Synthesis of Copper Ferrite/Hydroxyapatite Nanoparticles Composite Based on Cuttlebone for the Adsorption and Photocatalytic Degradation of Diazinon Pesticide

Abstract Diazinon is a persistent and environmentally resistant organophosphorus pesticide that is challenging to remove due to its aromatic structure. In this study, we developed three solid samples: copper ferrite nanoparticles (CFe), hydroxyapatite nanoparticles (NHp) based on cuttlebone, and copper ferrite/hydroxyapatite composite nanoparticles (CFHp) for the diazinon elimination through both the adsorption and photocatalytic degradation methods. The fabricated solid samples were characterized by utilizing different physicochemical techniques, including TGA, N 2 adsorption/desorption, SEM, TEM, XRD, ATR-FTIR, zeta potential, and DRS. The major experimental parameters were established for dose of solid adsorbent sample, initial concentration of diazinon, time of shaking, temperature, pH, and UV light effect. The diazinon adsorption data showed that the maximum capacity of adsorption of 432.12 mg/g was achieved via CFHp composite at adsorbent dose of 2.0 g/L, pH 7, shaking time of 3 h, and 25 °C. In addition to the nonlinear kinetic models of pseudo-second order and Elovich onto all the synthesized adsorbents, the experimental results showed the best agreement with Langmuir and Temkin nonlinear isotherm models, suggesting the beneficial and physical adsorption process. Acetone achieved the best results for desorption and regeneration up to the eight cycles. The maximum diazinon degradation percentage (100%) was achieved using 1.0 g/L as catalyst dosage, 15 mg/L of initial diazinon concentration, 90 min illumination time, and 40 °C for CFHp composite. The diazinon photodegradation was well fitted by Eyring–Polanyi and Arrhenius models onto the CFe and CFHp catalysts surface. The reusability of CFHp manifested in a 5.0% decline in degradation efficiency, demonstrating its high capability as the first copper ferrite/hydroxyapatite employed in eliminating diazinon from wastewater using the two approaches in the same article.