CN109321237B

CN109321237B - Nitrogen-sulfur double-doped carbon dots and preparation method and application thereof

Info

Publication number: CN109321237B
Application number: CN201811145738.1A
Authority: CN
Inventors: 许利娜; 杨小华; 丁海阳; 夏建陵; 李梅; 李守海; 张燕
Original assignee: Institute of Chemical Industry of Forest Products of CAF
Current assignee: Institute of Chemical Industry of Forest Products of CAF
Priority date: 2018-09-29
Filing date: 2018-09-29
Publication date: 2021-11-23
Anticipated expiration: 2038-09-29
Also published as: CN109321237A

Abstract

A nitrogen-sulfur double-doped carbon dot and a preparation method and application thereof comprise the following steps: taking papermaking waste sodium lignin sulfonate and cysteine as raw materials, placing the raw materials in a hydrothermal reaction kettle, carrying out hydrothermal reaction, cooling to room temperature after the reaction is finished, and centrifuging the obtained black product. And filtering the collected solution part by using a filter membrane to obtain a brown yellow solution which is a blue fluorescent carbon quantum dot solution. The raw material sodium lignosulphonate used in the invention is papermaking waste, the cost is low, and the preparation process is simple. The obtained carbon quantum dots can be used for Fe in water³⁺The analysis and detection of (2).

Description

Nitrogen-sulfur double-doped carbon dots and preparation method and application thereof

Technical Field

The invention belongs to the field of fluorescent material preparation, and particularly relates to a nitrogen-sulfur double-doped carbon dot and a preparation method and application thereof.

Background

The carbon quantum dots are also called carbon dots, are novel fluorescent carbon materials with the size less than 20nm, and have the advantages of good water solubility, low toxicity, low cost, rich raw materials and the like. These advantages make carbon dots have wide application in many fields, such as biological imaging, fluorescence sensing and other research fields. At present, carbon dots have the defects of low detection sensitivity, poor adsorption selectivity and the like in the field of metal ion detection, and the fluorescence property of the carbon dots needs to be improved by doping heteroatoms through chemical modification. Sodium lignosulfonates are a waste material from the paper industry. The annual output of the lignosulfonate in China is more than 450 million tons, and only a small amount of lignosulfonate is used as an additive of building materials, so that not only is the resource waste caused, but also the environment is seriously polluted.

Iron ions are an important transition metal element, and the content of the iron element in human bodies directly influences hematopoiesis, synthesis of various enzymes, growth promotion and the like. When the iron element in the human body is excessive, vomiting, diarrhea and the like can occur, and various health problems are caused. In addition, iron is one of the most commonly used industrial raw materials, and has a very adverse effect on the ecological environment due to long-term irregular sewage treatment. Therefore, the development of a simple and green preparation method of the fluorescent carbon dots has important significance for quickly and effectively detecting iron ions.

Disclosure of Invention

The technical problem to be solved is as follows: the invention provides a nitrogen-sulfur double-doped carbon dot, a preparation method and application thereof.

The technical scheme is as follows: a preparation method of nitrogen-sulfur double-doped carbon dots comprises the following steps: the first step is as follows: weighing sodium lignosulfonate and cysteine, adding the sodium lignosulfonate and the cysteine into deionized water to prepare a mixed solution, wherein the mass ratio of the sodium lignosulfonate to the cysteine is (1-50): 5, and the mass ratio of the sodium lignosulfonate to the distilled water is (1): 5-50); the second step is that: adding the mixed solution obtained in the first step into a reaction kettle with a polytetrafluoroethylene inner container, and reacting for 10-24 hours at 150-220 ℃; the third step: and centrifuging and filtering the product obtained in the second step by using a filter membrane to finally obtain the nitrogen-sulfur double-doped carbon dots.

The temperature in the second step of reaction is 150-220 ℃, and the duration is 10-24 h.

And (3) performing solid-liquid separation on the product in the third step by adopting centrifugation or filtration, and removing macromolecular impurities from the obtained liquid by using a microporous filter membrane.

The nitrogen-sulfur double-doped carbon dots prepared by the preparation method.

The nitrogen-sulfur double-doped carbon dots are used for preparing and detecting Fe in water body³⁺Application in reagent。

According to the selective identification experiment of the synthesized carbon quantum dot on the metal ions, 3 mL of carbon quantum dot solution and 50 mu M of a series of metal ions Ag are respectively added into a 5 mL fluorescent cuvette⁺、Co²⁺、Ca²⁺、Cd²⁺、Mg²⁺、Pb²⁺、Zn²⁺、Mn²⁺、Ni²⁺、Cu²⁺、Fe³⁺And the fluorescence properties of each solution were measured.

Application of carbon quantum dots to water sample Fe³⁺The detection method comprises the following steps:

(1) establishing a standard curve: preparing multiple standard solutions, wherein carbon quantum dots with the same concentration are added in the standard samples, and Fe³⁺Gradually increases in concentration. Determination of fluorescence intensity and Fe by fluorescence Spectroscopy³⁺A quantitative relationship between concentrations of (c);

(2) and (3) detection: in Fe³⁺Adding carbon quantum dots into the solution to be detected to prepare a solution with the same concentration as the composite quantum dots in the step (1), measuring the fluorescence intensity of the solution to be detected by using fluorescence spectroscopy, and determining Fe in the solution to be detected according to a quantitative relation³⁺The concentration of (c).

Has the advantages that:

the carbon quantum dot raw material prepared by the method is derived from papermaking waste and biomass resources. Secondly, the carbon quantum dot provided by the invention has good biocompatibility, simple and easy preparation process, high detection sensitivity and can be used for detecting Fe³⁺. The invention has great significance for high-value utilization of biomass resources and environmental protection.

Drawings

FIG. 1 is a fluorescence spectrum of a carbon dot prepared in example 1 (a is an excitation spectrum, b is an emission spectrum).

Fig. 2 is a graph showing selective recognition performance of the carbon dots prepared in example 1 for a series of metal ions.

Detailed Description

The present invention is described in detail below by way of examples, which give detailed embodiments and specific operating procedures for further illustration of the invention and are not to be construed as limiting the scope of the invention.

Example 1

1) 0.2 g of sodium lignosulfonate and 0.3 g of cysteine are weighed into a beaker, 30 mL of distilled water are added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 170 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

2) Application of testing carbon quantum dots as fluorescent probes in metal ion detection

The prepared carbon quantum dots emit blue fluorescence under the irradiation of an ultraviolet lamp with the wavelength of 340 nm, and the fluorescence property of the carbon quantum dots and the selectivity experiment on metal ions are determined by using a fluorescence spectrum (figure 2).

Example 2

1) 0.3 g of sodium lignosulfonate and 0.2 g of cysteine are weighed into a beaker, 30 mL of distilled water is added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 14 h at 180 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

The prepared carbon quantum dots emit blue fluorescence under the irradiation of an ultraviolet lamp with the wavelength of 340 nm, and fluorescence performance of the carbon quantum dots and selectivity experiments on metal ions are determined by using fluorescence spectra.

Example 3

1) 0.4 g of sodium lignosulfonate and 0.1 g of cysteine are weighed into a beaker, 30 mL of distilled water are added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 160 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

Example 4

1) 0.1 g of sodium lignosulfonate and 0.4 g of cysteine are weighed into a beaker, 30 mL of distilled water are added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 180 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

Example 5

1) 0.4 g of sodium lignosulfonate and 0.1 g of cysteine are weighed into a beaker, 30 mL of distilled water are added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 180 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

Example 6

1) 0.4 g of sodium lignosulfonate and 0.1 g of cysteine are weighed into a beaker, 20 mL of distilled water are added, and stirring is carried out for 0.3 h. Adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 180 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.

Claims

1. The application of the nitrogen-sulfur double-doped carbon dots in the preparation of a reagent for detecting Fe3+ in a water body is characterized in that the nitrogen-sulfur double-doped carbon dots are prepared by the following method: weighing 0.2 g of sodium lignosulfonate and 0.3 g of cysteine, putting into a beaker, adding 30 mL of distilled water, and stirring for 0.3 h; adding the obtained solution into a 50 mL reaction kettle with a polytetrafluoroethylene inner container, reacting for 24h at 170 ℃, cooling to room temperature after the reaction is finished, centrifugally separating the obtained black product, collecting the solution part, and filtering by using a microporous filter membrane to obtain a brown yellow solution which is the carbon quantum dot with the fluorescence property.