Veronika Priliana, Clarissa Sucitro, Ronald Wijaya, Valentino Bervia Lunardi, Shella Permatasari Santoso, Maria Yuliana, Chintya Gunarto, Artik Elisa Angkawijaya, Wenny Irawaty
Kaffir lime peels extract was used as an agent for the reduction of graphene oxide (GO) into reduced graphene oxide (rGO) via a simple room temperature-dispersion process. The GO obtained from the Hummers process is dispersed in polyphenols rich extract at a varied GO-to-extract ratio of 1:1, 1:2, 1:3, and 1:4. The formation of rGO was confirmed through SEM, FTIR, XPS, XRD, and N2 sorption characterization. The restoration of C=C group and the reduction of several oxygen-containing groups confirmed the successful formation of rGO from GO. The resultant rGOs were used in the adsorption system for methylene blue uptake. The results indicated that the rGOs prepared at a GO-to-extract ratio of 1:2 had the highest adsorption capacity than rGO at other ratios. The XPS spectrum analysis of rGO 1:2 showed a higher C-C/C-O ratio than the other rGOs, indicating a higher number of adsorption sites which aid in improving the adsorption performance. The adsorption isotherm and kinetic studies were conducted to gain insight into the mechanism and rate of methylene blue uptake by the rGOs. The adsorption isotherm systems were consistent with Langmuir isotherm model with the highest adsorption capacity of 118 mg g–1 by rGO 1:2. The kinetic adsorption data are well represented by the pseudo-second order model, the adsorption equilibrium was achieved within 400 min with the overall uptake rate of 0.3 mg g–1 min–1. © 2022 by the authors.
Chemical Engineering Department, Faculty of Engineering, Widya Mandala Surabaya Catholic University, East Java, Surabaya, 60114, Indonesia; Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan; Chemical Engineering Master Program, Widya Mandala Surabaya Catholic University, Dinoyo 48A, East Java, Surabaya, 60265, Indonesia; Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan