Purification of industrial wastewater using a photoelectroflotation process powered by solar energy

Abstract

The main problem of all existing electroflotation methods of wastewater treatment is salinization of the near-anode space during electroflotation, which leads to the formation of salt deposits on the anode, which strongly cover the anode surface, which can lead to a complete stop of the electroflotation process. The anode, used by electroflotation devices has a dense grid of small cells, which, on the one hand, increases the current density, but, on the other hand, sharply reduces the passage of electrolytic bubbles through it and, consequently, the number of electrolytic bubbles that stimulate the electroflotation process.In critical cases, the salt can close the mesh and generally block the exit of bubbles through the mesh. Another disadvantage of the wastewater treatment process is the misuse of the type of gas bubbles, generated in the electroflotation process. The above problems and disadvantage of all existing electroflotation methods of wastewater treatment were eliminated by the author in the developed method of photoelectroflotation and the built complex: photoelectrolyzer + flotation cell for industrial wastewater treatment. The article presents the use of a new developed method of photoelectroflotation and the built complex: a photoelectrolyzer + a flotation cell for industrial wastewater treatment using the effect of solar energy on a silicon semiconductor with a non-aggressive attached mesh anode, generating a potential difference between the mesh anode and the cathode, located at the bottom part of the photoelectrolysis cell, which contributes to the electrolysis of water, resulting in the formation of electrolytic hydrogen bubbles on the cathode with a calculated dispersion, allowing complete wastewater treatment in a separate flotation chamber. The photoelectrolyzer has a specially designed electrolysis base, including a fire hose material membrane, located between a silicon semiconductor with an attached mesh anode and a burnt graphite cathode, which prevents the penetration of electrolytic oxygen bubbles into the near-cathode zone, which are formed as a result of the splitting of a water molecule under the action of two photons of light on a silicon semiconductor into half an oxygen molecule and into full oxygen molecule as a result of the electrolysis of water, which occurs due to the potential difference, formed during this action, between the grid anode and the cathode, and OH-hydroxyls, also formed as a result of the electrolysis of water; mechanism for adjusting the interelectrode gap. The developed electrolysis base is located in the lower part of the photoelectrolyzer