超声空化辅助磷酸浸渍一步炭化制备高活性铅检测传感器

Preparation of highly active lead detection sensor through ultrasound-assisted phosphoric acid impregnation and one-step carbonization

开发高活性且低成本的生物质炭电极是构建高性能铅检测传感器的关键。以棉秆生物质为原料,通过超声空化辅助磷酸浸渍一步炭化法制备了系列不同温度(700、750、800、850℃)的磷改性棉秆炭,并基于这些炭材料构建了铅检测传感器。采用N2吸脱附、傅里叶红外光谱、X射线光电子能谱、循环伏安、电化学阻抗谱和阳极溶出差分脉冲伏安法等现代表征及测试技术,探究了不同温度棉秆炭电极孔径分布、化学结构、高活性磷官能团与电化学传感性能间的构效关系。结果表明,800℃制备的棉秆炭(CS800)具有更高的比表面积(1338.57 m^(2)·g^(−1))和优异的微/中孔分级结构以及更丰富的C3-P-O基团。这些独特优势的结合使CS800电极具有更高的电化学活性、最低的电子转移电阻(Rct)和更强的Pb^(2+)富集能力。在1~100和100~1000μg·L^(−1)Pb^(2+)浓度下,CS800检测峰电流与Pb^(2+)浓度呈现良好的线性关系,线性相关系数R2均高达0.97,检测限灵敏度低至1.38μg·L^(−1),并表现出优异的重复性、重现性、稳定性及抗干扰性,表明所制备的棉秆炭电极对Pb^(2+)检测具有巨大的应用潜力。本研究结果可为该类生物质炭电极的制备及性能优化提供参考,也可为重金属监测及分析提供技术支持。

The development of biochar electrodes with high activity and low cost is essential for the construction of high-performance lead detection sensors.A series of phosphorus-modified cotton stalk carbons at different temperatures(700,750,800,850℃)were prepared through ultrasonic cavitation-assisted phosphoric acid impregnation and one-step carbonization method using cotton stalk biomass as raw material,and a lead detection sensor was constructed based on these carbon materials.Using N2 absorption-desorption,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,cyclic voltammetry,electrochemical impedance spectroscopy and anode stripping differential pulse voltammetry and other modern characterization and testing techniques,the structure-activity relationship between pore size distribution,chemical structure,high active phosphorus functional groups and electrochemical sensing properties of cotton stalk carbon electrodes at different temperatures was investigated.The results showed that cotton stalk carbon(CS800)prepared at 800℃possessed higher specific surface area(1338.57 m^(2)·g^(−1)),more abundant micropore/mesopore structure as well as C3-P-O groups.The combination of these unique advantages gived the CS800 electrode a higher electrochemical activity,the lowest electron transfer resistance(Rct),and a stronger Pb^(2+)accommodation capability.At Pb^(2+)concentrations of 1~100μg·L^(−1)and 100~1000μg·L^(−1),the peak current of CS800 appeared a good linear relationship with Pb^(2+)concentration.The linear correlation coefficients R2 were all up to 0.97,and the detection limit sensitivity was as low as 1.38μg·L^(−1).Furthermore,excellent repeatability,reproducibility,consistency and anti-interference performance were shown,which indicated that the prepared cotton stalk carbon electrode had great application potential for Pb^(2+)detection.The results of this research not only shed light on the preparation and performance optimization of biochar electrodes,but also offer technical support for the monitoring and analysis of heavy metals.