Catalytic combustion of soot over ceria-zinc mixed oxides catalysts supported onto cordierite

Modified substrates as outer heterogeneous catalysts was employed to reduce the soot generated from incomplete combustion of diesel or diesel/biodiesel blends, a process that harms the environment and public health. The unique storage properties of ceria(CeO2) makes it one of the most efficient catalysts available to date. Here, we proposed that ceria-based catalysts can lower the temperature at which soot combustion occurs; more specifically, from 610℃ to values included in the diesel exhausts operation range(300–450℃). The sol-gel method was used to synthesize mixed oxide-based catalysts(CeO2:ZnO); the resulting catalysts were deposited onto cordierite substrates. In addition, the morphological and structural properties of the material were evaluated by XRD, BET, TPR-H2, and SEM. Thermogravimetric(TG/DTA) analysis revealed that the presence of the catalyst decreased the soot combustion temperature by 200℃ on average, indicating that the oxygen species arise at low temperatures in this situation, promoting highly reactive oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy(DRS) showed that catalyst-impregnated cordierite samples efficiently oxidized soot in a diesel/biodiesel stationary motor: soot emission decreased by more than 70%.     

基于压电效应的声波发电机实验研究

噪声在人类的生产生活中随处可见,而至今还没有有效的手段对声音能量来进行收集与利用。本实验通过亥姆霍兹共鸣器对声音能量进行收集,并利用压电陶瓷进行声电转换,得到的微小电流利用LTC3588-1进行收集并加以利用。得出结论:虽然通过亥姆霍兹共鸣器可以有效收集声波能量,但压电陶瓷的低效阻碍了声波发电的进一步推广。     

钛板SCR脱硝催化剂的制备及性能研究

选用钛板作为催化剂的骨架,预先在钛板表面制备二氧化钛涂层,再浸渍活性组分以制备催化剂。用SEM结合能谱分析的方式表征催化剂表面性能,通过固定床实验来测试不同NO负荷、不同温度、不同O2含量、二氧化硫、水蒸气等烟气条件对脱硝效率的影响,并对该催化剂的抗冷热性能和稳定性进行了测试。     

Heterogeneous Fenton-like degradation of 4-chlorophenol using iron/ordered mesoporous carbon catalyst

Ordered mesoporous carbon supported iron catalysts(Fe/OMC) were prepared by the incipient wetness impregnation method and investigated in Fenton-like degradation of 4-chlorophenol(4CP) in this work. XRD and TEM characterization showed that the iron oxides were well dispersed on the OMC support and grew bigger with the increasing calcination temperature. The catalyst prepared with a lower calcination temperature showed higher decomposition efficiency towards 4CP and H2O2, but more metals were leached. The effect of different operational parameters such as initial pH, H2O2 dosage, and reaction temperature on the catalytic activity was evaluated. The results showed that 96.1% of 4CP and 47.4% of TOC was removed after 270 min at 30°C, initial pH of 3 and 6.6 mmol/L H2O2. 88% of 4CP removal efficiency was retained after three successive runs, indicating Fe/OMC a stable catalyst for Fenton reaction. 4CP was degraded predominately by the attack of hydroxyl radical formed on the catalyst surface and in the bulk solution due to iron leaching. Based on the degradation intermediates detected by high performance liquid chromatography, possible oxidation pathways were proposed during the 4CP degradation.     

Photocatalytic removal of NO and NO2 using titania nanotubes synthesized by hydrothermal method

In this study, the photocatalysts of titania nanotubes(TNTs) were synthesized at different calcination temperatures using commercial Degussa TiO2(P25) as a precursor. The materials were then characterized by BET, SEM, TEM, and XRD analyses. The photocatalytic reactions with NO and NO2 under UV-A irradiation were both performed. The results showed that the photocatalytic reaction rate of NO was much faster than that of NO2, and the conversion of NO2 to nitrate was the rate-limiting step for photocatalytic removal of NOx if the nitrate produced cannot be removed continuously from the photocatalyst surface. For TNTs calcined at different temperatures, a significant enhancement was observed on the total NOx removal efficiency by TNT calcined at 500°C for both NO and NO2 photocatalytic reaction, which could be attributed to its high anatase crystallinity as well as high surface area. These two factors affect primarily on the NO2conversion step in which the high anatase crystallinity could be responsible for the high efficiency at the beginning, while the high surface area could be accounted for retaining this high efficiency from nitric acid poisoning during the test period.     

Combination of heterogeneous Fenton-like reaction and photocatalysis using Co-TiO2 nanocatalyst for activation of KHSO5 with visible light irradiation at ambient conditions

A novel coupled system using Co–Ti O2 was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction（SR-Fenton） and visible light photocatalysis（Vis-Photo）, for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50 mg/L Rhodamine B（Rh B） degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the Ti O2 lattice is the reason for the visible light photocatalytic activity of Co–Ti O2. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability,and almost no dissolution of Co2＋was found.     

气相中乙酸乙酯光解的光子效率:波长和催化剂的影响

采用4种不同波长的准分子光源(Xe Cl*、Kr Cl*、Xe Br*和Kr Br*)降解气相的乙酸乙酯.对比了外加3种负载型光催化剂(有机膜负载Ti O2、有机膜负载石墨烯和纱网负载Ti O2)条件下乙酸乙酯的去除率,考察了光源类型、辐射功率和气体初始浓度对去除率的影响.同时,测定了不同光源的辐射光谱和辐射功率,计算了不同反应条件下的光子效率.结果表明,乙酸乙酯去除率按Kr Br*Kr Cl*Xe Cl*Xe Br*依次降低,而Xe Cl*和Kr Br*光源降解乙酸乙酯气体可以得到较高的光子效率;有机膜负载Ti O2比不加催化剂时乙酸乙酯去除率和光子效率都有所提高,但提高幅度不大.气体流速和乙酸乙酯初始浓度升高,光子效率升高.采用Kr Br*准分子灯直接光解乙酸乙酯,实验条件为:辐射功率0.76 W,乙酸乙酯初始浓度946mg·m-3,气体流速600 m L·min-1,光子效率为5.63%.     

改性贵金属催化剂催化还原脱除NO

含有NO的工业废气直接排放会严重污染空气,须对含有NO的工业废气进行净化处理.采用NH3为还原剂贵金属铂催化剂进行了低温还原NO脱除烟气中氮氧化物性能的研究.结果表明:实验室制备的贵金属铂催化剂具有高的低温活性和选择性催化还原脱除NO的性能,但该催化剂易被原料气中少量的硫化物(SO₂)中毒而影响其稳定性;用稀土元素La和Ce对贵金属铂催化剂进行改性,改性后贵金属铂催化剂的稳定性得到了大幅度提高,出口气体中氮氧化物浓度大幅度降低.本实验Pt∶La∶Ce最佳摩尔比为1∶3.78∶3.56.     

沼渣生物炭基Fenton催化剂的制备及其高效降解吡虫啉农药废水的研究

以废弃物沼渣和含铁剩余污泥为原料,采用一步热解法制备沼渣生物炭基Fenton催化剂(以下简称催化剂),构建了非均相Fenton反应体系处理含吡虫啉模拟废水,考察了H2 O2和催化剂用量对吡虫啉去除率的影响.结果表明,非均相Fenton反应体系中,H2 O2最佳投加量为0.50 g/L,催化剂最佳投加量为1.00 g/L...     

环保新产品DDS胶硫催化剂

江西永丰县博源实业有限公司研发成功DDS脱硫催化剂，较之现有的脱硫及其催化剂具有较高的载氧性和稳定性，是一种全新的湿法脱硫技术，是用DDS脱硫催化剂及相关辅料水溶液吸收气体中的有机硫、无几硫、氧化氮，溶液在DDS脱硫催化剂与酚类物质的协同催化下，空气氧化再生，副产硫磺，再生液全部循环使用，从而达到脱硫、脱氮的目的。