The figure below represents biochar at the molecular level as formed at relatively low temperature. a) Identify the types of oxygen functional groups. b) What would be the expected pH of an aqueous suspension of this material? (provide justification for your answer by reaction or equation) c) Sketch a graph to illustrate the zeta potential dependence upon pH, marking (as best estimate) the point of zero charge (pZc). d) What effect would adding a high concentration of A13+ ions have if added HOOC (e.g. as a dissociating salt) to the O AO suspension? e) Suggest a process for formation of biochar. OH OH HOOC 0 OH HO COOH BV HOOC COOH