Which of the processes involve electrophoresis?

(1) Smokes and dust are solid aerosols. Removal of these particles from air involves the principle of electrophoresis. The air from a furnace or an industrial plant carrying these particles is passed between metal electrodes under high voltage. The particles are discharged and deposited as precipitates on the oppositely charged electrodes. (2) Rubber plating (for insulation) and chrome tanning of leather are based on electrophoresis.(3) Sewage water consists of particles of dirt, rubbish, mud etc, which are of colloidal dimensions and carry electric charge. On creating an electric field in the sewage tank, coagulation takes place a case of electrophoresis.(4) Reverse osmosis (RO) is the purification of water when there is osmosis in reverse direction. It is not based on electrophoresis.