| Aluminum-water（Al-H2O）reaction hydrogen production technology has become a research focus in the field of hydrogen production in recent years due to its unique advantages such as simple operation,integrated storage and transportation,and online hydrogen supply.Considering that the Al-H2O reaction for hydrogen production generates alumina hydrate at the same time.If this byproduct can be exploited and utilized with high value-added,it will certainly promote the market application of Al-H2O reaction hydrogen production technology from an economic point of view.Based on this background,this thesis investigated its byproducts to prepare high-purity pseudoboehmite（PB）and applied it on catalytic support in petrochemical field;Based on the obtained high-purity PB,support-type composite photocatalysts were successfully prepared.Meanwhile,their photocatalytic properties and mechanisms were also investigated.Through the optimization of the support and photocatalyst,a composite photocatalyst with more ideal synergistic effect was further constructed.Using it as an aluminum source to replace the traditional aluminum source with complicated production process,the nanoscale long afterglow luminescent materials have been successfully prepared,and applied to advanced anti-counterfeiting and fingerprint recognition,which further improves the application value and application potential of high-purity PB.As an important support material in chemical industry,high purity PB has more advantages than ordinary PB in catalytic reactions such as catalytic reforming,（de-）hydrogenation.Domestic demand reaches tens of thousands of tons per year,but the domestic technology is still immature and heavily relies on imports.The only international producer of high-purity PB is the German company-Sasol（trade name SB Powder）,which is produced by hydrolysis of alcoholic aluminum and sold at a high price.In this thesis,high purity PB was prepared through the study of the byproducts of hydrogen production technology by Al-H2O reactions,and the pilot production of tonnage products was realized as well as the catalytic bench test was also carried out.The purity of the product is comparable to that of SB powder and the process is simple and low-cost,which breaks bottlenecks in domestic production of high-purity PB while realizing the added value increase of the byproduct of hydrogen production from aluminum water reaction.Further,the pore structures of the obtained high-purity PB was modulated to expand its application scope as catalyst carriers.In this thesis,a novel process pathway for the preparation of high-purity PB was constructed based on the aluminum-water reaction.And the corresponding products were subjected to performance modulation and application development,which provided the theoretical and application basis for realizing the industrial application of high-purity PB in multiple fields and aspects.The main research contents and conclusions of this thesis include the following parts:1.The by-products of the aluminum-water reaction for hydrogen production technology were studied and characterized in detail.By temperature control of the aluminum-water reaction,high-purity PB was prepared at 80℃,which is comparable to SB powder.Comparison of the purity and pore structures shows that the high-purity PB prepared by this method not only has a low total impurity content,with the representative impurity Na and Fe much lower than that of SB powder,but also has pore structures comparable to those of SB powder.Therefore,the high-purity PB prepared based on the Al-H2O reaction is highly competitive in terms of production cost and process route,which provides new approach for the industrial production of high-purity PB.Meanwhile,the products bayerite and bohmite obtained at 40～50°C and 130～160°C of Al-H2O reaction,as well as the calcined products of the three alumina hydrates were characterized and analyzed.This work not only deepens the understanding of hydrogen production technology by Al-H2O reaction and realizes the full utilization and value-added enhancement of its by-products,but also provides a basis for the property modulation and application development of high-purity PB.2.In order to further broaden the application field,the pore structures of obtained high-purity PB were modulated based on aluminum-water reaction using（NH4）2CO3,economical and easy to remove,as a pore expander.Bird’s nest PB with high specific surface area and excellent pore structures were prepared based on structure-directed and decomposed punching action.The bird’s nest-like PB is composed of cross-packed nanostrips structures with the specific surface area up to 465.2 m2 g-1,pore volume of 1.0 cm3 g-1,and pore diameter of 8.7 nm.In order to explore its potential application in the field of photocatalyst support,the support-type composite photocatalyst Ti O2/γ-Al2O3 was successfully prepared by using it as a support precursor.The prepared Ti O2/γ-Al2O3 can remove 75.85%of tetracycline hydrochloride（TCH）（Ti O2:PB=1:0.5）under LED light（380-780 nm）irradiation,which was much higher than that of pure Ti O2.Meanwhile,the composite catalyst still maintained a high removal efficiency after four cycles.Benefiting from the high purity,high specific surface area and excellent pore structures of the PB,the composite catalyst has stronger adsorption capacity and excellent recycling performance.γ-Al2O3 can supports and disperses the Ti O2 nanoparticles and provides defective energy levels,which reduces the compounding efficiency of carrier,and therefore significantly enhances the photocatalytic activity.This work provides an economical and simple method to improve the pore structures of PB,and confirms the potential application of bird’s nest-like PB obtained in the construction of support-type composite photocatalysts.3.Compared with TiO2,BiVO4 has strong visible light response and higher solar energy utilization.Therefore,Bi VO4 was selected as the photocatalyst,and the bird’s nest-like PB previously prepared was used as the support to construct the support-type composite photocatalyst Bi VO4/PB for the photocatalytic removal of antibiotics.Based on the synergistic effect of adsorption and photodegradation,Bi VO4/6%PB could remove 87%of TCH after 2 h of irradiation with LED lamps（380-780 nm）,in which the photodegradation rate could reach 63%.Its adsorption efficiency and photodegradation rate constant were three and two times higher than those of pure Bi VO4,respectively.Meanwhile,the removal rate could still reach 80%after four cycles.In addition,Bi VO4/6%PB also showed excellent AMX（amoxicillin）removal performance（76%）.It was analyzed that the loading of PB can effectively solve the problem of Bi VO4 nanoparticle agglomeration,which is not only conducive to increasing the photogenerated carrier separation and transfer efficiency,and enhancing the light absorption,but also improving the cycling stability and adsorption performance of the catalyst.This work demonstrates the outstanding advantages of bird’s nest-like PB as a support in improving the agglomeration of active components,increasing the specific surface area,and increasing the cecycling performance and thus provides a theoretical basis for the wider and deeper application of PB in the field of photocatalytic field.4.As a byproduct of hydrogen production by Al-H2O reaction,high-purity PB has the advantages of high purity,low cost and simple preparation process,making it an ideal candidate for aluminum source.Using it as aluminum source,nanoscale aluminate long afterglow luminescent materials SAO-G and SAO-B were prepared and applied in the fields of anti-counterfeiting encryption and latent fingerprint identification in this work.Both SAO-G and SAO-B exhibit unique hexagonal nanosheet morphology with green and blue light emission,respectively.The average afterglow times were 11 s and 61 s,respectively.Based on the different colors,different afterglow times and the overlapping of images,a highly covert and reliable anti-counterfeiting process was achieved.Finally,SAO-G was functionalized by LBA（lysozyme-binding aptamer）though the process of Si O2 coating,carboxyl group modification,and aptamer binding.Beneficial from the molecular recognition and excellent afterglow properties,the SAO-G@Si O2-LBA realizes latent fingerprint visualization process with anti-interference and high sensitivity.This work expands new application fields and shows the broad application prospects of high-purity PB.It also provides a more economical method for the preparation of nanoscale long afterglow luminescent materials and a new idea for its application direction. |
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