Resource utilization of oak fruit peel as biomass waste for the synthesis of carbon with graphene oxide-like composition and its composite with Mg1−xCaxFe2O4 for Cd(ii) removal from water: characterization, magnetic properties, and potential adsorption study

• Published in: Environmental science water research & technology Vol. 10; no. 8; pp. 1920 - 1937
• Main Authors: Zohrabi, Younes, Mohammad Ebrahim Ghazi, Izadifard, Morteza, Valipour, Alireza, Sivasankaran Ayyaru
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 26.07.2024
• Subjects: Adsorption; Aqueous solutions; Biomass; Cadmium; Carbon dioxide; Cations; Cerium gadolinium oxides; Cobalt; Composition; Contaminants; Electrostatic properties; Fruits; Gels; Graphene; Heavy metals; Ion exchange; Iron; Kinetics; Lead; Magnetic properties; Metal ions; Nanocomposites; Resource utilization; Room temperature; Sol-gel processes; Wastewater; Wastewater treatment; Water pollution
• ISSN: 2053-1400; 2053-1419
• DOI: 10.1039/d4ew00059e

In this study, carbon with graphene oxide (GO)-like composition (CGO) was prepared from oak fruit peel (OFP) using a room-temperature method. CGO was decorated with sol–gel synthesized Mg1−xCaxFe2O4 (x = 0.2 (MCF2) and 0.8 (MCF8)) via a hydrothermal method to obtain CGO/MCF nanocomposites. The samples were characterized using XRD, RS, FTIR, FESEM, EDX, TEM, BET, and VSM analysis. CGO/MCF nanocomposites were assessed for their Cd2+ adsorption capacity from aqueous solutions via flame AAS. Factors such as contact time (1–60 min); nanocomposite dose (0.002–0.01 g); initial Cd2+ concentration (5–60 mg L−1); and coexisting ions of Pb2+, Co2+, and Ni2+ (10 mg L−1 each) at pH 7 were examined. The results indicated that the Cd2+ adsorption capacity of CGO/MCF2 (357.5 mg g−1) was higher (30%) than that of CGO/MCF8 (250 mg g−1) at a contact time of 1 h, nanocomposite dose of 0.002 g, and initial Cd2+ concentration of 60 mg L−1. The Cd2+ adsorption capacity of CGO/MCF nanocomposites was fitted with pseudo-second-order kinetics (R2 > 0.99) and the Langmuir isotherm (R2 > 0.99). The adsorption mechanisms involved pore filling, electrostatic attraction, surface complexation, ion exchange, and cation–π attraction. However, coexisting metal ions affected Cd2+ removal by CGO/MCF2, reducing the efficiency by 33%. Using wastewater from a plating metal restoration workshop, it was demonstrated that the CGO/MCF2 nanocomposite exhibits high removal efficiencies of 71% for Cd, 100% for Pb, 32% for Zn, and 28% for Fe. This study suggests that CGO prepared from green biomass of OFP, in combination with MCF2, can be a promising adsorbent for removing metal contaminants from water and wastewater.