Studies On The Inhibited Effects Of Paeonol And Four Types Of Microstructure Silica Gel On Navicula Minima

The traditional antifouling methods do harm to the surroundings and they are adverse to the sustainable development of the ecosystem. Therefore, it is urgent to explore new antifouling methods that are environmental friendly. In the future, this measure will do benefit to the society.The new antifouling methods include adding natural antifouling products to the paints, synthesizing new materials able to preventing the attachment of the antifouling creatures and making bionic microstructures on some material with low energy. This paper mainly studied the antifouling performance of paeonol and four types of microstructure silica gel on Navicula minima. The probable antifouling mechanism were also inferred.Paeonol was a natural product extracted from the root bark of peony. In the inhibited effect test, copper sulfate was as control medicine. The influence of paeonol to the attachment and growth of Navicula minima were also studied. The concentration of paeonol were 0, 1, 10, 20, 30, 40, 50, 60, 120, 240 and 300 mg/L, respectively. While the concentration of copper sulfate were 0, 10, 50, 100, 120, 240, 300, 400, 500, 600 and 800 mg/L, respectively. The inhibition ratio was tested when the time of the attachment was 72 hours. The results showed that the inhibition ratio of paeonol and copper sulfate increased when the concentrate became larger. The inhibition ratio of paeonol surpassed 50% once its concentrate was 40 mg/L; The inhibition ratio of copper sulfate surpassed 50% once its concentrate was 100 mg/L. In summary, the antifouling performance of paeonol was better.The concentration of paeonol were 0, 50, 200, 400 and 600 mg/L, respectively in the growth test of paeonol. While the the concentration of copper sulfate were 0, 10, 50, 100, 120, 240, 300, 400, 500, 600 and 800 mg/L, respectively. The influence of paeonol and copper sulfate were recorded in 96 hours. The index were the growth concentrate, the chlorophyll-a and the EC50. The results showed that the lager the concentrate were, the smaller the growth concentration. The EC50 of the paeonol and the copper sulfate were 180.708 mg/L and 121.91 mg/L, respectively. The difference of chlorophyll-a contents in the 0 hour and 96 hours were obvious(P<0.01) when the concentration of paeonol and copper sulfate were 400-600 mg/L and 200-300 mg/L, respectively. Therefore, paeonol was not only effectively deterring the attachment of Navicula minima, but also environmental friendly.And then the influence of paeonol on the cellular activity was studied by Alternating Current Scanning Electrochemical Microscope(AC-SECM) and Laser Scanning Confocal Microscope(LSCM). The fluorescence activity was weaker after the diatoms were immersed in the paeonol solution. In the AC-SECM test, we applied AC-SECM to measure the electrochemical activity of diatom biofilm. We found that the diatom biofilm presented insulating effect to decrease the current, when the electrode was close to the biofilm. The alternating current impedance of diatom biofilm was overall smaller than that of the bare glass. To investigate the possible effect of chemical stimulus on cellular activity, the diatoms were immersed into paeonol solution(200 μg/m L-1), and AC-SECM imaging experiments were conducted when immersion time reached 20 h, 25 h and 35 h. The AC measurements performed at high frequencies showed that phase angle decreases over time, which preliminarily indicates that the cellular activity of diatoms was affected by paeonol. The inhibited effect of paeonol may have relation with its property of blocking calcium.In addition, this paper also study the inhibited effects of four types of microstructure silica gel on Navicula minima in statistic and dynamic state. In statistic state, the inhibited rate was 11%-13% after 2 hours’ attachment. In dynamic state, the runner type flushing equipment was working for 5 minutes. The removal rate was test in the water flow rate of 5, 10, 15, 20 and 25 m3 / h. The results showed that the removal rate increased from 10% to 75% when the water flow rate increased. The antifouling performance of H2 and H3 were better than H1 and H4. The inhibited effects of silica gel materials may concern with the relation between the size of microstructure and diatoms.