The Preparation Of Novel Sensor And Application Study To The Detection Of Carbonate Ion

In this dissertation,two intercalation materials Mg-Al-2-NSA-LDH and Mg-Al-4A-4S-LDH were prepared with magnesium-aluminum LDH(Mg-Al-CO3-LDH)as the host material,anionic dyes 2-Naphthalene Sulfonic Acid(2-NSA)and 4-Aminoazobenzene-4-Sulfonate(4A-4S)as the guest materials.The prepared Mg-Al-2-NSA-LDH and Mg-Al-4A-4S-LDH intercalation materials were used as fluorescent sensors to detect the carbonate ion by ion exchange method,take advantage of the feature that the layers of Mg-Al-LDH has a strong affinity for carbonate ion.The work of the thesis is mainly divided into two parts:(1)Preparation of Mg-Al-2-NSA-LDH fluorescenct sensor and its detection of carbonate ion.Firstly,Mg-Al-CO3-LDH was prepared by co-precipitation method.Then,the intercalation product Mg-Al-2-NSA-LDH was prepared by one-step ion exchange method using ethanediol as dispersing media.The structure and stability of Mg-Al-2-NSA-LDH were studied by X-ray diffraction,Fourier transfrom infrared spectroscopy,fluorescence spectra,and elution experiment.The results indicated that the 2-NSA has intercalated into the interlayer of Mg-Al-LDH,the Mg-Al-2-NSA-LDH has good structural stability,and its photo stability is better than the 2-NSA.The relationship between the fluorescence intensity of 2-NSA and its concentration in aqueous solution was studied.The results indicated that the fluorescence intensity of 2-NSA in aqueous solution varies significantly with the change of concentration.The Mg-Al-2-NSA-LDH was used as a fluorescent sensor to detect different concentrations of carbonate ions.It was found that within 0.2-2.0 mmol/L of CO32-concentration,the fluorescence intensity decreased with increasing concentration of carbonate ion,and it has a good linear relationship.We established the linear regression equation I=3058.1-771.7C(mmol/L),R2=0.9943,and the limit of detection(LOD)is 9.5 ?mol/L.It was found that Mg-Al-2-NSA-LDH showed good detection selectivity for carbonate ion within a certain range.Within the allowable error of ±5%,the same concentration of F-,Cl-,Br-,I-,SO42-,SO32-,SCN-,Ac-anions do not substantially interfere with the detection of CO32-by Mg-Al-2-NSA-LDH sensor.The method of detecting the carbonate ion by Mg-Al-2-NSA-LDH sensor was validated.The relative standard deviation was in the range of 0.97-1.45%,showing good repeatability and accuracy.(2)Preparation of Mg-Al-4A-4S-LDH fluorescent sensor and its detection of carbonate ion.Firstly,Mg-Al-CO3-LDH was prepared by co-precipitation method.Then,the intercalation product Mg-Al-4A-4S-LDH was prepared by two-step ion exchange method using ethanediol as dispersing media.The structure and stability of Mg-Al-4A-4S-LDH were studied by X-ray diffraction,Fourier transfrom infrared spectroscopy,fluorescence spectra,and elution experiment.The results indicated that the 4A-4S has intercalated into the interlayer of Mg-Al-LDH,the Mg-Al-4A-4S-LDH has good structural stability,and its photo stability is better than the 4A-4S.The relationship between the fluorescence intensity of 4A-4S and its concentration in aqueous solution was studied.The results indicated that the fluorescence intensity of 4A-4S in aqueous solution varies significantly with the change of concentration.The Mg-Al-4A-4S-LDH was used as a fluorescent sensor to detect different concentrations of carbonate ions.It was found that within 0.01-0.50 mmol/L of CO32-concentration,the fluorescence intensity increased with increasing concentration of carbonate ion,and it has a good linear relationship.We established the linear regression equation I=20.97+6394.68C(mmol/L),R2=0.9944,and the limit of detection(LOD)is 1.1 ?mol/L.It was found that Mg-Al-4A-4S-LDH showed good detection selectivity for carbonate ion within a certain range.Within the allowable error of ± 5%,the same concentration of F',Cl-,Br-,I-,SO42-,SO32-,SCN-,Ac-anions do not substantially interfere with the detection of CO32-by Mg-Al-4A-4S-LDH sensor.The method of detecting the carbonate ion by Mg-Al-4A-4S-LDH sensor was validated.The relative standard deviation was in the range of 0.98-1.32%,showing good repeatability and accuracy.In summary,two intercalation materials Mg-Al-2-NSA-LDH and Mg-Al-4A-4S-LDH were successfully prepared by traditional fluorescent dyes 2-NSA and 4A-4S intercalated with LDH.Using the ion exchange principle,these two kinds of intercalation materials were used as fluorescent sensors to achieve selective detection of carbonate ion,extending the application of functional materials with LDH as a carrier,and also providing new ideas for the detection of carbonate ion.