Iron-catalyzed synthesis of biowaste-derived magnetic carbonaceous materials for environmental remediation applications

Abstract

The conversion of biowastes to carbonaceous materials (CNMs) has received increasing attention in the context of environmental sustainability. Herein, we report the synthesis of magnetic CNMs from the waste biomass, palm kernel shell (PKS), together with iron salts using a combination of hydrothermal and pyrolysis processes for the first time. Specifically, the addition of FeSO4·7H2O and FeCl3·6H2O to PKS tends to produce iron carbide and iron oxides, which contribute to the catalytic conversion of biowastes to various CNMs. The outcome of adsorption experiments reveals that the simultaneous adsorption of p-nitrophenol (PNP) and Cu(II) onto magnetic CNMs is mainly controlled by the availability of surface adsorption sites and the occurrence of intra-particle diffusion. The synergistic adsorption of PNP and Cu(II) is found when the initial concentration of PNP is less than 20 mg/L. With the concentration of PNP exceeding 20 mg/L, the adsorption of Cu(II) is suppressed due to preferential adsorption of PNP onto magnetic CNMs. The spent magnetic CNMs can be easily recovered, regenerated and reused in their adsorption capacity. Our study outcomes provide a novel strategy to synthesize biowaste-derived magnetic CNMs for practical environmental remediation applications.