Thermal behaviour of arsenic trioxide adsorbed on activated carbon.
Thermal behaviour of arsenic trioxide adsorbed on activated carbon.
复制标题
活性炭吸附三氧化二砷的热行为。
DOI：
10.1016/j.jhazmat.2008.12.048
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发表时间：
2009
影响因子：
13.6
通讯作者：
L. Helsen
中科院分区：
文献类型：
--
作者：
Frederic Cuypers;C. De Dobbelaere;A. Hardy;M. V. van Bael;L. Helsen
研究了三氧化二砷（As2O3）吸附在活性炭（AC）上的热稳定性和解吸性，这一现象有望影响铬化砷酸铜（CCA）木材废料低温热解过程中砷的释放。首先，对As2O3的同素异形体亚砷石进行了热重实验。样品在低于200℃的温度下开始升华，升华峰温度为271℃。随后，对吸附在AC上的as2o3样品进行了TG实验，结果表明，只有很少的as2o3(最大。在低于280℃的温度下，as2o3的挥发率为6±3wt%，而在440℃和600℃的温度下，砷的原始浓度分别为41.6（±5）wt%和28.5（±3）wt%。砷的主要挥发发生在300°C至500°C之间。通过对实验数据拟合Arrhenius模型，确定了脱附动力学参数、脱附活化能（Ed）和指前因子(A)，得到Ed=69kJ/mol， A=1.21×104s−1。可见，As2O3在AC上的吸附有助于As2O3的热稳定。因此，在CCA木材的低温热解过程中，as2o3吸附在木材热分解形成的煤型产物上，可以阻止砷的释放。
The thermal stability and desorption of arsenic trioxide (As2O3) adsorbed on activated carbon (AC) was investigated as this phenomenon is expected to influence the arsenic release during low temperature pyrolysis of chromated copper arsenate (CCA) wood waste. Firstly, a thermogravimetric (TG) experiment with arsenolite, an allotropic form of As2O3, was performed. The sample starts to sublime at temperatures lower than 200°C with a sublimation peak temperature of 271°C. Subsequently, TG experiments with samples of As2O3adsorbed on AC revealed that only very little (max. 6±3wt%) As2O3was volatilised at temperatures below 280°C, while still 41.6 (±5)wt% of the original arsenic concentration was retained at 440°C and 28.5 (±3)wt% at 600°C. The major arsenic volatilisation occurred between 300°C and 500°C. The kinetic parameters of desorption, activation energy of desorption (Ed) and pre-exponential factor (A), were determined by fitting an Arrhenius model to the experimental data, resulting in Ed=69kJ/mol, A=1.21×104s−1. It can be concluded that the adsorption of As2O3on AC can contribute to the thermal stabilisation of As2O3. Consequently, during low temperature pyrolysis of CCA wood arsenic release may be prevented by adsorption of As2O3on the coal-type product formed during the thermal decomposition of the wood.