| HUA Yu,WANG Gongxun,LIU Fucai,HUANG Bo,ZHU Mingqiao.Preparation of TiO2-loaded Functional Aggregates and Their Photocatalytic Performance[J],53(18):231-241 |
| Preparation of TiO2-loaded Functional Aggregates and Their Photocatalytic Performance |
| Received:February 19, 2024 Revised:August 13, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.18.021 |
| KeyWord:TiO2 suspension stability NT loaded functional aggregates photocatalytic performance NO degradation rate |
| Author | Institution |
| HUA Yu |
School of Civil Engineering, Hunan Xiangtan , China |
| WANG Gongxun |
School of Civil Engineering, Hunan Xiangtan , China ;Hunan Engineering Research Center for Intelligently Prefabricated Passive House, Hunan University of Science & Technology, Hunan Xiangtan , China |
| LIU Fucai |
School of Civil Engineering, Hunan Xiangtan , China ;Guangdong Gaiteqi New Materials Technology Co,.Ltd, Guangdong Qingyuan , China |
| HUANG Bo |
School of Civil Engineering, Hunan Xiangtan , China |
| ZHU Mingqiao |
School of Civil Engineering, Hunan Xiangtan , China ;Hunan Engineering Research Center for Intelligently Prefabricated Passive House, Hunan University of Science & Technology, Hunan Xiangtan , China |
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| Abstract: |
| The work aims to apply a loading method for the preparation of functional nano-TiO2 (NT) aggregates on a carrier substrate, so as to increase the effective surface area of NT by capitalizing on its distinctive light absorption characteristics, enhance the photocatalytic performance of the aggregates, and optimize the utilization efficiency of NT. The integration of these functional aggregates into building materials has the potential to enhance their overall functionality and environmental sustainability. Quartz sand was selected as the support material and NT suspension was prepared by combining a surfactant solution with the NT powder. The loading of NT onto the surface of quartz sand was achieved through immersion, resulting in the formation of functional aggregates with loaded NT. A range of analytical techniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF) and Fourier transform infrared spectroscopy (FT-IR), were employed to characterize the materials. These analyses were conducted with the objective of evaluating the dispersion stability of the NT suspension, the microstructure of the NT functional aggregates and the loading amount of NT. The photocatalytic performance and stability of the loaded NT functional aggregates were evaluated by measuring the degradation rate of NO gas with a gas analyzer. The effects of NT suspension concentration, loading time and cyclic loading on the photocatalytic performance and stability of the functional aggregates were investigated. The results demonstrated that the stability of the NT suspension was optimized when it was prepared with a 0.5% SDS surfactant solution at a concentration of 1%. The quartz sand, which had been pre-treated with a 2 mol/L NaOH solution for 24 hours, exhibited the most effective alkali modification, thereby facilitating the subsequent loading process. The immersion of silica sand in the NT suspension for 30 minutes, followed by drying and cyclic loading for five times, resulted in the formation of functional aggregates with a surface NT content of approximately 0.34%. Notably, these aggregates exhibited an exceptional NO degradation rate of 98% when subject to NO gas testing. Further experiments were conducted to assess the stability of the loaded NT functional aggregates. These were immersed in freshwater and saturated Ca(OH)2 solution for 7 days. The results demonstrated that the loss rates of surface Ti content were 11.3% and 9.5%, respectively, with a slight reduction in NO degradation rates of 88% and 91%. Notwithstanding the increase in the loss rate of surface Ti content to 21.9% under rinsing conditions, the photocatalytic performance remained at 70%. In conclusion, the photocatalytic performance of the loaded NT functional aggregates demonstrates a positive correlation with increasing NaOH solution concentration, pretreatment time, NT suspension concentration, and cyclic loading times. Cyclic loading is identified as the factor with the greatest effect on the photocatalytic performance of the aggregates. Moreover, the alkali pre-treatment process facilitates the formation of Ti—O—Si chemical bonds, thereby enhancing the photocatalytic performance and durability of the functional aggregates. The successful integration of these loaded NT functional aggregates into building materials promises to enhance their environmental sustainability and functionality in various applications. |
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