Moderate-temperature catalytic incineration of cooking oil fumes using hydrophobic honeycomb supported Pt/CNT catalyst

Composition analysis and health risk assessment of the hazardous compounds in cooking fumes emitted from heated soybean oils with different refining levels

The cooking fumes generated from thermal cooking oils contains various of hazardous components and shows deleterious health effects. The edible oil refining is designed to improve the oil quality and safety. While, there remains unknown about the connections between the characteristics and health risks of the cooking fumes and oils with different refining levels. In this study, the hazardous compounds, including aldehydes, ketones, polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) in the fumes emitted from heated soybean oils with different refining levels were characterized, and their health risks were assessed. Results demonstrated that the concentration range of aldehydes and ketones (from 328.06 ± 24.64 to 796.52 ± 29.67 μg/m3), PAHs (from 4.39 ± 0.19 to 7.86 ± 0.51 μg/m3), and PM (from 0.36 ± 0.14 to 5.08 ± 0.15 mg/m3) varied among soybean oil with different refining levels, respectively. The neutralized oil showed the highest concentration of aldehydes and ketones, whereas the refined oil showed the lowest. The highest concentration levels of PAHs and PM were observed in fumes emitted from crude oil. A highly significant (p < 0.001) positive correlation between the acid value of cooking oil and the concentrations of PM was found, suggesting that removing free fatty acids is critical for mitigating PM concentration in cooking fumes. Additionally, the incremental lifetime cancer risk (ILCR) values of PAHs and aldehydes were 5.60 × 10-4 to 8.66 × 10-5 and 5.60 × 10-4 to 8.66 × 10-5, respectively, which were substantially higher than the acceptable levels (1.0 × 10-6) established by US EPA. The present study quantifies the impact of edible oil refining on hazardous compound emissions and provides a theoretical basis for controlling the health risks of cooking fumes via precise edible oil processing.

Response surface methodology (RSM) for optimizing ozone-assisted process parameters for formaldehyde removal

Formaldehyde, a volatile organic compound (VOC), is one of the main gaseous pollutants from commercial cooking. The present study evaluated the effectiveness of a laboratory-scale ozone-assisted indirect plasma method for formaldehyde removal using response surface methodology (RSM). A dielectric barrier discharge (DBD) reactor was used for ozone generation. Inlet HCHO concentration, ozone concentration, and residence time were considered the design parameters, and formaldehyde removal efficiency (response 1) and energy yield (response 2) were considered response parameters. The optimized models showed a positive correlation between the predicted and experimental outcomes. Inlet ozone concentration, the most significant parameter in the removal efficiency model, represented a positive correlation with this response in most parts of the operating region. The optimal point with the highest desirability (i.e., D1 point) was obtained at the inlet HCHO concentration of 120 ppm, inlet ozone concentration of 40 ppm, and reaction time of 11.35 s within the parameter ranges studied, resulting in 64% removal efficiency and 2.64 g/kWh energy yield. At the point with the second highest desirability (D2), 100% removal efficiency along with 0.7 g/kWh energy yield was achieved indicating the very good performance of the process. The indirect plasma approach used in this study presented a successful performance in terms of removal efficiency along with acceptable energy yield compared to other plasma-assisted processes reported in the literature. The results suggested that ozone-assisted indirect plasma treatment can be utilized as an efficient alternative method for formaldehyde removal in commercial kitchens, while efficiency or energy yield should be prioritized for optimizing operating conditions.

Study on degradation of cooking fume by compound filter material and UV photodegradation

Environmental contamination issues have steadily surfaced with the rapid development of the cooking industry. In this paper, the front end of the cooking fume exhaust was filtered by the filter material, and then, the ultraviolet photolysis technology was used for in-depth treatment. The filter material filtration performance of glass fiber, molecular sieve, and composite filter material was studied by the filter efficiency, filter resistance, and quality factor three filter performance indexes. The results show that the filter wind speed has a significant influence on the filter material fume filtration characteristics. The filtration efficiency of the pre-filter material changes the least with the increase of the wind speed when the wind speed is 18 m·s^-1 and the filter material tilt Angle is 60°; meanwhile, the pressure drop of the two kinds of filter material is reduced, and the quality factor is improved. Under the optimal wind speed and angle, the composite filter material of glass fiber and molecular sieve combined with UV photolysis technology was used to study the treatment of formaldehyde and acrolein, which are two volatile organic pollutants with high content in cooking fume, and the mineralization mechanism of formaldehyde and acrolein under UV light was analyzed. The results showed that the removal rates of formaldehyde and acrolein could reach 99.84% and 99.75%, respectively.

Review of Emission Characteristics and Purification Methods of Volatile Organic Compounds (VOCs) in Cooking Oil Fume

Volatile organic compounds (VOCs) in cooking oil fumes need to be efficiently removed due to the significant damage they cause to the environment and human health. This review discusses the emission characteristics, which are influenced by different cooking temperatures, cooking oils, and cuisines. Then, various cooking oil fume purification methods are mainly classified into physical capture, chemical decomposition, and combination methods. VOCs removal rate, system operability, secondary pollution, application area, and cost are compared. The catalytic combustion method was found to have the advantages of high VOC removal efficiency, environmental protection, and low cost. Therefore, the last part of this review focuses on the research progress of the catalytic combustion method and summarizes its mechanisms and catalysts. The Marse-van Krevelen (MVK), Langmuir-Hinshelwood (L-H), and Eley-Rideal (E-R) mechanisms are analyzed. Noble metal and non-noble metal catalysts are commonly used. The former showed excellent activity at low temperatures due to its strong adsorption and electron transfer abilities, but the high price limits its application. The transition metals primarily comprise the latter, including single metal and composite metal catalysts. Compared to single metal catalysts, the interaction between metals in composite metal catalysts can further enhance the catalytic performance.

Effect of Morphological Modification over g-C3N4 on Photocatalytic Hydrogen Evolution Performance of g-C3N4-Pt Photocatalysts

In this study, the morphological properties of g-C3N4 in g-C3N4-Pt photocatalysts were modified by a simple hydrothermal treatment for photocatalytic hydrogen evolution. In addition, the morphological modification effect of g-C3N4 on the hydrogen evolution performance was investigated. The long-time hydrothermal treatment clearly changed the morphology of g-C3N4 by building extended melem units with more oxygen functional groups at the defect edges of the extended melem units, which was evidenced by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) measurements. The different morphological features of g-C3N4 resulted in lower photoluminescence (PL) emission intensity in PL spectra and a smaller semicircle radius in electrochemical impedance spectroscopy (EIS) data. This indicates the more efficient charge separation of the g-C3N4-Pt photocatalyst with a modified morphology. Consequently, morphologically modified g-C3N4-Pt showed a higher photocatalytic hydrogen evolution rate due to the better charge separation efficiency.

Insights into the Titania (TiO2) Photocatalysis on the Removal of Phthalic Acid Esters (PAEs) in Water

In this era of globalization, plastic is regarded as one of the most versatile innovations, finding its uses ranging from packaging, automotive, agriculture, and construction to the medical and pharmaceutical industries. Unfortunately, the single-use nature of plastics leads to ecological and environmental problems. Among conventional disposal management of plastic waste are landfilling dumping, incineration, and recycling. However, not all plastic waste goes into disposal management and ends up accumulating in lakes, rivers, and seas. In the aquatic environment, the action of photochemical weathering plastics has resulted in the release of chemical additives such as phthalic acid esters (PAEs), an important plasticizer added to plastic products to improve their softness, flexibility, and durability. Nowadays, PAEs have been ubiquitously detected in our environment and numerous organisms are exposed to PAEs to some extent. As PAEs carry endocrine disruptive and carcinogenicity properties, an urgent search for the development of an efficient and effective method to remove PAEs from the environment is needed. As a viable option, titania (TiO2) photocatalysis is a promising tool to combat the PAEs contamination in our environment owing to its high photocatalytic activity, cost-effectiveness, and its ability to totally mineralize PAEs into carbon dioxide and water. Hence, this paper aims to highlight the concerning issue of the contamination of PAEs in our aquatic environments and the summary of the removal of PAEs by TiO2 photocatalysis. This review concerning the significance of knowledge on environmental PAEs would hopefully spark huge interest and future development to tackle this plastic-associated pollutant. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Reduction of aldehyde emission and attribution of environment burden in cooking fumes from food stalls using a novel fume collector

Uncontrolled cooking emissions from commercial kitchens are problematic due to their corresponding health effects and malodors. To reduce cooking emissions, medium and large commercial kitchens install air pollution control devices, such as electrostatic precipitators and wet scrubbers, while small-scale commercial cooking workplaces, such as street-food stalls, use smaller, simpler, and less costly filtration and absorption devices. However, these smaller devices may be poorly designed and recirculate cooking emissions in the workplace. The objectives of this study were to design and implement a novel fume collector and evaluate its effectiveness in reducing aldehydes and the corresponding environmental burden emitted by food stalls. Two stalls, which had malodor problems despite the use of fume collectors, volunteered to participate in the study. To increase the efficiency of the existing fume collectors, a new collector was designed comprising two buckets connected in series, each with pollutant absorption (NaClO-surfactant mixed solution) and particulate filtration (activated-carbon filters) components. Total aldehyde concentrations measured at the exhaust outlets of the original and new collectors were 342.2 and 80.8 μg/m³ for stall A, and 622.7 and 283.1 μg/m³ for stall B, respectively. The corresponding concentration reductions for stall A and B were 76% and 55%, and the emission rate reductions were 91% (from 749 to 71 g/yr) and 76% (from 1040 g/yr to 248 g/h), respectively. These results demonstrate that the effectiveness of the novel collector at removing cooking fumes was significantly improved. The high efficiency and low-cost nature of the collector make it highly applicable in small-scale commercial kitchens and street-food stalls.

In vivo respiratory toxicology of cooking oil fumes: Evidence, mechanisms and prevention

BACKGROUND

As cooking is an essential part of people's daily life, cooking oil fumes (COF) has been recognized as one of the major indoor air pollutant. Mounting epidemiological evidence has indicated that COF exposure is significantly associated with an increased risk of various health effects including lung cancer, but toxicological studies are very limited.

OBJECTIVES

We conduct a systematic study to provide toxicological evidence of COF exposure on the lungs, to examine the underlying toxicological mechanism, and to suggest intervention measures to mitigate this toxicity.

METHODS

A total 96 female rats were randomly divided into control groups, COF exposure groups (0.2, 2, 20 mg/kg) and vitamin E protection groups, receiving appropriate treatment for 30 days. First we measured airway hyperresponsiveness (AHR) followed by a lung histological analysis to investigate the toxicological effects of COF. We next analyzed the biomarkers of oxidative stress, inflammation, and apoptosis to examine the underlying toxicological mechanism, and finally we investigated the protective effects of vitamin E against the toxicity of COF.

RESULTS

AHR measurement indicated that the airway resistance increased with the COF dose and the lung histological assay showed narrowing of the airway lumen, which provided evidence of the toxicological effects of COF. The biomarkers of oxidative stress (ROS and MDA), pro-inflammation (TNF-α and IL-1β), and apoptosis (NF-κB and Caspase-3) were all significantly increased with COF dose. We observed that above toxicological effects and biomarker levels induced by COF were significantly ameliorated after administration of VE.

CONCLUSION

The toxicity of cooking oil fumes on the lungs is clear from the evidence and mechanism, and can be ameliorated by vitamin E. We suggested that oxidative stress may be primarily responsible for the observed cooking oil fumes-induced toxicity.

Feasibility of using bed filters packed with rice-straw-based activated carbon and selected biomass waste for the control of frying fume exhaust

Open-air burning of rice straw (RS) on sites after harvesting produces tremendous amounts of air pollutants in Southeast Asia. Additionally, cooking oil smoke (COS) from high-temperature frying is classified as "Probably carcinogenic to humans" (Group 2A) by the International Agency for Research on Cancer. To mitigate the air pollution from COS, RS was recycled to prepare activated carbon (AC), which was used as a bed filter (BF) packing material for COS removal, and to our best knowledge, this study is the first one. Besides, a negative air ionizer (NAI) was firstly utilized to enhance the removal efficiency (η) of COS particles. Other biomass waste, including tea leaves (TL), wood dust (WD), rice hulls (RH), and coffee grounds (CG), were also used as packing materials for comparison. Specific surface area and pore volume of the packing materials were determined by nitrogen adsorption/desorption isothermal. Laser airborne particle counters and volatile organic compound (VOC) monitors (photoionization detector) were utilized for real-time recording of the particle and VOC concentration of COS. Economic assessments for the control of COS was also conducted. For submicron particles, the removal efficiency of the BFs ranged from 0 to 98% and the AC filter had the highest quality factor. The NAI remarkably enhanced the η value and filter quality factor. For the removal of particles larger than 2.5 μm, all BFs had η > 96%. The removal efficiency of volatile organic compounds (VOCs) (ηVOC) of the test BFs ranged from 18.22 to 90.8%. The AC filter had the largest pore volume (0.432 cm3/g) and surface area (877 m2/g) among all packing materials, causing this filter to have the highest ηVOC and adsorption capacity (over 28.3 mg-VOCs/g-AC). The annual operating costs of the TL, WD, RH, CG, and AC filters were 319.4, 23.3, 29.1, 189.4, and 62.9 US$, respectively. Therefore, using RS to prepare an AC bed filter for the removal of COS is a practical and sustainable strategy for COS control.