Pesticide pollution of irrigation water is one of the most significant problems that researchers are concerned about. In this work, cobalt oxide nanoparticles were prepared using an effective photochemical synthesis, which was used to remove pentachlorophenol pesticide from irrigation water. By using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), the structural and morphological properties of the synthesized cobalt oxide nanoparticles are characterized. Adsorption experiments revealed that the maximum removal efficiency was achieved at a temperature of 323 K, pH 2, with 0.1 g of Co3O4 and a contact time of 60 min. Thermodynamic parameters (ΔH° = +10.27 kJ·mol−1, ΔS° = +41.51 J·mol−1·K−1, and ΔG° = −3.13 kJ·mol−1) were calculated to evaluate the nature of the adsorption process, where the results indicated that the adsorption of PCP onto Co3O4 NPs is endothermic and spontaneous under the tested conditions. Also, the equilibrium data were determined using the Freundlich (R2 = 0.997) and Langmuir isotherms (R2 = 0.5333), which illustrate that the adsorption process was multilayer on the Co3O4 nanoparticle surface. On the other hand, the kinetic data indicate that the adsorption process is related to the pseudo-first-order model (R2>0.9095).
Mahmood et al. (Thu,) studied this question.