The visible-light photodegradation of nonylphenol in the presence of carbon-doped TiO2 with rutile/anatase ratio coated on GAC: Effect of parameters and degradation mechanism

Nonylphenol (NP) is a non-biodegradable compound with harmful effects on the endocrine system. The removal of NP in solution was investigated using visible light active carbon-doped TiO2 (CDT) with anatase/ruble. (A/R) ratio and immobilized on the surface of granular activated carbon (GAC). The physicochemical characteristics of synthesized samples were determined in detail by means of XRD, SEM-EDX, TEM, BET, and UV-vis absorption spectra. The results showed the incorporation of C into TiO2 lattice and the identified A/R ratio of 53.06/46.94 can enhance the visible light utilization. It was observed that the band gap decreased from 3.17 eV to 2.72 eV after C doping, and to 2.66 eV by changing the calcination temperature from 475 degrees C to 600 degrees C. The maximum removal of NP was observed at pH of 9.5, initial NP concentration of 4 mg L-1, and optimal carrier dosage of 0.22 g in 0.1 L-1. The obtained findings showed that the scavenging agents compete with NP species for the center dot OH, h(+) and O center dot(-)(2) oxidizing species. The experimental data of photo catalytic degradation of NP using CDT (A/R)/GAC had highest correlation with Langmuir-Hinshelwood model and pseudo-first order kinetics and t(1/2). Based on LC-MS analysis, the possible NP decomposition pathway was proposed.