Mg/Fe-pyro-hydro char derived from corn cob as effective adsorbent of lead removal from aqueous solutions

The corn cob was investigated as available agrowaste material for the production of potential efficient material for heavy metals removal. The hydrothermal carbonization (HTC) technology is one of the appropriate methods for biomass transformation into high-value carbonaceous products than can be utilized as adsorbents. In this study, modified pyrohydrochar derived from corn cob (MCC) was effectively prepared by modification with Mg-Fe solution and pyrolysis. This material was used for Pb ions removal from aqueous solutions. The effect of solution pH, contact time and initial Pb concentration were examined in batch system. The achieved results revealed that the most effective Pb adsorption take place at pH 5. The experimental results were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. The best data fit was achieved with the Sips isotherm model with maximum adsorption capacity for Pb removal of 214.9 mg/g. Additionally, the experimentally results from kinetic study were fitted by pseudo-first and pseudo-second order models. According to kinetic parameters, the Pb removal using MCC follows pseudo-second order model, which assumes that chemical interaction between Pb ions and functional groups on the MCC surface was involved in metal adsorption. According to data from this investigation and in comparisons to other adsorbents can be concluded that investigated material can be used as potential suitable adsorbent of Pb from aqueous solutions.