Formaldehyde decomposition of air purification functional interior wall paint

A novel nano-TiO2-xNx composite was used as photocatalyst and added to the interior wall paint. The average diameter of nano-TiO2-xNx was about 20 nm. The majority crystal component of the sample was anatase and its optical absorption edge was shifted from 387 nm to 520 nm significantly. Nano-composite paint containing different dosage of nano- TiO2-xNx was investigated to study the properties of formaldehyde decomposition in the air. Testing results show that the formaldehyde decomposition ratio of that nano-paint can almost reach above 80%, especially for that of the paint containing 3% （w/w） nano-TiO2-xNx which exceeded 90%. The primary investigation on the reaction kinetics of photocatalytic formaldehyde decomposition indicated that the experiment data well fit the model of first-order reaction kinetics.

Enhanced air filtration performance under high-humidity condition through electrospun membranes with optimized structure

The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%.The developed hydrophobic filters possess comparable separation performance with the hydrophilic one,but greatly enhanced stability.After the introduction of beadon-string structure,the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity.Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons.

A Review of Metal–Organic Framework-Based Compounds for Environmental Applications

Metal–organic framework-based compounds have recently gained great attention because of their unique porous structure,ordered porosity,and high specific surface area.Benefiting from these superior properties,metal–organic framework-based compounds have been proven to be one of the most potential candidates for environmental governance and remediation.In this review,the different types of metal–organic framework-based compounds are first summarized.Further,the various environmental applications of metal–organic framework-based compounds including organic pollutant removal,toxic and hazardous gas capture,heavy metal ion detection,gas separation,water harvesting,air purification,and carbon dioxide reduction reactions are discussed in detail.In the end,the opportunities and challenges for the future development of metal–organic framework-based compounds for environmental applications are highlighted.

Applications of metal–organic frameworks for green energy and environment: New advances in adsorptive gas separation, storage and removal

The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.

A comparative study of the effects of ventilation-purification strategies on air quality and energy consumption in Beijing,China

In countries suffering from heavy ambient air pollution,ventilation is a problem,as ventilation intakes outdoor air pollutants,such as particulate matter with an aerodynamic diameter less than 2.5 μm(PM_(2.5)),while removing indoor air pollutants.Thus,it is important to identify appropriate ventilation-purification strategies to build healthy indoor environments with low energy consumption.This study reports the comparison of two sets of strategies,i.e.,mechanical ventilation with filters and natural ventilation with indoor air cleaners,in respect to energy consumption and the PMzs and carbon dioxide(CO_(2))exposure of occupants in a typical apartment in Beijing,China.A dynamic mass balance model was employed to calculate the PM2.5 and CO_(2) exposure concentrations,while the energy consumption of heating and cooling was simulated with the Designer's Simulation Toolkit.It was found that natural ventilation with air cleaners provided lower PIVhs exposure compared with that of mechanical ventilation with filters;however,mechanical ventilation achieved a lower CO_(2) exposure concentration.The annual cooling,heating,and fan energy consumption of natural ventilation strategies are lower than those of mechanical ventilation strategies.With respect to natural ventilation,an infiltration rate of 0.3-0.4 h^(-1)was the preferred setting,which led to low PM23 and CO_(2) exposure with lower energy consumption.The basic requirements for controlling indoor PM2.5 could be met if the threshold is set at 25 pg/m3.The results provide guidelines on how to combine multiple ventilation purification strategies to improve indoor air quality with lower energy usage.

Advances and challenges of photocatalytic technology for air purification

With the acceleration of the urban industrialization process,air pollutant emission has increased sharply,which seriously endangers the ecological environment and human beings.Solar-driven photocatalysis has the broad-spectrum activity for various inorganic to organic pollutants at ambient temperature without harsh reaction conditions,which shows a very broad application prospect in air purification.However,the photocatalysis technology suffers from the unrevealed reaction me-chanism and the deactivation of photocatalysts,which severely limits its practical application.Currently,there is still a huge gap between basic research and industrial application in the field of photocatalytic air purification.This review summarizes recent progress on photocatalytic degradation of air pollutants and categorizes them based on the types of photocatalytic materials and air pollutants,with a focus on photocatalytic reaction mechanisms and the application scenarios of photocatalytic air purification to identify this gap.We also critically discussed the major challenges for promoting applications of photo-catalytic technology and put forward the development prospect.

Design of an air isolation and purification (AIP) desk for medical use and characterization of its efficacy in ambient air isolation and purification

The incidences of nosocomial infections(NIs)are increasing throughout the world,especially for those airborne diseases caused by pathogens or air particulates that float in air.In this study,we designed and manufactured a desk for clinic consultation room air purification and air isolation between doctor and patient.The air isolation and purification(AIP)desk has a high efficiency particulate air(HEPA)filter on the tope and several primary efficiency filters on the sides for air purification.The air circulating between inlet and outlet forms a wind-curtain between doctor and patient.The Computational Fluid Dynamics(CFD)model was used to calculate the speed of the air flow and the angle of sampler.We tested the air purification function of the AIP desk in rooms sized about 3.6×2.8×2.8 m(L×W×H)and found that the AIP desk could significantly remove the tested air pollutants like smoke particulates and microorganisms like Staphylococcus albus(S.albus)and human adenovirus type 5(HAdV-5).The wind-curtain can significantly block the exhale air of patient being transmitted to the respiratory area of doctor setting in the opposite of AIP desk.Thus,the AIP desk can be used in hospital setting to reduce the risk of NIs and protect both doctors and patients.

Research on the Performance of Cedarwood Essential Oil in Removing Formaldehyde

This paper tested cedar essential oil as a new formaldehyde removal ingredient on gel format,it showed a better formaldehyde removal performance,reaching equilibrium at 7 h with a formaldehyde removal rate of 64%,and at 24 h with a formaldehyde removal rate of 67%.The 24 h formaldehyde removal rate increased by 25%compared with the gel without cedar essential oil,and efficiency is improved by 60%.The ingredients come from natural sources with a woody aroma,which can soothe the body and mind.After the stability test,the formaldehyde removal gel has no odor,precipitation or discoloration.

China Begins Air Purification Programme

Government institutions have been called on to im-prove urban air quality in a bid to create a healthier en-vironment for people. On April 6～7, Vice Premier Li Lanqing made an important speech on the national con-ference of "Air Purification Programme——cleaning motor vehicle operation", he said that the improvement should start with accelerated development of cleaner fu-els and reducing pollution exhausted from motor vehi-cles. Industrial and domestic coal-burning and vehicle e-missions have produced large amounts of pollutants in-cluding sulphur dioxide, dust and nitrogen oxide. Air pollution has become a major factor which

Removal of Low-concentration Ammonia from Ambient Air by Aluminophosphates

A series of aluminumphosphate materials was prepared and used as adsorbents for the removal of ammonia at low concentrations. The influence of various preparation parameters, including the pH value of sol, calcination temperature and molar ratio of P/A1, on the structure and surface properties as well as adsorption capacity was investigated. The results showed that large amount of P-OH present on the surface of aluminophosphates was suitable for the removal of ammonia. They were the major source of weak Br6nsted acid sites and acted as the main active centers for capturing ammonia.

Reusable and durable electrostatic air filter based on hybrid metallized microfibers decorated with metal–organic–framework nanocrystals

As global air pollution becomes increasingly severe,various types of fibrous filters have been developed to improve air filter performance.However,fibrous filters have limitations such as high packing density that generally causes high-pressure drop and ultimately deterioration in the filtration efficiency.High-pressure particulate matter precipitators are limited in terms of scope for commercialization because they require high voltage supplies and ozone generators.In this study,we develop fibrous filters with enhanced durability and improved performance using metallized microfibers decorated with metal-organic-framework(MOF)nanocrystals.Not only does the efficiency of the developed filters remain at or above 97%for 0.50-1.5μm PMs but the durability also significantly increases.In addition,using the water purification ability of the MOF,we explore the dye degradation effect of the hybrid microfibers by immersing them into Rhodamine B aqueous solution.In such an experiment the Rhodamine B aqueous solution is completely purified by the presence of the hybrid microfibers under the UV irradiation.

Electrocatalytic oxidation of gaseous toluene in an all-solid cell using a foam Ti/Sb-SnO2/β-PbO_(2) anode

Mineralization of benzene,toluene,and xylene (BTX) with high efficiency at room temperature is still a challenge for the purification of indoor air.In this work,a foam Ti/Sb-Sn O2/β-Pb O_(2)anode catalyst was prepared for electrocatalytically oxidizing gaseous toluene in an all-solid cell at ambient temperature.The complex Ti/Sb-Sn O_(2)/β-Pb O_(2)anode,which was prepared by sequentially deposing Sb-Sn O_(2)and β-Pb O_(2)on a foam Ti substrate,shows high electrocatalytic oxidation efficiency of toluene (80%) at 7 hr of reaction and high CO_(2)selectivity (94.9%) under an optimized condition,i.e.,a cell voltage of 2.0 V,relative humidity of60%and a flow rate of 100 m L/min.The better catalytic performance can be ascribed to the high production rate of·OH radicals from discharging adsorbed water and the inhibition of oxygen evolution on the surface of foam Ti/Sb-Sn O_(2)/β-Pb O_(2)anode when compared with the foam Ti/Sb-Sn O_(2)anode.Our results demonstrate that prepared complex electrodes can be potentially used for electrocatalytic removal of gaseous toluene at room temperature with a good performance.

A comparative study between ionic liquid coating and counterparts in bulk for toluene absorption

The structure-activity relationship(SAR)for toluene absorption and desorption in ionic liquids(ILs)has been investigated for seven commercial ILs in bulk and thin liquid layer.ILs with imidazolium cations of different alkyl chain lengths and a Hofmeister series of anions including[CH3COO],[I],[BF4],[HSO4],and[PF6]were included.Absorption capacity for toluene increases with increasing kosmotropicity of the cation and anion,while the absorption rate in bulk ILs is governed by viscosity and that in thin ILs layer by the oil-water partition coefficient(Kow).A regenerability coefficient(Rp)measures toluene desorption and IL regeneration.The release rate as measured by dRp/dt correlates well with the Kow and viscosity of the ILs and tx,the time required to completely desorb toluene is related to its ionic strength as measured from v(C2H)of the imidazolium cation.These properties are in turn governed by the kosmotropicity of the cation and anion pair forming the IL.