Study On Fe-based MOFs For Detecting Phenolic Pollutants

With the development of industry,the environment pollution has attracted more and more attention.The sensitive detection of phenolic environmental pollutants was focused using electrochemical methods due to its advantages of simple operation,fast response,good selectivity and high sensitivity.Metal-organic frameworks（MOFs）can be explored as effective electrode modification materials because of the excellent characteristics including crystal structure ordering,permanent porosity,high specific surface area and thermal stability.Moreover,the electrochemical performance can be improved when the composite of MOFs and other nanoparticles are synthesized.The calcination of MOFs is another method to enhance the electrochemical performance.Fe-MOFs-based nanomaterials were prepared and the corresponding modified electrodes were fabricated for the sensitive detection phenolic organic pollutants.The main research contents of this paper are as follows:1.A series of MILs nanomaterials were synthesized using solvothermal method,with Fe³⁺as Iron source,terephthalic acid and trimellitic acid as organic ligands.The prepared nanomaterials were characterizes by SEM,FT-IR,XRD,XPS.The electrochemical behavior of HQ and CC on the MIL-（Fe）modified carbon paste electrode was studied,and the influence of factors such as modification amount,pH and scan rate were carried out.It was shown that MIL-101（Fe）/CPE is the most sensitive modified electrode for the detection for HQ and CC.The optimized experimental conditions were PBS solution of pH 7,the modification amount of 1%,and the scanning speed of 50 m V/s.The linear ranges of HQ and CC are 5～50μM and 5～80μM,respectively.The detection limit of HQ and CC is 0.0142μM and 0.00556μM,respectively.In addition,MIL-101（Fe）/CPE was used for the simultaneous detection of HQ and CC in actual water samples,and the recoveries were 90.21%～102.36%and91.11%～102.19%for HQ and CC,respectively.2.MWCNTs@MIL-100（Fe）composite material was simply synthesized by one-step solvothermal method.MWCNTs@MIL-100（Fe）/CPE was used for the simultaneously detection of o-NP and p-NP.The determination sensitivity of o-NP and p-NP was significantly improved due to the synergistic effect of MWCNTs and MIL-100（Fe）.The linear ranges of o-NP and p-NP are 20～110μM and 5～60μM,and the detection limit of o-NP and p-NP is 0.00090μM and 0.00094μM,respectively.Thus,the modified elec-trode has high sensitivity and good selectivity for the determination of o-NP and p-NP,and can be used to detect o-NP and p-NP in actual samples with the recoveries of98.25%～102.45%and 97.57%～101.56%,respectively.3.The MIL-88（Fe）nanomaterial was calcinated at different temperatures of 300℃,350℃,400℃,450℃and 600℃.It was found that the calcination of MIL-88（Fe）can improve the electrochemical performance for the detection of BPA.Among them,Fe_xC-350/CPE exhibited the highest sensitivity because iron oxide is embedded among the uncollapsed MIL-88（Fe）structure after calcinated.The experimental conditions were optimized as pH 6.5 PBS solution,5%modification amount,50 m V/s,and 80 s enrichment.The linear range of detecting BPA is 5～100μM,and the detection limit is0.0126μM.In addition,Fe_xC-350/CPE is used for the detection of BPA in actual sam-ple plastic bottles,and the recovery rate is among 92.76%～106.7%.