《空气氧》、《水氢》复习指导

1．空气的成分；空气的污染和防治；氧气、氢气的物理性质和用途；氧气的工业制法；水的物理性质；水的污染和防治；水的组成。

和你一起走进化学世界——第一章《空气 氧》学习指导

金色的秋天是一个收获的季节。此时,同学们也迎来了初中学习的收获时节——初中学习的最后一年.同学们除了继续学习熟悉的学科外,还将步入一个五彩缤纷的新世界——化学天地。在化学世界里邀游能否使自己的视野更广阔、思维更活跃、动手动脑能力更强,关键是同学们要有正确的学习方法。

Effect of preparation routes on activity of Ag-MnO_x/C as electrocatalysts for oxygen reduction reaction in alkaline media

The effect of preparation routes on the physical characteristics and activity of the Ag-MnOx/C composites toward the oxygen reduction reaction （ORR） in alkaline media were studied by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, energy-dispersion spectroscopy （EDS） as well as scanning electron microscopy （SEM） and electrochemical techniques. The results show that more Ag and Mn species present on the surface of the Ag-MnOx/C composite prepared by two-step route （Ag-MnOx/C-2） compared to the one prepared by one-step route （Ag-MnOx/C-1）, which contributes to its superior activity toward the ORR. The higher electron transfer number involved in the ORR can be observed on the Ag-MnOx/C-2 composite and its specific mass kinetic current at -0.6 V （vs Hg/HgO） is 46 mA/μg, which is 23 times that on the Ag/C. The peak power density of zinc-air battery with the Ag-MnOx/C-2 air electrode reaches up to 117 mW/cm^2.

“组成”与“构成”在描述物质时的应用

在《空气氧》一章中，常用到“组成”与“构成”这两个词，这是从宏观和微观两个不同的角度对物质进行描述。要正确地理解并准确地应用它们，必须从它们的匹配关系、从属关系等几个方面予以掌握。

Pt nanoparticles encapsulated on V_(2)O_(5)nanosheets carriers as efficient catalysts for promoted aerobic oxidative desulfurization performance

Platinum group metals(PGMs)usually exhibit promising aerobic catalytic abilities,providing a green and feasible oxidative desulfurization method.However,often,the PGM nanoparticles(NPs)get leached,and the catalysts are deactivated.In this work,Pt NPs with particle sizes of approximately 4–5 nm were encapsulated effectively and uniformly on the surface of vanadium pentoxide(V2O5)nanosheets(with thicknesses of approximately six atomic layers)through strong metal-support interactions.The synthesized catalysts promote catalytic aerobic oxidation reactions,realizing deep desulfurization(99.1%,<5μg g^(–1))under atmospheric pressure and 110℃reaction temperature.Remarkable degrees of sulfur removal could be achieved for oils with different initial S-concentrations and substrates.Additionally,the as-prepared catalysts could be recycled for reuse at least seven times.

A contrast study on different gasifying agents of underground coal gasification at Huating Coal Mine

To optimize the technological parameter of underground coal gasification （UCG）, the experimental results of air gasification, air-steam gasification, oxygen-enrichment steam gasification, pure oxygen steam gasification and two-stage gasification were studied contrastively based on field trial at the Huating UCG project. The results indicate that the average low heat value of gas from air experiment is the lowest （4.1 MJ/Nm3） and the water gas from two-stage gasification experiment is the highest （10.72 MJ/Nm3）. The gas productivity of air gasification is the highest and the pure oxygen steam gasification is the lowest. The gasification efficiency of air gasification, air-steam gasification, oxygen-enriched steam gasification, pure oxygen steam gasification and two-stage gasification is listed in ascending order, ranging from 69.88% to 84.81%. Described a contract study on results of a field test using steam and various levels of oxygen enrichment of 21%, 32%, 42% and 100%. The results show that, with the increasing of O2 content in gasifying agents, the gas caloricity rises, and the optimal O2 concentration range to increase the gas caloricity is 30%-40%. Meanwhile, the consumption of O2 and steam increase, and the air consumption and steam decomposition efficiency fall.

Precipitation of antimony from the solution of sodium thioantimonite by air oxidation in the presence of catalytic agents

The behavior of antimony oxidation in the solution of sodium thioantimonite was studied in the presence of catalytic agents. The catalytic effects of the respective addition of cupric sulfate, sodium tartrate, potassium permanganate, phenol, 1,2 dihydroxybenzene and their combination on the oxidation of sodium thioantimonite were investigated. A pilot test was carried out. The results show that the respective use of sodium tartrate, cupric sulfate, potassium permanganate, phenol and 1,2 dihydroxybenzene have little catalytic effect on the oxidation of sodium thioantimonite. However there exists obvious catalytic oxidation by the combination of 0.25 g/L 1,2 dihydroxybenzene, 0.5 g/L potassium permanganate and 1.0 g/L phenol. Moreover, high blast intensity, the increase of temperature and NaOH concentration favor the oxidation of antimony. The oxidation process of antimony has such advantages as quick reaction and low operation costs. The results of the pilot test are consistent with those of laboratory experiments.

Water, CO_2 and Energy Exchange at Vegetation-air Interface

[Objective] The aim was to analyze water and heat fluxes, CO2 fluxes and energy balance in wheat ecosystem in Luancheng County of Hebei Province. [Method] Based on data of water and heat flux, and CO2 fluxes, routine meteorological and biomass data in Luancheng in 2008, water and heat fluxes, CO2 fluxes and energy balance in wheat ecosystem were explored. [Result] The results showed that latent and sensible heat and CO2 fluxes were of obvious daily and seasonal changes; latent and sensible heat fluxes shaped an inverted U in daily change, and CO2 fluxes were of a U-shape; daily flux peak differed significantly. Furthermore, the change of latent heat, sensible heat and CO2 fluxes were closely related to environ- mental factors. Detailedly, the three were sensitive to light intensity and net radiation, and correlation coefficients were 0.92, 0.66, 0.65 and 0.90, 0.69, 0.74, respectively. Besides, the fluxes, sensitive to temperature, proved better in sunny day, especially for latent flux which is more sensitive to water in soils after precipitation. In addition, closure degree of energy balance in wheat fields was 0.91 and non-closure, caused by measurement error and neglection of heat storage, was observed, too. What＇s more. closure degree differed in months and time periods within a day. [Conclusion] The research concluded water and heat fluxes, CO2 fluxes, transport mechanisms and concerning factors, providing scientific reference for revealing mechanism of evapo- ration and heat dissipation of canopy, relationship between photosynthesis and water use efficiencyand energy distribution mechanism.

Time evolution of coal structure during low temperature air oxidation

The time evolution of coal structure during low temperature oxidation was investigated by oxidizing coal samples in air at 120℃ for periods of up to 14 days. The structure of the oxidized coal samples was char- acterized by Fourier transform infrared spectroscopy （FFIR） and curve fitting analysis. The results show that carboxyl and ether groups are the main oxygen containing moieties in oxidized coal. Ethers are most abundant during the first 3 days of oxidation, thereafter carboxyl groups predominate. The content of carboxyl and ester functionality increases with oxidation time. The other oxygen containing groups vary in concentration over time. The amount of hydroxyl groups first decreases then increases and finally decrease again during the oxidation. The aliphatic structure and the degree of branching of the aliphatic chains is reduced as the oxidation proceeds. The proportion of aromatic structure increases with oxida- tion time. Obvious decomposition of aromatic rings occurs after about 9 days of oxidation. The aryl ester bands and the CH3/CH2 ratio both have a good linear relationship to oxidation time.

Preparation and properties of transition metal nitrides caged in N-doped hollow porous carbon sphere for oxygen reduction reaction

A series of transition metal nitrides(MxNy,M=Fe,Co,Ni)nanoparticle(NP)composites caged in N-doped hollow porous carbon sphere(NHPCS)were prepared by impregnation and heat treatment methods.These composites combine the high catalytic activity of nitrides and the high-efficiency mass transfer characteristics of NHPCS.The oxygen reduction reaction results indicate that Fe2N/NHPCS has the synergistic catalytic performance of higher onset potential(0.96 V),higher electron transfer number(~4)and higher limited current density(1.4 times as high as that of commercial Pt/C).In addition,this material is implemented as the air catalyst for zinc−air battery that exhibits considerable specific capacity(795.1 mA·h/g)comparable to that of Pt/C,higher durability and maximum power density(173.1 mW/cm2).

Global air quality change during the COVID-19 pandemic:Regionally different ozone pollution responses COVID-19

The explosive spread of the 2019 novel coronavirus(COVID-19)provides a unique chance to rethink the relationship between human activity and air pollution.Though related studies have revealed substantial reductions in primary emissions,obvious differences do exist in the responses of secondary pollutants,like ozone(0_(3))pollution.However,the regional disparities of O_(3)responses and their causes have still not been fully investigated.To better elucidate the interrelationship between anthropogenic emissions,chemical production,and meteorological conditions,O_(3)responses caused by lockdowns over different regions were comprehensively explored at a global scale.Observational signals of air-quality change were derived from multi-year surface measurements and satellite retrievals.With similar substantial drops in nitrogen dioxide(NO_(2)),ozone shows rising signals in most areas of both East Asia and Europe,even up to~14 ppb,while a non-negligible declining signal exists in North America,by about 2-4 ppb.Furthermore,the drivers behind the different O_(3)responses are discussed based on meteorological analysis and O_(3)sensitivity diagnosis.On the one hand,O_(3)responses to NO_(2)declines can be affected by the primary dependence on its precursors.On the other hand,it is also highly dependent on meteorological factors,especially temperature.Our study further highlights the great importance of taking into consideration both the regional disparities and synergistic effects of precursor reductions and meteorological influence for scientific mitigation of O_(3)pollution.

Catalytic Partial Oxidation of Methane with Air to Syngas in a Pilot-Plant-Scale Spouted Bed Reactor

On the basis of hydrodynamic and scaling-up studies, a pilot-plant-scale thermal spouted bed reactor (50 mm in ID and 1500 mm in height) was designed and fabricated by scaling-down cold simulators. It was tested for making syngas via catalytic partial oxidation (CPO) of methane by air. The effects of various operating conditions such as operating pressure and temperature, feed composition, and gas flowrate etc. on the CPO process were investigated. CH4 conversion of 92.2% and selectivity of 92.3% and 83.3% to CO and H2, respectively, were achieved at the pressure of 2.1 MPa. It was found that when the spouted bed reactor was operated within the stable spouting flow regime, the temperature profiles along the bed axis were much more uniform than those operated within the fixed-bed regime. The CH4 conversion and syngas selectivity were found to be close to thermodynamic equilibrium limits. The results of the present investigation showed that spouted bed could be considered as a potential type of chemical reactor for the CPO process of methane.

Preparation and application of perovskite-type oxides for electrocatalysis in oxygen/air electrodes

Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.

Effect of CO Combustion Promoters on Combustion Air Partition in FCC under Nearly Complete Combustion

With CO combustion promoters, the role of combustion air flow rate for concerns of economics and control is important. The combustion air is conceptually divided to three parts: the air consumed by coke burning,the air consumed by CO combustion and the air unreacted. A mathematical model of a fluid catalytic cracking(FCC)unit, which includes a quantitative correlation of CO heterogeneous combustion and the amount of CO combustion promoters, is introduced to investigate the effects of promoters on the three parts of combustion air. The results show that the air consumed by coke burning is almost linear to combustion air flow rate, while the air consumed by CO combustion promoters tends to saturate as combustion air flow rate increases, indicating that higher air flow rate can only be used as a manipulated variable to control the oxygen content for an economic concern.

pH variation mechanism of high sulfur-containing bauxite

In order to fundamentally solve the acidification problem of high sulfur-containing bauxite during storage, by simulating the environment of minerals storage in laboratory, the acidification mechanism and influencing factors of high sulfur-containing bauxite were studied and confirmed using the single variable method to control the atmosphere, water and other variables. The results show that the acidification is mostly caused by the oxidation of sulfur-containing bauxite, which is mainly the natural oxidation of Pyrite(Fe S2), then the alkaline minerals dissolute in the presence of water, leading to the acidification phenomenon, which is influenced by moisture and air flow. Finally, more acid-producing substances are formed, resulting in the acidification of high sulfur-containing bauxite. The acidification of high sulfur-containing bauxite results from the combined effect of the oxygen in the air and water, which can be significantly alleviated by controlling the diffusion of the oxygen in air.

Kinetics of Wet Air Oxidation of Wastewater from Natural Fiber Web Desizing

This work described the application of wet air oxidation (WAO) to the treatment of desizing wastewater from natural fiber processing. A two-liter autoclave batch reactor was used for the experiments. The range of operating temperature examined was between 150 and 290℃, and partial pressure of oxygen ranged from 0.375 to 2.25 MPa standardized at 25℃. Variations in Chemical Oxygen Demand(COD) and Total Organic Carbon(TOC) were monitored during each experiment and used to assess the performance of the process. Experimental results showed that WAO can be an efficient method for the treatment of desizing wastewater. Furthermore, Catalytic Wet Air Oxidation (CWAO) was applied to reduce the reaction temperature and pressure in WAO process. A higher COD removal ratio was achieved under more mild reaction condition with the aid of CWAO. A mathematical model was also proposed to simulate the WAO process of desizing wastewater, in which three distinct kinetics steps were considered to describe the degradation of starch. The model simulations were in well agreement with the experimental data.

Purification Effect of Potted Taxus for Indoor Sulfur Dioxide Pollution

The aim was to explore the purification ability of potted taxus for indoor sulfur dioxide pollution. Three taxus cultivars were placed in different rooms. The air in the rooms was sampled continuously at the flow rate of 0.5 ml/min, and the content of sulfur dioxide was determined by formaldehyde absorbing-pararosaniline spectrophotometry. The obtained linear equation for sulfur dioxide was as follows： y=0.030 1 x＋0.023 5, F=0.999 7. The content of sulfur dioxide in the three rooms placed with different taxus cultivars all declined, suggesting that potted taxus has a certain ability to purify sulfur dioxide. Among the taxus cultivars, Taxus yunnanensis showed the highest purification rate, followed by Taxus chinensis vat. mairei and Taxus media cv. Hicksii.

Two-in-one strategy to construct bifunctional oxygen electrocatalysts for rechargeable Zn-air battery

Integrating two different catalytic active sites into one composite is a useful 2-in-1 strategy for designing high-efficient bifunctional catalysts,which can easily tailor the activity of each reaction.Hence,we adopt the 2-in-1 strategy to design the metal oxyhydroxide supported on N-doped porous carbons(PA-CoFe@NPC)as the oxygen bifunctional catalyst,where NPC provides the activity for oxygen reduction reaction(ORR)while the metal oxyhydroxide is responsible for oxygen evolution reaction(OER).Results demonstrate that the PA-CoFe@NPC indeed exhibits both super ORR and OER activities.Impressively,using bifunctional PA-CoFe@NPC as the oxygen electrode,the resulting Zn-air battery exhibits outstanding charge and discharge performance with the peak power density of 156.3 mW cm^(-2),and also exhibits a long-term cycle stability with continuous cyclic charge and discharge of 170 hours that is obviously better than the 20%Pt/C+IrO_(2)based one.The 2-in-1 strategy in this work can be efficiently extended to design other bi-or multi-functional electrocatalysts.

Study on the catalyst in the decomposition reaction for BI organic waste water to adipic acid

The influences of kinds and level of catalyst, time of decomposition reaction on the distribution of dibasic acid and apparent yield of adipic acid were researched; the acidic washing waste water （BI waste water） producing from the equipment of cyclohexane oxidation by air was as stuff, the component of products by decomposed and oxidated in different conditions were analysed. It indicated that in the presence of cobalt salt the apparent yield of adipic acid was upto 10%-12% for the total BI waste water after the concentrated BI waste water refluxed for two hours, and then oxidated by nitric acid.