Experimental and density functional theory study of the adsorption of N2O on ion-exchanged ZSM-5: Part II. The adsorption of N2O on main-group ion-exchanged ZSM-5

The adsorption and desorption of N2O on main-group ion-exchanged ZSM-5 was studied using temperature-programmed desorption (TPD) and density functional theory (DFT) calculations. TPD experiments were carried out to determine the desorbed temperature Tmax corresponding to the maximum mass intensity of N2O desorption peak and adsorption capacity of N2O on metal-ion-exchanged ZSM- 5s. The results indicated that Tmax followed a sequence of Ba2+ > Ca2+ > Cs+ > K+ > Na+ > Mg2+and the amount of adsorbed N2O on main-group metal cation followed a sequence of Ba2+ > Mg2+ > Ca2+ > Na+ > K+ > Cs+. The DFT calculations were performed to obtain the adsorption energy (Eads), which represents the strength of the interaction between metal cations and the N-end or O-end of N2O. The calculation results showed that the N-end of the N2O molecule was favorably adsorbed on ion-exchanged ZSM-5, except for Cs-ZSM-5. For alkali metal cations, the Eads of N2O on cations followed the order which was the same to that of Tmax: Cs+ > K+ > Na+. The calculated and experimental results consistently showed that the adsorption performances of alkaline-earth metal cations were better than those of alkali metal cations.     

植物叶面滞留颗粒物的数量和质量特征及方法比较

为定量认识并寻找可能方法来弥补或修正目前常用的水洗-滤膜法测定植物叶面滞尘能力的不足,更加直观和准确地反映叶面滞尘能力,选择北京市相对清洁的北京植物园和污染严重的国贸桥2个地点,利用环境扫描电镜测定了大叶黄杨(Euonymus japonicas)、国槐(Sophora japonica)、毛白杨(Populus tomentosa)、银杏(Ginkgo biloba)和紫叶李(Prunus cerasifera)5个树种的上、下叶表面滞留的颗粒物(PM)数量和粒径组成,计算出单位植物叶面积滞尘量,并与水洗-滤膜法进行比较。结果表明:植物叶面滞留的颗粒物数量以PM<10(粒径<10μm的颗粒物)为主,占总数的90%以上;污染严重的国贸桥叶表滞留的PM<2.5数量高于相对清洁的北京植物园;采用颗粒物计数法与水洗-滤膜法测定得到的叶面滞尘量之间存在显著线性关系,但两者数值相差很大。有必要进行严格的控制实验来确定导致差异的主要原因与机制,并藉此提出水洗-滤膜法的修正技术或发展多种方法的联合运用技术。     

苏胶地体碱质闪石柯石英榴辉岩的意义

苏胶地体碱质闪石柯石英榴辉岩有两类：含碱质闪石（蓝闪石）黝帘石榴辉岩和含兰晶石碱质闪石榴辉岩．在这两类岩石的石榴石和辉石中均能见到柯石英残晶或其假象。估算其温压条件，温度为750－980℃、压力28．5～31．5×108pa；推测它们的形成是苏胶地体发生、发展、定位的终结产物。     

造纸黑液直接碱回收技术中试

造纸黑液直接碱回收技术是国外70年代发明的一项新技术．它借助于中间氧化物(Fe2O2)用浓缩、干燥、燃烧等热工手段处理造纸黑液，利用其中有机固形物的化学能回收黑液中的碱，从而消除黑液污染，井实现造纸用碱的基本自给．该技术的原理是将造纸黑液固形物和赤铁矿石(Fe2O3)在高温下反应，     

芒杆制浆碱回收工艺改造的几点探讨

介绍了建阳造纸厂碱回收的技术特点，分析了存在问题，提出了整改措施。     

盐生植物碱蓬在土壤修复及废水处理中的研究现状

介绍了我国土壤污染与水污染概况,论述了盐生植物碱蓬的生态学特性及其在土壤修复和废水处理中的研究现状,提出将碱蓬应用于高盐有机污染物的去除这一研究新方向.     

用镍矿渣生产碱激发镍矿渣水泥研究

本研究在碱矿渣水泥的研究基础上，以镍矿渣作为主要原料研究了碱激发镍矿渣水泥及其主要性能。研究结果表明，采用校正剂对镍矿渣的化学成分进行校正后再用碱性激发剂进行激发，可获得镍矿渣含量达78％，强度标号达525＃的碱激发镍矿渣水泥。该种水泥能够充分利用镍矿渣，减少环境污染。