A novel Fe-containing carbon foam with hierarchical porous structure for efficient removal of organic dyes

Abstract

A novel Fe-containing carbon foam (Fe-CF) was achieved with a hierarchical porous structure by carbonization of nano‑magnesium oxide/epoxy resin mixture followed by Fe(NO3)3 activation. The structures and properties of as-prepared Fe-CF were characterized via XRD, compression strength test, FESEM, TEM, BET, Raman and XPS, meanwhile the effects of adsorption conditions on the removal performance of Congo red (CR), Malachite green (MG) and Methylene blue (MB) by the Fe-CF are investigated through batch adsorption experiments. Results show that the Fe-CF obtained at 1000 °C possesses a fluffy and porous structure without obvious collapse and closure, and the iron oxide particles are evenly distributed on its surface, which endows it with high adsorption capacities for CR (1263.36 mg g−1), MG (679.84 mg g−1) and MB (483.66 mg g−1) at the optimum conditions, respectively. Furthermore, the adsorption process can be depicted well by the Langmuir and pseudo-second-order models, and the thermodynamic analysis results reflect that the adsorption processes are thermodynamically feasible and spontaneous. More importantly, the prepared adsorbent retains relatively high adsorption ability and stability even after five regeneration cycles.