Gamma irradiation synthesis of pectin- based biohydrogels for removal of lead cations from simulated solutions

Abstract

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.

“Gamma Irradiation Synthesis of Carboxymethyl Chitosan-Nanoclay Hydrogel for the Removal of Cr(VI) and Pb(II) from Aqueous Media”

“…This indicates that the adsorption was better fit by pseudo-first order and implies that the adsorption process is probably due to formation of chelate structure or electrostatic attraction between the active groups on the chitosan derivative and the metal ions. This finding is in a good agreement with our previous work [23,89,90]. The intraparticle diffusion model for the adsorption of both Pb(II) and Cr (VI) by CsAA 3 Cl revealed three regions: 1st step hydrogel diffusion, which corresponds to the rapid adsorption of metal ions from the aqueous phase to the boundary layer of the hydrogel; 2nd step gradual adsorptions, which correspond to the diffusion of metal ions within the porous sites of the hydrogel; and 3rd step equilibrium stage, which is the adsorption of metal ions into the interior surface of the hydrogel.…”

“…It can be depicted that the complete equilibrium metal uptake for both metal ions were attained within 90 min although about 80% of total adsorption was achieved in the first 50 min due to the abundancy of the active sites available for adsorption and the higher initial concentration gradient. This data is comparable to those obtained in our previous work [23].…”

“…According to our previous works [8,23], the AFM was successfully utilized to confirm the metal uptake process by considering the following: the height and roughness measurements, phase analysis and change in topographic features.…”

“…Environmental Protection Agency, and the International Agency for Research on Cancer [19,20]. Therefore, elimination of these metals from aqueous solutions was the top topic of many research works [13,[21][22][23][24]. There are several methods applied for wastewater treatment; such as coprecipitation [25], cation exchange [26], Ultrafiltration [27], reverse osmosis [28], nanofiltration [29], adsorption-reduction [30] and adsorption [31].…”

Green synthesis of chitosan/erythritol/graphene oxide composites for simultaneous removal of some toxic species from simulated solution

“…The specific toxicity of mercury is mainly a consequence of its strong bioaccumulation and endurance in the food chain (Zhang et al 2015a). One of the significant concerns of water treatment processes is reducing the excessive quantities of heavy metals to acceptable levels (Khozemy et al 2020;Sayed et al 2022a). Several protocols have been applied to remove mercury, including ion exchange, ultra-filtration, and adsorption.…”