Study On Synthesis Of Functionalized Gold Nanoparticles For Heavy Metal Ions Detection And Recovery

Heavy metal ions in water have serious harm to animals,plants and environment,so it is particularly important for environment protect and human being health to detect and recover heavy metal ions in aqueous solutions.Aimed at the problems of insufficient sensitivity,poor anti-interference of heavy metal ion detection methods and heavy metal ion recovery problem,chromium ion detection methods on-site have been established.Those methods have many advantageous of high sensitivity,fast reaction and fast operation with colorimetric detection.Meanwhile,chromium ions recovery in aqueous solution could be easily operated avoid secondary pollution.The specific research results are as follows:（1）Synthesis of gold nanoparticles functionalized by 4-MBA and PEI and detection of chromiumIn this study,gold nanoparticles were synthesized using chloroauric acid as raw material.The functionalized reagents were screened to synthesize 4-mercaptobenzoic acid and polyethyleneimine functionalized gold nanoparticles.The functional nanomaterial detection system was used to construct detection platform for Cr³⁺ions detection in water.The effects of the concentrations of modifier 4-MBA and PEI,and the p H of the system on the detection system were investigated.The results showed that comparing 4-MBA and PEI with 4-NTP functionalized gold nanoparticles,4-MBA and PEI functionalized gold nanoparticles were ultimately selected and synthesized.By investigating the effects of modifier concentration and p H on the detection system,the optimal concentration of 4-MBA,PEI and p H was 10μM,10 ng/m L,and 5.6,respectively.At this time,the detection range of the system for Cr³⁺ions are the range from 5 to 10μM.The detection limit of the detection system can reach to 4μM.It has good anti-interference,selectivity,good linear relationship,good recovery and high repeatability.（2）Synthesis and Chromium Detection of Functionalized Nanogold with MSA and PEIIn this study,gold nanoparticles were synthesized using chloroauric acid.The functionalized reagents were screened to synthesize thiosuccinic acid and polyethyleneimine functionalized gold nanoparticles.The functional nanomaterial detection system was used to construct detection platform for Cr³⁺ions detection in water.The effects of the ratio of chloroauric acid to sodium citrate,the concentration of modifier MSA and PEI,and the p H of the system on the detection system were investigated.The results showed that comparing 4-MBA with PEI and MSA functionalized gold nanoparticles,MSA and PEI functionalized gold nanoparticles were ultimately selected and synthesized.By investigating the effects of the ratio of chloroauric acid to sodium citrate,modifier concentration,and p H on the detection system,the optimal ratio of chloroauric acid to sodium citrate was determined to be 1:3,and the optimal concentration of MSA,PEI and p H was 100μM,10 ng/m L and 4.5,respectively.At this time,the detection range of the system for Cr³⁺ions are the range from 2 to 5μM.The visual detection limit of the system for the concentration of Cr³⁺ions can reach to 3μM,and UV absorption spectrum detection limit can reach to 2μM.The system has good anti-interference,selectivity,good linear relationship,good recovery and high repeatability.（3）Study on synthesis of magnetically functionalized gold nanoparticles and recovery of chromium ionsIn this study,magnetic ferric oxide nanoparticles was synthesized by coprecipitation method.The magnetic materials nanoparticles were synthesized by the reduction of chloroauric acid with sodium borohydride.A magnetic functional nanomaterial was synthesized by selecting functional reagents to recover Cr³⁺ions from water.The effects of the ratio of Fe³⁺to Fe²⁺,the concentration of ferric oxide,the adsorption time,and the content of adsorbent on the adsorption efficiency were investigated.The results showed that the optimal ratio of Fe³⁺to Fe²⁺for the preparation of magnetic iron trioxide was 1.25:1.When the concentration of iron trioxide in the solution was 0.01 mg/ml,the particle size of the iron trioxide material was mainly distributed at 194.7 nm.The adsorption rate of the magnetic nanomaterial prepared by the sodium borohydride method was above 85%,and the maximum adsorption rate of the adsorbent was 73.85%when the adsorption time was60 minutes.This provides a good application prospect for the recovery of chromium ions from water using magnetic functionalized nanomaterials.