Amine-modified silica surface applied as adsorbent in the phenol adsorption assisted by ultrasound

Phenolic compounds are toxic pollutants that are harmful to the human body and aquatic environments, with carcinogenic potential and frequently found in industrial effluents at high levels. Adsorption processes are often employed for the removal of these compounds. Mesoporous materials based on modified silica with amine have been used as adsorbents and can be considered promising for this job due to its high selectivity and better adsorption capacity when compared to materials without any modifications. In addition, adsorption studies can be performed using ultrasound as a mixing mechanism, improving mass transfer through cavitation and acoustic current. In this context, the goal of this study is to modify the surface of mesoporous silica with 3-aminopropyltriethoxysilane (APTES) and to evaluate its efficiency in the adsorption of phenol in an ultrasonic bath. In the phenol adsorption experiments, the Si-APTES showed higher adsorption capacity (12 mg g−1) than the SiO2 (2 mg g−1). The kinetic models of pseudo second-order have shown to be good fits to the experimental data. The adsorption equilibrium data of the phenol on the materials studied were best described in the Langmuir isotherm.