Aminopropyl-functionalized mesoporous carbon (APTMS-CMK-3) as effective phosphate adsorbent

Abstract

Abstract Excess phosphate discharge into water bodies can lead to severe eutrophication. Adsorption has been considered as one of the most effective approaches for phosphate removal and recovery. A new aminopropyl-functionalized mesoporous carbon CMK-3 (denoted as APTMS-CMK-3) was prepared and the materials were used as adsorbents for the removal of phosphate in water. The structure, functional groups and surface charge of the materials were characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption-desorption, elemental analysis, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and zeta potential measurements. The effects of contact time, initial phosphate concentration, solution pH, coexisting anions and dissolved humic acid were studied. The adsorption capacity of APTMS-CMK-3 was 38.09 mg g−1 at the equilibrium concentration of 49.06 mg L−1, and the adsorption data were well fitted with the Freundlich model. As for the reuse of APTMS-CMK-3, a relatively stable adsorption performance was observed after five adsorption-desorption cycles. Therefore, the way of grafting aminopropyl groups on the CMK-3 efficiently enhanced the capability for phosphate adsorption, indicating that it could be used as potential adsorbents for the removal of phosphate in water.