Efficiency of biochars in the removal of heavy metals

Abstract

Toxic metals are naturally present in the environment even if there is no anthropic action. Several methods are used for the removal of these metals from water and effluents, such as: chemical precipitation, oxidation/reduction, filtration, ion exchange, membrane separation, and adsorption. Biosorption stands out as an effective treatment because it has a high rate of renewal in nature, low production costs, and high removal of metals due to the possibility of recovery of the contaminant, either by incinerating the biomass or by desorbing it. Thus, this study identified some biochars used as adsorbents for the removal of  copper, lead, chromium, and mercury in water. It can be concluded from this study that adsorption is a very efficient technique for removing or recovering heavy metals from the environment. These biocarbons are alternatives that can replace commercial activated carbon because, besides having a low production cost, they have been shown to efficiently remove metal ions, ensuring an effective treatment in compliance with effluent release standards.