Acrylic acid functionalized graphene oxide: High-efficient removal of cationic dyes from wastewater and exploration on adsorption mechanism. (December 2020) - Wang, Guanglin
Abstract: A novel p(AA)-g-GO material was prepared by grafting polymerization of acrylic acid (AA) onto graphene oxide (GO) skeleton, presenting efficient removal of dyes from wastewater, because the layer spacing of GO is expanded and successfully introduced numerous polar carboxyl groups. The study revealed a rapid adsorption kinetic process and the adsorption capacity for methylene blue (MB) increases with pH, contact time, initial dye concentration and temperature. The maximum adsorption capacity is about 1448.2 mg/g at 25 °C for MB according to the Langmuir isotherm. More importantly, the adsorbent maintains excellent adsorption capacity after five cycles of adsorption-desorption and has remarkable selective separability for methylene blue/methyl orange mixed solution at pH = 10. Furthermore, the equilibrium adsorption capacities for other cationic dyes as malachite green (MG), basic fuchsin (BF) and rhodamine B (RhB) reached 582.1, 571.7 and 437.1 mg/g, respectively. Additionally, the mechanism analysis indicated that electrostatic interactions, π-π conjugation and hydrogen bonding are the predominant forces for adsorbing cationic dyes. Therefore, p(AA)-g-GO is an outstanding adsorbent and has a potential application prospect in the treatment of dye wastewater. Graphical abstract: Image 1 Highlights: A series of p (AA)-g-GO was synthesized by grafting acrylic acid onto GO surface. The adsorption performance and mechanism of different cationic dyes were studied. P (AA)-g-GO maintained high removal efficiency for MB dye after five recycling. The material has excellent selective separation effect for MB/MO mixed solution. The uptake capacity of MB, MG, BF and RhB was 634.2, 582.1, 571.7 and 437.1 mg/g.