Mechanisms Of Electrolytic Inhibition Of Algae By Lowamperage Electric Current

Protecting lakes and controlling algae bloom are the important subjects at home and abroad. Previous research has shown that micro-current electrolytic method, as a kind of electrochemical technology, can use the direct oxidation of electrode and the indirect oxidation of active material produced by electrolysis to effectively inhibit the growth of algae in water, influencing little on other components in water without causing secondary pollution. This paper adopts the micro-current electrolytic method to effectively inhibit the growth of Microcystis aeruginosa; first, it explores the optimum condition of effective algal inhibition, and then studies the influence of electrolysis on physic-ecological characteristics of algal cell and the algal inhibition efficiency of electrolytic indirect oxidation, explaining the detailed mechanism of electrolytic algal inhibition from several angles. The main research conclusions are as follows:(1) Compare the difference of electrolytic algal inhibition under different electrode material combination. The result shows that anode material has great influence on the electrolytic algal inhibition, cathode material has little effect on that, then choose the ruthenium-titanium and stainless steel as the anode and cathode materials respectively. On this basis, explore the main influence factors of electrolytic algal inhibition.It is shown that the increase of CaCl2 concentration, current density and electrolytic time can help improve the algal inhibition ability of micro-current electrolysis within a certain range, but the increase of the concentration of Na2CO3 and MgSO4 can inhibit electrolytic algal inhibition to some extent. The study finds that adopting BG-11 medium to make 100 ml solution of Microcystis aeruginosa with the initial cell density of 5×105 /mL, using ruthenium-titanium and stainless steel as the anode and cathode materials and conducting electrolytic treatment with current density of 10mA/cm2 for 15 min can continuously inhibit algal cells.(2) Study the change of chlorophyll fluorescence parameters of Microcystis aeruginosa under different current density, and reveal the functional mechanism of electrolytic algal inhibition from the perspective of ecological and physiological characteristics. The study indicates that for the solution of algae under a certain condition, there is corresponding critical current threshold in algal inhibition. When the current density is less than the critical value, the electrolysis force will not exceed algal cells’ endurance ability, and the solution of algae can restore the photosynthetic activity in the later culture. But if the current density is greater than the critical value, the electrolysis force will exceed algal cells’ endurance ability; electrolytic will destroy the structure of photosynthetic system II and block the connection between it and phycobilisome, making photosynthesis impossible, eventually leading to the deaths of algal cells.(3) At first, verify the algal inhibition ability of active material from the perspective of electrolytic indirect oxidation. The result shows that enough active material has good inhibitory effect for Microcystis aeruginosa and can keep damaged algal cells from repair themselves. Furthermore, explore the algal inhibition ability of indirect oxidation under different conditions. It is found that the increase of Cl- concentration, current density and electrolytic time can help improve the algal inhibition ability of micro-current electrolysis indirect oxidation within a certain range.(4) Measure and compare the electrolytic production of active chlorine and hydrogen peroxide in active material, find that under different current density, electrolytic time or Cl- concentration, the change rule of algal inhibiting efficiency of active material keeps consistent in that of electrolytic production of active chlorine, but different from the hydrogen peroxide production. On this basis, compare the growth conditions of algae with or without certain kinds of active material, find that both active chlorine and hydrogen peroxide have certain algal inhibiting capacity, but the algal inhibiting capacity of active chlorine is slightly higher than that of hydrogen peroxide. Active chlorine plays a leading role in algal inhibition of active material.