Application of Fe-Impregnated Biochar from Cattle Manure for Removing Pentavalent Antimony from Aqueous Solution

Abstract

This study assessed the applicability of Fe-impregnated biochar derived from cattle manure (Fe-CMB) as an adsorbent for removing Sb(V) from aqueous solutions and investigated the Sb(V) adsorption mechanism. Fe-CMB was mainly composed of C, O, Cl, Fe, Ca, and P, and the adsorption of Sb(V) onto Fe-CMB was identified using an energy dispersive spectrometer and Fourier transform infrared spectroscopy. Sb(V) adsorption reached equilibrium within 6 h, and the Sb(V) adsorption data as a function of time were well described by the pseudo-second-order model. The Langmuir isotherm model fit the equilibrium data better than the Freundlich model. The maximum adsorption capacity of Fe-CMB for Sb(V) obtained from the Langmuir model was 58.3 mg/g. Thermodynamic analysis of Sb(V) adsorption by Fe-CMB indicated that the adsorption process was exothermic and spontaneous. The Sb(V) removal percentage increased with the Fe-CMB dose, which achieved a removal of 98.5% at 10.0 g/L Fe-CMB. Increasing the solution pH from 3 to 11 slightly reduced Sb(V) adsorption by 6.5%. The inhibitory effect of anions on Sb(V) adsorption followed the order: Cl− ≈ NO3− 42− 3− 43−.

Keywords

• antimony
• biochar
• cattle manure
• removal
• adsorption
• Fe impregnation