Study on Fe(III) and Mn(II) modified activated carbons derived from Zizania latifolia to removal basic fuchsin

Zizania latifolia was prepared for activated carbons with the method of H3PO4 activation. On the basis of Zizania latifolia activated carbons (ZLAC), adsorption of basic fuchsin (BF) on Fe(III) and Mn(II) modified ZLAC and ZLAC was investigated respectively. Surface morphology and function groups of ZLAC were measured by scanning electron microscopy (SEM), BET surface area and Fourier transform infrared spectroscopy (FTIR). Both of the results from the Fourier transform infrared spectroscopy and Boehm's titration indicated that the ZLAC owned more acid oxygen functional groups than the alkaline functional groups. The discussions of contact time, dosage and pH were in favor for explaining the adsorption mechanism. The adsorption process agreed well with the pseudo-second-order kinetics (R2 > 0.99) and the Langmuir isotherm equation (R2 > 0.99), and the maximum adsorption capacity acquired can reach 238.10 mg/g. The negative free energy (ΔG) and positive enthalpy (ΔH) indicated a spontaneous and endothermic adsorption process. Results also showed that the adsorption effect of Fe(III) and Mn(II) modified ZLAC was much better than ZLAC.

► Zizania latifolia is used to prepare the activated carbon as the precursor.
► The original and modified carbons were used to adsorb the basic fuchsin.
► We correlate the properties of carbons with the ability to adsorb basic fuchsin.
► The maximum adsorption capacity of ZLAC-Mn increased by 102.96 mg/g than ZLAC.