Superabsorbent copolymers of carboxymethyl cellulose/polyacrylamide (CMC/PAM) and carboxymethyl celullose/polyacrylamide/silica (CMC/PAM/Si) were synthesized using a c-irradiation technique. The effects of irradiation dose, content of CMC, AM, and Si on swelling percentage of the produced hydrogels were evaluated. It was found that the maximum swelling percent increased dramatically up to 12,000 % at pH 12 with increasing content of silica up to 5 % in the CMC/PAM/Si composite hydrogel. The prepared copolymers were characterized by FTIR, and SEM techniques. In order to evaluate their controlled release potentials, different hydrogels were loaded with potassium nitrate (KNO 3 ), and the release of the KNO 3 was studied and evaluated at various pH values.

This study focuses on the surface modification of polyamide (PA) thin-film composite reverse osmosis (RO) membranes using irradiated chitosan/titanium dioxide (CS/TiO 2) via Co 60 gamma ray. This modification was achieved through coating of a thin layer of gamma preirradiated chitosan onto the surface of commercial PA thin film composite membrane. The chitosan concentrations ranged from 0.2 to 0.6 wt% with different contents of TiO 2 nanoparticles irradiated at different doses. The surface morphology, surface hydrophilicity and membrane chemical composition before and after the modification were analyzed by scanning electron microscope (SEM), contact angle measurements and FT-IR spectroscopy. FT-IR spectroscopy of the synthesized membranes proved the incorporation of both CS and TiO 2 nanoparticles on the polyamide active layer. The performance of both neat and modified membranes for water desalination was evaluated. The results showed an improvement in the permeate flux of the membranes by increasing TiO 2 concentration up to 0.125 wt%, and then decreased at higher concentration of TiO 2. Moreover, the salt rejection (%) increased at lower concentrations of TiO 2 and then decreased with increasing the TiO 2 content. Contact angle measurements revealed that the surface hydrophilicity of the membranes, improved by increasing TiO 2 concentration in chitosan solution.

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