含新結合相DGT的構筑及其在富營養(yǎng)水體中磷原位測定中的應用
發(fā)布時間：2018-11-02 19:18
【摘要】：磷酸根離子的準確測定對于水體富營養(yǎng)化和水環(huán)境污染的防治與治理有著重要的意義。由于待監(jiān)測環(huán)境中待測物質(zhì)的濃度低、組成成分繁雜、干擾物多、會隨環(huán)境條件轉(zhuǎn)變,傳統(tǒng)監(jiān)測技術需進行繁瑣的前處理,方可進行檢測實驗。樣品預處理工藝需要復雜的手工操作,工作強度大,操作時間長,重現(xiàn)性差,給最終的測量分析帶來很大的誤差。故研究原位被動采樣新技術以降低傳統(tǒng)測定方法中樣品預處理過程引入的誤差具有重要的意義。薄膜梯度擴散技術(Diffusive Gradients in Thin Films Technique,DGT)是以Fick第一擴散定律為基礎的新型監(jiān)測技術,其近年來被廣泛應用于水體、沉積物及土壤中磷含量的原位監(jiān)測。本文選用新型結合相——含碳酸鑭和CaAl-LDH的聚丙烯酰胺凝膠膜,研究DGT放置時間、初始磷濃度、pH、離子強度以及溫度對其富集磷酸根離子能力的影響,最后在實際水體中,探究其應用性能,結果如下:(1)選用碳酸鑭聚丙烯酰胺凝膠膜用作DGT結合相。在環(huán)境條件為pH=7.00,溫度T=25℃,磷初始濃度為5μg/mL時,碳酸鑭-DGT對磷的最大吸附容量為68.73μg,有效吸附容量為12.82μg;洗脫液是5 mL,2 mol/L的H2SO4,洗脫效率為92.35%;當pH在3.21-6.90,離子強度在10-6-0.1 mol/L范圍內(nèi)時,碳酸鑭-DGT檢測磷酸根離子結果變化不顯著;溫度在5-35℃范圍內(nèi),碳酸鑭-DGT對磷的富集量隨著溫度的升高而增加。磷初始濃度為0.10-5.04μg/m L時,碳酸鑭-DGT測定值與磷鉬藍比色法測定值相吻合;存儲時間為0.5-10個月,碳酸鑭-DGT對磷的富集能力波動變化不顯著。方法對磷的檢出限為98.12 ng/L。將碳酸鑭-DGT和傳統(tǒng)Ferrihydrite-DGT在模擬水樣、易海及巢湖中進行實地監(jiān)測實驗,比較實驗結果得,碳酸鑭-DGT可以更好的監(jiān)測不同水環(huán)境中的磷。(2)CaAl-LDH的聚丙烯酰胺凝膠膜作為DGT的結合相。該CaAl-LDH采用乙醇輔助液相共沉淀法制備而成。洗脫液為5 mL,2.0 mol/L的NaOH,洗脫效率為76.0%;在溫度T=25℃,pH=7.00,離子強度NaNO3=0.01 mol/L,磷初始濃度為5μg/m L,放置時間為15-360 min的條件下,CaAl-LDH-DGT所測得的實際磷吸附量與計算公式所得吸附磷量相一致;當初始磷濃度在0.1-5μg/mL時,CaAl-LDH-DGT測定磷濃度值與磷鉬藍比色法測定磷濃度值相基本一致;當pH在3.12-7.79,離子強度在10-6-0.1 mol/L范圍內(nèi)時,CaAl-LDH-DGT檢測磷結果變化不顯著;在10-30℃下,CaAl-LDH-DGT對磷的富集量隨著溫度的升高而增加,方法對磷的檢出限為81.71ng/L。CaAl-LDH-DGT和傳統(tǒng)的Ferrihydrite-DGT應用于模擬水樣、易海、巢湖水中的對比研究結果可知,CaAl-LDH-DGT更能準確測定不同水體中的磷濃度。
[Abstract]:The accurate determination of phosphate ion is of great significance for the prevention and control of water eutrophication and water environmental pollution. Because the concentration of the substances to be tested in the environment is low, the composition is complex and the interference is many, it will change with the environmental conditions, so the traditional monitoring technology needs tedious pretreatment before the detection experiments can be carried out. The sample pretreatment process needs complicated manual operation, high working intensity, long operating time and poor reproducibility, which brings great error to the final measurement and analysis. Therefore, it is of great significance to study the new technique of in situ passive sampling to reduce the error in the process of sample pretreatment. Thin film gradient diffusion (Diffusive Gradients in Thin Films Technique,DGT) is a new monitoring technique based on the first diffusion law of Fick. It has been widely used in the in-situ monitoring of phosphorus content in water, sediment and soil in recent years. In this paper, polyacrylamide gel membrane containing lanthanum carbonate and CaAl-LDH was used to study the effects of DGT storage time, initial phosphorus concentration, pH, ion strength and temperature on the ability of phosphate ion enrichment. The results are as follows: (1) Lanthanum carbonate polyacrylamide gel film is used as DGT binding phase. The maximum adsorption capacity of lanthanum carbonate-DGT for phosphorus was 68.73 渭 g and the effective adsorption capacity was 12.82 渭 g when the initial concentration of phosphorus was 5 渭 g/mL and the temperature of pH=7.00, was 25 鈩，
本文編號：2306717
[Abstract]:The accurate determination of phosphate ion is of great significance for the prevention and control of water eutrophication and water environmental pollution. Because the concentration of the substances to be tested in the environment is low, the composition is complex and the interference is many, it will change with the environmental conditions, so the traditional monitoring technology needs tedious pretreatment before the detection experiments can be carried out. The sample pretreatment process needs complicated manual operation, high working intensity, long operating time and poor reproducibility, which brings great error to the final measurement and analysis. Therefore, it is of great significance to study the new technique of in situ passive sampling to reduce the error in the process of sample pretreatment. Thin film gradient diffusion (Diffusive Gradients in Thin Films Technique,DGT) is a new monitoring technique based on the first diffusion law of Fick. It has been widely used in the in-situ monitoring of phosphorus content in water, sediment and soil in recent years. In this paper, polyacrylamide gel membrane containing lanthanum carbonate and CaAl-LDH was used to study the effects of DGT storage time, initial phosphorus concentration, pH, ion strength and temperature on the ability of phosphate ion enrichment. The results are as follows: (1) Lanthanum carbonate polyacrylamide gel film is used as DGT binding phase. The maximum adsorption capacity of lanthanum carbonate-DGT for phosphorus was 68.73 渭 g and the effective adsorption capacity was 12.82 渭 g when the initial concentration of phosphorus was 5 渭 g/mL and the temperature of pH=7.00, was 25 鈩，
本文編號：2306717
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