Induced effects of gamma irradiation on activated carbon derived from Hyphaene Thebaica husks as a potential adsorbent for Chlorpyrifos pesticide-air purification

In the current study, Doum palm husk of Hyphaene Thebaica (HT), a local agrow-waste, was utilized as a new source for the production of activated carbon (HT-AC). The thermally prepared adsorbent was chemically activated by phosphoric acid aqueous solution and exposed to gamma-ray at doses of 2.5-10 Grays for capacity enhancement. Characterization of the obtained products were tested using FT-IR, SEM-EDX, XRD, BET and Raman spectroscopy.Thecarbonspecies were then utilized in the ambient air purification from the (chlorpyrifos) O,O-Diethyl O-(3,5,6-trichloropyridin-2-yl) phosphonothioate,(trade name, Ictafos) pesticideair pollutant. Results showed the development of very high surface area of 1439, 1702 and 1561m(2)/g for the parent HT-AC and its HT-AC(2.5Gy) and HT-AC(5 Gy) irradiated forms, respectively. The XRD, FT-IR and Raman testing of the carbons indicated better-organized structure of the sample subjected to the least gamma dose of 2.5Gy than the other irradiated versions. The experimental and theoretical results clarified the best fitting of pseudo-first-order model in describing the Chlorpyrifos sorption reaction. Thermodynamic analysis revealed physical sorption of the hazardous material onto the surfaces of the activated carbons with exothermic process of non-spontaneous nature. Experimental kineticspresentedthat,HT-AC(2.5Gy)hadexcellent fitting to the Langmuir isotherm model, wherein the adsorption was proceeded in a monolayer manner with a uniform surface energy. Conversely, Freundlich isotherm was perfectly fitted to the original HT-AC and HT-AC 5Gy, where the multilayer and heterogeneous adsorption mechanism was exhibited