自由基化学改性氧化石墨烯对亚甲基蓝的吸附性能
Adsorption of Methylene Blue by Graphene Oxide Chemically Modified with Free Radicals
投稿时间:2017-03-17  修订日期:2017-04-28
中文关键词:氧化石墨烯  羟基自由基  吸附性能  亚甲基蓝
英文关键词:graphene oxide  hydroxyl radical  sulfate radical  adsorption capacity  methylene blue
基金项目:国家重点研发计划项目(2016YFC0400501/2016YFC0400509)
作者单位E-mail
孙林燕 东华大学环境科学与工程学院国家环境保护纺织工业污染防治工程技术中心上海 201620 835472858@qq.com 
杨飞 东华大学环境科学与工程学院国家环境保护纺织工业污染防治工程技术中心上海 201620 1009478942@qq.com 
封敏 东华大学环境科学与工程学院国家环境保护纺织工业污染防治工程技术中心上海 201620 14718130@qq.com 
王兆慧 东华大学环境科学与工程学院国家环境保护纺织工业污染防治工程技术中心上海 201620 zhaohuiwang@dhu.edu.cn 
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中文摘要:
      氧化石墨烯(Graphene Oxide,GO)拥有较大的比表面积和较高的稳定性,可用来吸附水体中的多种污染物,其潜在功能稳定性具有规模化应用前景。考虑到GO在高级氧化体系中结构和形貌会发生改变,探究了经UV/H2O2和UV/过硫酸盐(Persulfate, PS)产生强氧化性自由基的体系处理后所得GOs对亚甲基蓝(Methylene Blue, MB)的吸附性能。氧化性自由基体系光源为300 W中压汞灯,30 mL GO储备液(1 mg/mL)在2种氧化体系下反应1、2、4 h后制得GOs。实验考察了不同反应条件对GOs吸附动力学的影响,傅里叶变换红外光谱(FTIR)研究了GOs氧化前后表面官能团的变化。结果显示,经UV/H2O2, UV/PS氧化1 h后,GOs表面的含氧官能团数量开始明显减少;吸附动力学过程更符合准二级动力学模型(R2>0.999);吸附热力学过程更符合Langmuir模型,MB饱和吸附量(经UV/H2O2和UV/PS氧化1、2、4 h后分别记G1-1, G1-2, G1-3, G2-1, G2-2, G2-3)依次为580.26, 591.80, 598.63, 521.77, 554.91, 568.00 mg/g。研究表明,GO可以快速吸附较大浓度范围内的MB,且对低浓度染料表现出更好的去除效果;GO对MB的吸附量随着pH值的增加逐渐增大,且在碱性条件下的增加得更明显;经氧化处理后,GOs的吸附性能随着氧化时间的增长,性能减弱,尤其在UV/PS体系中更为显著。
英文摘要:
      Graphene oxide (GO) has been used to absorb pollutants from water due to its large specific surface area and high stability. However, large-scale production of GO has raised concerns about its functional stability, given that the GO structure could be altered by advanced oxidation processes. In this study, the removal efficiency of methylene blue (MB) by GO was investigated after GO oxidation by UV/H2O2, generating the hydroxyl radical, or UV/ persulfate (PS), generating the sulfate radical. A series of GOs with varying degrees of oxidation were synthesized by exposing GO stock solutions (1 mg/mL) to a 300 W medium-pressure Hg lamp for 1, 2 and 4 h in the presence of H2O2 or PS. We explored the influence of reaction conditions on the adsorption kinetics of GO by setting the initial MB concentration at 5, 20, 50 or 100 mg/L and pH in the range 2-10. Changes in GO surface functional groups were characterized with Fourier Transform infrared spectroscopy (FITR) and functional group density began to decline after one hour of oxidation. The adsorption kinetics of GO were well described by pseudo-second-order kinetics (R2>0.999). The Langmuir model best fit the adsorption data and was used to calculate the maximum MB adsorption by GO. The various GO preparations were designated by two subscripts, the first denoting the oxidant system (1=UV/H2O2 and 2=UV/PS) and the second denoting the time of UV exposure (1, 2 or 4 h). The maximum MB adsorbed by G1-1, G1-2, G1-3, G2-1, G2-2 and G2-3 were, respectively, 580.3, 591.8, 598.6, 521.8, 554.9 and 568.0 mg/g. Absorption by GO decreased with increasing oxidation time, particularly when oxidized by the UV/PS system, but increased with increasing pH values and alkaline conditions obviously enhanced the absorption process. The modified GO displayed rapid adsorption at higher MB concentrations, but better removal efficiency at lower MB concentrations.
孙林燕,杨飞,封敏,王兆慧.2018.自由基化学改性氧化石墨烯对亚甲基蓝的吸附性能[J].水生态学杂志,39(6):106-113.
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