Researchers from the "CoAct" project have produced activated carbons from leaves and other residual biomass. TZW's investigations have demonstrated the thoroughly satisfactory performance of the activated carbons for the removal of trace substances from wastewater.
In order to be able to evaluate the activated carbons and their production conditions in a first step for use in the elimination of trace substances in wastewater, they were initially characterised using simple, inexpensive methods such as the iodine and methylene blue number and the reduction of the spectral absorption coefficient at 254 nm (SAK-254) in wastewater samples with different activated carbon additions. This allowed conclusions to be drawn about the parameters during carbon production and activation and the production parameters to be optimised.
In the next step, CoAct activated carbons were analysed for their ability to remove trace substances from wastewater. For the evaluation, the CoAct carbons were compared with two commercially available powdered activated carbons. While the inner surfaces of the CoAct activated carbons showed lower values for all activated carbons produced from the residual biomass than the commercially available powdered activated carbons, very good results were achieved in the actual (average) removal performance for organic micropollutants (OMP) present in the wastewater from the treated wastewater.
For example, activated carbons made from maize straw and wood pellets removed organic micropollutants extremely well. The other CoAct activated carbons adsorb smaller quantities of the unwanted OMP from the wastewater.
These laboratory tests and the comparison with commercially available powdered activated carbons show that activated carbons were produced within the CoAct project that are competitive in terms of their adsorption properties for organic micropollutants.
In addition, the purity of the carbons with regard to heavy metals, polycyclic aromatic hydrocarbons (PAHs) and cyanide was analysed and classified as sufficiently good for safe use in the wastewater sector.
