Removal of phenol and formaldehyde from wastewater by adsorption in activated carbon

Abstract

The aim of this thesis, done on commission by Mirka Ltd., was to study the possibility to purify wastewater from a washing unit, to make it possible to circulate and to calculate the saving potential in terms of water usage of the Jeppo facility. The wastewater from the washing unit contains residuals of phenol-formaldehyde resin and a laboratory scale batch adsorption test was set up where the ad-sorption of phenol and formaldehyde onto two types of activated carbon was studied. In the analysis of phenol concentration, a spectrophotometric method was used and for the analysis of formaldehyde a titrimetric method.

The phenol adsorption achieved with the activated carbons were 12,4 % and 44,7 % at ambient tem-perature for 10 min while at adsorption for 60 min in 90 °C results of 94,0 % and 97,2 % phenol re-moval. An increase in temperature was found to be advantageous for the adsorption of phenol. The formaldehyde concentration in the samples analysed was found to be lower than that of untreated wastewater from the washing unit but not more specific due to the detection limit of the method used. The washing unit was found to be the source of a significant part of the discharge water of the Jeppo facility. The washing process would be a good candidate for piloting a circulating process using acti-vated carbon for purifying the process water. An alteration of the washing unit could reduce the water discharge by close to 20 %.