Method for recovering phosphorus in sewage through electrolytic process

Abstract

The invention discloses a method for recycling phosphorus in sewage through an electrolytic process. The method comprises the following specific steps that S1, an electrolytic tank is divided into an anode chamber and a cathode chamber through a proton exchange membrane; s2, a pure iron sheet serves as an electrolytic anode, and a high-conductivity carbon felt is adopted as a cathode; s3, introducing the phosphorus-containing wastewater into the anode chamber as anolyte, and introducing a sodium chloride solution into the cathode chamber as electrolyte; s4, introducing nitrogen into the anode chamber; s5, connecting the positive electrode with the iron anode and connecting the negative electrode with the cathode through an external power supply; s6, switching on a power supply, forming ferrous ions through directional flow of positive and negative electrons and anode electron loss, combining the ferrous ions with phosphorus in the solution to form blue iron ore, enabling protons to flow to the cathode through a proton exchange membrane, maintaining the pH value of an anode chamber, and forming stable current; and S7, phosphorus is recycled in a blue iron ore mode through an electrolytic method. The electrolysis device can stably operate through an external power supply, and phosphorus-containing wastewater with any concentration can be effectively removed by controlling current and voltage.

Description

technical field [0001] The invention relates to the technical field of water treatment, in particular to a method for recovering phosphorus in sewage by an electrolysis method. Background technique [0002] People first obtained phosphorus directly from guano phosphate deposits as phosphate fertilizers, and later developed other types of phosphate deposits in nature, which opened the prelude to the large-scale exploitation and utilization of phosphorus resources by humans. [0003] With the growth of population and the continuous improvement of human living standards, the society's demand for phosphorus is getting higher and higher. How to convert "phosphorus removal" in wastewater into "phosphorus reuse" has become the development trend of wastewater phosphorus removal. New green and environmentally friendly phosphorus resources Recycling technology needs to be explored urgently. [0004] The patent CN 110902781 A iron-air fuel cell can realize the effective removal of pho...

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Problems solved by technology

[0004] Patent CN 110902781 A Iron-air fuel cell can effectively remove phosphorus while generating electricity, but the disadvantage is that it is difficult to control the efficiency of phosphorus treatment. It can recycle phosphorus in the form of blue iron ore at a voltage of 1.2v, but in Under the condition of high phosphorus wastewater, the period of phosphorus removal is longer. At the same time, in low phosphorus wastewater, due to the limitation of anion and cation concentration, the open circuit voltage may be affected, and the expected removal effect cannot be achieved.

[0005] In addition, due to the metal dissolution characteristics of the cathode and anode of the primary battery device, it is easy to cause the concentration of certain ions in the cathode and anode and the membrane exchange area to be too high or too low, that is, concentration polarization occurs, which may affect Complexation of cyanite in solution, thereby reducing reaction efficiency

[0006] The phosphorus removal efficiency of iron-air fuel cells is slightly different due to the different phosphorus concentrations. Under the condition of high phosphorus wastewater, the phosphorus removal cycle is longer. At the same time, in low phosphorus wastewater, due to the limitation of anion and cation concentration, it may affect Open circuit voltage, can not achieve the expected removal effect

In addition, due to the unavoidable concentration polarization phenomenon of electrolysis reaction, the reaction rate may be reduced and the phosphorus removal period may be prolonged.

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