Removal of Bisphenol A and Methylene Blue by <i>&#x3b1;</i>-MnO₂ Nanorods: Impact of Ultrasonication, Mechanism, Isotherm, and Kinetic Models

Abstract

This study will investigate the applicability of α-MnO2 nanorods, green synthesized using sugarcane juice for the treatment of toxicants in wastewater; Bisphenol A (BPA) and methylene blue (MB). Analysis of parameters that influence adsorption, such as pH, adsorbent dose, concentration of pollutant, contact time, temperature, humic acid (HA), ionic strength, ultrasound frequency, and power will be performed. Treatment results for silent (86.1%, 97.54%) and ultrasonic assisted (36.52%, 94.98%) adsorption of BPA and MB respectively, will be obtained at optimum conditions. The impact of ultrasonication and mechanisms that control adsorption will be assessed. Improved results (BPA: 36.52% to 81.2%) under ultrasonic assisted coadsorption might be due to hydrophobic interactions. Among various isotherms and kinetic models, the Langmuir isotherm and pseudo-second-order kinetic model showed the best correlation for both water contaminants. The growth mechanism of α-MnO2 nanorods is explained using LaMer's theory. The adsorbent characterization will be performed using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunaeur-Emmet-Teller (BET), X-ray photoelectron spectroscopy (XPS), and Fourier Transform Infrared (FTIR) spectroscopy. The results suggest α-MnO2 nanorods are a potential nanomaterial for the adsorption of persistent micropollutants and dyes.