阻尼式脉动气流分选装置处理电子废弃物的基础研究

采用机械物理回收方法对电子废弃物进行资源化利用具有巨大的经济效益和社会效益。针对电子废弃物的特点,作者采用阻尼式脉动气流分选装置对电子废弃物中有价组分的分选进行了研究。研究表明,与传统气流分选装置相比,阻尼式脉动气流分选装置可获得更高的分选效率和更宽范围的操作条件。     

旋风除尘器压力损失的试验研究

分析了旋风除尘器压力损失的成因,通过系统的试验考查了压力损失与进口气流平均速度的关系,探讨了粉尘含量对旋风除尘器压力损失的影响和灰斗的压力分布,总结了排气芯管截面积与入口截面积 A0/Ai之比的大小对除尘器压力损失的影响,从而为旋风除尘器的优化设计及操作性能的改善提供了重要的参考价值。     

试论空分装置的防爆技术

空分装置的安全运行是工业制氧安全生产的关键环节 ,也是最难控制的危险源。本文从空分爆炸原理入手 ,系统阐述了碳氢化合物在液氧中的积聚机理 ,激发能源的种类与形成 ,并提出了综合控制空分爆炸的若干措施     

膜分离技术在染料工业中的应用进展

在染料工业中 ,膜分离技术主要用于传统生产工艺改造和工业废水处理两个方面 ,旨在实现节水、减污和降耗等目的。本文介绍了其主要应用进展 ,并结合染料工业特点 ,概述了影响膜污染的主要因素 ,如膜的荷电性、亲疏水性、截留分子量、料液性质等。     

水中VOCs的渗透蒸发分离技术研究进展

介绍了水中VOCs的各种分离方法,重点分析了渗透蒸发分离技术的技术优势;提出了渗透蒸发膜的选择标准;归纳了渗透蒸发过程的传质机理与模型;探讨了原料液浓度、温度、流量,渗透侧压力、添加剂、膜组件型式等因素对渗透蒸发效率的影响;简要预测了渗透蒸发过程的发展趋势与动态。     

Unraveling SO2-tolerant mechanism over Fe2（SO4）3/TiO2 catalysts for NOx reduction

Developing low-temperature SO₂-tolerant catalysts for the selective catalytic reduction of NO_x is still a challenging task. The sulfation of active metal oxides and deposition of ammonium bisulfate deactivate catalysts, due to the difficult decomposition of the as-formed sulfate species at low temperatures（<300 °C）. In recent years, metal sulfate catalysts have attracted increasing attention owing to their good catalytic activity and strong SO₂ tolerance at hi...     

水环境中汞的形态及其分析方法

概述了近年来国内外对水环境中汞的形态、分离富集手段及其测定方法的研究报道。文献表明随着对汞环境化学行为研究的深入 ,汞的形态分析技术在今后依然是极富挑战的课题。     

Pre-instrumental perspectives on Arkansas River cross-watershed flow variability

We present four reconstruction estimates of Arkansas River baseflow and streamflow using a total of 78 tree-ring chronologies for three streamflow gages, geographically spanning the headwaters in Colorado to near the confluence of the Arkansas-Mississippi rivers. The estimates represent different seasonal windows, which are dictated by the shared limiting forcing of precipitation on seasonal tree growth and soil moisture—and subsequently on the variability of Arkansas River discharge. Flow extremes that were higher and lower than what has been observed in the instrumental era are recorded in each of the four reconstructions. Years of concurrent, cross-basin (all sites) low flow appear more frequently during the 20th and 21st Centuries compared to any period since 1600 A.D., however, no significant trend in cross-basin low flow is observed. As the most downstream major tributary of the Mississippi River, the Arkansas River directly influences flood risk in the Lower Mississippi River Valley. Estimates of extreme high flow in downstream reconstructions coincide with specific years of historic flooding documented in New Orleans, Louisiana, just upstream of the Mississippi River Delta. By deduction, Mississippi River flooding in years of low Arkansas River flow imply exceptional flooding contributions from the Upper Mississippi River catchments.     

Mechanistic insights into the selective photocatalytic degradation of dyes over TiO2/ZSM-11

● TiO₂/ZSM-11 was prepared by a facile solid state dispersion method. ● Mechanism for photocatalytic degradation of dyes was investigated. ● Both experimental and MD simulations were conducted. ● Chemisorption instead of electrostatic interaction played a critical role. Photocatalytic degradation is a promising way to eliminate dye contaminants. In this work, a series of TiO₂/ZSM-11 (TZ) nanocomposites were prepared using a facile solid state dispersion method. Methyl orange (MO), methylene blue (MB), and rhodamine B (RhB) were intentionally chosen as target substrates in the photocatalytic degradation reactions. Compared to pristine TiO₂, negative effect was observed on MO degradation while promoted kinetics were collected on MB and RhB over TZ composites. Moreover, a much higher photocatalytic rate was interestingly achieved on RhB than MB, which indicated that a new factor has to be included other than the widely accepted electrostatic interaction mechanism to fully understand the selective photodegradation reactions. Systematic characterizations showed that TiO₂ and ZSM-11 physically mixed and maintained both the whole framework and local structure without chemical interaction. The different trends observed in surface area and the photo-absorption ability of TZ composites with reaction performance further excluded both as the promotion mechanism. Instead, adsorption energies predicted by molecular dynamics simulations suggested that differences in the adsorption strength played a critical role. This work provided a deep mechanistic understanding of the selective photocatalytic degradation of dyes reactions, which helps to rationally design highly efficient photocatalysts.     

NiB2O4 (B = Mn or Co) catalysts for NH3-SCR of NOx at low-temperature in microwave field

● Microwave-assisted catalytic NH₃-SCR reaction over spinel oxides is carried out. ● SCR reaction temperature is tremendously lowered in microwave field. ● NO conversion of NiMn₂O₄ is highly up to 90.6% at 70°C under microwave heating. Microwave-assisted selective catalytic reduction of nitrogen oxides (NO_x) was investigated over Ni-based metal oxides. The NiMn₂O₄ and NiCo₂O₄ catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH₃-SCR in a microwave field. The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N₂-physisorption, NO adsorption-desorption in the microwave field, H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results verified that microwave radiation reduced the reaction temperature required for NH₃-SCR compared to conventional heating, which needed less energy. For the NiMn₂O₄ catalyst, the catalytic efficiency exceeded 90% at 70 °C and reached 96.8% at 110 °C in the microwave field. Meanwhile, the NiMn₂O₄ also exhibited excellent low-temperature NH₃-SCR reaction performance under conventional heating conditions, which is due to the high BET specific surface area, more suitable redox property, good NO adsorption-desorption in the microwave field and rich acidic sites.