以三维多孔Ti为基底、Sb₂O₃-SnO₂和α-PbO₂为中间层、β-PbO₂为表面活性层制备了一种用于化学需氧量检测的新型电化学传感器,并考察了该传感器的电化学特性。结果表明,该传感器最优的COD检测条件为:电解电位1.6 V,支持电解质Na₂SO₄浓度0.1 mol/L,pH 5~11。最优检测条件下该传感器在50~600 mg/L COD标准葡萄糖溶液中呈现良好的线性响应性能,检出限为8.37 mg/L(S/N=3)。实验研究了6种不同有机物的ΔI与COD的线性关系,发现有机物种类会影响羟基自由基的消耗速率,进而影响检测标准曲线与检出限。为了减少误差,在测定水样的COD时,应根据水中有机物种类按照相应的比例建立工作曲线。

A novel electrochemical sensor for the detection of chemical oxygen demand is prepared by using three-dimensional porous Ti as the substrate,Sb₂O₃-SnO₂ and α-PbO₂ as the intermediate layer,and β-PbO₂ as the surface active layer.The electrochemical characteristics of the sensor are evaluated.It is shown that the optimal COD detection conditions for the sensor are as follows:electrolytic potential is 1.6 V,the concentration of supporting electrolyte (Na₂SO₄) is 0.1 mol·L^-1,and pH is in the range of 5-11.Under the optimal detection conditions,the sensor presents a good linear response performance in 50-600 mg·L^-1 COD standard glucose solution,with a detection limit of 8.37 mg·L^-1 (S/N=3).The linear relationships between ΔI and COD of six different organic compounds are studied.It is found that the consumption rate of hydroxyl radical can be affected by the types of organic compounds,which further has impact on the detection standard curve and detection limit.In order to reduce the error,the working curve should be established according to the proportion of organic matters in the water when COD in water sample is measured by the sensor.

刘海涛(1997-),男,硕士生