Application Of Functional Material ARPOP-1 In The Electrochemical Analysis Of Chlorophenol Organic Pollutants

The nitrogen-containing porous organic polymer ARPOP-1 has an extended π-conjugated main chain and N-containing aromatic properties,and its affinity for aromatic molecules can be enhanced through π stacking and H-bond interactions,making it a promising adsorbent in analytical chemistry applications.In this study,nitrogen-containing porous organic polymer ARPOP-1 was mainly used as an adsorbent to analyze organic pollutants such as chlorophenols（CPs）in water samples.Chlorophenol is highly toxic.It will not only cause mutagenesis of estrogen production in humans,but also cause carcinogenesis.And even destroys the environment and pollutes the ecosystem.At lower doses,CP stimulates the human central nervous system and respiratory system,but at higher doses,it can cause cancer.Therefore,the US Environmental Protection Agency（EPA）has made CP as the one of the priority hazardous toxic chemicals.The sources of CP in the environment are produced through human and industrial activities,such as the chlorination of pulp,the hydrolysis of chlorinated herbicides,and oil refining.In addition,CP can also be used as a disinfectant for municipal water,agricultural fungicides and chlorinated pesticides.The use of these CPs is the main cause of CP pollution in groundwater and surface water.Therefore,there must be a sensitive and convenient detection system to analyze CP in environmental water samples.Among the analysis methods for detecting chlorophenol,the electrochemical analysis method has better advantages.Electrochemical methods of current and electric potential are becoming more and more popular.These methods can directly detect unsafe and carcinogenic toxic chemicals in the environment.Moreover,the square wave voltammetry（SWV）of electrochemical analysis showing great hope is due to its high sensitivity,high efficiency and low detection limit.First,this research used electrochemical methods in combination with carbon paste electrode（CPE）sensors.The carbon paste electrode has the characteristics of easy preparation,convenient modification,renewable surface,low background current and fast response speed.Taking advantage of these characteristics,in addition to the enrichment of the carbon paste electrode for electroactive substances,it mainly depends on adsorption and extraction.Carbon paste electrode introduces modifier ARPOP-1 to make ARPOP-1 material modified carbon paste electrode（ARPOP-1-CPE）electrochemical sensor.However,ARPOP-1 itself is not electrochemically active,which will lead to a decrease in the electrical conductivity of the carbon paste electrode.Moreover,the contact surface between ARPOP-1 in the carbon paste electrode and the target analyte 2,4-dichlorophenol（2,4-DCP）in the solution is small.And the ideal effect of enrichment and lower detection limit cannot be achieved.Therefore,in this study,ARPOP-1 was still used as the adsorption material.The microfilter solid phase extraction（MFSPE）device was used to pre-enrich the samples.The filter solid phase extraction（FSPE）technology was combined with the microporous membrane filter to simultaneously complete the enrichment of the target and the purification of the sample.After enriching by MFSPE,the target compound was detected by electrochemical square wave voltammetry.The two target analytes 2,4-DCP and 3,5-dichlorophenol（3,5-DCP）not only can be detected simultaneously,but also have lower detection limits.The main research contents are introduced as follows:（1）Based on the nitrogen-containing porous organic polymer ARPOP-1 material,it has a good adsorption effect on 2,4-DCP.In this work,a modified carbon paste electrode sensor that can be used to detect 2,4-DCP was prepared using ARPOP-1 as a modifier.Using a modified carbon paste electrode sensor,square wave anode stripping voltammetry（SW-ASV）was used to investigate the effect of ARPOP-1 content,solution stirring rate,enrichment potential,enrichment time,PBS buffer solution concentration and PBS buffer solution pH on the response current of 2,4-DCP at a certain concentration.The optimal conditions were achieved: ARPOP-1 content was 4%,stirring rate was 500 rpm,enrichment potential was-0.5 V,enrichment time was 120 s,concentration of PBS buffer solution was 0.4 mol L^-1and the pH of the solution was 8.0.The results show that under optimal conditions,2,4-DCP has a linear relationship with the peak current of the SW-ASV curve in the range of 0.2 20.0 μmol L^-1（R² = 0.9991）.The exit limit was 0.073 μmol L^-1（S/N = 3）.The ARPOP-1 material modified carbon paste electrode（ARPOP-1-CPE）was applied to the determination of the content of 2,4-DCP in tap water samples and Nanhu water samples in Wuhan,Hubei.The recovery rates were 86.35% 102.18% and 88.10% 98.94%.It can be shown that this method can be used to determine 2,4-DCP in actual water samples.（2）Based on the adsorption and aggregation of ARPOP-1,it has a natural advantage for the detection of CP.In this work,2,4-DCP and 3,5-DCP were simultaneously used as target analytes.Microfilter solid phase extraction（MFSPE）technology was used to perform routine steps including conditioning,adsorption,and elution of the sample solution.The square wave voltammetry（SWV）at-0.5 V potential was used to investigate the amount of ARPOP-1,the pH of the sample solution,the contact time of ARPOP-1 with DCP,and 300 μL of desorption solvent NaOH on the response current of 2,4-DCP and 3,5-DCP.The optimal conditions were determined: the amount of ARPOP-1 was 4 mg,the pH of the sample solution was 2.0,the contact time of ARPOP-1 with DCP was 60 s,and the desorption solvent was 65 mmol L^-1of NaOH.Under the optimal conditions,the concentration of 2,4-DCP in the concentration range of 0.04 μmol L^-1 1.8 μmol L^-1had a good linear relationship with the peak current of the SWV curve,and the detection limit was 0.75 nmol L^-1（S/N = 3）.The concentration of 3,5-DCP increased from 0.04 μmol L^-1to 1.4 μmol L^-1.The oxidation peak current increased in a good linear relationship.And the detection limit was 1.37 nmol L^-1（S/N = 3）.This method was used to analyze 2,4-DCP and 3,5-DCP in wastewater samples of plastic products factories.The recovery rates of spiked were between 101.44% 119.21% and 90.69% 115.73%,which proved the method can be used to analyze 2,4-DCP and 3,5-DCP in polluted water simultaneously.