人工影响天气飞机播云作业有效催化范围的模拟评估

针对人工影响天气飞机播云作业效果评估需求,提出一种基于拉格朗日粒子扩散模式FLEXPART-WRF的催化剂催化范围模拟评估方法。以典型催化剂碘化银为例,开发催化剂物理化学特性参数清单模块,结合飞机播云特点和模式源项特点,将飞机不规则线性播撒方式离散化为连续移动点源播撒方式,实现模式对飞机播云的模拟能力。通过对一次飞机播云作业的模拟试验,证实了模拟评估方法的可行性和有效性。

高炮、火箭和飞机催化扩散规律和作业设计的研究

文章基于扩散计算的解析解,提出了针对高炮、火箭和飞机等不同催化方式的点源、多线源和移动点源的数值计算方案,分别研究了不同催化方式催化剂扩散规律和有效范围,并利用卫星捕获的一次飞机播云实例检验了计算方案,同时研究了实现目标区充分催化的作业设计等问题。主要结论有:高炮做为点源催化,单个高炮作业,达到有效催化浓度的范围半径约只有0.5 km,应当采用多炮弹密集作业,比较有利于浓度和催化范围的维持,提高炮弹成核率能够很大程度地提高高炮作业效果;火箭和飞机作为线源催化,1 h内达到有效催化浓度的宽度分别为7和6.6 km,此宽度可作为多线播撒作业飞行间距设计的参考依据;飞机单线播撒达不到充分催化的要求,而耕作式播撒,在风速作用下,扩散区域会分散或重叠。根据风速大小设计的"8"字形来回播撒飞行路线,可使目标区得到充分播撒。在扩散计算方案研究基础上研发的各类催化扩散计算和作业设计软件系统,可方便准确地计算飞机、高炮和火箭实际作业时催化剂在云中扩散的范围、浓度及其随时间的演变,并可针对不同目标区进行充分播撒催化的作业设计,结果直观简明,为催化扩散计算的实际业务应用和作业设计提供了帮助。

Exploring a broadened operating pH range for norfloxacin removal via simulated solar-light-mediated Bi_2WO_6 process

Semiconductor photocatalysis can be operated over a narrow pH range for wastewater treatment. In this study, a simulated solar-light-mediated bismuth tungstate (SSL/Bi2WO6) process is found to be effective for norfloxacin degradation over a narrow pH range. To broaden the operating pH range of the SSL/Bi2WO6 process, an NH4+ buffer system and an Fe3+ salt were introduced under extremely basic and acidic pH conditions, respectively. The NH4+ buffer system continuously supplied hydroxyl ions to generate ·OH radicals and prevented acidification of the solution, resulting in improved norfloxacin removal and mineralization removal under alkaline conditions. In contrast, the Fe3+ salt offered an additional homogeneous photo-sensitization pathway. The former treatment assisted in norfloxacin decay and the latter increased the collision frequency between the photo-generated hole and hydroxyl ions. Moreover, the effect of parameters such as pH and Fe3+ dosage was optimized.

Kinetic studies on the dimerization of isobutene with Ni/Al_2O_3 as a catalyst for reactive distillation process

Isooctane is a promising gasoline additive that could be produced by dimerization of isobutene(IB) with subsequent hydrogenation.In this work,the dimerization of IB has been carried out in a batch reactor over a temperature range of 338-383 K in the presence of laboratory prepared Ni/Al_2O_3 as a catalyst and n-pentane as solvent.The influence of various parameters such as temperature,catalyst loading and initial concentration of IB was examined.A Langmuir-Hinshelwood kinetic model of IB dimerization was established and the parameters were estimated on the basis of the measured data.The feasibility of oligomerization of IB based on the reactive distillation was simulated in ASPEN PLUS using the kinetics developed.The simulation results showed that the catalyst of Ni/Al_2O_3 had higher selectivity to diisobutene(DIB) and slightly lower conversion of IB than ion exchange resin in the absence of polar substances.

Low Temperature Growth of SWNTs on a Nickel Catalyst by Thermal Chemical Vapor Deposition

Single-walled carbon nanotubes （SWNTs） have been grown on a silica-supported monometallic nickel （Ni） catalyst at temperatures ranging from as low as 450℃to 800℃. Different spectroscopic techniques, such as Raman, photoluminescence emission （PLE）, and ultra violet-visible-near infrared （UV-vis-NIR） absorption spectroscopy were used to evaluate file diameter and quality of the SWNTs grown over the Ni catalyst at different temperatures. The analysis revealed that high quality SWNTs with a very narrow diameter distribution were obtained at a growth temperature of 500 ℃. In the PLE and absorption spectra, differences were observed between the SWNTs grown oil Ni and those grown on cobalt （Co）. This result expands the potential of growing a specific （n, m） tube species with relatively high abundance by tuning the catalyst composition. Furthermore, the prerequisites for the low temperature growth of SWNTs over a monometallic transition metal catalyst have been elucidated.

Interlayer engineering of molybdenum disulfide toward efficient electrocatalytic hydrogenation

Electrocatalytic hydrogenation(ECH)enables the sustainable production of chemicals under ambient condition;however,suffers from serious competition with hydrogen(H2)evolution and the use of precious metals as electrocatalysts.Herein,molybdenum disulfide is for the first time developed as an efficient and noble-metal-free catalyst for ECH via in situ intercalation of ammonia or alkyl-amine cations.This interlayer engineering regulates phase transition(2H→1 T),and effectively ameliorates electronic configurations and surface hydrophobicity to promote the ECH of biomass-derived oxygenates,while prohibiting H2 evolution.The optimal one intercalated by dimethylamine(MoS_(2)-DMA)is capable of hydrogenating furfural(FAL)to furfuryl alcohol with high Faradaic efficiency of 86.3%–73.3%and outstanding selectivity of>95.0%at−0.25 to−0.65 V(vs.RHE),outperforming MoS_(2) and other conventional metals.Such prominent performance stems from the enhanced chemisorption and surface hydrophobicity.The chemisorption of H intermediate and FAL,synchronously strengthened on the edge-sites of MoS_(2)-DMA,accelerates the surface elementary step following Langmuir-Hinshelwood mechanism.Moreover,the improved hydrophobicity benefits FAL affinity to overcome diffusion limitation.Discovering the effective modulation of MoS_(2) from a typical H2 evolution electrocatalyst to a promising candidate for ECH,this study broadens the scope to exploit catalysts used for electrochemical synthesis.