Preparation Of The Ceramic-based Microreactor And Its Application In Photocatalytic Reaction

The microreactors with channel sizes between submicron and submillimeter have the advantages of high mass transfer efficiency and enhanced reaction process Currently,microreactors are mostly prepared by metals,polymers and glass.The processing technology of the microreactors is complicated and the cost is high.The limitations of materials make it difficult to meet the requirements of special reaction conditions.The ceramic material has good chemical stability and thermal stability,which can deal with harsh environments such as high temperature and corrosion However,ceramic materials have the problems of preparing,such as difficulty in micromachining,poor sealing strength and difficulty in connecting components Therefore,the selection of suitable ceramic materials and the development of micromachining and packaging technologies are necessary conditions for broadening the application fields of microreactors.Alumina ceramics have the advantages of wear resistance,high temperature resistance and strong chemical resistance,but alumina is easily deformed after sintering and has poor thermal shock resistance.Compounding it with cordierite can improve the overall performance of the composite material and make it more suitable for micromachining.The introduction of ceramic-based microreactors into the field of photocatalysis can also provide a reliable solution to the problems of low mass transfer efficiency and low photon transfer efficiency in conventional reactorsIn this paper,alumina-cordierite composite ceramic material was selected as the substrate.Through mechanical micromachining,sacrificial template,resin bonding and curing,a ceramic-based microreactor suitable for photocatalytic degradation reaction was prepared.The main researches were as follows(1)Research on the preparation of alumina-cordierite composite ceramic materials Through single factor experiments,the best material ratio and the best sintering mechanism were studied,and the material system A2 in accordance with the microreactor preparation was obtained.The composition and conditions of A2 were 20%cordierite,80%alumina,3%titanium dioxide,appropriate amount of other additives,Sintering at 1400? for 60min,bulk density 3.173g/cm3,water absorption rate of 0.047%,alkali resistance loss of 0.021%,thermal shock resistance of 12 times,flexural strength of 163 MPa(2)Research on the preparation of ceramic-based microreactor with transparent window.By simplifying the mechanical micromachining method,a serpentine microchannel with a width of 0.5mm,a depth of 1mm and a length of 300mm was processed on the surface of the composite green ceramic.Than the hydrophobic modification and catalyst loading were carried out.The transparent window encapsulated the ceramic microchannel by optimizing the process of sacrificial template and resin bonding(3)Research on the application of photodegradation in ceramic-based microreactor.The ceramic-based microreactor module was connected to each component through a self-made fixture.A 22.5W UV-LED ultraviolet lamp was used as the degradation light source.Than a photodegradation microreaction system was built to study the basic performance of the photodegradation ceramic-based microreactor.Through the flow experiment,the optimum flow rate of the microreactor was determined to be 40 ?l/min.By comparing the degradation effects of different catalysts in microreactors and conventional suspension reactors,the results showed the existence of photodegradation reactions in microreactors and the microfluidic reaction have a certain promotion effect on the degradation performance of catalysts.After repeated experiments,the microreactor remained intact after 30 working cycles and the degradation efficiency remained at 47.3%.This indicated that the photodegradable ceramic-based microreactor prepared in this study has good degradation performance and durability.