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Effects of Ultrasound Pretreatment on Eucalyptus Thermal Decomposition Characteristics As Determined by Thermogravimetric, Differential Scanning Calorimetry, and Fourier Transform Infrared Analysis.
ACS Omega ( IF 3.7 ) Pub Date : 2018-06-20 , DOI: 10.1021/acsomega.8b00382
Zhengbin He 1 , Jing Qian 1 , Zhenyu Wang 1 , Songlin Yi 1 , Jun Mu 1
Affiliation  

Samples were pretreated by ultrasound at 300 W and 28 kHz in three different solutions. The thermal degradation characteristics of the samples were then characterized via thermogravimetric, differential scanning calorimetry, and Fourier transform infrared analysis in a nitrogen environment. The characteristic of gas product release, the formation mechanisms of the main products, and the mechanistic basis for the effects of ultrasound on wood components were studied. The results showed that the gaseous products are the same with ultrasound pretreatment but the amounts are changed. The gaseous products mainly constitute of CO, H2O, CO2, CH4, and CH3COOH, and more gaseous products were produced at 361 °C than at 308 °C. The reaction rates for specimens pretreated in aqueous soda solution proceeded faster than specimens pretreated in aqueous acetic acid solution and distilled water. Moreover, the maximum FTIR spectra absorbance appeared around 341 °C for specimens pretreated in aqueous soda solution but appeared around 369 °C for the control sample and samples pretreated in distilled water or acetic acid solution. The heat flows for specimens pretreated in aqueous soda solution, compared to control group, was much lower. Additionally, hydroxyl and hydroperoxy radicals provided by ultrasound cavitation in alkaline conditions act to intensify the overall rates of reactions.

中文翻译:

超声预处理对桉树热分解特性的影响,通过热重,差示扫描量热法和傅里叶变换红外分析确定。

样品在三种不同溶液中以300 W和28 kHz的超声波进行了预处理。然后通过热重法,差示扫描量热法和氮气环境下的傅立叶变换红外分析对样品的热降解特性进行表征。研究了气体产物释​​放的特征,主要产物的形成机理以及超声对木材成分影响的机理基础。结果表明,超声预处理后的气态产物相同,但数量有所变化。气态产物主要由CO,H2O,CO2,CH4和CH3COOH组成,并且在361°C产生的气态产物比在308°C产生的气态产物更多。在苏打水溶液中预处理的样品的反应速率比在乙酸水溶液和蒸馏水中预处理的样品的反应速率快。此外,在苏打水溶液中预处理的样品的最大FTIR光谱吸光度出现在341°C左右,而对照样品和在蒸馏水或乙酸溶液中预处理的样品的最大FTIR光谱吸光度出现在369°C左右。与对照组相比,在苏打水溶液中预处理过的样品的热流要低得多。另外,在碱性条件下由超声空化作用提供的羟基和氢过氧自由基可增强反应的总速率。在苏打水溶液中预处理的样品的最大FTIR光谱吸光度出现在341°C左右,而对照样品和在蒸馏水或乙酸溶液中预处理的样品的最大FTIR光谱吸光度出现在369°C左右。与对照组相比,在苏打水溶液中预处理过的样品的热流要低得多。另外,在碱性条件下由超声空化作用提供的羟基和氢过氧自由基可增强反应的总速率。在苏打水溶液中预处理的样品的最大FTIR光谱吸光度出现在341°C左右,而对照样品和在蒸馏水或乙酸溶液中预处理的样品的最大FTIR光谱吸光度出现在369°C左右。与对照组相比,在苏打水溶液中预处理过的样品的热流要低得多。另外,在碱性条件下由超声空化作用提供的羟基和氢过氧自由基可增强反应的总速率。
更新日期:2018-06-20
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