Removal of chlorinated hydrocarbons by means of direct electric current - a laboratory experiment

The direct current method of removing pollutants from the environment is an innovative and progressive remediation method. The use of electrokinetic phenomena enables the transport of pollutants and their degradation during electrolytic reactions. The goal of the work was to demonstrate the effectiveness of the innovative remediation method on a native groundwater sample from a model site. The site of interest, from which a native groundwater sample was taken and used for laboratory purposes, is located in the area of the former Calex plant in Zlate Moravce. The area is long-term polluted by petroleum substances and especially chlorinated hydrocarbons (ClU) originating primarily from the operational activities of the Calex plant (production of refrigerators) and laundries. Based on the processing of the experimental results, it can be concluded that the high efficiency of this remediation method in the degradation of ClU was confirmed. A higher efficiency of anodic degradation of 92.7 % was demonstrated, a lower efficiency of 88.12 % was achieved by cathodic degradation. A high and at the same time the greatest rate of ClU degradation was already observed at a voltage of 20 V. During the experiment, the anodic dissolution of the electrodes and the formation of white coatings (carbonates) on the cathode were observed. The formation of these carbonate coatings probably also resulted in a lower efficiency of ClU degradation in the cathode compartment. The method of removing organic pollutants through DC has its pros and cons. The advantages are its non-invasiveness to the environment, technical and financial ease of installation, while relatively affordable electrode materials such as iron or steel can also be used for effective degradation of ClU. The use of iron and steel electrode materials showed and confirmed their contribution to the efficiency of the ClU dechlorination method, which points to a great potential for their practical use. The disadvantage of using such electrodes can be considered the dissolution of the anodes (although the team probably increases the efficiency of the method due to the released iron), which will need to be changed regularly in practical use. (authors)