Levitt Nicholas P, Zhang Renyi, Xue Huaxin, Chen Jianmin
Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843, USA.
J Phys Chem A. 2007 Jun 7;111(22):4804-14. doi: 10.1021/jp0700480. Epub 2007 May 12.
We have investigated the heterogeneous interaction between a number of carboxylic acids and soot generated from different fuel sources and formation mechanisms. A low-pressure fast flow reactor in conjunction with ion drift-chemical ionization mass spectrometry detection was employed to study uptake of monocarboxylic (benzoic, oleic, and steric) and dicarboxylic (glutaric, maleic, oxalic, and phthalic) acids on deposited soot surfaces formed by combustion of methane, propane, and kerosene. Most acids exhibited irreversible uptake on the soot surfaces and the uptake coefficient was measured in the range of 9 x 10(-4) to 1 x 10(-1) estimated based on the geometric surface areas. Brunauer, Emmett, and Teller surface areas of the deposited soot surfaces were measured and the soot bulk and surface chemical compositions were evaluated with Fourier transform infrared spectroscopy and attenuated total reflection spectroscopy. Plausible uptake mechanisms were discussed on the basis of the measured soot physiochemical properties by comparing the mono and dicarboxylic acids.
我们研究了多种羧酸与不同燃料源及生成机制产生的烟灰之间的非均相相互作用。采用低压快速流动反应器结合离子漂移 - 化学电离质谱检测，研究一元羧酸（苯甲酸、油酸和硬脂酸）和二元羧酸（戊二酸、马来酸、草酸和邻苯二甲酸）在由甲烷、丙烷和煤油燃烧形成的沉积烟灰表面上的吸附情况。大多数酸在烟灰表面表现出不可逆吸附，基于几何表面积估算，吸附系数在9×10⁻⁴至1×10⁻¹范围内。测量了沉积烟灰表面的布鲁诺尔、埃米特和泰勒表面积，并用傅里叶变换红外光谱和衰减全反射光谱评估了烟灰的整体和表面化学成分。通过比较一元和二元羧酸，基于测得的烟灰物理化学性质讨论了合理的吸附机制。
