Titanium anode electrolytic seawater antifouling technology
The titanium anode electrolytic seawater antifouling technology is an innovative and effective means of marine antifouling. Its working principle is to utilize the electrolytic reaction of the titanium anode in seawater to produce substances with antifouling effects, thereby preventing the attachment and growth of marine organisms on the surfaces of ships, marine facilities, etc.
For example, applying this technology to the hull of ships can reduce the attachment of organisms such as barnacles and algae, reduce the resistance of ship navigation, save fuel consumption, and improve navigation efficiency. When used on facilities such as offshore oil platforms, it can extend the service life of the facilities and reduce maintenance costs.
This technology has the advantages of high efficiency, environmental protection, and durability. Compared with traditional chemical antifouling methods, it has less impact on the marine ecological environment and conforms to the requirements of sustainable development.
Electrolytic seawater antifouling is a method in which seawater is electrolyzed through specially designed electrodes. The chlorine and hypochlorite ions generated are strong oxidants, which are toxic to marine organisms and can kill them, achieving the purpose of preventing the attachment and growth of marine organisms. During the electrolysis of seawater, the following main reactions occur:
Anode reaction:
2Cl- → Cl2 + 2e
40H- → O2 + 2H2O + 4e
Cathode reaction: 2H2O + 2e → 2OH- + H2
The products of the anode and cathode are mixed to generate sodium hypochlorite:
C12 + 2NaOH → NaOCl + NaCl + H2O
The method of electrolyzing seawater to prevent fouling of seagoing vessels. Seawater contains 3% to 3.5% of salts. When direct current is applied, the seawater undergoes electrolysis, generating chlorine, hypochlorous acid, sodium chlorate, etc. They have a strong killing effect on organisms such as algae and shells attached to the ship’s hull. This can be used to keep the ship’s hull clean and prevent fouling.
Electrolytic Seawater Antifouling Technology
The prevention and removal of marine biological fouling is collectively referred to as electrolytic seawater antifouling. The harms caused by marine biological fouling include reducing the cross-sectional area of seawater supply and circulating water systems, increasing flow resistance, reducing flow rate; increasing the resistance of ships; accelerating the corrosion of metals; causing malfunctions of instruments and rotating mechanisms in the sea, etc. There are many methods to prevent marine biological fouling. Among them, the most widely used are the antifouling coating method and the seawater electrolysis method. The seawater electrolysis method has developed rapidly and been widely used due to its safety, economy, convenient management and no pollution to the environment.
Seawater electrolysis antifouling adopts coated titanium anode to electrolyze seawater under the condition of no diaphragm to produce available chlorine (HClO), and utilizes the strong oxidizing property of available chlorine to kill the larvae or spores of marine fouling organisms, thereby achieving the purpose of preventing fouling.
The reaction formula of seawater electrolysis is: Main reaction
Anode:
2Cl– → Cl2 + 2e
Cathode: 2H2O + 2e → H2+ 2OH–
Solution: Cl2 + H2O → HClO + Cl- + H+
HClO → H+ + ClO–
Side reaction
Anode: 6ClO–+ 3H2O → 2ClO3– + 4Cl– + 6H+ + 3/2O2 + 6e
2H2O → O2 + 4H+ + 4e
Cathode: ClO– + H2O + 2e → Cl– + 2OH–
Solution: HClO + ClO– → ClO3- + 2Cl– + 2H+
2ClO– → H2O + Cl–
H2 + ClO– → H2O + Cl–
Other reactions
Mg2+ + 2OH– → Mg(OH)2
Ca2+ + 2OH– → Ca(OH)2
To ensure the safe, continuous and efficient operation of the electrolytic antifouling device, it is necessary to suppress the side reactions that consume HClO needlessly, pay attention to hydrogen exhaust, and remove calcium and magnesium salt deposits by acid washing at a certain cycle.
In ship transportation, there are currently devices that adopt seawater electrolysis technology for ship antifouling. There are also technologies such as electrolytic chlorine-copper and electrolytic copper-aluminum for antifouling. The available chlorine generated by seawater electrolysis technology and copper ions work together to prevent the attachment of fouling organisms. In recent years, there has also emerged a combination of seawater electrolysis technology and antifouling coating technology. A layer of insulating coating is applied to the outer layer of the ship, followed by a conductive coating. The conductive coating is used as the anode to electrolyze seawater and generate available chlorine to achieve the purpose of antifouling. Seawater electrolysis technology has a broader application prospect due to its characteristics of safety, environmental protection, economy, applicability, and ease of operation and management.
