Membrane-Assisted Liquid-Phase Extraction of Lu(III) in a U-Shaped Contactor with a Single Hollow Fiber Membrane

Study on CO2 Desorption Behavior of a PDMS-SiO2 Hybrid Membrane Applied in a Novel CO2 Capture Process

In this present work, a novel approach has been proposed by which a solvent absorption and membrane desorption methods can significantly reduce the carbon dioxide (CO₂) emission and energy consumption. In this method, the CO₂ capture processing is based on the combination of membrane and physical solvent. Here, dimethyl carbonate and polydimethylsiloxane (PDMS)-SiO₂ nanocomposite were used as the physical solvent and desorption membrane, respectively. However, the main focus of this research was on the CO₂ desorption behavior of PDMS-SiO₂ hybrid membrane. To do so, the influence of the operating conditions and membrane properties on the pervaporation process to capture CO₂ have been investigated. The PDMS-SiO₂ hybrid membrane containing 10 wt % SiO₂ was the most effective membrane. Results revealed that increase in CO₂ concentration from 1.5 to 3 wt % led to decrease in the selectivity from 94 to 47 and increase in flux from 1.7 to 5.38 (kg/m²·h). In addition, an increase in temperature increased the flux and reached the highest level (8.17 kg/m²·h) at 40 °C. However, the selectivity decreased to 36.13. It was found that the addition of SiO₂ nanoparticles to the PDMS membrane not only enhanced the membrane performance but also decreased the energy consumption about 75% compared with gas stripping method and mass transfer about 49% compared with pure PDMS membrane. Finally, these results illustrated that such a novel technique used for pervaporation separation process is a green and promising alternative to separate CO₂ from the physical solvent.

Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins

The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption.