Preparation and Application of a Magnetic Oxidized Micro/Mesoporous Carbon with Efficient Adsorption for Cu(II) and Pb(II)

Abstract

Water pollution is a worldwide problem that requires urgent attention and prevention and exceeding use of heavy-metal ions is one of the most harmful factors, which poses a serious threat to human health and the ecological environment. In this work, a magnetic oxidized micro/mesoporous carbon (MOMMC) was prepared for the easy separation of Cu(II) and Pb(II) from water. The dual-template method was used to prepare micro/mesoporous carbon using sucrose as the carbon source, silica nanoparticles formed by tetraethyl orthosilicate as the microporous templates, and triblock copolymer F127 as the mesoporous template. MOMMC was obtained by oxidation using potassium persulfate and then magnetized through in situ synthesis of Fe3O4 nanoparticles. FTIR, TG-DSC, XRD, TEM, SEM, nitrogen adsorption–desorption isotherms, zeta potential, and VSM were used to confirm the synthetic process, structure, and basic properties of MOMMC. The high-saturation magnetization (59.6 emu·g−1) of MOMMC indicated its easy and fast separation from water by an external magnetic field. Kinetics studies showed that the adsorption of Cu(II) and Pb(II) on MOMMC fit the pseudo-second-order model well. Isotherm studies showed that the adsorption behavior of Cu(II) was better described by the Langmuir model, and the adsorption behavior of Pb(II) was better described by both Langmuir and Redlich–Peterson models. MOMMC obtained efficient adsorption for Cu(II) and Pb(II) with the large adsorption capacity of 877.19 and 943.40 mg·g−1 according to the Langmuir adsorption isotherm equation, and a better selectivity for Pb(II) was observed in competitive adsorption. MOMMC still possessed a large adsorption capacity for Cu(II) and Pb(II) after three adsorption–desorption cycles. These findings show that MOMMC represents an excellent adsorption material for the efficient removal of heavy-metal ions.