Derivatization techniques for determination of carbonyls in air

Szulejko, Jan E.,Kim, Ki-Hyun Elsevier 2015 Trends in analytical chemistry Vol.64 No.-

<P><B>Abstract</B></P> <P>This review critically assesses the derivatization techniques employed in sampling and detection of carbonyl compounds in air. We explore the most common techniques reported for the collection of vapor- phase carbonyl compounds by focusing on the hydrazine-derivatization techniques developed with the aid of diverse sorptive media [solution (e.g., in impingers), solid sorbents, solid-phase extraction, solid-phase microextraction, and denuder, or other approaches]. We discuss the advantages and the disadvantages of each sampling and pretreatment option for key carbonyl compounds with reference to measurement data obtained under laboratory and field conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> To quantify ambient carbonyls, derivatization is employed in sampling and detection. </LI> <LI> Common derivatization techniques have shortcomings as sources of bias. </LI> <LI> Up-to-date review of progress in derivatization for carbonyl compounds in air. </LI> </UL> </P>

Review of progress in solvent-extraction techniques for the determination of polyaromatic hydrocarbons as airborne pollutants

Szulejko, J.E.,Kim, K.H.,Brown, R.J.C.,Bae, M.S. Elsevier Scientific Pub. Co 2014 Trends in analytical chemistry Vol.61 No.-

In this review, we concentrate on sample-pretreatment options with the main emphasis on all aspects of solvent extraction prior to GC-based analysis of airborne polyaromatic hydrocarbons (PAHs). To this end, we review developments in these applications covering many different approaches that have commonly been used or introduced recently. Generally, sample pretreatment comprises (1)solvent extraction of PAHs from filters and sorbents; (2)extract concentration; (3)some form of liquid, or solid, chromatography clean-up; (4)eluent concentration; and (5)injection into a GC for analysis. Recent developments in these areas include: cold-fiber solid-phase microextraction of PAH extracts; the ''Quick, Easy, Cheap, Effective, Rugged, and Safe'' (QuEChERS) extraction technique; and, using vehicle-engine air-intake filters to collect airborne particulate matter. We also discuss some aspects of ''green chromatography'', used in recent years to reduce solvent usage.

A review of sampling and pretreatment techniques for the collection of airborne amines

Szulejko, J.E.,Kim, K.H. Elsevier Scientific Pub. Co 2014 Trends in analytical chemistry Vol.57 No.-

This review critically assesses the methodologies available for sampling and pretreatment of amines in air and bound in airborne particulate matter. We emphasize the most common techniques reported to date for the collection of vapor-phase amines based on sorptive media [solution (e.g., with the aid of impinger), solid sorbents, solid-phase extraction (SPE), solid-phase microextraction (SPME), and denuder] or other approaches (e.g., derivatization). Moreover, we extend discussion to cover amines found in airborne particulate matter through membrane filters, impactors, or scrubbers. Finally, based on measurements made under laboratory and field conditions, we discuss the advantages and the disadvantages of each sampling and pretreatment technique for key amine species.

A practical approach to estimate emission rates of indoor air pollutants due to the use of personal combustible products based on small-chamber studies

Szulejko, J.E.,Kim, K.H. Pergamon Press 2016 CHEMOSPHERE - Vol.144 No.-

As emission rates of airborne pollutants are commonly measured from combusting substances placed inside small chambers, those values need to be re-evaluated for the possible significance under practical conditions. Here, a simple numerical procedure is investigated to extrapolate the chamber-based emission rates of formaldehyde that can be released from various combustible sources including e-cigarettes, conventional cigarettes, or scented candles to their concentration levels in a small room with relatively poor ventilation. This simple procedure relies on a mass balance approach by considering the masses of pollutants emitted from source and lost through ventilation under the assumption that mixing occurs instantaneously in the room without chemical reactions or surface sorption. The results of our study provide valuable insights into re-evaluation procedure of chamber data to allow comparison between extrapolated and recommended values to judge the safe use of various combustible products in confined spaces. If two scented candles with a formaldehyde emission rate of 310 @?g h<SUP>-1</SUP> each were lit for 4 h in a small 20 m<SUP>3</SUP> room with an air change rate of 0.5 h<SUP>-1</SUP>, then the 4-h (candle lit) and 8-h (up to 8 h after candle lighting) TWA [FA] were determined to be 28.5 and 23.5 ppb, respectively. This is clearly above the 8-h NIOSH recommended exposure limit (REL) time weighted average of 16 ppb.

Estimation of emission factor for odorants released from swine excretion slurries

Szulejko, Jan E.,Kim, Bo-Won,Kim, Ki-Hyun,Lee, Min-Hee,Kim, Yong-Hyun,Jo, Sang-Hee,Kwon, Eilhann,Cho, Sung-Back,Hwang, Ok-Hwa Elsevier 2016 Science of the Total Environment Vol.548 No.-

<P><B>Abstract</B></P> <P>In this study, the odorant emission rates from excretory wastes collected in sealed containers from a large swine facility were determined offsite in a laboratory using both raw slurry from ([1] windowless pigpen (WP) and [2] open pigpen (OP)) and treated waste samples ([3] composting facility (CF) and [4] slurry treatment facility (SF)). The emission rates of up to 41 volatile odorants were measured for 100g waste samples (of all four types) in a 0.75L impinger with an air change rate of 8h<SUP>−1</SUP>. The initial emission rates (mgkg<SUP>−1</SUP>·h<SUP>−1</SUP>) for the most dominant species from each waste type can be summarized as: (1) WP: NH<SUB>3</SUB> (16.3) and H<SUB>2</SUB>S (0.54); (2) OP: H<SUB>2</SUB>S (1.78), NH<SUB>3</SUB> (1.69), and p-cresol (0.36); (3) CF: NH<SUB>3</SUB> (7.04), CH<SUB>3</SUB>SH (0.30), and DMS (0.12); and (4) SF: NH<SUB>3</SUB> (11.7), H<SUB>2</SUB>S (11.7), and p-cresol (0.25). Accordingly, the emission factors for the key odorant (m<SUB>E</SUB>, kg·pig<SUP>−1</SUP>)) for fattening pigs in the WP and OP facilities of S. Korea were extrapolated as 3.46 (NH<SUB>3</SUB>) and 0.38 (H<SUB>2</SUB>S), respectively. The emission factors were estimated assuming exponentially decaying emission rates and slurry production rates obtained from the literature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Odorant emissions inventory was investigated using the excretory wastes of pigpen facilities. </LI> <LI> Flux data for different wastes are analyzed to estimate the emission rates and emission factors. </LI> <LI> The total and per pig annual malodorant emissions are estimated and critically analyzed. </LI> <LI> Emission models for key odorants are constructed for both raw and processed wastes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Seeking the most powerful and practical real-world sorbents for gaseous benzene as a representative volatile organic compound based on performance metrics

Szulejko, Jan E.,Kim, Ki-Hyun,Parise, John Elsevier 2019 Separation and purification technology Vol.212 No.-

<P><B>Abstract</B></P> <P>To assess the best sorbents available in real-world treatment of airborne volatile organic compounds (VOCs), we explored four sorbent performance metrics (10% breakthrough volume, space velocity, regeneration cycles, and cost) against benzene, a representative VOC, using well-known sorbents in the partial pressure (P<SUB>benzene</SUB>) range 0.01 – 1 Pa. Accordingly, some common materials (e.g., activated carbons) outperformed novel materials like MOFs. The performance of MOFs was often exaggerated as data were generally collected under unrealistic P<SUB>benzene</SUB> (e.g., >5,000 Pa). The use of metrics appropriate to real-world conditions is thus critical for selecting sorbents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Performance of sorbents in real-world treatment of VOC is important for AQM purposes. </LI> <LI> Metrics were selected as breakthrough volume, space velocity, regeneration cycles, and cost. </LI> <LI> Sorbent performance metrics were checked for benzene in the partial pressure 0.01–1 Pa. </LI> <LI> Some common materials (e.g., activated carbons) have the potential to outperform others. </LI> <LI> The use of metrics appropriate to real-world conditions is critical for selecting sorbents. </LI> </UL> </P>

Is mass-scale electrocatalysis of aqueous methanol an energetically and economically viable option for hydrogen production?

Jan E. Szulejko,Eilhann E. Kwon,김기현 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

The use of primary alcohols (such as methanol) in the production of hydrogen (H2) has been spotlightedas one of the indispensable measures to pursue a greener economy. Here, we address some potentialshortcomings concerning the production of H2 based on aqueous methanol electrolysis in reference tosteam methane reforming (SMR) as a mature commercial technology. After all, is SMR an economicand low-energy route for H2 production? Is it feasible to use methanol to electrolytically generate H2?The liquid-phase methanol-based hydrogen evolution reaction (HER) at 335 K is an example of a potentiallyentropy driven reaction (exoergic, even though very endothermic) with a suitable catalyst usingeither ambient or waste heat. Further, would it be more efficient to use methane as a source of hydrogenvia SMR or consume it directly as energy? The suitability of HER is assessed in the context of industrialenergy analysis, thermodynamics, and sustainability.

Airborne volatile aromatic hydrocarbons at an urban monitoring station in Korea from 2013 to 2015

Khan, Azmatullah,Szulejko, Jan E.,Kim, Ki-Hyun,Brown, Richard J.C. Elsevier 2018 Journal of environmental management Vol.209 No.-

<P><B>Abstract</B></P> <P>The concentrations of C<SUB>6</SUB>-C<SUB>10</SUB> volatile aromatic hydrocarbons (AHCs) in air were measured at an urban air quality monitoring station in Jong-Ro, Seoul, Korea, between 2013 and 2015. Their temporal patterns (e.g., diurnal, intraweek, daily) were assessed individually and collectively as groups of benzene, toluene, ethylbenzene, styrene, and xylene (BTESX); total aliphatic hydrocarbon (TALHC: C<SUB>2</SUB>-C<SUB>12</SUB>); total aromatic hydrocarbon (TARHC: C<SUB>6</SUB>-C<SUB>10</SUB>); and total hydrocarbon (THC: C<SUB>2</SUB>-C<SUB>12</SUB>). The highest mean AHC concentrations over the 3-year study (in ppb (v/v)) were observed for toluene (6.0 ± 4.3), followed by the xylenes (1.5 ± 1.3), ethylbenzene (0.85 ± 0.93), benzene (0.73 ± 0.77), and styrene (0.16 ± 0.30) nL/L. The mean ppbC ((v/v), nL∙atm∙C/nL∙atm) values for BTESX, TALHC, TARHC, and THC were 65.8, 113, 77.7, and 191 ppbC, respectively. For most AHC species (e.g., toluene, styrene, and BTESX), only weak seasonal trends were observed in contrast to temporally varying species like nitric oxide (NO) (e.g., 26.3 ppb (January–February) vs. 8.5 ppb (July–August) during weekdays in 2013). Furthermore, toluene and NO concentrations were much higher (up to a factor 3) on weekdays than on Sunday for most weeks. This might reflect reduced anthropogenic activities on Sunday.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Toluene was the major BTESX. </LI> <LI> Propane was major hydrocarbon in all 56 hydrocarbons. </LI> <LI> Toluene and NO has strong correlation. </LI> <LI> Both toluene and NO showed much higher working day levels compare to Sunday. </LI> </UL> </P>

A comparison of figure of merit (FOM) for various materials in adsorptive removal of benzene under ambient temperature and pressure

Khan, Azmatullah,Szulejko, Jan E.,Kim, Ki-Hyun,Sammadar, Pallabi,Lee, Sang Soo,Yang, Xiao,Ok, Yong Sik Elsevier 2019 Environmental research Vol.168 No.-

<P><B>Abstract</B></P> <P>To effectively remove gaseous pollutants from air using sorbents, a thorough knowledge of the actual sorption performance is needed at ambient conditions rather than at unrealistically high-pressure conditions, as is commonly presented in the literature. To this end, the sorbent capacities of gaseous benzene were evaluated at a constant sorbent bed inlet pressure (50 ppm or ~5 Pa) in 1 atm of N<SUB>2</SUB>, room temperature (298 K), a fixed flow rate (50 mL min<SUP>−1</SUP>), and equal outlet sampling intervals (5 min). The benzene adsorption patterns were investigated against six sorbent types in a total of 17 different forms: 1- zeolite in five forms: beads (ZB), ground to 212 µm (ZG212), beads ground to 300 µm (ZG300), coarsely ground/washed zeolite (ZWc), and coarsely ground/washed/thermally treated zeolite (ZTc), 2- activated carbon in two forms: 212 µm (ACd212) and granular (ACdg), 3- Carbopack-X (CX), 4- Tenax TA (TA), 5- used black tea leaves of 150 or 300 µm in three forms: dry (TD150/TD300), wet (TW150/TW300), and wet dust (TWd), and 6- used ground coffee in either dry (CD) or wet forms (CW). Accordingly, the largest adsorption capacities at 5 Pa (e.g., >10 mg g<SUP>−1</SUP>) were observed for ACd212 (79.1) and ACdg (73.6). Moderate values (e.g., 5 < < 10 mg g<SUP>−1</SUP>) were obtained for ZG212 (7.98), CX (6.79), ZG300 (5.70), and ZB (5.58), while the remainder were far lower at < 5 mg g<SUP>−1</SUP> (e.g., tea leaves, ground coffee, TA, ZWc, and ZTc). The experimental benzene capacities of the tested sorbents were further assessed by the Langmuir, Henry's law, Freundlich, Dubinin-Radushkevich, and Elovich isotherm models. The linearized Langmuir adsorption isotherms of ACd212, ACdg, and CX showed the presence of more than one adsorption site (i.e., retrograde at the lowest pressures and two others at higher pressures). However, TA, zeolite, tea leaves, and ground coffee exhibited a type-V isotherm, wherein the sorption capacity continued to increase with loaded volume (i.e., multilayer adsorption). Thus, ACd212 has the best figure-of-merit based on a high 10% breakthrough volume (BTV) and low cost for real-world applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Activated carbon (ACd212) has retrograde isotherm. </LI> <LI> The ground sorbent has higher BTV compare to granular sorbent. </LI> <LI> The Langmuir adsorption isotherms identified more than one adsorption site. </LI> <LI> Tea leaves and ground coffee followed multilayer adsorption isotherm. </LI> <LI> The practicality of different sorbents is finally evaluated in terms of FOM. </LI> </UL> </P>

The effect of varying battery voltage output on the emission rate of carbonyls released from e-cigarette smoke

Qu, Yao,Szulejko, Jan E.,Kim, Ki-Hyun,Jo, Sang-Hee Elsevier 2019 Microchemical journal Vol.145 No.-

<P><B>Abstract</B></P> <P>The effect of vaping voltage (range: 3.6 to 7.0 V) on the emission of carbonyl compounds (CC) from electronic cigarettes (ECs) was investigated in this study. Changes in the CC levels were compared between prior to (e–liquid samples) and after vaping (EC-aerosol samples) using a total of six different e-liquid samples. Three of them were lab-made binary e-liquid solutions (composed only of propylene glycol (PG) and vegetable glycerin (VG) at the following 3 mixing ratios: 7:3, 5:5, and 10:0), while the remaining three were retail e-liquid products. The CCs in aerosol samples were captured from 10 EC puffs on 2,4-dinitrophenylhydrazine (DNPH) cartridges (2 s puff duration with a 10 s interpuff interval). All six e-liquids analyzed prior to EC use contained formaldehyde (FA) and acetaldehyde (AA) in the range of 0.12–50.0 and 0.53–14.9 μg mL<SUP>−1</SUP>, respectively. As the vaping voltage increased from 3.6 to 7.0 V, their emission factors increased from 1.12 to 1.64 and from 1.30 to 2.02 (μg puff<SUP>−1</SUP>), respectively. Such patterns were also observed for other CCs. The 40-year cancer risk (CR) of FA and CA for a typical user (120 puffs day<SUP>−1</SUP>) was estimated to be 7.0 × 10<SUP>−4</SUP>–1.1 × 10<SUP>−3</SUP> and 3.2 × 10<SUP>−5</SUP>–1.4 × 10<SUP>−4</SUP>, respectively; these CR values increased by 1.2 and 1.7–2.0 times, respectively with an increase in vaping voltage (3.6–7.0 V). The CR due to FA exposure from the three tested retail e-liquids was estimated to be 2.6–56 times higher than that of traditional tobacco cigarettes. Therefore, the use of ECs may expose users to high levels of certain CCs (like FA and AA), which may increase the risk for cancer in humans.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electronic cigarettes (e-cigarettes or ECs) are widely used around the world. </LI> <LI> Use of EC releases infamous pollutants (e.g., carbonyl compounds (CCs) - formaldehyde (FA)). </LI> <LI> A heating element is activated to vaporize the e-liquid to release various CCs like FA. </LI> <LI> Here, the effect of EC vaping voltage was investigated with regard to CC emission factors. </LI> <LI> Accordingly, we quantified CCs in two different phases (EC liquid vs. aerosolized samples). </LI> </UL> </P>