Electrocombustion of humic acid and removal of algae from aqueous solutions

Abstract

This paper reports experiments involving the electrochemical combustion of humic acid (HA) and removal of algae from pond water. An electrochemical flow reactor with a boron-doped diamond film anode was used and constant current experiments were conducted in batch recirculation mode. The mass transfer characteristics of the electrochemical device were determined by voltammetric experiments in the potential region of water stability, followed by a controlled current experiment in the potential region of oxygen evolution. The average mass transfer coefficient was 5.2 × 10⁻⁵ m s⁻¹. The pond water was then processed to remove HA and algae in the conditions in which the reaction combustion occurred under mass transfer control. To this end, the mass transfer coefficient was used to estimate the initial limiting current density applied in the electrolytic experiments. As expected, all the parameters analyzed here—solution absorbance at 270 nm, total phenol concentration and total organic carbon concentration—decayed according to first-order kinetics. Since the diamond film anode successfully incinerated organic matter, the electrochemical system proved to be predictable and programmable.