STUDIES ON THE PREPARATION AND CHARACTERIZATION OF METAL-DOPED BIOCHAR

Abstract

The physicochemical properties of groundnut husk biochar: pH, 6.90, bulk density (g.cm-3) 0.39 ± 0.02, cation exchange capacity (mmol.kg-1) 42.50 ± 1.36, electrical conductivity (ms.cm-1) 3.83 ± 0.14 and proximate composition (wt %), moisture content 24.53 ± 1.01, ash content 4.76 ± 0.08: volatile matter 57.48 ± 1.24 and fixed carbon 4.93 ± 0.06 indicated that the surface chemistry could retain nutrient elements relevant to agronomic benefits. The proximate composition was used following the to the Parikh et al. and Klasson equations to deduce the ultimate composition (wt%), C 29.30 and 31.31; H 3.72 and 4.92 and O 28.86 and 27.33, respectively for groundnut husk biochar and the allowed values of H/C 0.13 and 1.57, and O/C 3.72 and 4.92 respectively to obtained for the biochar. These values a degree of recalcitrant and stability of the groundnut husk biochar to degradation. The FTIR spectrum of the metal-doped biochar revealed absorption band at 550 cm-1 which was absent in the spectrum of the unmodified biochar. The elemental oxygen contents of the metal-doped biochar obtained for EDX was markedly higher than in the unmodified biochar; while the elemental carbon in the unmodified biochar (89.56%) was markedly higher than the level 43.20% in the modified biochar. The specific surface area of the iron-doped biochar (5.06 m2.g-1) was found to be markedly lower than that of the unmodified biochar 110.09 m2.g-1. The porous structures, pore diameter (nm) and pore volume (cm3) of the iron-doped 10.28 and 0.09 where markedly higher than the corresponding value of 1.67 and 0.02 for the unmodified biochar.