Preparation method and application of carbon quantum dots for penetrant testing of stone cultural relics

Abstract

A preparation method of carbon quantum dots for penetrant testing of stone cultural relics comprises the following steps: mixing ginkgo leaves serving as a raw material with deionized water, performing high-pressure cooking at 110-125 DEG C and 180-200KPa for 2-3 hours, filtering out filtrate, and removing impurities. The carbon quantum dots prepared by using the ginkgo leaves as the raw material have high fluorescence quantum yield (up to 6.2%), and have excellent fluorescence intensity; the particle size distribution is narrow and uniform and is about 3.1 nm, and the carbon quantum dots are excellent in stability and not prone to sedimentation and aggregation; and very strong fluorescence intensity can still be detected under the ultra-low concentration of 2 ng / L, and the method is suitable for penetrant testing of cultural relics with relatively large volumes and long internal crack paths.

Description

technical field [0001] The invention relates to the technical field of nanomaterials, in particular to a preparation method and application of carbon quantum dots used for leak detection of stone cultural relics. Background technique [0002] In cultural relics and historic sites, as time goes by, a large number of cracks will appear in stone cultural relics, and the main reasons for the formation of cracks are natural rainfall erosion, seepage of rock mass, water seepage and erosion are common phenomena of cultural relics damage, usually, cultural relics There are cracks inside, and the upper end of the cultural relics receives rainwater or water seepage from the rock mass flows to the lower end of the cultural relics with the cracks, and forms erosion and weathering at the seepage points, forming cracks, and gradually expanding the cracks, causing serious damage to cultural relics. In the treatment of the water seepage problem of cultural relics, it is an important basic w...

AI Technical Summary

Problems solved by technology

However, carbon-14 technology involves expensive materials, preparation equipment and complicated processes, which severely limit the practical application of carbon-14 technology

The disadvantage of potassium iodide is that when the water in the potassium iodide solution evaporates, potassium iodide will generate solid crystals with increased volume in the crack, causing the original crack to expand

Carbon quantum dots (CQDs) are a new type of fluorescent nanoparticles with high fluorescence intensity, excellent photostability, high biocompatibility, and environmental friendliness. They are the preferred materials for tracers. At present, there are many methods for preparing carbon quantum dots. Such as acid-base assistance, microwave treatment, hydrothermal and other methods, the most common of which is the hydrothermal method, but the disadvantage of the hydrothermal method is that the yield of the hydrothermal method is low, resulting in high production costs, and it is not suitable for large-scale production , if it is used in large-scale penetration testing projects, the hydrothermal method cannot satisfy

[0003] In the existing technology, there are special instruments for detecting cracks and defects inside cultural relics, but the depth that can be measured is relatively shallow, and it is not suitable for large-scale detection, especially for large-scale cultural relics such as the Leshan Giant Buddha, facing the leakage of larger cultural relics During detection, due to the large size of cultural relics and the long path of internal cracks, the requirements for tracers are extremely high. When carbon quantum dots are used as leak detection tracers, the problems faced are as follows: In nature, they are susceptible to external interference , during the infiltration process of the long detection path, the carbon quantum dots are prone to sedimentation or degradation, so that they cannot flow to the seepage point with the water body. In addition, due to the large size of the cultural relics, the detection time is long, and the detection process is easily affected by rainwater. Flushing dilution, the concentration of carbon quantum dots reaching the water seepage point is low, resulting in no fluorescence response detected at the water seepage point

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