Irradiation membrane

Figure 24, Potentiometric responses toward RbCI of membrane 89 with various concentrations of ionophore 89 under UV and visible light irradiation. Membrane composition DBP/PVC = 2 1 wt/wt containing (a) 1 mM, (b) 0.1 mM, and (c) 0.01 mM of 89, respectively.

In order to investigate the structure changes in the irradiated membranes, the UV-Vis and FTIR optical absorption measurements were performed at room temperature in air. Figs. 4 and 5. show typical UV-Vis and FTIR spectra in the wavelength regions of 190-300 nm and wavenumber of 500-1900 cm The UV-Vis optical absorption spectra of the unirradiated membrane in Fig. 4 exhibit three bands around 190, 215 and 275 nm. The intensities of the optical absorption increased with increasing the dose. The results almost coincide with... 

The influence of radiation on the transport properties of different reverse osmosis composite membranes was smdied by Chmielewski and Harasimowicz [1]. Reverse osmosis membranes were irradiated with a Co source, with a linear accelerator, and were also immersed in a Cs high activity solution, reaching absorbed dose values around 40 kGy. The results of some tests with the irradiated membranes showed that aromatic polyamide composite membranes are highly radiation resistant. This allows these membranes to be used in radioactive solutions with an activity below 3.7 x lO Bq/m, which corresponds to absorbed dose values around 30 kGy. 

The irradiated membranes were then tested in a pilot plant with a plate-and-frame module with capacity for two membranes with an effective area of 90 cm each. Permselective results of irradiated membranes were compared to those of nonirradiated membranes [3]. It was observed that the performance of the samples irradiated with electronic or gamma radiation was very similar to that of the nonirradiated membranes. Tables 32.1 and 32.2 show the results of permeate flux and retention index for gamma- and electron-irradiated membranes, respectively. 

FIGURE 32.2 Permeate flux of gamma-irradiated membranes. 

FIGURE 32.3 Permeate flux of electron-irradiated membranes. 

For gamma-irradiated membranes, the values of experimental selectivity are higher than the upper limit of the nonirradiated dispersion, so it can be said that gamma radiation can even have a beneficial effect on membrane selectivity. 

Figures 5.25,5.26, and 5.27 show the AFM images (scan size 1x1 jim) of the fresh membranes and the membranes after 180 min of irradiation, except for BO. Table 5.15 shows the data on the average roughness parameters of fresh and 180-min-irradiated membranes obtained from AFM images of a scan size of 1 x 1 pm.

Madaeni S S and Ghaemi N (2007), Characterization of setf-cleaning RO membranes coated with TiOj particles under UV irradiation , / Membrane Sci, 303, 221-233. 

C2) and O-C-0 (C3) (rj = C2/C3 in Table 2) is lower than 5, the theoretical value for cellulose, which also indicates the polymer oxidation on the surface of both membranes. Such ratio is slightly lower for the irradiated membrane, which points out a slightly higher oxidation on the surface of the irradiated membrane. The y-radiation also seems to promote the sorption of adventitious or aliphatic carbon, since the oxidized/non-oxidized carbon ratio (r2 = ((C2 + C3 + C4)/C1) in Table 2) is slightly lower for the irradiated membrane (Figure 3 also shows that Cl is slightly more intense for RC5/160). 

Pneumatic detector (Golay cell) IR irradiated membrane heats a cavity filled with gas and changes its volume... 

The decrease in the diffusion coefficients for different gases through UV irradiated polymeric membranes (films) can be interpreted by the formation of chemical crosslinks and the decrease of free volumes. In the case of photo-oxidative degradation the decrease in diffusion through an irradiated membrane can be the result of physical interactions between primary hydroperoxide photoproducts, and can be used as a sensitive criterion to characterize the photo-oxidative evolution of polymers [1717]. 

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