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411.
2种孔径沸石分子筛对水中土霉素的去除研究 总被引:4,自引:3,他引:1
选择2种不同孔径的亲水性沸石分子筛5A和13X作为吸附材料,对水中的土霉素(OTC)进行吸附和脱附实验,重点考察pH、温度对吸附的影响,进行吸附动力学和热力学的计算,分析亲水性沸石分子筛的吸附机制.结果表明,2种分子筛对OTC均有较大的吸附量,吸附过程可用单层吸附模型拟合,在温度为298K、pH=7.0条件下5A和13X的饱和吸附量分别为667mg/g和1429mg/g;同一温度下13X的吸附量明显大于5A;二级动力学方程能较好地描述2种分子筛对OTC的吸附动力学,在解吸时,5A和13X分别得到91%和95%的OTC脱附率;溶液pH值对吸附影响较大,中性条件下分子筛对OTC的吸附量达到最大;热力学计算显示2种分子筛对OTC的吸附均属于自发的吸热反应,综合表观为化学氢键力占主导作用. 相似文献
412.
Mingqiang Huang Weijun Zhang Liqing Hao Zhenya Wang Li Fang Ruihong Kong Xiaobin Shan Fuyi Liu Liusi Sheng 《环境科学学报(英文版)》2010,22(10):1570-1575
Smog chamber experiments were performed to investigate the composition of products formed from photooxidation of aromatic
hydrocarbon ethylbenzene. Vacuum ultraviolet photoionization mass spectrometer and aerosol time-of-flight mass spectrometer were
used to measure the products in the gas and particle phases in real-time. Experimental results demonstrated that ethylphenol,
methylglyoxal, phenol, benzaldehyde, and 2-ethylfurane were the predominant photooxidation products in both the gas and particle
phases. However, there were some di erences between detected gas phase products and those of particle phase, for example,
2-ethylfurane, ethylglyoxylic acid, nitroethylbenzene, 3,4-dioxopentanal and ethyl-nitrophenol were only existing in the particle-phase.
The possible reaction mechanisms leading to these products were also discussed and proposed. 相似文献
413.
微波辐照程序升温与恒温解吸载甲苯活性炭 总被引:2,自引:2,他引:0
利用微波作为加热手段,采用恒温解吸和程序升温解吸两种方法对吸附了甲苯的活性炭进行了解吸研究。两种方法的操作条件分别为:1.恒温400℃;2.程序升温,初始温度及升温幅度均为100℃,每个温度点保持时间10min,终温500℃保持5min。结果表明,微波恒温解吸和程序升温解吸产生的甲苯气体浓度最高可达到56.7g/m3、28.7g/m3;两种解吸方法都可以在45min左右使活性炭达到90%以上的解吸效率。对两种方法的能量消耗进行分析后发现,相比400℃恒温解吸,程序升温解吸的能量消耗可以降低23.7%。 相似文献
414.
Contribution of black carbon to nonlinearity of sorption and desorption of acetochlor on sediment 总被引:2,自引:1,他引:1
Jianqiu Liu Yaobin Zhang Hong Chen Yazhi Zhao Xie Quan 《Frontiers of Environmental Science & Engineering in China》2009,3(1):69-74
In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption
isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and
desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400
and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores
on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the
desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich
sorption coefficient (K
f) increased from 4.07 to 35.74, and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower
than 23%, the sorption isotherm had a significant linear correlation (p = 50.05). In case of desorption, a significant nonlinear change could be observed when the content of BC was up to 13%. Increase
of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity, which
indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable. 相似文献
415.
通过振荡平衡吸附试验,研究了兽药金霉素在鸡粪和猪粪上的吸持特征并对其吸附机制和影响因素进行探讨.结果表明,金霉素能被畜禽粪便强烈吸附,吸附过程属于快速吸附,吸附等温线呈非线性,能用Freundlich模型很好地描述;雨水很难解吸被粪便吸附的金霉素,存在解吸迟滞现象,用甲醇、3 mol/L NaCl和3 mol/L MgCl2 3种溶液仅分别解吸出了18.3%~20.4%、18.7%~19.4%和55.7%~57.6%被粪便吸附的金霉素.金霉素在畜禽粪便上的吸附受pH和离子强度影响,随pH值和离子强度增大吸附量减少,二价钙离子体系比一价钠离子体系对吸附的影响大.表明有机质吸附和阳离子交换可能是金霉素在畜禽粪便上主要的吸附机制. 相似文献
416.
417.
为揭示煤中瓦斯解吸过程中加载微波作用对解吸特性的影响,分析探讨了微波辐射促进煤层瓦斯解吸的基本原理,研制了微波作用下煤中瓦斯解吸实验装置,对微波间断加载作用及无微波作用条件下煤中瓦斯解吸特性进行了对比实验研究。实验表明:微波作用对煤中瓦斯解吸具有明显的促进作用,微波作用时间越长,解吸量越大,解吸率越高。在微波作用40 s条件下,微波间断加载作用使得煤样瓦斯解吸量增加290%,解吸率达到87%,解吸速度最大提高率为1 020%。 相似文献
418.
419.
Jianqiu LIU Yaobin ZHANG Hong CHEN Yazhi ZHAO Xie QUAN 《Frontiers of Environmental Science & Engineering》2009,3(1):69-74
In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400 and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich sorption coefficient (K f) increased from 4.07 to 35.74, and desorption hysteresis became gradually obvious.When the content of BC in TOC was lower than 23%, the sorption isotherm had a significant linear correlation (p = 50.05). In case of desorption, a significant nonlinear change could be observed when the content of BC was up to 13%. Increase of BC content in the sediment would result in shifting the sorption-desorption isotherms from linearity to nonlinearity, which indicated that contribution of BC to nonlinear adsorption fraction became gradually remarkable. 相似文献
420.