Rice Straw as Green Waste in a HTiO2@AC/SiO2 Nanocomposite Synthesized as an Adsorbent and Photocatalytic Material for Chlorpyrifos Removal from Aqueous Solution

A nano-HTiO2@activated carbon-amorphous silica nanocomposite catalyst (HTiO2@AC/SiO2) is utilized to photo breakdown catalytically and adsorb chlorpyrifos insecticide. SEM, TEM, and X-ray diffraction were used to examine HTiO2@AC/SiO2, synthesized through sol-gel synthesis. With an average size of 7-9 nm, the crystallized form of HTiO2 is the most common form found. At varied pH, catalyst doses, agitation speed, initial pesticide concentrations, contact periods, and temperatures, HTiO2@AC/SiO2 was examined for efficiency under visible light and in darkness. Because of the pseudo-second-order kinetics observed for chlorpyrifos, chemisorption is believed to dominate the adsorption process, as indicated by an estimated activation energy of 182.769 kJ/mol, which indicates that chemisorption dominates the adsorption process in this study. The maximal adsorption capacity of chlorpyrifos is 462.6 mg g(-1), according to the Langmuir isotherms, which infer this value. When exposed to visible light, the adsorption capacity of HTiO2@AC/SiO2 increased somewhat as the temperature rose (283 k 323 k 373 k), indicating an exothermic change in Gibbs free energy during the process (-1.8 kJ/mol), enthalpy change (-6.02 kJ/mol), and entropy change (0.014 J/mol K), respectively, at 298.15 K. Negative (Delta S) describes a process with decreased unpredictability and suggests spontaneous adsorption. HTiO2@AC/SiO2 may be a promising material.

Automated summary

A nano-HTiO2@activated carbon-amorphous silica nanocomposite catalyst (HTiO2@AC/SiO2) was used for photocatalytic breakdown and adsorption of chlorpyrifos insecticide. The study showed that chemisorption dominated the adsorption process, and HTiO2@AC/SiO2 exhibited good adsorption performance and thermodynamic properties.