Odor Research Articles

Photocatalyst Technology for Deodorization in Household Refrigerator Based on Odor Removal

This paper describes what the sources of odor gas are in the refrigerator and analyzes how well the existing deodorization technology seems like. Here comes the TiO2-based photocatalyst for refrigerator deodorization. As for its work principle, this is an elaboration in details. It is also discussed how various types of factors such as carrier type, humidity and temperature affect the odor removal effect of photocatalyst materials in the refrigerator. A test is also cited for application of this technology to deodorize the refrigerator and the test results are analyzed. This test reveals that the deodorization device in the refrigerator has an odor removal rate of more than 90%. In the end, in view of the defects of photocatalyst used for the odor gas purification in the refrigerators, the prospect is visualized herein in order to provide the clues to subsequent studies in the field.

Odour Measurements at Different Methanisation Sites

The number of methanisation production sites increase in Europe. However, the installation of a new site sometimes creates problems with the neighborhood of the sites. The main concern is odours. To respond to these fears, the odour levels emitted by 3 biogas production plants were measured. In order to study the methanisation diversity, different waste treatment plants have been monitored. The waste came from farming (manure, slurry), WWTP sludge, or agro-food were compared. For each plant, 5 sources were investigated. A one year survey indicates that odour emissions changed according to the season. For each site, the main potential odour annoyance impact comes from the input preparation area.

Investigations into Off Notes in Foods, Products and Materials by GC-Olfactometry

GC-Olfactometry (GC-O) is the most powerful tool for characterization of odour compounds. This technique is widely used, especially in the sector of products and materials, and allows identifying the odour relevant compounds in the sample(s). GC-O data can also be used for quality control, development of value added products or to measure how efficient implemented modifications have been. This research describes case studies of the detection and identification of off notes in food samples such as tea, soy milk or chicken aroma production, and other products and materials such as polymers, packaging and cosmetics. The results obtained show a visual comparison of the aromatic profiles of samples, allowing clear conclusions to be drawn about products. In addition, chemical and sensory identifications of off notes are very important, as they allow acting directly on the product for example by changing the production chain or eliminating the raw material causing the undesirable odour. One of the cases shown in this study refers to the detection of off notes in food (ice cream) coming from the packaging. The use of low-quality recycled cardboard was responsible for the presence of volatile compounds such as aldehydes and sulphides. These compounds were responsible for generating fatty, aldehydic and garlic odour notes.

Methodological Aspects of Odorimetry in Environmental Audits of the Wastewater Treatment Plants

Environmental assessments play an important role among environmental protection instruments in the economy. Three main cases of such assessments can be distinguished: forecasts of the effects of the implementation of the plan, program, strategy (i.e. the so-called strategic assessments), environmental impact assessment of planned projects, as well as environmental audits, including post-implementation assessments, of existing installations and facilities. In each case, the objectives of the procedure can be different and the assessment methods are defined differently too (Barczak and Kulig, 2017; Zarra et al., 2014). Generally, it is to show that a newly built facility, also modernized or extended, meets the environmental protection standards included in legal regulations and administrative decisions. In the case of modernization or extension of the facility, it must additionally be shown that the ecological goal of the project has been achieved. As far as odour effects are concerned, the main goal of the research is to determine whether the plant (installation) being potential source of odorants emission put into operation will not be nuisance for other users of the area and residents in general. In the article, the methodological aspects of odour testing in post-implementation assessments in sewage management were analysed on the example of a modernized and expanded wastewater treatment plant (installation of the WWTP) located in Central Poland. Field studies on the impact on the environment were carried out based on scented air pollution of objects causing odour nuisance in the analysed area.

Sewage Odor Elimination Based on Photocatalytic Oxidation

The odorous gas discharged during the treatment of municipal sewage can not only reduce the wastewater reproducibility but also cause harm to the human health. It is mainly composed of ammonia nitrogen and sulfides. This paper focuses on odor elimination for sewage treatment plant based on photocatalytic oxidation. Study results reveal that when using WO3 or TiO2 alone, a higher degradation will be active for sulfides. Under visible light conditions, the catalytic performance of WO3 is higher than that of TiO2. The addition of WO3 to the TiO2/WO3 can improve the photocatalytic activity that gets more intense for ammonia nitrogen and sulfides as the content of TiO2 increases. While the degradation of organic pollutants is on the decline when TiO2 increases to a certain extent. Three types of catalysts are prepared by different ratios of TiO2 and WO3 for the sewage odor removal. It is found that, among them, the catalyst 2 (WO3: TiO2, 3.2:1) has a significantly better effect against inorganic pollutants than others.

Seasonal Variations in Odorous Compounds Emission from A Municipal Solid Waste Disposal Plant

Waste treatment plants are among the major sources of odor nuisances and health risk to workers and nearby residents. In this work, we present an assessment of the seasonal variations in volatile compounds emission and the odor nuisance effects from a waste treatment plant. Air samples were seasonally collected in four different processing units in the plant, and analyzed by both instrumental and sensory methods. Results showed that a total of 17, 27, 23 and 14 volatile compounds were detected in the air samples collected in the four seasons, with average total chemical concentration of 1515.4, 5364.7, 3282.5 and 1067.6 µg m-3. On the other hand, the non-carcinogenic risk of H2S (1.7 and 1.3 in summer and autumn) and dichloromethane (1.7 in summer) exceeded the acceptable risk levels (HI = 1). Carcinogenic risk of ethylbenzene ranged from 2.1E-05 to 4.2E-05 in spring, autumn and winter, exceeding the acceptable carcinogenic risk level (1.0E-06). Moreover, the carcinogenic risk of tetrachloroethylene and ethylbenzene was larger than 1.0E-04 and reached the level of “definite risks” in summer.

Risk Level Analysis of Petrochemical Hazardous Gas Leakage Based on Odour Recognition and CFD Simulation Technology

Petrochemical enterprises have made an indelible contribution to the global modernization. However, as the high risk-level enterprises, once gas leak occurs, it will cause great harm to the surrounding environment and residents. At present, there still exists some weakness in China’s research on petrochemical hazardous gas leak detection and risk classification is still weak. Based on odour recognition (rotten egg odour) and CFD simulation technology, this paper conducts analysis of risk levels for the hydrogenation process in petrochemical processing. The study has found that CFD can be used to simulate the concentration of harmful gas (H2S) diffusion and characterize the severity of harmful gas leakage; the wind direction of the hydrogenation unit and the installation and arrangement of the equipment have an important impact on the leakage of harmful gases, and then CFD simulation can be used to analyse the risk level. This is of guiding significance for the placement of H2S detector.

SiO 2 Adsorption Aerogel Odor Dissipation Control Technology Based on Active Purification Technology

As the use of automobiles increases, people spend more time in the car, and the air quality inside the vehicle is receiving more and more attention. Due to the large use of organic chemical materials in automotive decorative materials, it is easy to produce a variety of toxic and harmful volatile compound gases, which would cause the odor inside the car to affect the health of the driver. The unique nano-porous structure of SiO2 aerogel gives it excellent adsorption properties. Therefore, in this paper, the concentrations of the CO, PM2.5 and TVOC under different road environments and driving conditions are detected and analyzed, based on the active purification technology related to SiO2 adsorption aerogel, and studies the in-car air odor dissipation control technology. The results show that the concentration of CO in each ventilation mode is higher in the congested road sections, and the road congestion is the main influencing factor of CO concentration in the vehicle; the PM2.5 concentration in the air of the vehicle is greatly affected by the air quality outside the vehicle, and the road condition and form status have no decisive influence on it; the TVOC concentration in the car is relatively stable when the window is closed, but in unobstructed road conditions, the TVOC concentration is lower than that in the congested road conditions and it presents a declining trend; in the air inside the vehicle, for the CO, TVOC and PM2.5 suspended particulate matters, etc., we can use active purification technology related to SiO2 adsorption aerogel to control and dissipate the odor and air pollutants in the vehicle effectively.

Bluetooth Electronic Nose for Odour Monitoring and Control

A novel miniaturized and battery operated electronic nose (60x60 mm) for measuring different odorous compounds is presented in this paper. It can be connected with any smart device or personal computer through a Bluetooth link, which is used for commands and measurement data exchange based on a simple protocol. The system is controlled by a high performance 8-bit microcontroller and includes four miniaturized metal oxide (MOX) sensors for odour detection, an integrated sensor for temperature and humidity measurement, and the appropriate signal conditioning circuits.

Development of on-line and Field Dual TD-GC-FID/MS for Automatic and Continuous Volatile Organic Compounds (VOCs) Ambient Air and Odour Monitoring

Ambient air is polluted by many Volatile Organic Compounds (VOCs) coming from anthropogenic and natural sources. VOCs from PAMS, TO14 and TO15 lists can be measured in many ranges of concentration, from ng/m3 up to mg/m3 depending on the location of the measurements. Due to the large number of molecules, the complete separation of all compounds is difficult to perform using chromatographic columns. Therefore, it is difficult to quantify precisely all compounds using a chromatograph equipped with a nonspecific detector. The goal of this study is to perform automatic and continuous identification and quantification of VOCs using a dual Thermal-Desorber Gas Chromatograph equipped with two Flame Ionization Detectors (FIDs) and one Mass Spectrometer (MS). The device is required to identify automatically coeluted compounds by MS technology adapted to industrial context. The coupling of two different TD-GC-FIDs to a Quadrupole MS allowed by an elaborated multiplexer system is the originality of the project: one TD-GC-FID for monitoring of light compounds and one for heavy compounds with specific analytical conditions for each system. A measurement campaign in petrochemical new site shows the concentration of about 100 compounds at different steps of the commissioning. Thanks to the continuous measurements every 30 minutes, variations of concentrations during specific hours can be monitored. Potentially coeluted compounds like terpenes or organochlorinated are identified and monitored at ppt level. This solution enables to monitor odorants compounds at level of concentration lower than what human nose can detect. It also offers good capabilities for odour monitoring with molecule speciation. This fully automatic system allows non-specialist operators to access expertise level results.

Design and Implementation of WSN Detection System for Harmful Gas Based on Odour Recognition

In view of the safety problem with the harmful gas leakage in chemical environment, this paper develops one wireless sensor network (WSN) detection system for harmful gas based on odour recognition. In this system, the sensor array is used to make odour recognition of the four harmful gases such as Cl2, CO, NO2 and SO2 in the chemical environment; then, the data is transmitted through the ZigBee technology-built WSN to the central sink node for data analysis. Thus, the effective recognition and detection of harmful gases in the chemical environment can be achieved so as to avoid potential safety hazards.

Design and Implementation of Toxic Gas Concentration Monitoring System for Indoor Decoration Based on Odour Sensor Technology

With the improvement of people’s material living standards, they have also put forward higher quality requirements for the living environment, but the resulting toxic gases such as formaldehyde, toluene and organic volatiles brought about by decorations are fatal to human health. To this end, this paper designs one odour sensor-based toxic gases concentration monitoring system for indoor decoration: at the front end of the system, it is equipped with an independently-developed highly sensitive formaldehyde sensor; Wi-Fi technology with high stability and long transmission distance is selected as the main information transmission method; the front-end monitoring circuit can monitor the environmental parameters such as temperature, humidity, formaldehyde concentration, and CO concentration of each unit in real time; the design of the Web interface is based on the development of SpringMVC3+Hibernate3 development software and Oracle11g database. Finally, through the test of the toxic gas concentration monitoring system for indoor decoration, it’s found that it works stably in line with the design requirements.

Odour Detection Method of Silk Products Based on Electronic Nose Technology

Silk is a natural animal protein with special odour. Polyester yarns, similar in appearance to silk, are often used in silk production. Electronic nose (e-nose) technology can distinguish different gases by different pattern recognition methods. In this paper, e-nose technology was applied to obtain data sets of silk/polyester yarns with different mixing ratios, and cluster analysis was carried out for silk samples. The experimental results show that the results of e-nose response are related to the headspace, sample quality, and headspace generation time etc.; as the response time increases, the relative standard deviation of each sensor turns to be smaller, and the response value is more stable. There are significant differences in the fluctuations between the ten metal sensors, and different samples have significant effects on the response of sensors No. 2, 7, and. 9. The e-nose sensor has a higher prediction accuracy when identifying different ratios of silk/polyester yarns at the accuracy rate up to 90.286%.

Test on Noxious Gases in Urban Sewage Pipe Based on Odor Classification

Urban sewage pipes are filled with flammable, explosive, toxic and other noxious gases, which have brought hidden troubles during system maintenance and operation. To ease these threats to the urban sewage pipeline network, we should perform spot inspection and take some measures against safety risks that may occur on them. But of those, the test of noxious gases is the most challenging. Based on the odor classification method, we take an urban sewage pipe network in Chongqing as a study case for sample collection and spot inspection. The purpose of this paper is to classify and test the methane CH4 and hydrogen sulfide H2S by different methods. Data available from individual supervision spots are compared and analyzed in parallel, in order to explore how to measure these noxious gases and what’s the distribution and concentration change laws of them in urban sewage pipes, hoping to provide the clues to the early warning and safety operation of urban sewage pipeline network.

Design and Implementation of the Management and Detection System of Dangerous Production Raw Materials Based on Odor Sensor Technology

With the rapid development of electrification, both productivity and human civilization have made rapid progress and electrification has led to more and more fires. Therefore, it is of great significance to strengthen the investigation and prevention of fires, especially the confirmation of the origin of fire. Considering the post-combustion residual characteristics of common flammable production raw materials (carbon dioxide and dust) at the scene of the fire, this paper designs a detection system based on odor sensor for rapid detection, data analysis and recognition. The system designs a multi-function sensor array for detecting dangerous production raw materials (carbon dioxide and dust), and develop a good method for spot sampling. It introduces embedded technology and uses it together with chromatographic technology and sensor array, achieving the accurate detection of the combustion residues of dangerous production raw materials (carbon dioxide and dust) is realized. The detection signals are post-processed by feature extraction technology and pattern recognition algorithm. The research results are helpful for rapid analysis and recognition of residues, providing certain technical support for the recognition for the cause of fire.

Analysis for Improvement of Kitchen Odour by Oil Fume Purification Technology

The purpose of this study is to improve the kitchen odour. To this end, the comparative experiments were conducted in the methods such as mechanical purification, electrostatic purification, adsorption cleansing, filtration purification, washing purification, composite purification, and catalytic combustion etc. The experimental results show that there is a clear correlation between the purification effect and cost, that is, the method with better purification effect has higher purification cost. Through the comprehensive comparison, it’s found that the catalytic combustion method has the best cost performance. Thus, it’s suitable for large-scale promotion.

Hybrid Odor Detection System for Search and Rescue Robot Based on PSO

Aiming at the problem of the search and rescue robots' perception of various gases in chemical engineering sites, a hybrid odor detection system for search and rescue robots based on particle swarm optimization was proposed. In order to improve the stability and prediction accuracy of the system, a method of using particle swarm (PSO) to optimize the weighting coefficients of the integrated neural network is proposed, that is, using the global search ability of PSO and introducing an improved PSO algorithm to optimize the weights and thresholds of the BP neural network on the basis of the original BP neural network, and the optimized network is used in the detection system, thus reducing the detection error of the system. The system analyzed the response signals of the 4 gas mixtures of the sensor array, the experimental results show that the neural network algorithm based on particle swarm optimization is applied to the training of gas mixture quantitative identification, the convergence speed is faster and the detection accuracy is higher than that of BP neural network algorithm.

Graphene aerogel for the removal of bad smells from recycling of post-consumer polymers

Graphene aerogel was fabricated by a facile chemical reduction of a graphene oxide dispersion. The chemical reduction of graphene oxide was confirmed by different techniques. The resulting graphene aerogel showed large specific surface area (163 m2 g-1), high absorption capacity to incorporate odour and superior absorption recyclability. When graphene aerogel was added to the melting waste plastics, all the GC peaks of classified VOCs were reduced in intensity: of about 85% alcohols and carboxyl acids compounds; of more than 70 % aldehydes, ketones, esters and ethers; and in a lower content (62 % and 68 %, respectively) aliphatic and aromatic compounds, i.e. they were absorbed by GA. Thus, it displays promising application prospects in the field of organic volatile compounds treatment techniques, while allowing the adsorption and removal of molecules responsible for bad smells.

Application of Electronic Nose Technology in Coal Mine Risk Prediction

Coal resources are an important strategic resource in China. The safety situation of coal production is quite serious, and the foundation of coal mine risk prediction is weak. In this paper, the identification and concentration detection of CO and CH4 released during coal oxidation or oxidative spontaneous combustion are detected by electronic nose (e-nose) gas sensing technology. The influence of temperature and humidity on gas sensors is studied, and the correlation between the degree of coal oxidation and the output frequency of gas sensors is analyzed. The experimental results show that the sensitivity of the five kinds of e-nose gas sensors to CH4 is almost the same as that of CO, and the sensitivity of 112AJ sensor is the best. The e-nose gas sensors can capture the tiny changes of odor release in the initial stage of coal oxidation, and the artificial neural network analysis method is applied to the gas sensor array, which greatly improves the ability of coal mine risk prediction.

Application of Cleaner Production for Environmental Management in Mezcauchos SAS

Mezcauchos S.A.S, is a medium-sized manufacturing company with negative environmental impacts in the production of rubber soles. As part of their corporate responsibility, it requires alternatives for an environmental management, through a cleaner production.The environmental impacts are generated in the manufacturing process and are caused by many reasons: raw material waste, water expenditure for the drying process, strong odours in the injection and painting processes. The polyurethane waste is generated in different compositions, as well as the high rates of defective products that must be reprocessed, which brings with it a loss of time, high costs, and unnecessary material expenses, delay of the production process and decreases the profitability. In order to reduce these negative environmental impacts, were developed cleaner production tools that involves alternative solutions like the use of recycling water, the replacement of faucets and flushometers in bathrooms, the maintenance of pipes and connections to the hydraulic network. In addition, the company installed electronic ballasts (T8), 32 W lamps, a RYMEBUS inverter and, movement sensors in bathrooms and corridors. As recommendations that not are installed jet, were found that the company need to establish an appropriate route for the transport and separation of hazardous waste, the installation of containers for disposal, training the personnel for source separation practices. The purchase of a WINTECH injection machine is required to reduce the impact of noise. The internal rate of return (IRR) for the proposed alternatives is 26 % with an annual effective discount rate of 12 %.