Researh On Preparation And Performance Of Anode For Electrocataytic Treatment Of Ship’s Ballast Water

The discharge of ship’s ballast water without treatment has made damage to the ecological environment and food chain in the emitted aquatorium. It has become one of contemporary topics to effectively, safely treat ballast water. Among the ship’s ballast water treatment field, the ruthenium coated titanium electrode has been one of extensively used electrodes. However, the imperfect service life of ruthenium coated titanium electrode has limited its practice.The sol-gel method was used to prepare ruthenium-titanium coated titanium electrodes and the doping of iridium was studied. Ru-Ir-Ti/Ti electrodes were characterized by some measurements including scan electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltemmetry (CV), total residual oxidant (TRO) tests, and current efficiency tests. It was found that the addition of iridium could effectively increase the accelerated service life from 5 h to 35 h and advance the difference between the oxygen evolution potential and chlorine evolution potential. Furthermore, the impacts of coating layer number on the electro-catalytic performance of Ru-Ir-Ti/Ti electrodes were investigated, and the optimal coating layer number, 30, was obtained. In the optimal coating layer condition, electrodes possessed the most active sites and most significant difference between chlorine evolution potential and oxygen evolution potential. Meanwhile, the accelerated service life increased to 138 h and current efficiency reached 73.99 %.The introduction of tin ions was investigated to improve the electro-catalytic activity and service life. The results showed that the accelerated service life was further increased to 175 h and that the potential difference of chlorine evolution and oxygen evolution reactions was advanced from 0.450 V to 0.550 V. Compared with the electrode without tin, the electrode modified with tin was suitable to the treatment of seawater and fresh water.On the basis of the above experimental results, the two-side electrode was studied with one side composed of the ruthenium-iridium-titanium sol and the other side of tin-antimony-iridium sol. It was found that the potential difference of the two-side electrode was further advanced from 0.550 V to 0.593 V. It also has ideal accelerated service life Through electrolyzing sodium chloride solutions with different concentrations, it was found that the two-side electrode was more suitable to treating seawater and fresh water than Ru-Ir-Ti/Ti electrode.