| With the continuous development of society,water pollution,air pollution and bacterial pollution have become increasingly serious,human living environment has further deteriorated,and the world is facing environmental pollution crisis.In recent years,nanomaterials(NMs)have been widely used in the field of environmental purification due to their unique volume effect,surface effect and quantum size effect.Nano zinc oxide(Zn O)is a kind of multifunctional wide band gap semiconductor metal oxide,which is one of the the most morphologic nanoparticles.Due to its good biocompatibility,antibacterial,photocatalytic activity,piezoelectricity,and economy,it has attracted great interest.Nano Zn O is an n-type semiconductor with wide band gap and high surface energy.It is a material with rich and complex chemical defects.In order to improve the performance of nano Zn O and expand its application in the field of environmental purification,it is necessary and important to construct novel structures and functionalize nano Zn O without damaging its physical and chemical properties.The structure,morphology,and stability of nano Zn O are the key factors to determine its performance.Modified cellulose nanocrystals(CNC)with rich COO~-and OH~-groups and Zn O were used to construct nano particles,and CNC acted as a template and dopant.By adjusting the p H reaction conditions,multi morphology nano Zn O/CNC hybrid particles were obtained,which improved the interface properties of Zn O.It is a key problem to be solved that Zn O nanoparticles are easy to agglomerate in the preparation process.The choose of a substrate is one of the effective methods to solve the problem.Polypropylene(PP)non-woven fabrics are a kind of flexible material with three-dimensional network structure,which have rich pores and huge specific surface area.It provides an excellent base for improving the agglomeration of nano Zn O,and solves the problems of difficult recovery and recycling of nano Zn O powder materials.Furthermore,the performance improvement and function enhancement of Zn O/CNC hybrid particles is an important topic for practical application.The purpose of this paper is to explore the control methods of multi morphology nano Zn O,through the template doping,inorganic doping,organic doping,and composite methods to modify the function of nano Zn O on PP non-woven fabrics by in-situ and non-in-situ preparation of nano Zn O/CNC particles,to build a variety of shapes of non-woven fabrics-based p-n heterostructure,to design active response intelligent structure nano Zn O/CNC composite function materials.In order to expand the application of nano Zn O/CNC in the field of environmental purification,the effects of morphology and size on the structure and properties of nano Zn O/CNC were compared and analyzed.This paper mainly carried out the following work and obtained the relevant conclusions.(1)The key role of the dispersion,stability,morphology and size of Zn O nanoparticles to improve the performance is experimentally demonstrated.Spherical,flake and flower like Zn O/CNC hybrid materials were prepared by one-step green method by doping with mixed acid modified CNC template and adjusting p H reaction conditions.The formation mechanism was discussed.In addition,the antibacterial properties of Zn O/CNC hybrid materials with three morphologies were evaluated,and the antibacterial rates against S.aureus and E.coli were all over90%.Taking spherical Zn O/CNC as a typical example,its adsorption capacity for cationic dyes was investigated.The removal rates of methylene blue(MB)and malachite green(MG)reached more than 90%in 5 min.The adsorption process was in line with the pseudo second-order adsorption kinetic model.Zn O/CNC hybrid materials have good practical application value in the field of wastewater treatment and environmental purification.(2)ZnO/Cu2O heterojunction nanoparticles were experimentally constructed,and the key role of the size and morphology of Zn O/Cu2O heterojunction nanoparticles for their photocatalytic activity is experimentally demonstrated.Aiming at the problem of low photocatalytic performance of nano Zn O in visible region,and improving the separation efficiency of photoelectrons and holes of Zn O nanoparticles,p-n heterojunction structure nanocomposites were constructed by using Cu2O(p-type)with narrow band gap(2.0 EV)doped Zn O(n-type).In addition,in order to solve the problem of agglomeration in the preparation process of nano Zn O,three kinds of heterojunction Zn O/Cu2O photocatalysts with different morphologies were constructed by one-step water bath in situ growth method with PP non-woven fabrics(embedded into CNC by thermal ultrasonic method)as the substrate and p H reaction conditions were adjusted.The experimental results show that the flexible photocatalytic material has high photocatalytic degradation efficiency and recycling stability for both anionic and cationic dyes in the visible light region.The granular ZC12.0 has the fastest photocatalytic degradation rate,and the Zn O/Cu2O non-woven fabrics have excellent self-cleaning performance.In the construction of Zn O/Cu2O heterojunction structure,not only the formation of heterojunction is important,but also the size and morphology of heterojunction nanoparticles play an important role in its photocatalytic activity.(3)A high-sensitivity ZnO/PANI gas sensor with p-n heterojunction structure based on PP non-woven fabrics was constructed.In order to solve the problem of low conductivity of nano Zn O and improve the gas sensing performance of nano Zn O,three kinds of n-type nano Zn O with different morphologies were prepared by one-step water bath in situ growth method with PP non-woven fabrics as the substrate and controlling the p H reaction conditions.Uniform and compact p-type PANI nanofiber films were prepared on the surface of Zn O by vapor phase polymerization method(VPP).THe sensitive Zn O/PANI gas sensor supported on PP non-woven fabrics was prepared by constructing a p-n heterojunction structure.The PP non-woven fabrics substrate gives the sensor good flexibility and mechanical properties.The structure and morphology of heterojunction have a great influence on the gas sensitivity performance.At room temperature,PZN9.7 with tile masonry structure is responsive to a variety of volatile organic compounds(VOC)gases and humidity.The sensitivity to NH3(10 ppm)is as high as 4158%,and the detection limit is as low as 0.5 ppm.Meanwhile,it has good stability and high selectivity for NH3 detection.(4)Traditional nano ZnO materials are passive materials and cannot actively respond to environmental changes and stimuli.For this problem,an active response type PP non-woven fabrics loaded with core-guard structure nano-Zn O@PNIPAM/TD composite phase change material is successfully constructed,which has good temperature response.In this composite phase change material,PP non-woven fabrics are used as a flexible substrate,spherical nano Zn O/CNC hybrid particles are the core,and N-isopropylacrylamide(PNIPAM)nano-gel microspheres are used as small molecule reservoirs for loading drugs.The core-guard structure of Zn O@PNIPAM is encapsulated in the phase change matrix tetradecanol(TD).PNIPAM gel microspheres are diffusion barriers that control the release kinetics of small molecules,while TD is a container for microspheres and a switch for controlling the release.Using FITC dextran to simulate small molecules,and using fluorescent confocal to successfully monitor the intelligent temperature-sensitive controlled release process of the nuclear-guard structure nano Zn O@PNIPAM/TD composite phase change material.With tetracycline hydrochloride(TH)as a typical drug,the influence of external stimuli(temperature,p H)on the drug release behavior of smart composite phase change materials and the"on-off"temperature-sensitive switching effect were studied.Through temperature-sensitive antibacterial performance analysis,the material has a good temperature-sensitive antibacterial effect,and can realize the intelligent antibacterial and long-term antibacterial effects.In conclusion,this paper mainly used the p H template method to successfully regulate the multi-morphology nano Zn O.And a series of PP non-woven fabrics loaded with nano Zn O/CNC composite functional materials with novel structure were prepared by in-situ and non in situ methods,which showed excellent performance in antibacterial,gas sensing,dye adsorption,and photocatalytic degradation,and promoted the development of nano Zn O composite functional textiles in the field of environmental purification... |
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