Benzene Concentrations Research Articles

Effect of Biowaste Materials on the Physical Properties of Blended Fuel for Industrial Application

In this study, PMS gasoline gotten from randomly selected commercial fuel stations was blended with ethanol gotten from agricultural waste and developed nanoparticles Additives (D-NA). The blended samples were analyzed for their physical properties using methods recommended by the American Society for Testing and Materials (ASTM). The tests were carried out on the fuel's density, oxygenates, benzene content, research octane number (RON) and sulphur content. The results shown in the physical property tests done on these blended fuels when compared with the neat gasoline gotten from the Nigerian National Petroleum Corporation (NNPC), industry standards (DPR/SON) and global markets (United States US & United Kingdom UK) shows that the blended fuels meet all required standards and specifications. The additives had little effect on the fuel’s density but showed a sharp drop in its benzene content levels which makes it a healthier choice of fuel. Ethanol blended fuel had a higher oxygenate level than neat gasoline and the D-NA blended fuel. The research octane number for the three fuel samples showed favorably high numbers that fit the standards of the global market. The most interesting result is the Sulphur content which showed an increase in its values for the blended fuels although the values are within industrial and global limits. Keywords: PMS Fuel; physical properties; density; oxygenates; nanoadditives; ethanol

Explication on distribution patterns of volatile organic compounds in petro-chemistry and oil refineries of China using a species-transport model and health risk assessment

Volatile organic compounds (VOCs) from industrial emissions have attracted great attention due to their negative effects on human, but there is lack of deterministic air quality model for VOC emissions. In this study, airborne VOCs from a typical petrochemical and oil refinery region, Lanzhou, Gansu province of China, were on-site measured. The regional pollution patterns were investigated using a species transport model and the health risks were evaluated. The spatial distribution of VOCs showed that 87.5 % of the airborne VOCs were benzene, toluene, ethylbenzene, and xylene having higher concentration (146 μg/m3) in the north direction oil refinery industrial areas. The concentrations of toluene and benzene were as high as 41.5 and 33.3 μg/m3 in the 4 km2 area away from the petrochemical emission source, respectively, and the concentration of o−/m + p-xylene was up to 79.7 μg/m3. Based on the measured concentration data, the numerical results showed that the accumulation of high concentration of VOC species by mass transfer in the region is related to the atmospheric diffusion driven by downward-moving air over the valley areas. Non-carcinogenic risk assessments showed that airborne benzene exposure had acceptable hazard quotient of 0.185 for adults, which was 1.8 times of children's (0.102), whereas it was found that a high carcinogenic risk (>10−4) from benzene in several sampling sites and diffuse distance become significant for carcinogenic risk. This study verified the effectiveness of VOC atmospheric diffusion model through a large number of on-site monitoring data, providing data support for model-based risk assessment.

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CONSUMER PRODUCTS Reactions ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2022, 100 (43), p 5December 5, 2022Cite this:C&EN 100, 43, 5Letters to the editorMoose adventures in CanadaThe photo of the crash test dummy moose in Newscripts (C&EN, Sept. 19, 2022, page 32) brought back the memory of motoring with my wife on the Trans-Canada Highway north of Lake Superior in about 1980. As we registered in a motel in Wawa, Ontario, the desk clerk asked me if I had noticed a little red sports car in the lot. It and its driver had survived driving under a moose.Incidentally, when I had a summer job in the research lab of Canadian Industries Limited at McMasterville, Quebec, in 1947, the lab had a system of prizes: the One Bell Prize for a helpful bit of lab technique, the Two Bell Prize for finding a new substance of interest, the Three Bell Prize for a major advance, and the No Bell Prize for a conspicuous goof.Robert A. StairsPeterborough, OntarioRegulation of benzene in liquefied petroleum gasThe propane, butane, and isobutane mentioned in the article on benzene in dry shampoo (C&EN, Oct. 24/31, 2022, page 10) are sold as liquefied petroleum gas, known to the consumer as propane. Liquefied petroleum gas is a commodity produced by oil refineries and sold as a fuel for cooking, heating, grain drying, forklift trucks, and even backyard barbecues.The benzene discovery indicates contamination of some of it. As a commodity, it is easily commingled in distribution, as some may be supplied from multiple sources. Benzene in liquefied petroleum gas used as fuel may not be a concern, but caution is required when liquefied petroleum gas is used as a propellant in aerosol consumer products. In addition to cosmetic products, bug sprays and spray paints might be affected.The benzene content of gasoline is regulated. Is benzene regulated in liquefied petroleum gas?Paul E. EcklerWildwood, Missouri ACS 2021 IRS Form 990 availableThe American Chemical Society’s 2021 IRS Form 990 is now available on the ACS website. To access the information, go to www.acs.org/acsirsform990. Please scroll toward the bottom of the page to access the 2021 form and related Guide to Schedule J for explanatory information regarding ACS executive compensation. If you have any access problems, please contact [email protected]

Ambient exposures to selected volatile organic compounds and the risk of prostate cancer in Montreal.

This study is based on a population-based case-control study of incident prostate cancer (PROtEuS) in men ≤ 75 years of age living in Montreal, Canada, in 2005 to 2012. We included 1172 cases and 1177 population controls. We had personal information, lifetime residential addresses, occupational exposures, and a variety of area-wide covariables. We inferred concentrations of the five VOCs using Bayesian geostatistical models using data from a dense environmental survey conducted in Montreal in 2005 to 2006. We used different sets of adjustments to estimate odds ratios (OR) and confidence intervals. We found nonlinear associations such that the ORs increased monotonically and then either flattened or fell off with increased exposures. The model that contained other environmental variables and contextual variables led to lower ORs and results were similar when we restricted analyses to controls recently screened or tested for prostate cancer or cases with low- or high-grade tumors. A change from the 5th to 25th percentile in mean environmental benzene levels led to an adjusted OR of 2.00 (95% confidence interval = 1.47, 2.71). We found positive associations between prostate cancer and concentrations of benzene and ethylbenzene, independently of previous testing for prostate cancer or tumor grade, suggesting that exposure to certain ambient VOCs may increase incidence.

Changes in the biochemical indicators of metabolism in employees of the oil company

Introduction. Due to the constant presence of harmful chemical components in the air of the working area at an oil-producing enterprise, the length of work experience exacerbates their negative impact on the human body, which can lead to dysmetabolic disorders. The purpose of the work is to assess changes in the biochemical parameters of metabolism in workers of an oil producing enterprise. Materials and methods. A study and assessment of the content of polycyclic aromatic hydrocarbons in the bioenvironments of workers, biochemical indicators of metabolic processes, statistical analysis, modelling of cause-and-effect relationships were carried out. Results. In oil and gas production operators, benzene and o-xylene are identified in the blood, the concentration of which is up to 1.5 times higher than that of workers not associated with the oil production process. There is and gain in the level of benzene in the blood up to 1.4 times, depending on the increase in work experience. Significant differences were found in the content of C-peptide, glucose, total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides in oil and gas production operators relative to similar indicators in workers not exposed to chemical production factors of the enterprise. Among workers involved in oil and gas production, a dependence of an elevation of glucose and C-peptide in the blood serum on an increase in the concentration of benzene in the blood and the length of work experience was established; an increase in the level of total cholesterol, LDL cholesterol, triglycerides in the blood serum - only depending on the increase in work experience. Limitations. The conducted study takes into account the influence of only chemical factors and the duration of work experience on the health of oil production workers. Conclusions. The constant presence of polycyclic aromatic hydrocarbons in the air, in particular benzene and O-Cixille (up to 1.5 times higher than the MPC of the working area), leads to their increased concentration in the blood. In operators of oil and gas production there was established an increase in the level of a number of biochemical indicators of the negative effects of metabolic syndrome, which are dependent on the length of service and the content of benzene in the air of the working area.

Prevalence of sick building syndrome symptoms and subjective–objective indoor air quality of stores in underground shopping districts of Korea

Most sick building syndrome (SBS) studies have been conducted on workers in office buildings, whereas those assessing store workers in underground shopping districts (USDs) are limited. The purpose of this study was to determine the relationship between SBS symptoms of USD store workers and subjective–objective indoor air quality (IAQ). In 2020, 128 stores across 10 USDs in Korea were assessed. One worker in each store was asked about 16 SBS symptoms and seven subjective IAQ perceptions (categorized into two levels [Yes or No]) via questionnaire. Objectively, indoor concentrations of aldehydes and volatile organic compounds (VOCs) were measured in each store. The prevalence of SBS symptoms within the previous month was 16.4%, 39.1%, 28.9%, and 43.8% for skin, eye irritation, respiratory, and general symptoms, respectively. IAQ perceptions were correlated with the concentrations of several aldehyde compounds and VOCs. After adjusting for demographic (e.g., sex, age, or education) and job-related variables (e.g., working hours), logistic regression models showed all SBS symptom groups (except skin) were significantly associated with IAQ perception. Environmentally, eye irritation symptoms were associated with n-butanol, n-heptane, and xylene; respiratory symptoms with n-heptane; and general symptoms with benzene, n-heptane, and decanal concentrations. The association of SBS symptoms with aldehyde compounds and VOCs suggests that the chemical levels in USD stores may require further control to reduce these symptoms in workers. As controlling the products sold or cooking activities within USDs is difficult, increasing ventilation rates or using low-VOC-emission building materials may be more practical.

Exposure to Crude Oil-Related Volatile Organic Compounds Associated with Lung Function Decline in a Longitudinal Panel of Children.

Children in the affected area were exposed to large amounts of volatile organic compounds (VOCs) from the Hebei Spirit oil spill accident. We investigated the lung function loss from the exposure to VOCs in a longitudinal panel of 224 children 1, 3, and 5 years after the VOC exposure event. Atmospheric estimated concentration of total VOCs (TVOCs), benzene, toluene, ethylbenzene, and xylene for 4 days immediately after the accident were calculated for each village (n = 83) using a modeling technique. Forced expiratory volume in 1 s (FEV1) as an indicator of airway status was measured 1, 3, and 5 years after the exposure in 224 children 4~9 years of age at the exposure to the oil spill. Multiple linear regression and linear mixed models were used to evaluate the associations, with adjustment for smoking and second-hand smoke at home. Among the TVOCs (geometric mean: 1319.5 mg/m3·4 d), xylene (9.4), toluene (8.5), ethylbenzene (5.2), and benzene (2.0) were dominant in the order of air concentration level. In 224 children, percent predicted FEV1 (ppFEV1), adjusted for smoking and second-hand smoke at home, was 100.7% after 1 year, 96.2% after 3 years, and 94.6% after 5 years, and the loss over the period was significant (p < 0.0001). After 1 and 3 years, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV1. After 5 years, the associations were not significant. Throughout the 5 years' repeated measurements in the panel, TVOCs, xylene, toluene, and ethylbenzene were significantly associated with ppFEV1. Exposure to VOCs from the oil spill resulted in lung function loss among children, which remained significant up to 5 years after the exposure.

The Relationship of Individual Characteristics, Benzene Concentration with DNA Degeneration in Car Painting Workshop Workers

Background: A car paint shop is one of the works that use paint as the main working material containing benzene. Benzene is a colorless liquid aromatic compound that is carcinogenic to humans. This compound is classified as a group 1 human carcinogen by the IARC (International Agency for Research on Cancer).
 Objectives: This study aimed to analyze the correlation between individual characteristics and workplace benzene concentrations with DNA degeneration of workers in an automotive paint shop in Kalijudan, Surabaya.
 Methods: This study is an observational study with a cross-sectional design and a quantitative approach. Secondary data from the previous study were collected from 20 respondents, all of whom were paint workers in an auto paint shop. The dependent variable in this study is DNA degeneration and the independent variables are age, body mass index (BMI), number of years working, smoking behavior, and benzene concentration. To analyze the correlation of independent and dependent variables, the chi-square test was used. And then the phi test and Cramer's v are used to analyze the strength of the correlation between the two variables. 
 Results: Measurements of benzene concentrations in the workplace showed higher mean concentrations than TLV-TWA. As a result of laboratory tests, 13 out of 20 workers showed DNA degeneration. At the same time, the results showed a moderate correlation between BMI and DNA degeneration, and a very weak correlation between benzene concentration at work, individual characteristics (worker age, years of work, and smoking behavior) and DNA degeneration.
 Conclusions: This study found no correlation between individual characteristics and workplace benzene concentration with DNA degeneration in Surabaya auto paint shop workers.
 
 Keywords: benzene, car painting shop, DNA, individual characteristics

Prioritization of VOCs Emitted from Co-Processing Cement Kiln Using a Fuzzy Analytic Hierarchy Process Method

The violate organic compounds (VOCs) emission from co-processing cement kiln has not been comprehensively investigated and evaluated. In this study, we sampled and determined the VOCs emitted from a typical co-processing cement kiln in Beijing, China. VOCs characteristics, ozone formation potential (OFP), and main odor components for the emitted gas were analyzed. Additionally, a Fuzzy Analytic Hierarchy Process (F-AHP) was innovatively applied to estimate the priority VOCs. The study shows that aromatic (36.6%) and oxygen contained VOCs (O-VOCs) (30.3%) were the most abundant VOCs, with a high average concentration of benzene (1622.0 μg/m3) and acrolein (1105.5 μg/m3). Acrolein, propene, benzene, 1-butane, and 1,3-butadiene were the dominate OFP compounds, with the corresponding average OFP concentration of 8325.6, 3768.2, 1167.9, 1065.9, and 1027.2 μg/m3, respectively. Acrolein was also found to be the dominate main odor component. Eleven VOCs, including one O-VOC, one halohydrocarbon, and nine alkenes, were screened out by F-AHP. Alkene was the priority VOCs category and acrolein was the most important VOC in the stack gas. The results of this study are helpful to systematically understand the VOCs’ characteristics, OFP, main odor components, and priority compounds of VOCs in the stack gas of co-processing cement kiln, and provide a new method for the screening of priority VOCs compounds.

Performance and neural modeling of a compost-based biofilter treating a gas-phase mixture of benzene and xylene

Biofilter (BF) has been regarded as a versatile gas treatment technology for removing volatile organic compounds (VOCs) from contaminated gas streams. In order for BF to be utilized in the industrial setting, it is essential to conduct research aimed at removing VOC mixtures under different inlet loading conditions, i.e. as a function of the gas flow rate and inlet VOC concentrations. The main aim of this study was to apply artificial neural networks (ANN) and determine the relationship between flow rate (FR), pressure drop (PD), inlet concentration (C), and removal efficiency (RE) in the BF treating gas-phase benzene and xylene mixtures. The ANN model was trained and tested to assess the removal efficiency of benzene (REB) and xylene (REX) under the influence of different FR, PD and C. The model's performance was assessed using a cross-validation method. The REb varied from 20% to >60%, while the REx varied from 10% to 70% during the different experimental phases of BF operation. The causal index (CI) technique was used to determine the sensitivity of the input parameters on the output variables. The ANN model with a topology of 4-4-2 performed the best in terms of predicting the RE profiles of both the pollutants. Furthermore, the effect was more pronounced for xylene because an increase in the benzene concentration reduced xylene removal (CI = −25.7170) more severely than benzene removal. An increase in the xylene concentration had a marginally positive effect on the benzene removal (CI = +0.1178).

Evaluation of the Exposure to Benzene and SpmA using the Urine of Workers in the Shoe Home Industry in Surabaya

Introduction: Benzene is one of the pollutants in the shoe home industry that can cause cancer among the workers. The present research aimed to analyze the relationship between exposure to benzene and spmA (s-phenylmercapturic Acid) in the urine of shoe-making home industry workers in Surabaya. Methods: This was an observational study using an analytical research method where the total number of respondents in the sample was 10. The concentration of benzene was measured using Gas Chromatography-FID (Flame Ionization Detector). The data collection technique was descriptive analysis for each variable from among the worker’s characteristics. The analysis of the relationship between the level of spmA in their urine and the worker’s characteristics was performed using regression tests while the analysis of the relationship between the level of benzene in the air and the levels of workers’ spmA was performed using the Spearman correlation test. Results: The benzene I levels in the work environment were found to be between 0.06 ppm - 53.8 ppm. The average spmA was 6.68 μg/g creatinine. The p value of the relationship between the variable levels of benzene and the levels of spmA was 0.879 with a Spearman correlation coefficient of 0.056. Conclusion: The mean concentration of benzene in the air at the 6 point uptake was over the threshold. Based on the results of the spmA examination, the mean value of spmA was below the threshold value. The test results on the level of benzene in the air and the spmA indicate a very weak relationship.

City-scale assessment of long-term air quality impacts on the respiratory and cardiovascular health.

The impact of the urban environment on human health is a contemporary subject of environmental research. Air pollution is often considered a leading environmental driver. However, a plethora of other factors within the urban exposome may be involved. At the same time, the resolution of spatial data is also an important facet to consider. Generally, systematic tools for accurate health risk assessment in the urban environment are missing or are not implemented. The long-term impact of air quality (PM10, PM2.5, NO2, benzene, and SO2) on respiratory and cardiovascular health was assessed with a log-linear model. We used the most accurate health data in high city scale spatial resolution over the period 2010 to 2018. Selected external exposome parameters were also included in the analysis. Statistically significant associations between air pollution and the health of the urban population were found. The strongest association was between benzene and the incidence of bronchitis in the adult population [RR 1.552 95% CI (1.415-1.704) per 0.5 μg/m3 change in benzene concentration]. A similar relation was observed between NO2 and the same health condition [RR 1.483 95% CI (1.227-1.792) per 8.9 μg/m3 of change in NO2]. Other weaker associations were also found between asthma in children and PMs, NO2, or benzene. Cardiovascular-related hospitalizations in the general population were linked with NO2 [RR 1.218 95% CI (1.119-1.325) per 9.7 μg/m3 change in NO2]. The remaining pollutants were slightly less but still significantly associated with cardiovascular-related hospitalizations. Our findings are mostly highly statistically significant (p ≤ 0.001) and are in line with current literature on the adverse effects of air pollution on the human population. The results highlight the need for continual improvements in air quality. We propose the implementation of this approach as a systematic tool for the investigation of possible health risks over a long period of time. However, further research involving other variables is an essential step toward understanding the complex urban exposome and its implications for human health. An increase in data spatial resolution is especially important in this respect as well as for improving city health risk management.

Assessing the effect of BTEX on blood and spirometry parameters staff in a petroleum refinery.

This study aimed to investigate the impact of BTEX compound on blood and spirometry parameters of staff in the Abadan petroleum refinery (Iran). In 80 staff was examined in terms of BTEX exposure (40 exposed and 40 non-exposed). In this study, the air sampling was carried out according to the NIOSH 1,501 method and an automated hematology analyzer was used to analyze all blood samples to evaluate blood parameters and using a Micro Direct automated computerized spirometer. Spss20 software was used to interpret the performance. According to the obtained results, total BTEX concentrations with the recommended standard level showed that, toluene, ethylbenzene, and xylenes, concentrations in Abadan Oil Refining Company Workers' breathing zone were lower than the TLV-TWA recommended by ACGIH. However, the average concentration of benzene was higher than the allowable limit. Therefore, in this study the effect of benzene on the blood and respiratory parameters of the workers was evaluated, the comparison of the blood and respiratory parameters between the groups of exposed and unexposed workers did not reveal any statistical difference between the groups (p > 0.001). The results showed no statistically significant connection between mean blood and spirometry parameters and benzene exposure. Also, based on results the effect of benzene problems needs to be prevented in employees with adequate engineering and management controls and periodic inspection.

Comparing simulated shallow subsurface spills of diluted bitumen and conventional crude oil

Increased oil production in Canada has resulted in proposals to extend or develop new oil pipelines. Many of these proposals have been met by concerns from the public over potential environmental impacts related to construction and the potential for oil spills to negatively affect groundwater quality. Crude oil sourced from the Alberta oil sands represents a significant proportion of this increase in production. This crude oil is produced as bitumen, which is subsequently diluted with light hydrocarbons to lower viscosity to allow for pipeline transport producing diluted bitumen. In this study, we pumped water through tanks filled with sand to simulate groundwater flow. Tanks were injected with either conventional crude or diluted bitumen to simulate a crude oil spill from a pipeline rupture occurring below the water table representing a pipeline river crossing scenario. Water samples were collected from the downstream end of the tanks throughout the experiment period (∼two months). Compared to water quality guidelines, effluent waters from both conventional crude and diluted bitumen tanks contained elevated concentrations of dissolved organic compounds, particularly benzene, ethylbenzene, toluene and xylenes (BTEX). The effluent from each tank had similar concentrations of benzene, whereas discharge water from conventional crude tanks contained higher concentrations of ethylbenzene, toluene and xylenes. In both tanks, and as expected, the BTEX concentrations appeared to be proportional to those determined in their injected crude oils. The measured dissolved concentrations of benzene, ethylbenzene and toluene are lower than predicted which is attributed largely due to dilution along the flow path. In addition to organic constituents, effluent sampled from the diluted bitumen tank contained some metals (Co, Cr, Fe and V) which measured constituents of the oil.

Effect of calcium hydroxide on the characteristics of volatile organic compounds emission during sewage sludge incineration

AbstractEmission of volatile organic compounds (VOCs) during sludge incineration was explored after the addition of calcium hydroxide (Ca [OH]2), and the effects of incineration temperature, sludge particle size, and moisture content were investigated in a lab‐scale tubular furnace. Further, the contribution of the emission of VOCs in ozone formation potential (OFP) without Ca (OH)2 was calculated. The results indicated that incineration temperature in the range of 550–950°C can inhibit the emission of VOCs, with concentrations of the emissions varying from 3076.91 to 1277.11 μg/m3. Ca (OH)2 content had pronounced effects on the emission of VOCs during sludge incineration. The emission concentration of the VOCs decreased from 2421.16 to 1226.68 μg/m3 with Ca (OH)2 content increasing from 0 to 0.8 g. Sludge particle size and moisture content had little effects on the total amount of emitted VOCs during sludge incineration. Meanwhile, the contribution of the components of VOCs from sludge incineration in OFP was analyzed, which exhibited a decreasing trend: aromatic compounds > other substances > alkanes and olefins > chlorinated organic compounds. Aromatic compounds displayed the highest contribution rate at 92.72% because of the high concentration of benzene (1033.43 μg/m3). Our study provided theoretical data and a strong evidence of reduction in the emission of VOCs, OFP, and environmental regulation during sludge incineration.

The effect of fenugreek seed (Trigonella foenum-graecum) supplementation on the performance and milk yield characteristics of dairy goats.

The use of fenugreek seed as a galactagogue has been investigated in ruminants. However, only a few studies have analyzed the effects of fenugreek seed on the milk fatty acid composition. To the authors' best knowledge, none of these studies have investigated the effects of fenugreek seed on milk volatile compounds. The objective of this study, which lasted 8weeks, was to determine the effects of fenugreek seed supplementation on the performance, milk fatty acid profile, and milk volatile profile of goats. A total of 20 Turkish Saanen dairy goats that were mid-lactation were used in the study. This study was carried out with two homogeneous groups: the control group (CON) and fenugreek group (FG). Both groups were fed a total mixed ration (TMR), but the FG treatment had their diet supplemented with 0.1 kg d of fenugreek seed per animal. The feed intake, live weight, milk yield, milk chemical composition, serum cholesterol and triglyceride concentration, milk fatty acid profile, and milk volatile compound profile were determined. The feed intake, live weight gain, and milk yield of the goats did not significantly differ between the CON and FG treatments ( ), whereas the milk fat concentration increased ( ) and the serum cholesterol and triglyceride concentrations decreased ( ) in the FG treatment. The unsaturated fatty acid concentration in milk ( ) was also enhanced in the FG treatment. In addition, the FG treatment increased 2-propanone, 2-butanone, benzene, 1-methyl-3-(1-methylethyl), and eucalyptol concentrations in milk ( ). In conclusion, the supplementation of goats' diets with fenugreek seed during the mid-lactation period did not affect their performance and improved the unsaturated fatty acid profile of their milk. Of particular importance, we have also detected an increase in the 2-propanone concentration in milk following fenugreek supplementation.

Emission behavior and impact assessment of gaseous volatile compounds in two typical rural domestic waste landfills

Landfill sites are sources of gaseous volatile compounds. The dumping area (LDA) and leachate storage pool (LSP) of two typical rural domestic waste landfill sites in north China (NLF) and southwest China (SLF) were investigated. We found that 45, 46, 61 and 68 volatile organic compounds (VOC) were present in the air of NLF-LDA, NLF-LSP, SLF-LDA, and SLF-LSP, respectively. And there were 27, 29, 35 and 37 kinds of odorous compounds being detected. Oxygenated compounds (>48.88%), chlorinated compounds (>6.85%), and aromatics (>5.46%), such as organic acid, 1-chlorobutane, and benzene, were the most abundant compounds in both landfills. The SLF-LDA had the highest olfactory effect, with a corresponding total odor activity value of 29,635.39. The ozone-formation potential analysis showed that VOCs emitted from SLF landfills had significantly higher potential for ozone formation than those from NLF landfills, with ozone generation potentials of 166.02, 225.86, 2511.82, and 1615.99 mg/m3 for the NLF-LDA, NLF-LSP, SLF-LDA, and SLF-LSP, respectively. Higher chronic toxicity and cancer risk of VOCs were found in the SLF according to method of Risk Assessment Information System. Based on the sensitivity analysis by the Monte Carlo method, concentrations of benzene, propylene oxide, propylene, trichloroethylene, and N-nitrosodiethylamine, along with exposure duration, daily exposure time, and annual exposure frequency, significantly impacted the risk levels. We provide a scientific basis, which reflects the need for controlling and reducing gaseous pollutants from landfills, particularly rural residential landfills, which may improve rural sanitation.

Effect of H2O2 concentration as electron Acceptor on bioregeneration of activated carbon contaminated with a benzene-toluene mixture

Granular Activated carbon (AC) is commonly used for cleaning water contaminated with Benzene and toluene (BT). Regeneration is needed to extend the lifetime of GAC. This study examines the effect of H2O2 concentration as an electron acceptor for GAC bioregeneration by the consortium of Pseudomonas aeruginosa, Pseudomonas fluorescens, Aeromonas hydrophila, Bacillus coagulants, and Bacillus substilis in a fixed-bed bioreactor. Enrichment was carried out for adaptation to benzene and toluene. The enriched consortium was injected into a bioreactor column containing GAC saturated with benzene and toluene. The H2O2 concentration was varied 10 mg/l, 30 mg/l, 40 mg/l, and 50 mg/l. The contaminant mixture was continuously added with Lockhead and Chase (LC) and H2O2 at a flow rate of 18.2 ml/minute and 1 ml/minute, respectively. The outlet sample was analyzed using a Gas Chromatograph-Flame Ionization Detector (GC FID). The consortium regenerated the GAC by biodegradation of adsorbed benzene toluene. Initial inoculation of enrichment was 3.5 x 105 CFU/ml. The final stationary phase was at 120 hours with 1.37 x 1011 CFU/ml. The optimum biodegradation process was at a concentration of 30 mg/l H2O2 with a concentration of benzene and toluene outlet column II of 25 ppm and 40.5 ppm, respectively.

Robust prediction and optimization of gasoline quality using data-driven adaptive modeling for a light naphtha isomerization reactor

• A data-driven adaptive modeling was made for a light naphtha isomerization reactor. • A new integrated machine learning model (i.e., DLS-SVR) was proposed. • DLS-SVR model shows a better predictive peformance than RSM, SVR, and DLWELM models. • RON, RVP, and benzene content of the isomerate gasoline can be robustly predicted. • Gasoline quality was optimized using a combination of DLS-SVR and CPSO algorithm. In this research, a data-driven adaptive model is developed to predict the variables indicating gasoline quality in the light naphtha isomerization process and determine the optimal conditions leading to improved gasoline quality. To this end, an integrated method based on double-level similarity criterion and support vector regression (DLS-SVR) is proposed. The variables that indicate gasoline quality are research octane number (RON), benzene volume percentage (BVP), and Reid vapor pressure (RVP). In addition to the influential operating variables of pressure, temperature, feed weight hourly space velocity (WHSV), and hydrogen to naphtha feed molar ratio, the model considers benzene’s feed concentration and cycloparaffin content. Experiments are conducted using commercial Pt/Al 2 O 3 -CCl 4 catalyst in a pilot-scale packed-bed reactor. The developed model’s predictive performance and generalization ability are compared with the response surface methodology, support vector regression, and double-level locally weighted extreme learning machine through the fivefold cross-validation technique. The generalized DLS-SVR predicts gasoline’s RON, BVP, and RVP with R 2 = 0.901, 0.959, and 0.931 and RMSE = 0.055, 0.061, and 0.053, respectively, indicating that its performance is superior to alternative generalized models. The optimal conditions are computed using the DLS-SVR model and co-evolutionary particle swarm optimization algorithm (CPSO). The optimal operation of the reactor yielded a 6.78-unit increase in gasoline RON and a minimum BVP of 0.394 %. The results demonstrate that the proposed DLS-SVR model can accurately predict the variables indicating the quality of isomerate gasoline.

Synthesis of BiOI@NH2-MIL125(Ti)/Zeolite as a novel MOF and advanced hybrid oxidation process application in benzene removal from polluted air stream.

One of the popular process in volatile organic compounds removal in gas phase is advanced oxidation process. We in this research, synthesized BiOI@NH2-MIL125(Ti)/Zeolite nanocomposite as a novel nanocomposite to degradation of benzene in hybrid advanced oxidation process. The nanocomposite synthesized via solvothermal method. The effect of airflow, ozone gas concentration, hydrogen peroxide concentration, relative humidity and initial benzene concentration are the main parameters in the UV/O3/H2O2/ nanocomposite hybrid process that were studied. The characterization by XRD, FT-IR, FESEM, EDS element mapping, TEM, BET, and UV-vis spectra indicated that nanocomposite were well synthesized. Optimal operating conditions of the process were determined at air flow of 0.1l/min, ozone concentration of 0.3mg/min, hydrogen peroxide concentration of 150ppm, relative humidity of 45 ± 3% and benzene concentration of 50 ppmv. Under these conditions, more than 99% of benzene was degraded. The synergistic effect coefficient of the mechanisms is 1.53. The nanocomposite had good stability in the hybrid process and remained above 99% efficiency up to 5 times. The ozone concentration residual the system was reported to be negligible (0.013mg/min). The CO and CO2 emissions in the hybrid process was higher than other processes, which indicates better mineralization in the hybrid process. Formaldehyde, octane, noonan, phenol, decanoic acid were reported as the main by-products. The results indicated that UV/O3/H2O2/ nanocomposite hybrid process has fantastic efficiency in the degradation of benzene as one of the indicators of VOCs.