Poly(ether sulfone) (PES), because of its low chain mobility and high gas selectivity, was selected as a gas-separation membrane. Because poly(ethylene glycol) (PEG) contains polar ether groups favorable for carbon dioxide (CO 2 ) capture, we investigated the effects of PEG on the CO 2 /CH 4 and CO 2 /N 2 separation properties of PES-PEG blend membranes. PEG with different molecular weights (4000, 6000, and 10,000) and concentrations of up 30 wt % was added to PES. Scanning electron microscopy and wide-angle X-ray diffraction analyses on the blends confirmed the uniformity and dense surfaces of the membranes and no changes in the crystallinity, respectively. Fourier transform infrared spectra indicated good interactions between the PEG and PES segments. Gas permeation tests showed that with increasing PEG molecular weight, its weight fraction permeability of CH 4 and CO 2 increased, whereas the permeability of O 2 and N 2 decreased. The best composition of PES-PEG was a 70/30 ratio; with this composition, the selectivities of CO 2 /N 2 and CO 2 /CH 4 were enhanced by 64 and 14%, respectively, compared to that of the pure membrane.
Sesame leaf and stem, as a kind of useless agricultural waste, was used as a sort of low-cost biosorbent for the removal of cadmium ions from aqueous solutions in batch and continuous modes. The biomass was characterized by Fourier transform infrared spectroscopy, scanning electron microscope and energy-dispersive X-ray analysis before and after adsorption. There were hydroxyl group, carboxyl group, etc. on the surface of the adsorbent from Fourier transform infrared spectroscopy. A batch study was employed as a function of the initial concentration, adsorbent particle size, adsorbent dose, contact time and the pH of the solution. Maximum sorption was found to occur at an initial pH of 6. The equilibrium process was satisfactorily described by the Langmuir isotherm model with the maximum sorption capacity of 84.74 mg g -1 . Kinetic studies also indicated that both pseudo-first-order and pseudo-second-order kinetic models (with R 2 values of 0.9929 and 0.9952, respectively) were able to describe the process. A continuous study was carried out, and the maximum uptake of cadmium ions in a fixed-bed adsorption column was found to be 22.88 mg g -1 , where the initial concentration of cadmium ions, bed height, flow rate and pH were 60 mg L -1 , 2 cm, 2.5 mL min -1 and 5.5, respectively.
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