Synthesis Of Bio-carbon High Sensitive Quantum Dots And Their Sensing Properties

Antibiotics are widely used for their ability to inhibit or kill other infective microorganisms at low concentrations,but their overuse is gradually expanding,leading to serious problems.Living,aquaculture and medical wastewater containing various antibiotics are directly discharged into rivers and water courses.This causes increased amounts of antibiotic content in the water environment and soil,which can be transferred to food.Finally,they return to the human body through various channels,causing tolerance bacterial flora in the body,which greatly threatens human health.This situation has made the detection of antibiotics in the environment and the development of new antibiotic analysis methods extremely important.In this dissertation,quantum dots materials with high activity are selected as electrocatalytic active materials for this situation.Firstly,we used the canna stem with porous structure as a biological template to prepare high-sensitive quantum dots/bio-carbon materials.In the calcination temperature of 800°C,the micro-morphology of canna stem was precisely replicated by bio-carbon materials.On this basis,three kinds of quantum dots materials were synthesized on the basis of bio-carbon materials,namely,CeO₂,CeO₂-Cu₂O and CeO₂-Zn O.The obtained materials were characterized by X-ray diffraction,scanning electron microscopy?FESEM?,high resolution transmission electron microscopy?HRTEM?and energy dispersive spectroscopy?XPS?.The experimental results showed that quantum dots materials could be uniformly loaded on the surface of bio-carbon,and there was no agglomeration phenomenon.The crystal sizes of the quantum dots CeO₂bio-carbon material and quantum dots CeO₂-Cu₂O were about 6.7 nm and 6 nm.The crystal size of the cerium oxide crystal of the quantum dots CeO₂-ZnO bio-carbon material was about 6.2 nm,and the crystal grain size of the zinc oxide was about 7 nm.The effective small-size of quantum dots improved the electrocatalysis activity of the material and provided a good catalytic environment for electrochemical sensing.The effect of ceria quantum dots on sodium penicillin produced by cerium nitrate at different concentrations was studied by experiments.The results showed that when the concentration was 0.1 mol/L,the peak of redox current was the largest.When the molar ratio of cerium and copper was 1:2 and the molar ratio of cerium and zinc was1:2,the peak of redox current is the largest.In the case of the definite quantum dot material,the penicillin sodium solution with different concentrations was detected.The results showed that the oxidation peak current increased gradually when the concentration of penicillin sodium solution increased from 200 ppm to 800 ppm,and the value of the linear curve equation R² became excellent.As a result,it can be used to detect the residue of penicillin sodium in the actual sample.