The application of titanium wire in fixed-position marine fishing nets

The fixed-position fishing nets used in marine aquaculture, after coming into contact with organic matter and bacteria, will cause the proliferation of diatoms. The bivalves, barnacles, and other marine organisms that feed on diatoms will gather and attach to the nets. This not only leads to increased flow resistance and damage to the nets, but also causes oxygen deficiency infections and other problems that affect the growth of fish. Therefore, inhibitors and bactericides are generally used, but in this case, the service life of the fixed-position nets does not exceed 20 years. Moreover, in order to remove the attached microorganisms, the nets must be pulled ashore for mechanical removal, which leads to increased labor costs and deterioration of the nets. Researchers at the University of Tokyo studied the process of weaving titanium wires into existing polyethylene (PE) fishing nets, applying electricity to generate chlorine gas and C10_ near the titanium wires, thereby achieving the effect of sterilization and inhibiting bacterial proliferation. First, a net made of platinum-plated titanium wires with a diameter of 1mm was used as the anode, and a 312L stainless steel plate was used as the cathode for an electrolysis test. The results showed that after being placed in seawater for 14 days with a voltage of 3.0V, the weight of the titanium net did not change, while the un-electrified titanium net was covered with marine organisms. Then, the net weaving research was conducted, mainly focusing on the matching of the strength and elongation rate of the titanium wire and the PE thread. The existing fishing nets are made by twisting 10 PE single threads into a composite thread, and then twisting 2 composite threads into a twisted thread for weaving. The titanium net studied was made by twisting 10 PE single threads and 1 titanium wire into a composite thread, and then twisting 2 composite threads into a twisted thread for weaving. Different diameter titanium wires (0.10mm, <f>0.25mm, <0.50mm) and F*E threads of single wires, composite threads, and twisted threads were subjected to tensile tests. The results showed that the elongation rate of the titanium wire was smaller than that of the PE thread, especially for the 0.10mm titanium wire. The titanium wire in the titanium composite thread and the surrounding PE simultaneously broke, and the titanium wire in the titanium twisted thread (>0.25mm) also broke simultaneously with the surrounding PE. This indicates that the fishing nets with the woven titanium wire have the same strength as the existing polyethylene thread-woven fishing nets. The researchers estimated that the amount of titanium wire required for tuna aquaculture nets in the Japanese market is 350, and thus the estimated length of titanium wire is approximately 283km. This is the current scale, and the aquaculture industry will continue to develop in the future. The length of titanium wire required for each aquaculture net is 80.43m. Including both the domestic market in Japan and the markets outside Japan, it can be seen that the market is very large.