Synthesis and Characterization of a Multi-Walled Carbon Nanotube-Ionic Liquid/Polyaniline Adsorbent for a Solvent-Free In-Needle Microextraction Method.

Sample preparation is an essential process when handling complex matrices. Extraction without using a solvent requires the direct transfer of analytes from the sample to the adsorbent either in the gas or liquid phase. In this study, a wire coated with a new adsorbent was fabricated for in-needle microextraction (INME) as a solvent-free sample extraction method. The wire inserted into the needle was placed in the headspace (HS), which was saturated with volatile organic compounds from the sample in a vial. A new adsorbent was synthesized via electrochemical polymerization by mixing aniline with multi-walled carbon nanotubes (MWCNTs) in the presence of an ionic liquid (IL). The newly synthesized adsorbent using IL is expected to achieve high thermal stability, good solvation properties, and high extraction efficiency. The characteristics of the electrochemically synthesized surfaces coated with MWCNT-IL/polyaniline (PANI) adsorbents were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and atomic force microscopy (AFM). Then, the proposed HS-INME-MWCNT-IL/PANI method was optimized and validated. Accuracy and precision were evaluated by analyzing replicates of a real sample containing phthalates, showing spike recovery between 61.13% and 108.21% and relative standard deviations lower than 15%. The limit of detection and limit of quantification of the proposed method were computed using the IUPAC definition as 15.84~50.56 µg and 52.79~168.5 µg, respectively. We concluded that HS-INME using a wire coated with the MWCNT-IL/PANI adsorbent could be repeatedly used up to 150 times without degrading its extraction performance in an aqueous solution; it constitutes an eco-friendly and cost-effective extraction method.

In Vitro and In Vivo Human Body Odor Analysis Method Using GO:PANI/ZNRs/ZIF-8 Adsorbent Followed by GC/MS.

Among various volatile organic compounds (VOCs) emitted from human skin, trans-2-nonenal, benzothiazole, hexyl salicylate, α-hexyl cinnamaldehyde, and isopropyl palmitate are key indicators associated with the degrees of aging. In our study, extraction and determination methods of human body odor are newly developed using headspace-in needle microextraction (HS-INME). The adsorbent was synthesized with graphene oxide:polyaniline/zinc nanorods/zeolitic imidazolate framework-8 (GO:PANI/ZNRs/ZIF-8). Then, a wire coated with the adsorbent was placed into the adsorption kit to be directly exposed to human skin as in vivo sampling and inserted into the needle so that it was able to be desorbed at the GC injector. The adsorption kit was made in-house with a 3D printer. For the in vitro method, the wire coated with the adsorbent was inserted into the needle and exposed to the headspace of the vial. When a cotton T-shirt containing body odor was transferred to a vial, the headspace of the vial was saturated with body odor VOCs. After volatile organic compounds were adsorbed in the dynamic mode, the needle was transferred to the injector for analysis of the volatile organic compounds by gas chromatography/mass spectrometry (GC/MS). The conditions of adsorbent fabrication and extraction for body odor compounds were optimized by response surface methodology (RSM). In conclusion, it was able to synthesize GO:PANI/ZNRs/ZIF-8 at the optimal condition and applicable to both in vivo and in vitro methods for body odor VOCs analysis.

Characterization of scents from Juniperus chinensis by headspace in-needle microextraction using graphene oxide-polyaniline nanocomposite coated wire followed by gas chromatography-mass spectrometry.

Scents released by trees are the secondary metabolites that play various roles, including indirect plant defense against insects, attraction to pollinators, communication, adaptation to heat resistance, environmental stress, and protection from predators. In this study, the scents of three individual trees designated as Korean natural monuments (pair of Chinese junipers, Chinese juniper, and horizontal Chinese juniper tree) were analyzed using headspace in-needle microextraction (HS-INME) method with graphene oxide-polyaniline (GO-PANI) adsorbent followed by gas chromatography-mass spectrometry (GC/MS). GO-PANI layer was coated on a stainless steel wire using cyclic voltammetry (CV). It was characterized through thermogravimetric analysis (TGA), Fourier transform-infrared spectroscopy (FT-IR), and field emission-scanning electron microscope (FE-SEM). As a result, it was confirmed that the GO-PANI coating was successfully prepared. α-Longipinene, α-cedrene, and cedrol, which are representative scent components of common juniper trees, were selected as target compounds through a preliminary test and used in the optimization processes. Response surface methodology (RSM) with Box Behnken Design (BBD) was applied to optimize the experimental conditions. The developed analytical method was validated by checking the limit of detection (LOD), the limit of quantitation (LOQ), recovery rate, sensitivity, and reproducibility. Significant scientific findings from three Korean natural monuments of Juniperus chinensis were characterized by their major scent components such as α-cedrene, γ-cadinene, thujopsene, and cedrol of pungent-woody base note.

Recycling Black Tea Waste Biomass as Activated Porous Carbon for Long Life Cycle Supercapacitor Electrodes.

Value creation through waste recycling is important for a sustainable society and future. In particular, biomass, which is based on crops, is a great recyclable resource that can be converted into useful materials. Black tea is one of the most cultivated agricultural products in the world and is mostly discarded after brewing. Herein, we report the application of black tea waste biomass as electrode material for supercapacitors through the activation of biomass hydrochar under various conditions. Raw black tea was converted into hydrochar via a hydrothermal carbonization process and then activated with potassium hydroxide (KOH) to provide a large surface area and porous structure. The activation temperature and ratio of KOH were controlled to synthesize the optimal black tea carbon (BTC) with a large surface area and porosity suitable for use as electrode material. This method suggests a direction in which the enormous amount of biomass, which is simply discarded, can be utilized in the energy storage system. The synthesized optimal BTC has a large surface area of 1062 m2 and specific capacitance up to 200 F∙g-1 at 1 mV∙s-1. Moreover, it has 98.8% retention of charge-discharge capacitance after 2000 cycles at the current density of 5 A∙g-1.

Graphitic Porous Carbon Derived from Waste Coffee Sludge for Energy Storage.

Coffee is one of the largest agricultural products; however, the majority of the produced coffee is discarded as waste sludge by beverage manufacturers. Herein, we report the use of graphitic porous carbon materials that have been derived from waste coffee sludge for developing an energy storage electrode based on a hydrothermal recycling procedure. Waste coffee sludge is used as a carbonaceous precursor for energy storage due to its greater abundance, lower cost, and easier availability as compared to other carbon resources. The intrinsic fibrous structure of coffee sludge is based on cellulose and demonstrates enhanced ionic and electronic conductivities. The material is primarily composed of cellulose-based materials along with several heteroatoms; therefore, the waste sludge can be easily converted to functionalized carbon. The production of unique graphitic porous carbon by hydrothermal carbonization of coffee sludge is particularly attractive since it addresses waste handling issues, offers a cheaper recycling method, and reduces the requirement for landfills. Our investigations revealed that the graphitic porous carbon electrodes derived from coffee sludge provide a specific capacitance of 140 F g-1, with 97% retention of the charge storage capacity after 1500 cycles at current density of 0.3 A g-1.

Sol-gel-adsorbent-coated extraction needles to detect volatile compounds in spoiled fish.

Volatile compounds generated by fish spoilage were investigated by an inside-needle microextraction method followed by gas chromatography with flame ionization detection and gas chromatography with mass spectrometry. The inside of a needle was coated with an adsorbent to extract the target analytes from the headspace of the sample. The examined adsorbents included ß-cyclodextrin, polystyrene resin cross-linked with 1% divinylbenzene, and polyethylene glycol mixed with polydimethylsiloxane. The investigated volatile compounds generated by fish spoilage were acetone, 2-butanone, 2-butanol, 2-propanol, dimethyl disulfide, acetic acid, and benzaldehyde. The analysis conditions for the sorption and desorption processes were optimized. Each optimized condition was validated by determining the limit of detection and the limit of quantitation from the calibration curves, as well as the recovery, reproducibility, and concentration factors. As a result, all of the fabricated needles afforded successful recoveries, above 90%, with relative standard deviations below 10%. In particular, cyclodextrin and polystyrene resin cross-linked with 1% divinylbenzene mixed with polydimethylsiloxane show good sensitivities and concentration factors for the standard volatile compounds. The storage of fresh mackerel and salted mackerel at room temperature for 14 days caused the concentrations of dimethyl disulfide and acetic acid to significantly increase while those of acetone, 2-butanone, 2-propanol, and 2-butanol changed only slightly.

Effect of food wastewater on biomass production by a green microalga Scenedesmus obliquus for bioenergy generation.

Effect of food wastewater (FW) on the biomass, lipid and carbohydrate production by a green microalga Scenedesmus obliquus cultivated in Bold's Basal Medium (BBM) was investigated. Different dilution ratios (0.5-10%) of BBM either with FW or salt solution (NaCl) or sea water (SW) were evaluated. S. obliquus showed the highest growth (0.41 g L(-1)), lipid productivity (13.3 mg L(-1) day L(-1)), carbohydrate productivity (14.7 mg L(-1) day L(-1)) and nutrient removal (38.9 mg TN L(-1) and 12.1 mg TP L(-1)) with 1% FW after 6 days of cultivation. The FW promoted algal autoflocculation due to formation of inorganic precipitates at an alkali pH. Fatty acid methyl ester analysis revealed that the palmitic and oleic acid contents were increased up to 8% with FW. Application of FW improved the growth, lipid/carbohydrate productivity and biomass recovery efficiency of S. obliquus, which can be exploited for cost effective production of microalgae biomass.

Antimicrobial fabrication of cotton fabric and leather using green-synthesized nanosilver.

This study aims to investigate the green synthesis of silver nanoparticles (AgNPs) by Erigeron annuus (L.) pers flower extract as reducing and capping agent, and evaluation of their antibacterial activities for the first time. The obtained product was confirmed by UV-Vis spectrum, high resolution-transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction studies. The optimum AgNPs production was achieved at pH 7, metal silver (Ag(+) ion) concentration of 2.0mM, flower extract concentration 4%, and time 335 min. In addition, the antibacterial activity of cotton fabrics and tanned leather loaded with AgNPs, commercial AgNPs, flower extract, Ag(+) ion and blend of flower extract with AgNPs were evaluated against Gram-positive odor causing bacteria Brevibacterium linens and Staphylococcus epidermidis. The results showed maximum zone of inhibition (ZOI) by the cotton fabrics embedded with blend of flower extract and AgNPs against B. linens. The structure and morphology of cotton fabric and leather samples embedded with AgNPs, Ag(+) ion and blend of flower extract with AgNPs were examined under field emission scanning electron microscope.

New needle packed with polydimethylsiloxane having a micro-bore tunnel for headspace in-needle microextraction of aroma components of citrus oils.

A novel in-needle microextraction (INME) for headspace sampling evaluated in this study has significantly higher extraction speed and the practical merits of a durable stainless steel needle to overcome some exposed fiber related drawbacks. A prototype stainless steel needle (Hamilton 90022, 22 gauge bevel tip, 51 mm length) packed with polydimethylsiloxane (PDMS, 0.413 mm O.D., 10mm length) having a micro-bore (200 µm I.D.) tunnel was prepared as a new INME device. This needle with a barrel and a plunger is then inserted and exposed into the headspace over the sample. Headspace sampling can be speeded up by an automatic reciprocating pump. The extraction parameters have been optimized along with the validation of method performance. The methodology has been applied for the analysis of volatile aroma active components emitted from eight kinds of citrus essential oils by GC-FID or GC/MS. The proposed method showed excellent linearity, reproducibility, and low detection limit. This solventless technique is simple to operate, inexpensive to fabricate, and provides a facile means for collecting and introducing volatile aroma active components of essential oils.

Hydrothermal carbonization of municipal waste streams.

Hydrothermal carbonization (HTC) is a novel thermal conversion process that can be used to convert municipal waste streams into sterilized, value-added hydrochar. HTC has been mostly applied and studied on a limited number of feedstocks, ranging from pure substances to slightly more complex biomass such as wood, with an emphasis on nanostructure generation. There has been little work exploring the carbonization of complex waste streams or of utilizing HTC as a sustainable waste management technique. The objectives of this study were to evaluate the environmental implications associated with the carbonization of representative municipal waste streams (including gas and liquid products), to evaluate the physical, chemical, and thermal properties of the produced hydrochar, and to determine carbonization energetics associated with each waste stream. Results from batch carbonization experiments indicate 49-75% of the initially present carbon is retained within the char, while 20-37% and 2-11% of the carbon is transferred to the liquid- and gas-phases, respectively. The composition of the produced hydrochar suggests both dehydration and decarboxylation occur during carbonization, resulting in structures with high aromaticities. Process energetics suggest feedstock carbonization is exothermic.

Patterns of VOC and BTEX concentration in ambient air around industrial sources in Daegu, Korea.

Patterns of VOC and BTEX (Benzene, Toluene, Ethylvenzene, and Xylene) distribution at industrial emission sources, proximal residential areas of industrial estates, and ambient air were studied in Daegu, Korea. Daytime and night-time sampling was done at 12 sites and 9 emission sources to provide samples for analyses, using the TO-14 method. Measured BTEX component ratios B/T, T/EB, T/X and EB/X in ambient air were found to be 2.6 g, 11.3 g, 1.0 g and 1.2 g in the residential area; 2.2 g, 11.0 g, 1.0 g and 1.6 g in the commercial area; and 1.0 g, 14.9 g, 1.0 g and 1.3 g in the industrial area. The significant difference observed between the ratios for the residential and commercial areas implies that the two areas have different emission sources. This is also indicated by the significant differences observed between daytime and nighttime BTEX concentrations. Toluene and xylene were detected at very high concentrations, at the sampling sites. This pattern reflects the type of industrial processes and materials that are managed at the emission sources, as well as topographic/climatic factors that impact upon pollutant transport processes in the atmosphere. The BTEX distribution pattern in Daegu is observed to be similar to that of several Asian cities, particularly Hong Kong. These results are useful in the design of emission source control measures for VOCs and BTEX in Daegu.

Clay charge reversal effects on aqueous polymer sorption on lateritic soils.

The effects of charge reversal about the measured point of zero charge (pH(0) approximately 5.2) of untreated and treated Sete Lagoas lateritic soil of Brazil on aqueous polymer sorption was investigated. The polymers are anionic sodium carboxymethyl cellulose (CMCA), nonionic polyethylene oxide (PEO), and cationic polyacrylamide (PAM). They were prepared at aqueous concentrations and pH ranges of 0.1-2.0 g l(-1) and 2-9, respectively. Soil treatment involved the removal of iron oxides by treatment with dithionate-bicarbonate-citrate. Batch sorption test results show that the presence of iron oxides in lateritic soil tends to suppress sorption of CMCA (especially at pH=pH(0)) and PEO (for the whole pH range) but has uncertain effects on cationic PAM sorption. CMCA sorption on the untreated soil improves on either side of pH(0), in direct proportionality to solution concentration, except at pH<4.0, where disassociation of the polymer molecules may decrease sorption energy. Increase in the sorption of non-cationic polymers (CMCA and PEO) at pH>pH(0) is attributable to dispersion of clay, cation bridging and polymer molecular reconfiguration. For cationic PAM, electrostatic bonding to negatively charged soil particle surfaces accounts for the sorption increase. For treated soil samples, polymer sorption pattern is similar to those expected for the montmorillonitic clayey soils of temperate zones. These results indicate that the pH(0) of lateritic soils, within the regime that exists in the field, should be considered in assessing the potential effectiveness of polymer dust suppressants for tropical lateritic soils.

Effects of genetic polymorphisms of MDR1, FMO3 and CYP1A2 on susceptibility to colorectal cancer in Koreans.

The aim of the present study was to evaluate the effects on the susceptibility to colorectal cancer (CRC) of genetic polymorphisms in P-glycoprotein (PGP) and the metabolic enzymes cytochrome P450 1A2 (CYP1A2) and flavin-containing monooxygenase 3 (FMO3). We analyzed five single-nucleotide polymorphisms (SNP) in 93 cancer-free volunteers and 111 patients with CRC: one common genetic variant of the PGP-encoding MDR1 gene and four SNP in genes for metabolic enzymes (two SNP in FMO3 and two SNP in CYP1A2). The genotypes and allele frequencies of the MDR1/C3435T, FMO3/G488A, FMO3/A923G and CYP1A2/G-3860 A polymorphisms were not significantly different in cancer-free subjects and CRC patients. However, a significant association was found between the CYP1A2/A-163C polymorphism and the risk of CRC, particularly in elderly (>55 years) subjects and smokers. A phenotyping study in normal smokers showed that the CYP1A2 activity of subjects with the CYP1A2/-163 AA genotype was significantly lower than that of subjects carrying the CYP1A2/-163C allele. Combined results show that the CYP1A2/-163C allele is significantly associated with an increase in CYP1A2 activity and a consequent increased risk of CRC in Koreans, particularly in elderly people and smokers.

Soil desiccation rate integration into empirical dust emission models for polymer suppressant evaluation.

Dust constitutes an environmental and human health menace in many regions of the world. The rate of soil desiccation is a significant determinant of the availability of fine soil particles for entrainment in air as dust. Dust suppressants such as polymer solutions can reduce soil desiccation rate, thereby reducing dust emission factor. Herein, a dust emission estimation methodology that involves the integration of desiccation time curves to find the average desiccation rate is formulated. This is combined with soil characteristics, stressor (environmental and possibly vehicle) characteristics and liquid content in soil to estimate potential emission factors. Using this methodology, the dust suppression potential of aqueous polyethylene oxide (PEO) solution was investigated experimentally with Na-montmorillonite (Na-mmt) as the model dust-generating material. PEO with a molecular weight of 8 x 10(6) and at aqueous concentrations ranging from 0.5 to 10 g/L, was mixed with 10 g of Na-mmt (surface area=31.82+/-0.22 m2/g) and desiccated for 700 h in a specially designed chamber at 25 degrees C and 30% relative humidity. The results show that generally, aqueous PEO is superior to distilled water as a dust suppressant for Na-mmt at concentrations in the range of 0.5-2.0 g/L. The experimental data obtained are introduced into the formulated estimation methodology, and potential emissions of dust from PEO-admixed Na-mmt are determined.

Polyacrylamide sorption opportunity on interlayer and external pore surfaces of contaminant barrier clays.

Physico-chemical interactions among polymer molecules in aqueous solution and clay mineralogical/textural characteristics influence the sorption of polymer molecules on clay barrier minerals. Amendment of potentially unstable barrier clays with aqueous polymers can improve barrier material resistance to environmental stresses during service. In this research, the ability of molecular coils of polyacrylamide (PAM) to overlap in solution and to enter interlayer space in Na-montmorillonite (specific surface=31.82+/-0.22 m2 g(-1)) and kaolinite (specific surface=18+/-2 m2 g(-1)) were analyzed theoretically and experimentally, using solution viscosity measurements, and X-ray diffractometry. Experimental data on two theoretical indices: relative size ratio (RSR); and molecular availability (Ma) that are formulated to scale polymer molecular sorption on clay interlayer, indicate that the sorption of PAM A (Mw=4000000) and PAM B (Mw=7000000) does not produce any significant change in the d-spacing of both clay minerals. Although the negative Ma values of -3.51 g l(-1) for PAM A and -3.88 g l(-1) for PAM B indicate high levels of entanglement of polymer molecular coils in solution, sorption data confirm that the entangled coils are still able to sorb onto Na-montmorillonite highly and kaolinite to a lesser extent.

Effect of changing electrophilic center from C=O to C=S on rates and mechanism: pyridinolyses of O-2,4-dinitrophenyl thionobenzoate and its oxygen analogue.

Second-order rate constants have been measured spectrophotometrically for the reactions of O-2,4-dinitrophenyl thionobenzoate (1) and 2,4-dinitrophenyl benzoate (2) with a series of substituted pyridines in 80 mol % H(2)O/20 mol % DMSO at 25.0 +/- 0.1 degrees C. The Brønsted-type plots obtained are nonlinear with beta(1) = 0.26, beta(2) = 1.07, and pK(a) degrees = 7.5 for the reactions of 1 and beta(1) = 0.40, beta(2) = 0.90, and pK(a) degrees = 9.5 for the reactions of 2, suggesting that the pyridinolyses of 1 and 2 proceed through a zwiterionic tetrahedral intermediate T(+/-) with a change in the rate-determining step at pK(a) degrees = 7.5 and 9.5, respectively. The thiono ester 1 is more reactive than its oxygen analogue 2 except for the reaction with the strongest basic pyridine studied (pK(a) = 11.30). The k(1) value is larger for the reactions of 1 than for those of 2 in the low pK(a) region, but the difference in the k(1) value becomes negligible with increasing the basicity of pyridines. On the other hand, 1 exhibits slightly larger k(2)/k(-1) ratio than 2 in the low pK(a) region but the difference in the k(2)/k(-1) ratio becomes more significant with increasing the basicity of pyridines. Pyridines are more reactive than alicyclic secondary amines of similar basicity toward 2 in the pK(a) above ca. 7.2 but less reactive in the pK(a) below ca. 7.2. The k(1) value is slightly larger, but the k(2)/k(-1) ratio is much smaller for the reactions of 2 with pyridines than with isobasic secondary amines in the low pK(a) region, which is responsible for the fact that the weakly basic pyridines are less reactive than isobasic secondary amines.