REMOVAL OF FORMALDEHYDE FROM AQUEOUS-SOLUTIONS VIA OXYGEN REDUCTION USING A RETICULATED VITREOUS CARBON CATHODE CELL

The removal of formaldehyde from waste streams to <0.3 ppm has been demonstrated using a cell with a reticulated vitreous carbon cathode; the formaldehyde is oxidized by hydrogen peroxide, formed at the cathode by reduction of oxygen. In most electrolytes studied (e.g. NaOH, NaCl and Na2SO4), the formaldehyde is oxidised only to formic acid. On the other hand, the addition of a low concentration of an iron salt (i.e. 0.5 mM), catalyses the complete oxidation to carbon dioxide. The removal of formaldehyde can be achieved in media of low ionic strength (<10 mM) although the use of iron salts necessitates the adjustment of pH to 3 to maintain the catalyst in solution.