基于涤棉混纺织物的荧光碳点对Cr(Ⅵ)和Hg(Ⅱ)的检测

Detection of Cr(Ⅵ)and Hg(Ⅱ)by Fluorescent Carbon Dots Based on Polyester-Cotton Blended Fabrics

该文以废弃涤棉混纺织物为碳源,分别在乙二醇和硫酸溶液中通过溶剂热法合成了两种荧光碳点,实现了对溶液中Cr(Ⅵ)和Hg(Ⅱ)的检测。通过透射电镜与红外光谱表征了碳点的形貌与组成,并基于紫外吸收光谱和荧光光谱分析了碳点的电子跃迁形式及发光类型。在乙二醇体系中制得的碳点(ETCCDs)能够选择性检测Cr(Ⅵ),检出限为0.093 mg/L,其检测机理为荧光内滤效应;硫酸体系中制备的碳点(WTCCDs)能够选择性检测Hg(Ⅱ),检出限为0.018µmol/L,检测机理为能量转移。对实际水样中的Cr(Ⅵ)和Hg(Ⅱ)进行检测,验证了上述两种碳点的实用性。基于涤棉混纺织物制备的荧光碳点不仅实现了对两种重金属离子的检测,同时也为废旧纺织物的再生利用提供了借鉴意义。

In this study,two types of fluorescent carbon dots were synthesized through solvothermal method by using waste polyester-cotton blended textile as the carbon source,in ethylene glycol and sulfuric acid solutions,respectively,to achieve the detection of Cr(Ⅵ)and Hg(Ⅱ)in solution.The morphology and structure composition of the carbon dots was analyzed by transmission electron microscope and infrared spectroscopy,and the electronic transition forms,optimal excitation wave⁃length,optimal emission wavelength,and luminescence types of the carbon dots were analyzed by UV-visible spectrophotometer and fluorescence spectrophotometer.Then,the detection performance of the two carbon dots was studied.The carbon dots obtained in the ethylene glycol system(named ETCCDs)could selectively detect Cr(Ⅵ),with a minimum detection limit of 0.093 mg/L and the de⁃tection mechanism was fluorescence internal filtration effect.The carbon dots prepared in the sulfuric acid system(named WTCCDs)could selectively detect Hg(Ⅱ)with a detection limit of 0.018µmol/L,and the detection mechanism was caused by energy transfer.Furthermore,Cr(Ⅵ)and Hg(Ⅱ)in actual water samples were detected,verifying the practicality of these two carbon dots.The fluo⁃rescent carbon dots designed based on polyester cotton blended fabrics not only achieve the detection of two heavy metal ions,but also provide reference significance for the regeneration and utilization of waste textiles.