To tackle the problem of scaling and precipitation on titanium electrodes caused by concentration polarization, TOPTITECH offers several effective solutions that can eliminate or reduce scaling:
1. Utilize electrode inversion:
Regularly alternating the electrodes allows for a change in the migration direction of ions. The electrodes are typically exchanged every 2-8 hours, depending on the specific conditions. Automatic electrode exchanges have gained popularity, with intervals of approximately 15-30 minutes. This frequent inversion effectively removes any slight precipitation. However, it is crucial to select high-quality, corrosion-resistant electrode materials due to the demanding requirements and potential electrode loss associated with frequent reversals.
2. Employ pickling methods:
During electrodialysis operation, some scale may accumulate over time, especially in areas with poor water quality. Even with electrode exchanges, complete removal of the accumulated scale becomes challenging. In such cases, periodic pickling treatments offer a simple and effective solution without the need for equipment disassembly. The frequency of pickling depends on the specific situation. Typically, a cyclic cleaning using 1% to 2% hydrochloric acid is employed.
3. Implement current limitation:
Strategic control of the working current in electrodialysis is crucial to preventing polarization. By ensuring that the working current remains below the limiting current threshold, polarization can be avoided, thereby minimizing scaling issues.
4. Consider dismantling and washing as a last resort:
If scaling and fouling persist despite the aforementioned measures, thorough cleaning of the compartments and membranes becomes necessary. Disassembling the equipment allows for comprehensive washing and removal of internal fouling that could not be eliminated through other methods.
5. Strengthen raw water treatment:
To minimize sedimentation and scaling, it is essential to enhance the treatment of raw water. Removing suspended solids, colloidal substances, and organic impurities from natural water can effectively prevent or reduce scaling. Additionally, pretreatment methods can be employed to eliminate water hardness, which significantly contributes to scaling prevention.
