Studies on adsorption equilibrium of xylenes in AEL framework using biased GCMC and energy minimization

The adsorption of xylene isomers in AlPO₄-11 (AEL network) was investigated using biased grand canonical Monte Carlo (GCMC) simulations. Preferential o-xylene adsorption was predicted by the simulations, in agreement with previously reported experimental data. In AlPO₄-11 the selective adsorption behavior comes from the smaller length of the o-xylene molecule along the crystallographic c-axis compared to p-xylene. This is in contrast to AlPO₄-5 and AlPO₄-8, where the ortho-selectivity is caused by the characteristic face-to-face positioning of o-xylene. Energy minimization studies were also performed in a flexible AlPO₄-11 lattice to study the structural changes upon xylene adsorption. The energy minimization study showed that the AlPO₄-11 crystal distorts upon p- and o-xylene adsorption. The distortion mechanism is related to the strong interaction between xylene methyl groups and the sieve oxygen atoms in the O3 position in the wide region of the pore.     

Influence of Pt particle size on catalytic combustion of xylenes on carbon aerogel-supported Pt catalysts

Pt catalysts supported on a carbon aerogel with different Pt particle sizes were studied in the combustion of o-xylene and m-xylene. Results found show that the activity of the catalysts increased with larger Pt particle size. In addition, the catalysts were activated during consecutive combustion runs and during time on stream. This activation depends on the Pt particle size and type of xylene isomer. Activation was due to the increase in Pt particle size during reaction. The lower activity of catalysts with smaller Pt particle size was due to the stronger PtO bonds formed during xylene combustion by the smaller Pt particles.     

影响邻二甲苯进料负荷的技术分析

对苯酐生产中影响邻二甲苯进料负荷的主要因素进行了定性分析，从而为实际生产操作过程的调整及高负荷催化剂的开发提供了理论依据。     

抗菌灭病毒涂料的研制及表征

在评价多种杀菌剂的抗病毒性能的基础上,筛选出杀菌和抗病毒性能均优异的功能助剂三氯苯基马来酰亚胺,用以研制成一种杀菌灭病毒功能内墙涂料。     

二甲苯不饱和聚酯树脂在30%硝酸中的腐蚀行为

通过失重及表面腐蚀层厚度的测定以及红外吸收光谱（ＦＴ－ＩＲ）、扫描电镜（ＳＥＭ）等分析手段研究了二甲苯不饱和聚酯树脂（ＳＵＰＲ）在３０％硝酸溶液中的腐蚀行为，提出了材料耐该介质腐蚀的机理。结果表明，失重和表面腐蚀层厚度经一定时间浸泡后趋于稳定，不同温度下达到的稳定失重和腐蚀层厚度值不同。腐蚀机理为：浸泡过程中试样表面发生了物理吸附及化学反应，形成了一层淡黄色的特，其厚度与温度有关。该层物质阻止了硝     

Emission inventory of VOCs from mobile sources in a metropolitan region

Based on methodologies developed by US EPA, European EMEP/CORINAIR, and Australian NPI, and the former emission inventory in Korea, two methods were applied to 151 villages in northeastern Seoul, Korea to estimate emission of VOCs from line and area vehicle sources depending on vehicle types with different fuel types. A discharge coefficient method for the line source on the Eastern main road was calculated by multiplying the emission amounts per unit of mileage, and a fuel exhaust coefficient method for the area vehicle sources on other roads was determined as multiplying the emission rates by the actual consumption of excess fuel. Results indicated the methods could be adequate for estimating the amounts of mobile emissions when limited information on mobile emission is available. The methods can be used to develop the emission model for all VOCs emission sources (point and non-point sources), which provides input data of atmospheric models.     

亚磷酸法直接合成亚磷酸二辛酯的研究

采用辛醇和亚磷酸直接酯化法来制备亚磷酸二辛酯用正交试验法确定了适宜的合成条件:以二甲苯为溶剂,反应温度190℃,反应时间为6h,正辛醇和业磷酸的摩尔比为3∶1,合成产率可以达到95.4％,通过红外光谱仪对产品进 行了表征.     

Biokinetic modeling of in situ bioremediation of BTX compounds-impact of process variables and scaleup implications

The impact of three process parameters, i.e. ground water velocity, oxygen-to-BTX mass ratio, and benzene, toluene and xylene (BTX) concentrations on first-order biodegradation kinetics in a pilot-scale in situ bioremediation system was assessed. Generally, first-order biodegradation coefficients decreased with ground water velocity, and increased with hydrogen peroxide dose and BTX concentration. First-order biodegradation rate coefficients for benzene, toluene, and o-xylene varied from 0.3 to 0.81, 0.24 to 0.72, and 0.21 to 0.63 d(-1), respectively. Biomass-specific first-order rate coefficients were insensitive to ground water velocity, and decreased with increasing BTX concentrations. At 10mg/l BTX concentration, the specific first-order coefficients increased with peroxide dose. However, at the 50mg/l BTX concentration and a peroxide dose of 1020 mg/l, a 30-70% reduction in specific first-order biodegradation coefficients was observed. BTX biodegradation kinetics in this pilot-scale system were approximately one-to-two orders of magnitude slower than in soil microcosms and mixed culture bioreactors, and about 200-300% higher than full-scale systems.     

Kinetics of o‐Xylene Combustion over a Pt/Alumina Catalyst

o‐Xylene combustion in air over a Pt/γ‐Al₂O₃ catalyst was investigated in a laboratory reactor at low concentrations typical for depollution applications. The results evidenced a slightly negative influence of o‐xylene concentration on combustion rate. A kinetic model of the combustion process was developed by using the Langmuir‐Hinshelwood mechanism, assuming the surface reaction between adsorbed oxygen atoms and adsorbed o‐xylene molecules as controlling step. The rate expression includes the influences of o‐xylene and water adsorption on the active centers of the catalyst. The estimation of rate expression parameters is based on o‐xylene conversion measurements obtained under conditions free of influences of physical steps.     

气相色谱法测定粗苯中苯、甲苯和二甲苯含量

建立了毛细管气相色谱法测定粗苯中苯、甲苯、二甲苯含量的方法。采用HP-5毛细管柱分离,氢火焰离子化检测器检测,单点标准对照法定量。该方法分析速度快,测定重现性好,准确度和精密度高,三苯各个组分相对标准偏差均小于6%,回收率在96.0%~100.8%间。