Preparation,Properties And Application Of PX Chemical Sensors Based On Graphite Eletrode Modification

The rapid development of modern industrial technologies has resulted in the emission of"three wastes" in large quantities,which has led to environmental pollution,ecological damag-e,and threats to human health.The challenges facing nature are becoming more and more sev-ere.Among the many pollutants,heavy metal ion pollution has attracted widespread attention due to its great harm,wide range,and enrichment.Therefore,the study of rapid,simple,sensit-ive and on-line detection methods for heavy metal ions has become an important issue in the field of environmental monitoring and industrial process control.This paper explored the preparation of all-solid-state pZn sensors based on graphite electr-ode-modified electroactive materials.According to the difference of KSp(ms),a funct-ionalized pX chemical sensor was constructed by ion exchange.At the same time,all solid-state miniat-ure Sb-SbxOy-pH electrodes were studied.Based on the performance of the bare Ag-AgCl el-ectrode,an all-solid-state complex pH sensor was assembled.(1)By optimizing the preparation method of electroactive substances and the composite-on of sensitive membranes,the optimum ratio of hydrothermal preparation and nZns:nAg2s=2:1 and the hydrophobic pretreatment process of graphite matrix electrode were determined;(2)The all-solid-state pZn sensor has a linear response range of 1.00×10-1 to 1.00×10-4 mol/L,a detection limit of 4.38×10-5 mol/L,a response slope of-25.8 mV/pZn,and a response time of<1 min.Potential shift AE?0.1 mV/h;Determination of Zn2+ standard solution(n=10),RSD?6.89%;(3)The thermodynamic response mechanism of the all-solid-state pZn sensor is discussed.The formula derivation proves that the ion exchange equilibrium process is the main step to control the electrode response;(4)According to the Ksp(ms)of the electroactive material,the pZn sensor was converted to pX sensor(pAg,pCd,pCu)by ion exchange.The linear range was 10"1 to 10-5 mol/L,and the detection limit was 5.41×10-6 mol/L,response slope of 30.0 m?/p?,57.3 m?/p?,response time ? 1 min,breaking through the limitations of ion sensors can only measure one ion;(5)All-solid micro-compound pH sensor response range 2 to 12,response slope-58.5 mV/pH,response time ? 30 s,stability ?E ? 0.33 mV/h,pH standard buffer solution(n=10),RSD ? 0.55%,used for the actual sample pH measurement,compared with the pH glass electr-ode,? pH ?0.13;(6)Stability of exposed Ag-AgCl reference electrode(AE ? 0.2 mV/h),reproducibility(RSD ? 7.81%),good reversibility,low temperature effect(0.20 mV/?),and calomel The electrode eliminates the liquid junction potential.