Lakningsförsök med furubarksflis
en utredning om utsläpp av fenolföreningar samt metallsorption
Pine barkPhenolFilter materialsLeachingMetal sorptionToxicityFurubarksflisFenolFiltermaterialLakningMetallsorptionToxicitet
The filters used today to purify water are often expensive and the need to find new filter materials is substantial. Studies of pine bark have shown that this is a material that may be used as an alternative to conventional filter materials, such as activated carbon. However, the study of pine bark has shown that a leakage of phenolic compounds may occur when using the material for water purification. Therefore, the purpose of this report is to investigate the release of phenols from pine bark, in order to evaluate the use of pine bark as a filter material. Another assignment is to investigate the amount of metals adsorbed by the filter material. The studies were carried out through three leaching experiments. As leachates, double deionised water and storm water were used. The phenol concentration in the leachate was determined for both double deionised water and storm water. The degree of metal sorption was measured only for the storm water. The measured phenol concentration in the double deionised water was 4.40 mg/L and in the storm water 4.81 mg/L. These concentrations exceed the Canadian guideline value, of 4.0 ?g/L, more than a 1000 times. No metal sorption occurred as the metal content of the storm water was too low. Instead a release of metals from the pine bark into the eluate of the storm water occurred. The leaching attempts also resulted in a decline of the pH-values of the two different waters. The pH-values for the double deionised water and the storm water decreased from 7.0 to 4.3 and from 6.0 to 4.2 respectively. A release of phenols was ascertained with a significant difference in concentrations between double deionised water and storm water. Therefore it is not advisable to use pine bark filters for purification of water with low concentrations of metals, as the filter material may release metals into the water under such conditions.Keywords: pine bark, phenol, filter materials, leaching, metal sorption, toxicityNyckelord: furubarksflis, fenol, filtermaterial, lakning, metallsorption, toxicitet