The surface composition of different colloidal particles varies. Some of them can attract positive charges, while others can attract negative charges. So some colloidal particles carry positive charges, such as aluminum hydroxide colloids. Some colloidal particles carry negative charges, such as arsenic disulfide (As2S3) colloids. If a direct current is applied to the colloid, they either migrate towards the anode or towards the cathode. This is the so-called electrophoresis phenomenon.

In the smoke of a blast furnace, carbon black and dust often appear in the form of colloidal particles and carry electric charges. If a high-voltage electrode is installed on the chimney, it can absorb negatively charged colloidal particles and deposit them. This not only allows for the recovery of valuable products, but also reduces air pollution.