基于绿色生物质阿拉伯树脂的氮掺杂碳点用于检测工业废水中的Cr(VI)

Nitrogen-Doped Carbon Dots Derived from Green Biomass Arabic Gum for Detection of Chromium(VI) in Industrial Wastewater

以绿色生物质阿拉伯树脂(AG)为碳源,三羟甲基氨基甲烷(Tris)为氮源,二者按质量比1∶4混合,通过水热法制备了一种新型氮掺杂碳点(NACDs),并基于NACDs构建了一种荧光传感器,用于工业废水中Cr(VI)的检测。取200μL样品溶液、NACDs溶液100μL、0.2 mmol·L^(-1)磷酸氢二钠-磷酸二氢钠缓冲液(pH 8.0) 200μL加至2 mLEP管中,用水定容至1 mL。室温反应10 min后,在激发波长365 nm处扫描,并在430 nm处测量体系荧光强度。结果表明,在365 nm的激发波长下,NACDs于430 nm表现出强荧光信号,并可被Cr(VI)选择性猝灭。Cr(VI)的质量浓度在0.25~3.00 mg·L^(-1)内与NACDs的荧光猝灭值呈线性关系,检出限(3s/k)为0.13 mg·L^(-1)。按照标准加入法对模拟工业废水样品进行回收试验,回收率为103%~105%,测定值的相对标准偏差(n=6)均小于3.0%,加标样品所得测定结果与国家标准方法GB/T 15555.4—1995的无显著性差异。

Using green biomass Arabic gum(AG) as carbon source and trimethylaminomethane(Tris) as nitrogen source,the two raw materials were mixed at a mass ratio of 1∶4 to prepare a novel nitrogen-doped carbon dots(NACDs) by hydrothermal method,and a fluorescent sensor based on NACDs was constructed for the detection of Cr(VI) in industrial wastewater.200 μL of sample solution,100 μL of NACDs solution,and 200 μL of 0.2 mmol · L^(-1) disodium hydrogen phosphate-sodium hydrogen phosphate buffer solution(pH 8.0) were added to a 2 mL-EP tube,and the mixture was made its volume up to 1 mL with water.After reaction for 10 min at room temperature,the system was scanned at 365 nm of excitation wavelength,and the fluorescence intensity of the system was measured at 430 nm.As shown by the results,at the excitation wavelength of 365 nm,NACDs had strong fluorescence signal at 430 nm and its fluorescence could be selectively quenched by Cr(VI).Linear relationship between the fluorescence quenching values of NACDs and mass concentrations of Cr(VI) were found in the range of 0.25-3.00 mg · L^(-1),with detection limit(3s/k) of 0.13 mg · L^(-1).Test for recovery on the simulated industrial wastewater samples by the standard addition method,giving results in the range of 103%-105%,with RSDs of the determined values(n=6) less than 3.0%.There was no significant difference between the determined results obtained by this method and those obtained by the national standard method GB/T 15555.4—1995.