An Investigation on the Efficiency of Air Purification Using a Biofilter with Activated Bed of Different Origin

2014 ◽  
Vol 35 (4) ◽  
pp. 435-445
Author(s):  
Alvydas Zagorskis ◽  
Rasa Vaiškūnaitė
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Natural Zeolite ◽  
Wood Chips ◽  
Air Purification ◽  
Filtration Time ◽  
Purification Efficiency ◽  
Volatile Organic ◽  
Filter Bed ◽  
Different Origin

Abstract Recent studies in the area of biological air treatment in filters have addressed fundamental key issues, such as a biofilter bed of different origin composed of natural zeolite granules, foam cubes and wood chips. When foam and zeolite are mixed with wood chips to remove volatile organic compounds from the air, not only biological but also adsorption air purification methods are accomplished. The use of complex purification technologies helps to improve the efficiency of a filter as well as the bed service life of the filter bed. Investigations revealed that microorganisms prevailing in biological purification, can also reproduce themselves in biofilter beds of inorganic and synthetic origin composed of natural zeolite and foam. By cultivating associations of spontaneous microorganisms in the filter bed the dependencies of the purification efficiency of filter on the origin, concentration and filtration time of injected pollutants were determined. The highest purification efficiency was obtained when air polluted with acetone vapour was supplied to the equipment at 0.1 m/s of superficial gas velocity. When cleaning air from volatile organic compounds (acetone, toluene and butanol), under the initial pollutant concentration of ~100 mg/m3, the filter efficiency reached 95 %.

scholarly journals BIOLOGICAL PURIFICATION OF AIR POLLUTED WITH VOLATILE ORGANIC COMPOUNDS BY USING ACTIVE SLUDGE RECIRCULATION

2004 ◽  
Vol 12 (2) ◽  
pp. 45-52 ◽  
Author(s):  
Aušra Zigmontienë ◽  
Pranas Baltrënas
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Organic Substance ◽  
Air Purification ◽  
Organic Substances ◽  
Sorptive Capacity ◽  
Active Sludge ◽  
Biological Purification ◽  
Purification Efficiency ◽  
Volatile Organic

Various methods for removal of volatile organic compounds (VOC) from the air are applied in the world. Their selection is determined by the efficiency and costs of the method. Biofiltration is a new technology to control environmental pollutants helping to regulate emissions of VOC with unpleasant odours in to the air and working environment. When VOC are to be removed from large volumes of air, equipment of biological purification charged with active sludge is used. Such an equipment has a rather simple structure and efficiency of to 98–99 %. Active sludge as a biocharge has both a high concentration of microorganisms compared to stationary charges and good sorption features. Sorptive capacity changes when a load to active sludge is changed, and this has a negative impact on biochemical decomposition of organic substances and, at the same time, on purification efficiency. Calculation and evaluation of an optimal working mode of the equipment enable to avoid desorption of VOC in the system or to diminish it to a minimal value. In the biological air‐purification equipment sorption of an organic substance on the surface of active sludge is running at the initial stage. An organic substance is decomposed biologically only in the second stage, and oxygen dissolved in the system (in the charge) is used and VOC desorption from the system is blocked. One of the main parameters determining the biological air‐purification process and its intensity is change of the concentration of oxygen dissolved (CDO) in water phase and maintenance of its minimal value after termination of aeration (when the equipment is out of operation for some time). In operating equipment with a biocharge one more important problem is encountered ‐ the lifetime of the charge and its renewal in the equipment to maintain required concentration of the active sludge. The goal of the investigation is evaluation of purification efficiency of the equipment and the sorptive capacity of active sludge (depending on a load), selection of the working mode, uninterrupted biochemical decomposition of organic substances (based on the concentration of dissolved oxygen) when the charge is in its still state, and investigation of its biooxidating properties when a biofilter works with a biologically active charge and with an inactive charge having only sorptive properties.

scholarly journals Continuous Monitoring of Air Purification: A Study on Volatile Organic Compounds in a Gas Cell

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 934 ◽  
Author(s):  
Alaa Fathy ◽  
Marie Le Pivert ◽  
Young Jai Kim ◽  
Mame Ousmane Ba ◽  
Mazen Erfan ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Indoor Air ◽  
Air Purification ◽  
Gas Cell ◽  
Oxide Nanowires ◽  
Continuous Adsorption ◽  
Volatile Organic ◽  
Ftir Spectrometer ◽  
Preliminary Study

Air pollution is one of the major environmental issues that humanity is facing. Considering Indoor Air Quality (IAQ), Volatile Organic Compounds (VOCs) are among the most harmful gases that need to be detected, but also need to be eliminated using air purification technologies. In this work, we tackle both problems simultaneously by introducing an experimental setup enabling continuous measurement of the VOCs by online absorption spectroscopy using a MEMS-based Fourier Transform infrared (FTIR) spectrometer, while those VOCs are continuously eliminated by continuous adsorption and photocatalysis, using zinc oxide nanowires (ZnO-NWs). The proposed setup enabled a preliminary study of the mechanisms involved in the purification process of acetone and toluene, taken as two different VOCs, also typical of those that can be found in tobacco smoke. Our experiments revealed very different behaviors for those two gases. An elimination ratio of 63% in 3 h was achieved for toluene, while it was only 14% for acetone under same conditions. Adsorption to the nanowires appears as the dominant mechanism for the acetone, while photocatalysis is dominant in case of the toluene.

Status and challenges in photocatalytic nanotechnology for cleaning air polluted with volatile organic compounds: visible light utilization and catalyst deactivation

2019 ◽  
Vol 6 (11) ◽  
pp. 3185-3214 ◽  
Author(s):  
Seunghyun Weon ◽  
Fei He ◽  
Wonyong Choi
Keyword(s):  
Volatile Organic Compounds ◽  
Visible Light ◽  
Organic Compounds ◽  
Catalyst Deactivation ◽  
Semiconductor Nanoparticles ◽  
Air Purification ◽  
Environmental Technology ◽  
Light Utilization ◽  
Volatile Organic

Photocatalysis that utilizes semiconductor nanoparticles is one of the promising environmental technology for air purification.

Air purification system

2020 ◽  
pp. 118-122
Keyword(s):  
Hydrogen Sulfide ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
The Other ◽  
Air Purification ◽  
Purification System ◽  
Volatile Organic ◽  
High Concentrations

An air purification system based on the use of specialized catalytic filling, designed to reduce high concentrations of hydrogen sulfide and volatile organic compounds is represented. The system is a 20 or 40 foot heated sea container in which two catalytic charge units are located: one is a working and the other is a reserve. Each block contains one cleaning step with a specialized ferrous charge.

scholarly journals Kinetic studies on using photocatalytic coatings for removal of indoor volatile organic compounds

2019 ◽  
Vol 29 (5) ◽  
pp. 689-700 ◽  
Author(s):  
Zhuoying Jiang ◽  
Xiong (Bill) Yu
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Indoor Environment ◽  
Visible Spectrum ◽  
Air Purification ◽  
Small Scale ◽  
Ambient Conditions ◽  
Functional Coating ◽  
Volatile Organic

Titanium dioxide (TiO2) is a known photocatalyst with a capability of decomposing organic substances. However, the photocatalysis of the pure TiO2 is not effective for the indoor environment due to a lack of the ultraviolet irradiation inside a building. Doping TiO2 with substance such as C, N, or metal can extend the threshold of the absorption spectrum to the visible spectrum region. Thus, doped-TiO2 is able to decompose volatile organic compounds (VOCs) under an indoor environment. To date, most experimental works reported on photocatalytic kinetics were conducted inside small-scale devices. The performance of air purification function under the actual indoor application scenery need to be further clarified. For this purpose, it is crucial to predict the performance of autogenous air quality improvements by visible light-driven photocatalyst for the actual applications. This work has developed a model to evaluate the performance of functional coating with photocatalyst in removing VOCs. Factors such as the effects of coating designs and indoor ambient conditions on the air purification efficiency were studied. This work demonstrates that doped-TiO2 photocatalytic coating is effective to improve the indoor air quality.

scholarly journals Evaluation of Reductions in Fume Emissions (VOCs and SVOCs) from Warm Mix Asphalt Incorporating Natural Zeolite and Reclaimed Asphalt Pavement for Sustainable Pavements

2020 ◽  
Vol 12 (22) ◽  
pp. 9546
Author(s):  
Javier Espinoza ◽  
Cristian Medina ◽  
Alejandra Calabi-Floody ◽  
Elsa Sánchez-Alonso ◽  
Gonzalo Valdés ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Natural Zeolite ◽  
Asphalt Pavement ◽  
High Energy ◽  
Asphalt Mixtures ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Volatile Organic ◽  
Road Paving

Conventional asphalt mixtures used for road paving require high manufacturing temperatures and therefore high energy expenditure, which has a negative environmental impact and creates risk in the workplace owing to high emissions of pollutants, greenhouse gases, and toxic fumes. Reducing energy consumption and emissions is a continuous challenge for the asphalt industry. Previous studies have focused on the reduction of emissions without characterizing their composition, and detailed characterization of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) in asphalt fumes is scarce. This communication describes the characterization and evaluation of VOCs and SVOCs from asphalt mixtures prepared at lower production temperatures using natural zeolite; in some cases, reclaimed asphalt pavement (RAP) was used. Fumes were extracted from different asphalt mix preparations using a gas syringe and then injected into hermetic gas sample bags. The compounds present in the fumes were sampled with a fiber and analyzed by gas-liquid chromatography coupled to mass spectrometry (GC/MS). In general, the preparation of warm mix asphalts (WMA) using RAP and natural zeolite as aggregates showed beneficial effects, reducing VOCs and SVOCs compared to hot mix asphalts (HMA). The fumes captured presented a similar composition to those from HMA, consisting principally of saturated and unsaturated aliphatic hydrocarbons and aromatic compounds but with few halogenated compounds and no polycyclic aromatic hydrocarbons. Thus, the paving mixtures described here are a friendlier alternative for the environment and for the health of road workers, in addition to permitting the re-use of RAP.

INVESTIGATION INTO THE AIR TREATMENT EFFICIENCY OF BIOFILTERS OF DIFFERENT STRUCTURES

2010 ◽  
Vol 18 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Pranas Baltrėnas ◽  
Alvydas Zagorskis
Keyword(s):  
Natural Zeolite ◽  
Filtration Efficiency ◽  
Wood Chips ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Filtration Time ◽  
Air Treatment ◽  
Volatile Organic ◽  
Useful Life ◽  
A Charge

Biological air treatment devices, biofilters, of four different structures with different origin charges, composed of natural zeolite granules, foam cubes and wood chips, were used for the experimental investigation. Biological and ad‐sorptive air treatment methods are employed to clean the air from volatile organic compounds by mixing foam and zeolite with wood chips. The use of complex cleaning technologies improves the efficiency of the device and extends the useful life of a charge. The investigation showed that microorganisms predominant in the process of biocleaning could also propagate in the charges of inorganic origin composed of natural zeolite. The dependences of biofilter treatment efficiency on the nature, concentration and filtration time of the fed pollutant were determined when cultivating associations of spontaneous microorganisms in a charge. The best filtration efficiency of the charge was achieved when acetone‐polluted air was fed into the device at a speed of 0.3 m/s. The treatment efficiency of a biofilter with a humidifying chamber reached 98% when cleaning the air from acetone with an initial concentration of the pollutant of 305 mg/m3. The cleaning efficiency of the device increases when reducing the concentrations of pollutants fed into the device and increasing the time of their filtration. Santrauka Eksperimentiniams tyrimams atlikti naudota keturi skirtingu konstrukciju biologiniai oro valymo irenginiai - biofiltrai su skirtingos kilmes ikrovomis, sudarytomis iš gamtines kilmes ceolito granuliu, porolono kubeliu bei medienos skiedru. Porolona ir ceolita maišant su medienos skiedromis, lakiesiems organiniams junginiams iš oro valyti taikomi biologinis ir adsorbcinis oro valymo metodai. Irenginio valymo efektyvumas pagerinamas bei ikrovos naudojimo trukme ilgeja naudojant kompleksines valymo technologijas. Ištyrus nustatyta, kad biologinio valymo procese vyraujantys mikroorganizmai gali daugintis ir neorganines kilmes ikrovose, sudarytose iš gamtinio ceolito. Ikrovoje kultivuojant savaiminiu mikroorganizmu asociacijas nustatytos biofiltru valymo efektyvumo priklausomybes nuo i irengini tiekiamo teršalo prigimties, koncentracijos, filtracijos laiko. Geriausiai ikrova filtravo 0,3 m/s greičiu i biofiltra tiekiama acetono garais užteršta ora. Šalinant iš oro acetona, kai pradine teršalo koncentracija 305 mg/m3, biofiltro su drekinimo kamera valymo efektyvumas sieke 98 %. Mažinant i biofiltrus tiekiamu teršalu koncentracijas bei didinant ju filtracijos laika irenginiu valymo efektyvumas dideja. Резюме Для экспериментальных исследований использовались четыре устройства для биологической очистки воздуха – биофильтры разных конструкций. Загрузку биофильтров составляли гранулы естественного цеолита, поролон и древесина, которые использовались для очистки воздуха от летучих органических веществ. В случае применения для очистки воздуха поролона и цеолита в смеси с древесиной применялся биологический и адсорбционный методы. Применение комплексных технологий способствует улучшению эффективности очистки воздуха и продлению срока применения загрузки. Исследования показали, что в процессе биоочистки микроорганизмы могут размножаться и в неорганической загрузке, состоящей из природного цеолита. Культивируя в загрузке ассоциации микроорганизмов, найдены зависимости эффективности биофильтра от характера загрязнителя, его концентрации, времени фильтрации. Лучше всего загрузка фильтровала воздух, загрязненный парами ацетона и подаваемый в установку со скоростью 0,3 м/с. Эффективность очистки воздуха от ацетона при начальной концентрации загрязняющих веществ в 305 мг/м3 для биофильтра с камерой увлажнения составляла 98%. При снижении концентрации загрязняющих веществ, подаваемых в биофильтр, и повышении времени фильтрации загрязненного воздуха эффективность установки увеличивается.

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