壳聚糖-沸石杂化膜的制备及其对甲基橙的吸附

采用物理共混法制备了壳聚糖-沸石杂化膜,用扫描电镜(SEM)和热重分析仪(TGA)对其进行表征,并系统地研究了壳聚糖-沸石杂化膜对甲基橙的吸附行为。结果表明,最佳质量配比为(沸石/壳聚糖)为1∶20;pH值对吸附的影响最为关键,在实验浓度的范围内对甲基橙溶液最大吸附量为974.05 mg/g。杂化膜对甲基橙的等温吸附行为符合Lang-muir模型,吸附动力学模式符合准二级动力学方程,考虑以化学吸附行为为主。杂化膜有良好的再生能力。     

非均相Fenton和非均相US-Fenton体系中甲基橙降解动力学

在初始pH=3的条件下研究了甲基橙在非均相Fenton体系和非均相US-Fenton体系中的降解动力学。研究内容包括表观动力学方程和活化能。研究表明,超声的引入可以提高甲基橙的降解效率和降解速率。对比非均相Fenton和非均相US-Fenton体系中的表观动力学方程表明超声的引入可以提高反应速率常数,此外,还可以提高H2O2的利用率。通过对比分析,超声的引入可以降低反应所需的活化能,在超声的存在下,甲基橙的氧化活化能为25.12 kJ/mol,而在没有超声的条件下,需要的活化能为41.49 kJ/mol。     

负载Pt对锐钛矿-板钛矿双相TiO_2光催化性能的影响

采用水热法合成了板钛矿-锐钛矿双相TiO_2,通过浸渍和氢还原法将贵金属Pt负载在双相TiO_2表面制成Pt/双相TiO_2催化剂。TEM表征结果显示:Pt/双相TiO_2催化剂中Pt的晶粒尺寸很小,晶粒尺寸分布较窄;低负载量(质量分数0.2%和2.0%)时,Pt晶粒在TiO_2表面分布非常均匀,Pt负载量达到4.0%时,Pt晶粒在TiO_2表面的分散性变差。光催化活性实验结果表明:负载Pt能显著提高双相TiO_2催化剂的甲基橙降解率;2.0%Pt/双相TiO_2催化剂的光降解性能最佳。光催化活性提高的主要原因是由于Pt颗粒的电子贮存能力促进了光生电子-空穴对的分离。     

The effect of cerium oxide additive on the performance and emission characteristics of a CI engine operated with rice bran biodiesel and its blends

In this study, the rice bran oil (RBO) has been converted into methyl ester with an aid of transesterification reaction. Chemically, transesterification means conversion of triglyceride molecule or a complex fatty acid into alcohol and ester by removing the glycerin and neutralizing the free fatty acids. The B20 blend samples [80% diesel + 20% biodiesel] were prepared for each methyl ester obtained from RBO and then the cerium oxide (CeO₂) nanoparticles were added to the each B20 blend samples at a dosage of 50 ppm and 100 ppm with an aid of ultrasonicator. Moreover, in the absence of any engine modifications, the performance and emission characteristics of those blend samples have been investigated from the experimentally measured values such as density, viscosity, cloud point, pour point, and calorific value while the engine performance was also analyzed through the parameters like exhaust gas temperature (EGT), brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust emission of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx). The experimental results reveal that the use of CeO₂ blended biodiesel in diesel engine has exhibited good improvement in performance characteristic and reduction in exhaust emissions.     

炼油厂二硫醚恶臭污染物的监测

建立了气相色谱-质谱法(GC-MS)及硫化学发光检测气相色谱法(GC - SCD)定性和定量测定炼油厂二硫醚类恶臭污染物二甲二硫、乙基甲基二硫醚和二乙基二硫醚的方法.当进样体积为0.1mL时,GC - SCD法的二硫醚最低检出限为0.1～0.2 mg/m3,二甲二硫和乙基甲基二硫醚的RSD不超过2.4％(n=5),二甲...     

直喷式柴油机燃用脂肪酸甲酯的排放特性

脂肪酸甲酯是由生物脂肪经过酯化反应得到的脂肪酸单酯,具有良好的燃料品质和环境友好性,是生物柴油众多种类中的一种.以纯矿物柴油、脂肪酸甲酯、含30%脂肪酸甲酯与70%柴油的混合燃料和含50%脂肪酸甲酯与50%柴油的混合燃料为燃料,在四缸涡轮增压直喷式柴油机上进行的性能对比实验,表明柴油机燃用脂肪酸甲酯能够保持其动力性和燃料经济性,可以显著降低HC和碳烟排放,但会增加CO和NOx排放.脂肪酸甲酯可以作为柴油机的代用燃料进行推广.     

Decolorization and Complete Degradation of Methyl Red by a Mixed Culture

Synthetic dyes, azo dyes in particular, are widely found in the effluents from textile industries. The persistence and toxicity of these compounds cause adverse impacts in the receiving streams. A mixed culture isolated from a domestic wastewater treatment plant was found to remove the colour of the azo dye, methyl red, efficiently. Total decolorization and degradation occurred within 18 h. The mixed culture could degrade 700 mgl^–1 of methyl red efficiently in the presence of 200 mgl^–1 of glucose, whereas in the absence of glucose it could degrade only 100 mgl^–1 of methyl red. The mixed culture, when suspended in phosphate buffer along with methyl red at 100 mgl^–1 concentration could degrade methyl red efficiently within 2 h of incubation. The pH of the medium decreased continuously during degradation. After the complete removal of initial methyl red, another 100 mgl^–1 was added to the culture filtrate and incubated further. The mixed microbial cultures could degrade methyl red efficiently through three cycles but further degradation was not possible as the pH of the medium decreased to 3.5.     

掺杂镧硼TiO_2光催化剂的制备及可见光活性研究

采用溶胶一凝胶法,制备新型La3+/B/TiO2光催化剂,使用氙灯为光源研究了催化剂光降解甲基橙溶液的催化活性。结果表明,当掺杂0.05%La3+,2.0%B,在500℃下焙烧2 h时,所得催化剂对甲基橙具有最高的光催化活性,与单一的TiO2和单独La3+或者B掺杂的光催化剂比较,La3+/B/TiO2具有相对较高的催化活性。     

分子筛固载Fe2+-Fenton法降解水中甲基橙的研究

单因素实验考察了不同Fe2+负载量、甲基橙溶液初始浓度、温度、催化剂用量、pH值以及H2O2浓度对降解率的影响。正交实验优化了降解反应条件,得出各因素影响显著性的先后顺序为:pH值、温度、反应时间、催化剂用量、H2O2浓度。结果表明:在常压、温度为35℃,起始pH值为3.00、H2O2浓度为0.552mmol/L、催化剂浓度为0.83g/L、反应时间为80min的最佳条件下,甲基橙降解率可达98.15%。对催化剂进行了紫外照射处理回收再生,功率100W条件下,照射3h后再生催化剂活性可达原来的80.64%。     

甲醇燃料车尾气净化催化剂的研究(Ⅱ)──多组分催化剂对甲醇的深度氧化

利用色谱－微反联用技术研究多种多元催化剂对甲醇深度氧化的活性,并借助于ＸＲＤＢＥＴ等手段考察焙 烧温度对活性的影响,结果表明,不同的催化剂对甲醇氧化时均有甲醛及甲酸甲酯伴生,其伴生温度区间及最大伴生浓度随不同催化剂而变化;３２－３７号催化剂的活性明显高于双组分催化剂,添加少量稀土金属氧化物ＣｅＯ２和贵金属Ｐｄ对活性均有一定的改善作用,提高焙烧温度,催化剂表面发生烧结,对活性有不良影响。