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Preparation and characterization of a series of ion-exchange membranes for the purpose of separation and extraction of some heavy and toxic metal ions from their wastes were studied. Such ion-exchange membranes were prepared by ␥-radiation grafting of acrylonitrile (AN) and vinyl acetate (VAc) in a binary monomer mixture onto low-density polyethylene (LDPE) using the direct technique of grafting. The reaction conditions at which the grafting process proceeds successfully were determined. Many modification treatments were attempted for the prepared membranes to improve their ion-exchange properties. The possibility of their practical use in waste-water treatment to remove some heavy and toxic metal ions such as Pb 2ϩ , Cd 2ϩ , Cu 2ϩ , Fe 3ϩ , Sr 2ϩ , and Li ϩ were investigated. These grafted membranes showed great promise for possible use in the field of extraction and removal of some heavy and toxic metals from their wastes.

Reclaimed rubber powder (RRP) was treated by the addition of maleic anhydride (MA) to impart desired properties suitable for self-adhesive sheets and concrete lining applications. The produced MA-RRP was mixed with natural rubber (NR) with various compositions. A fixed 1 : 1 blend ratio of NR : RRP was reinforced with various contents of glass fiber (GF) in an open two-roll mixing mill. The composites were irradiated using a 1.5 MeV electron beam accelerator at 30 and 50 kGy irradiation doses. Different properties of composite such as tensile strength, elongation at break, hardness, swelling behavior in different media, thermal stability, and scanning electron microscope (SEM) for both unirradiated and irradiated samples with respect to the RRP and GF content were investigated. Results show that the tensile strength and swelling resistance increase with increasing RRP content in the NR/RRP blends, whereas the elongation at break exhibit opposite trend. It can be observed that the hardness increases with increasing the fiber content.

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In this study, cellulose nanocrystals (CNCs) were produced from pea peels by acid hydrolysis to be used with pectin and acrylic acid (AAc) to form Pectin-PAAc/CNC nanocomposite by γ-irradiation. The structure, morphology, and properties of the nanocomposite were investigated using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) techniques. The nanocomposite hydrogel was used for the removal of methylene blue dye (MB) from wastewater. The results revealed that the presence of CNCs in the polymeric matrix enhances the swelling and adsorption properties of Pectin-PAAc/CNC. The optimum adsorbate concentration is 70 mg/L. The kinetic experimental data were fit by pseudo-first-order (PFO), pseudo-second-order (PSO), and Avrami (Avr) kinetic models. It was found that the kinetic models fit the adsorption of MB well where the correlation coefficients of all kinetic models are higher than 0.97. The Avr kinetic model has the lowest ∆qe (normalized standard deviation) value, making it the most suitable one for describing the adsorption kinetics. The adsorption isotherm of MB by Pectin-PAAc follows the Brouers–Sotolongo model while that by Pectin-PAAc/CNC follows the Langmuir isotherm model. The negative values of ∆G confirmed the spontaneous nature of adsorption, and the positive value of ∆H indicated the endothermic nature of the adsorption.

Bio-based hydrogels (denoted as PC-PAAc/GA) comprised of Pectin (PC) and polyacrylic acid (PAAc) reinforced with different ratios of gallic acid (GA) were prepared by gamma radiation at irradiation dose 20 kGy. The prepared hydrogels were investigated by different analytical tools. The swelling performance was studied versus time, pH of the medium and gallic acid content. The experimental data depicted that the swelling increases with pH of medium until the equilibrium of swelling after 350 min. The maximum swelling was attained at pH10 for both PC-PAAc and PC-PAA/GA1.5. Also, the data reveal that the incorporation of GA in the hydrogel matrix enhanced the swelling performance of the hydrogel up to an optimum value of GA, i.e. PC-PAA/GA1.5. Further increase in GA concentration leads to formation of a highly crosslinked structure with reduced swelling. The results demonstrated that the prepared hydrogels displayed excellent antibacterial activity against gram + ve bacteria (E.coli) and gram-ve bacteria (S.aureus). This potent antimicrobial activity is mainly originated from GA which was proved as a strong antibacterial agent. Moreover, the removal performance of the investigated hydrogels was verified towards Pb+2 cation as one of the most poisonous heavy metals. The data revealed that the maximum removal percentage of Pb (II) was attained by PC-PAAc/GA1.5 hydrogel (90 mg g−1). The correlation coefficients of the Langmuir model are too higher than that of the Freundlich model that assumed the adsorption of lead cations is mainly a chemical process.

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In the current study, the performance of superabsorbent hydrogel composites comprised of Guar gum-Pectin/Polyacrylamide/ZnO crosslinked with gamma irradiation (10 kGy) has been investigated for sustainable agriculture. The claimed composites (GG/PC/PAAm/ZnOx) were characterized by FTIR, TGA, and AFM. The swelling capacity data reveal that the equilibrium water swelling (EW) of the composites was increased by increasing the ZnO content from 600 to 1050 g/g for zero to the highest concentration of ZnO, respectively. Furthermore, the physical properties of the soil mixed with the hydrogels were improved; water holding capacity (WHC) increased to 66% and water retention (WR) kept at 15% after 20 days. The composites showed a good degradability in the biodegradation test. They also portrayed super-absorption capacity at three swelling/deswelling cycles. This advancement is important for reducing water consumption through the irrigation of arid lands. The prepared composites were proved as excellent candidates in sustainable agriculture applications.