Humic Acids Derived from Lignocellulosic Biomass: Characterization and Utilizing for Environmental Applications

Abstract

The goal of this research is to evaluate waste lignocellulosic materials for the production humic acid (HA) as a natural, low-cost, and effective adsorbent for heavy metals (Ni, Cr, and Cu) removal from aqueous medium. The fourier transform infrared (FTIR) spectroscopy, fluoresence spectroscopy, LC-ESI-TOF/MS, and stable carbon isotopes analysis were applied to compare the chemical structure of humic acids obtained from wheat straw (C3) and corn straw (C4). The adsorption efficiency of humic acids obtained from different lignocellulosic sources was investigated and compared to the commercial HA. The adsorption efficiency for Cu ions was almost 70% and the metal adsorption capacity of corn-HA is remarkably higher than commercial HA. Ni ions exhibited the lowest adsorption percentage for which the removal reached 21.0% with corn-HA. This work showed that lignocellulosic-derived humic acids are suitable adsorbent for heavy metals and can be used for cleaning of waters or other systems with low concentrations of metal ions.