Batch sorption–desorption of As(III) from waste water by magnetic palm kernel shell activated carbon using optimized Box–Behnken design

In this study, we converted activated carbon (AC) into magnetic activated carbon (MAC), which was established to have removed arsenic (III) from wastewater. Arsenic (III) is a toxic heavy metal which is readily soluble in water and can be detrimental to human health. The MAC was prepared by incorporating Fe3O4 into the AC by using Fe3O4 extracted from a ferrous sulfate solution, designated: magnetic palm kernel shell from iron suspension (MPKSF). Batch experiments were conducted using two methods: (1) one-factor-at-a-time and (2) Box–Behnken statistical analysis. Results showed that the optimum conditions resulted in 95% of As(III) removal in the wastewater sample. The adsorption data were best fitted to the Langmuir isotherm. The adsorption of As(III) onto the MPKSF was confirmed by energy dispersive X-ray spectrometry analysis which detected the presence of As(III) of 0.52% on the surface of the MPKSF. The Fourier transform infrared spectroscopy analysis of the MPKSF–As presented a peak at 573 cm−1, which was assigned to M–O (metal–oxygen) bending, indicating the coordination of As(III) with oxygen through the formation of inner-sphere complexation, thereby indicating a covalent bonding between the MPKSF functional groups and As(III). The findings suggested that the MPKSF exhibited a strong capacity to efficiently remove As(III) from wastewater, while the desorption studies showed that the As(III) was rigidly bound to the MPKSF thereby eliminating the possibility of secondary pollution. © 2017, The Author(s).