電化學(xué)動力學(xué)
(1. 北京科技大學(xué) 冶金與生態(tài)工程學(xué)院，教育部生態(tài)與循環(huán)冶金重點實驗室， 北京 100083;
2. 北京有色金屬研究總院， 北京 100088)
摘 要: 研究Leptospirillum ferrooxidans溶液氧化還原電位φ與Fe2+氧化的內(nèi)在聯(lián)系， 得到φ隨溶液ln［c(Fe3+)/c(Fe2+)］的增加呈線性增長關(guān)系； 研究Fe2+、 細(xì)菌濃度、 溫度變化時Fe2+氧化反應(yīng)速率的變化規(guī)律。 在給定條件下， 當(dāng)溶液中Fe2+濃度較低時， 隨著Fe2+濃度的上升， Fe2+的氧化速率加快， 而當(dāng)Fe2+濃度在5 kg/m3以上時， Fe2+濃度的增加不但不會促使氧化速率加快， 反而會抑制Fe2+的氧化； 細(xì)菌濃度的增加， 氧化速率隨之上升， 當(dāng)細(xì)菌濃度在1.25×108 cells/dm3以上時， 氧化速率隨細(xì)菌濃度的增加有較大幅度的增長； 當(dāng)溫度在20~35 ℃范圍時， 溫度的升高會加快細(xì)菌氧化Fe2+的速率， 當(dāng)溫度再升高， 則會抑制Fe2+的氧化。 通過一系列電化學(xué)與生物化學(xué)分析， 導(dǎo)出了Leptospirillum ferrooxidan生長動力學(xué)方程， 并計算出活化能Ea、 頻率因子K0、 表觀飽和常數(shù)Km和單元附著系數(shù)K′i等動力學(xué)參數(shù)的值； 動力學(xué)模型能很好說明實驗結(jié)果。
關(guān)鍵字: Leptospirillum ferrooxidans; 細(xì)菌浸出; 生物冶金; 混合電位; 動力學(xué); 電化學(xué)
oxidation of Fe2+
（1. Ecology and Recycling Metallurgy Laboratory of National Education Ministry,
School of Metallurgy and Ecology Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. General Research Institute of Nonferrous Metals, Beijing 100083, China）
Abstract: The relatively relationship between solution rexdox potential and the ferrous iron oxidation rate was established, and it shows that the φ value increases linearly with ln［c(Fe3+)/c(Fe2+)］. All the ferrous ion, the bacteria cells concentration and temperature have apparent effect on the ferrous oxidation rate. When the concentration of ferrous is less than 5 kg/m3 the oxidation of ferrous ion increases, however the increase of ferrous ion concentration up to 5 kg/m3 would give inhibition of oxidation rate, as well as at the temperature range of 20 ℃ to 35 ℃, the increased temperature can enhance the ferrous ion oxidation, but when the temperature is above 40 ℃, the growth of bacteria inhibis and the oxidation decreases relatively. The increase of cells concentration of bacteria enhances the oxidation apparently especially when the concentration of cells increases to above 1.25×108 cells/dm3. Based on the ferrous ion oxidation and redox potential the growth kinetics models were established and the value of activation energy (Ea), frequency factor (K0), saturation constant (Km), and substrate inhibition coefficient (Ki) were determined. The kinetics model is well in coincidence to the experiments results.
Key words: Leptospirillum ferrooxidans; bioleaching; biohydrometallurgy; redox mixed potential; kinetics; electrochemistry
