EVALUATION OF INORGANIC CONTAMINANT REMOVAL FROM AQUEOUS SOLUTIONS USING PYROLIZED CHICKEN MANURE, CONIFER AND POPLAR WOOD AS ADSORBENT

Anthropogenic activities alter the natural flow of materials and introduce novel chemicals into the environment thereby causing serious soil and water pollution. Indeed, many industries produce aqueous effluents containing toxic substances, especially heavymetals. The presence of these contaminants in the environment is a great issue because of their toxicityand bioaccumulation ability which affect human life and the environment. Various physicochemical and biological techniques have been used to remove the heavy metals from waste waters, including chemical precipitation, ion exchange, chemical coagulation, electrolytic methods, membrane processes, and adsorption. Biochar is a carbonaceous material obtained from the pyrolysis of plant and animal biomasses. Due to its high porosity, it could be a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The aim of this work was the chemical-physical characterization of biochar produced from chicken manure (CM), conifers and poplar wood wastes in order to assess their ability in the removal of heavy metal from aqueous solutions. Chemical-physical characterization of the different CM chars was conducted by cross polarization magic angle spinning (CPMAS) 13 C NMR spectroscopy and NMR relaxometry together with a comparative study between the removal efficiencies of Cu(II), Ni(II) andPb(II) from synthetic wastewater by using adsorption onto biochars surfaces. From adsorption studies, it was observed that conifer biochar did not significantly adsorbed metals. This behavior is probably due to his own chemical characteristics, since it’s quite hydrophobic and probably its surface lacks functional groups able to bind ions. Conversely, chicken manure biochar proved to have the highest removal efficiencies for all the metals considered, in the order Pb(II)>Cu(II)>Ni(II) ions. In conclusion, different chars have different physicochemical characteristics so they should be addressed to different uses. For example, conifer char should not be used for remediation since it’s not effective in removing inorganic metals from aqueous solutions. The most effective in remediation was chicken manure biochar, probably thanks to the presence of nitrogen on its surface. In fact, nitrogen has a free electronic doublet/pair able to interact with cation. Finally, char metals absorption involves both a physical and a chemical mechanism and further studies should be addressed to explain it.