Rapid extraction of BTEX in water and milk samples based on functionalized multi-walled carbon nanotubes by dispersive homogenized-micro-solid phase extraction.

An advanced synthesis based on the phenylalanine (Phe) and task-specific ionic liquid (TSIL) functionalized on multi-walled carbon nanotubes (Phe/TSIL@MWCNTs), was used to extract benzene, ethylbenzene, toluene, and xylene (BTEX) from cow's milk, powdered milk, and farm water samples. The BTEX was efficiently extracted by ultrasound-assisted dispersive homogenized-micro-solid phase extraction (USA-DH-µ-SPE) between 95.1% and 103.4%. By procedure, 50 mg of Phe/TSIL@MWCNTs was added to 0.2 mL of acetone and injected into 10 mL of the samples. The upper aqueous solution was vacuumed, the vial heated to 80 °C, and the BTEX desorbed in the vial. Then, using a Hamilton syringe, 1-20 µL of gas in the headspace vial was determined by injecting it into the gas chromatography with flame ionization detection (GC-FID). The linear range, LOD, and LOQ for BTEX in milk and water samples were obtained at 0.05-500 µg L-1, 15 ng L-1, and 50 ng L-1, respectively (r = 0.9997, RSD% = 2.27).

An immobilization of aminopropyl trimethoxysilane-phenanthrene carbaldehyde on graphene oxide for toluene extraction and separation in water samples.

A new functionalized Nano graphene with aminopropyl trimethoxysilane-phenanthrene-4-carbaldehyde (NGO@APTMS-PNTCA) as a novel adsorbent was used to extract toluene from water samples by the ultrasound-assisted dispersive solid-phase microextraction procedure (USA-D-SPME). So, 50 mg of NGO@APTMS-PNTCA adsorbent was added to water samples and sonicated for 20 min. After toluene extraction, the NGO@APTMS-PNTCA adsorbent separated from the liquid phase with a Whatman membrane filter (200 nm). Then, the toluene was back-extracted from the adsorbent by 2.0 mL of the acetone/ethanol (1:1, eluent) at 25 °C. Due to the physical properties and structure of toluene, fluorobenzene was used as an internal standard. Finally, the toluene values were measured by a gas chromatography-flame ionization detector (GC-FID). In optimized conditions, the limit of detection (LOD), the working range (WR), and the enrichment factor (EF) were obtained at 2.5 µg L-1, 0.01-1.2 mg L-1, and 9.63, respectively (MRSD% = 3.38). Also, the limit of quantification (LOQ) 10 µg L-1 and extraction recovery of more than 95% was efficiently achieved for toluene. Standard additions of toluene to blank solutions had high recoveries between 95.2% and 104.5% with a relative standard deviation (RSD%) of 0.27-5.2. The absorption capacities of NGO and NGO@APTMS-PNTCA adsorbents for toluene extraction were obtained at 32.8 mg g-1 and 154.9 mg g-1, respectively. The USA-D-SPME method was validated by spiking the standard concentrations of toluene. The proposed method demonstrated relevant and suitable statistical results with high accuracy and precision for toluene extraction by a novel adsorbent synthesis.

Conversion of biomass to N, S co-doped porous graphene as an adsorbent for mercury vapor removal: optimization and DFT study.

This study is devoted to optimization synthesis conditions of the N, S co-doped porous graphene via a single step thermal chemical activation process from agricultural wastes such as cabbage waste. To this end, the response surface method (RSM) was considered, and the synthesis parameters were varied in specific ranges. By doing so, the optimum conditions in terms of the best performance in mercury removal was determined which was characterized by TEM, SEM, BET, XRD, XPS, and FTIR techniques. The chosen key process parameters were Activation agent to carbon precursor ratio (A: KOH/C), Reaction time (B: Time), Activation temperature (C: Temperature), and (Dopant to carbon precursor ratio (D: Dopant/C). Each parameter was investigated in 3 levels with lower and upper bounds being A: 2-6; B:30-90 min.; C: 600-800 ˚C; D:2-10. The optimum conditions of the process were determined to be as: A: 2; B: 30 min.; C: 600 ˚C and D: 2. The optimized sample was prepared in repeated runs with reproducible results with Hg vapor adsorption capacity of 2100 µg/g at 40 ˚C and 2266 µg/g at 90 ˚C. In addition to the experiments, DFT calculations were also carried out which elucidated the positive role of N and S co-doping in improving the mercury adsorption intensity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00712-y.

Single-step synthesis of N, S co-doped waste-derived nanoporous carbon sorbent for mercury vapor removal.

As well known, mercury is a toxic trace element due to its bioaccumulation and volatility which results in severe effects in health of ecosystems and humans' life. Herein, for the first time, the synthesis of a N and S dual-doped waste-derived graphene-like nanoporous carbon via a facile and single-step route is presented and its capability in mercury vapor removal from gas streams is investigated. To prepare a modified adsorbent, thiourea was utilized as the doping agent to induce nitrogen and sulfur dopants into the nanoporous carbon structure derived from pyrolysis of cabbage (Capitat. var. Brassica oleracea) waste from Brassicaceae family as an inherently S, N-containing precursor, which is produced in noticeable amounts annually. The prepared adsorbents were characterized through FTIR, XRD, BET, SEM, TEM, and CHNOS techniques to get an insight into the structure, morphology, and chemical characteristics of the adsorbents. The structural characterization revealed the successful synthesis of a graphene-like nanoporous carbon sheet which was doped with nitrogen and sulfur atoms. The S, N dual-doped graphene-like carbon nanosheets showed an enhanced activity toward mercury vapor adsorption. For this end, two different dopant to carbon source ratios were considered and it was found that the higher dopant amount results in a better performance. From the adsorption experiments, it was revealed that the pristine graphene-like carbon had a less performance in mercury removal (71%) compared with doped samples (more than 90%) which shows the necessity of reinforcement and surface modification of as mentioned cabbage base graphene. However, the best sample which was prepared with the dopant to carbon ratio of 10 had a performance of 94.5% removal (2100 µg/g) compared with 89% (1980 µg/g) for mercury removal by the sulfur-impregnated commercial activated carbon.

Assessing human vulnerability in industrial chemical accidents: a qualitative and quantitative methodological approach.

Iran as a developing country is experiencing the industrialization process quickly and is thus exposed to different industrial hazards mostly derived from chemicals. In the light of this problem, this study estimated the human vulnerability in chemical accidents using the software simulation of accidental chlorine gas releases. A mixed method (qualitative and quantitative) study carried out in 4 phases during 2015-2017 in Ray County, Tehran Province. It included a systematic literature review, software simulation, Fuzzy Delphi Analytical Hierarchy Process (FDAHP) hierarchy process study, and creating a reliable tool for purpose of this study in at-risk areas. The valuable finding indicated that decreasing the human vulnerability depends on both social and physical characteristics of area and even the social vulnerability indicators have more important role when compared with the physical vulnerability indicators. The statistical analysis revealed that the human vulnerability has the significant relationship with factors such as type of living place (rural or urban) areas, nationality, economic situation of households, the distance between housing and the nearest exit to main road, health centers, and manufacturing or storing chemical plants (P value < 0.01). The result also showed that the area under study is vulnerable from average to very high, both in its physical and social domains, against industrial chemical accidents. Additional comparative studies are needed to develop and generalize the appropriate set of indicators of human vulnerability to human induced disasters in Iran.

Industrial chemical accidents: a growing health hazard in the Islamic Republic of Iran.

BACKGROUND: Occupational chemical accidents have increased in recent years in the Islamic Republic of Iran. In June and August 2015, three large explosions occurred at chemical warehouses in Rey, Tehran Province, and toxic vapours were released. AIMS: This study reviewed the three chemical accidents and assessed the extent to which the requirements for chemical safety and preparedness for chemical incidents under the International Health Regulations (IHR) are in place, and implemented at local and national levels in the Islamic Republic of Iran. METHODS: Data were obtained from secondary data and field visits to selected chemical plants. The secondary data were used to complete a 33-item checklist based on the IHR and the Ministry of Health and Medical Education checklist. A sample of 15 warehouses in Kahrizak district, Rey County, were visited to assess their capacity in relation to the IHR using a 15-item checklist. RESULTS: Some weaknesses were seen in the IHR capacity in the study area. The main weaknesses were lack of an effective surveillance system for chemical accidents and low levels of safety in chemical plants and warehouses. Other weaknesses included the lack of awareness of residents about chemical hazards and poorly equipped health centres for the management of victims of chemical accidents. The study area was not prepared for chemical accidents both within industrial plants and residential areas. CONCLUSIONS: Action is needed to improve the areas of weakness so as to achieve the necessary capacities for chemical safety, and preparedness and response to chemical incidents in line with the IHR.

The data on the dispersion modeling of traffic-related PM10 and CO emissions using CALINE3; A case study in Tehran, Iran.

CALINE3 model predicts the dispersion of pollutants released from roadways in the receptor places at a certain radius from the source. This model was used to evaluate the dispersion of particulate matter < 2.5 µm (PM10) and carbon monoxide (CO) emitted from Yadegar-e-Emam Expressway (YEE) as one of the most congested highways in Tehran. The hourly concentrations of PM10 and CO, and the count and speed of vehicles were obtained from Tehran׳s Air Quality Control Company (TAQCC). Wind speed and direction, the height of mixing zone, air temperature, relative humidity, and stability class were acquired from IRAN Meteorological Organization (IRIMO). The emission factors (EF) of vehicles were acquired from those proposed for UK. The dispersion of PM10 and CO was predicted over the nearby area, and the modeled concentrations were estimated for a specific point, where an air quality monitoring station was working. The major portion of PM10 and CO released by vehicles in YEE was dispersed to the east. The comparison between the modeled and measured concentrations revealed that CALINE3 underestimates the concentrations of PM10 and CO by about 50%.

Areal location of hazardous atmospheres simulation on toxic chemical release: A scenario-based case study from Ray, Iran.

BACKGROUND AND AIM: Chemical accidents cause significant danger for residents living close to chemical facilities. For this reason, this study assessed the impacts of a simulated chemical accident on surrounding residents in the city of Ray, Iran. METHODS: In this scenario-based case study in 2015, the Areal Location of Hazardous Atmospheres (ALOHA) model was applied to simulate a toxic chemical release from a chlorine warehouse in Shourabad, Ray, Iran. The population of the area was calculated based on the latest census in Iran, 2011. The atmospheric variables included were wind speed, air temperature, and relative humidity. We also included data on pollution source such as diameter, length and volume, and condition of chemicals. The simulation was repeated for each seasonal period. The simulated threat zones were mapped using Geographical Information System. The percentage of residents sustaining injuries and death was calculated using probit. RESULTS: The maximum and minimum simulated threat zones by chlorine release are during summer and winter at 8.8 and 6.4 kilometers respectively. The total affected population was estimated at approximately 30,000 people. The greater percent of injuries and death was estimated to occur in the winter and autumn, compared to summer and spring, because of greater climatic instability. The number of individuals affected by chlorine release in the spring, summer, autumn and winter at 8.3, 8.8, 7.6 and 6.4 kilometers, are estimated at 22,500, 25,000, 28,100 and 27,500, respectively. Populations located in hot and warm zones of toxic chemical releases should have access to medical resources. CONCLUSIONS: The results showed that relevant factors impact human vulnerability, and these should be examined to mitigate the harmful consequences of chemical accidents. Establishing a multi-level Emergency Response Program is also recommended in the area under study.

Components of sustainability considerations in management of petrochemical industries.

Sustainability comprises three pillars of social, environmental, and economic aspects. Petrochemical industry has a great inter-related complex impact on social and economic development of societies and adverse impact on almost all environmental aspects and resource depletion in many countries, which make sustainability a crucial issue for petrochemical industries. This study was conducted to propose components of sustainability considerations in management of petrochemical industries.A combination of exploratory study-to prepare a preliminary list of components of sustainable business in petrochemical industries based on review of literature and Delphi-to obtain experts' view on this preliminary list and provide a detailed list of components and sub-components that should be addressed to bring sustainability to petrochemical industries, were used.Two sets of components were provided. First general components, which include stakeholders (staffs, society, and environment) with four sub-components, financial resources with 11 sub-components, improvement of design and processes with nine sub-components, policy and strategy of cleaner production with seven sub-components and leadership with seven sub-components. The second operational components included raw material supply and preparation with five, synthesis with ten, product separation and refinement with nine, product handling and storage with five, emission abatement with eight, and improvement of technology and equipment with 16 sub-components.

Constructing the Indicators of Assessing Human Vulnerability to Industrial Chemical Accidents: A Consensus-based Fuzzy Delphi and Fuzzy AHP Approach.

INTRODUCTION: Industrial chemical accidents have been increased in developing countries. Assessing the human vulnerability in the residents of industrial areas is necessary for reducing the injuries and causalities of chemical hazards. The aim of this study was to explore the key indicators for the assessment of human vulnerability in the residents living near chemical installations. METHODS: The indicators were established in the present study based on the Fuzzy Delphi method (FDM) and Fuzzy Analytic Hierarchy Process (FAHP). The reliability of FDM and FAHP was calculated. The indicators of human vulnerability were explored in two sets of social and physical domains. Thirty-five relevant experts participated in this study during March-July 2015. RESULTS: According to experts, the top three indicators of human vulnerability according to the FDM and FAHP were vulnerable groups, population density, and awareness. Detailed sub-vulnerable groups and awareness were developed based on age, chronic or severe diseases, disability, first responders, and residents, respectively. Each indicator and sub-indicator was weighted and ranked and had an acceptable consistency ratio. CONCLUSIONS: The importance of social vulnerability indicators are about 7 times more than physical vulnerability indicators. Among the extracted indicators, vulnerable groups had the highest weight and the greatest impact on human vulnerability. however, further research is needed to investigate the applicability of established indicators and generalizability of the results to other studies. KEY WORDS: Fuzzy Delphi; Fuzzy AHP; Human vulnerability; Chemical hazards.

Contribution of point and small-scaled sources to the PM10 emission using positive matrix factorization model.

BACKGROUND: The positive matrix factorization is a powerful environmental analysis technique which has been successfully utilized to assess air-born particulate matter source contribution. The new version of this model (PMF5) has two additional estimation error methods and some other useful advantages compared to the previous versions. In the present study, the capability of PMF5 for identification and contribution of small size particle source to the ambient particulate matter was evaluated. METHODS: The study area is surrounded by three industrial complexes and 2 locations of dumped tailing soils of mining activities and related manufactures. Ambient particulate matter were sampled at 2 sites in the urban area of Zanjan (Iran) and 196 collected samples were analyzed for 15 chemical elements. RESULTS: At downtown, the identified factors (and their contributions to particulate matter) were: soil particles (40.36%), fuel combustion and traffic (26.8%), tailing soils (lead and zinc) (21.32%), and nickel and industrial emission(5.7%). The identified factors at residential site of studied area (and their contributions to particulate matter) were general industrial emission (28.2%), tailing soils (lead and zinc) (39.2%), soil (25.8%), cadmium and general pollutants (6.7%). CONCLUSION: The results of modeled data by PMF 5 indicated that the applied model could identify the dumps of tailing soils as a separated factor. The other particulate matter sources in the studied area were traffic, fuel combustion, soil particles and industrial pollutants.