Preparation Of Composite Biofilms With Enhanced Photothermal Properties

Fossil energy is currently the most important energy source in the world,but its depletion crisis and the resulting serious environmental pollution have become major challenges.Fortunately,we found that solar energy can be used as a steady stream of clean energy,which can effectively solve the problem of energy shortage.The development of photothermal conversion materials is one of the means to effectively utilize solar energy and has received extensive attention due to it can convert the light into heat energy.Waste eggshell membrane(ESM),as a biomass material,has a three-dimensional(3D)interwoven fiber structure,can provide an unique support platform for nanoparticles functionalization.Au NP(Ag NP)can convert the light energy into heat energy through the surface plasmon resonance(LSPR)effect,which is related to its shape and size etc.The LSPR effect dependents on the composition of noble metal nanoparticles,and the intensity of light irradiation.Here,we attempted to adjust the sizes,shapes and types of noble metal nanoparticles,and studied their capabilities to the light absorption.Boron nitride nanosheets(BN)have high thermal conductivity and high surface area.Although BN does not converted light to heat energy,it can establish a thermal conductivity network,lead to the quickly conducting of heat energy from noble metal nanoparticles to the surface and concentrated to avoid the thermal lost.Carbon nanotubes(CNT)as a good thermal conductivity,have strong light absorption in the visible-near-infrared band and high photothermal conversion effect.This work aims to construct composite membranes with enhanced photothermal effect based on ESM biomass materials,and study the assembly method and their photothermal conversion mechanism.This composite membrane has wide potential applications in photothermal drug release,treatment and seawater desalination.The thesis includes the following three aspects:1.Photothermal properties of chloride ion-etched silver nanoparticles/eggshell membraneThe discs-shape Ag NP were loaded on the ESM via electrostatic self-assembly,and then were etched into the triangular plate Ag NP by chloride ion etching.The morphology and chemical composition of the composite film were analyzed and discussed.Subsequently,the photothermal conversion properties of the multifunctional composite films were further investigated,and it was found that the temperature was related to the LSPR properties of Ag NP and irradiation intensity.2.Photothermal properties of gold(silver)nanoparticles and boron nitride composite eggshell membraneAu NP were assembled on ESM fibers by in-situ generation,and then boron nitride was wrapped on the surface of ESM fibers by physical adsorption to prepare a multifunctional composite membrane.The obtained composite films shown excellent photothermal converted property,which was benefited from the synergistic effect of the LSPR effect of Au NP(Ag NP)and the high thermal conductivity of BN.3.Photothermal properties of gold(silver)nanoparticles and carbon nanotube composite eggshell membranes.CNTs were coated on the surface of Ag NP-loaded ESM membrane by ultrasonic dispersion to prepare a dual-composited ESM membrane.The multifunctional composite films shown stronger and wider light absorption due to excellent properties of CNTs,resulting in higher photothermal conversion efficiency.The multifunctional composite membrane has great potential applications in biomedicine and seawater desalination.