (TS2.1, Toray®) membranes. The primary endpoint was serum pCS reduction ratios (RRs) obtained with each dialyzer. Secondary outcomes included RRs of other solutes such as β2-microglobulin, the convective volume obtained after each dialysis session, and the dialysis dose estimated by ionic dialysance (Kt) and urea kinetics (Kt/V). The RRs for pCS were higher with the PMMA membrane than those obtained with polysulfone membrane (88.9% vs. 58.9%; p < 0.001), whereas the β2-microglobulin RRs (67.5% vs. 81.0%; p < 0.001), Kt (60.2 ± 8.7 vs. 65.5 ± 9.4 L; p = 0.01), Kt/V (1.9 ± 0.4 vs. 2.0 ± 0.5; p = 0.03), and the convection volume (18.8 ± 2.8 vs. 30.3 ± 7.8 L/session; p < 0.001) were significantly higher with polysulfone membrane. In conclusion, pCS removal by OL-HDF was superior with high-flux PMMA membranes, appearing to be a good dialysis strategy for improving dialytic clearance of pCS, enabling an acceptable clearance of β2-microglobulin and small solutes.

Copper Ions Removal by PSF-Si Spiral Wound Membranes of Different Porosity

Effluent discharged from various industries is one of the point sources of pollutions that affect the water quality. The effluent contains a high concentration of hazardous compounds of metal ions. Membrane technology using ultrafiltration membrane had proven successful in treating physical and organic impurities from water and wastewater. The importance of this study was to clarify the effectiveness of additive concentration in nanofiltration membrane for heavy metals removal. The physicochemical characteristics and copper ions removal efficiencies were determined for a different amount of silica extracted from sugarcane bagasse as an additive added to polysulfone polymer membranes. The PSF-Si membranes were fabricated via the phase inversion technique. The results show that silica in the formulation and fabrication of polysulfone membrane gives added value to membrane porosity, water content, and hydrophilicity. The most effective membrane in removing copper ions was the membranes with the lowest silica content, which is PSF-21 Si-2. The PSF-21 Si-2 membrane is hydrophilic, attracts a large amount of water, and gives a pure water flux of 56 L/m2hr to pass through the membrane. Moreover, the copper rejection increased from 92% to 98% as the copper concentration increased for the best membrane formulation PSF-21 Si-2.

Sub-Minute Analysis of Lactate from a Single Blood Drop Using Capillary Electrophoresis with Contactless Conductivity Detection in Monitoring of Athlete Performance

A simple and fast method for the analysis of lactate from a single drop of blood was developed. The finger-prick whole blood sample (10 µL) was diluted (1:20) with a 7% (w/v) solution of [tris(hydroxymethyl)methylamino] propanesulfonic acid and applied to a blood plasma separation device. The device accommodates a membrane sandwich composed of an asymmetric polysulfone membrane and a supporting textile membrane that allows the collection of blood plasma into a narrow glass capillary in less than 20 s. Separated and simultaneously diluted blood plasma was directly injected into a capillary electrophoresis instrument with a contactless conductivity detector (CE-C4D) and analyzed in less than one minute. A separation electrolyte consisted of 10 mmol/L l-histidine, 15 mmol/L dl-glutamic acid, and 30 µmol/L cetyltrimethylammonium bromide. The whole procedure starting from the finger-prick sampling until the CE-C4D analysis was finished, took less than 5 min and was suitable for monitoring lactate increase in blood plasma during incremental cycling exercise. The observed lactate increase during the experiments measured by the developed CE-C4D method correlated well with the results from a hand-held lactate analyzer (R = 0.9882). The advantage of the developed CE method is the speed, significant savings per analysis, and the possibility to analyze other compounds from blood plasma.