RESUMO
Electrochemical advanced oxidation process (EAOP) is known for its efficient and fast degradation of organic pollutants in polluted water treatment. In this study, the EAOP using a boron-doped diamond (BDD) anode was applied to treat two-season groundwater samples collected from four sampling wells (GS1 to GS4) with petrochemical contaminants including methyl tert-butyl ether (MTBE), benzene, toluene, chlorobenzene, total organic compounds (TOC), and total petroleum hydrocarbons (TPH) at a gas station in southern Taiwan. Moreover, toxicity tests (ATP, p53, and NF-κB bioassays) were performed to evaluate the biological responses of raw and EAOP-treated groundwater. Results show that the concentrations of chlorobenzene before and after EAOP treatment were all below its method detection limit. High degradation efficiencies were observed for MTBE (100%), benzene (100%), toluene (100%, except that of GS2 in the first season), TPH (94-97%, except that of GS4 in the first season), and TOC (85-99%). Cell viability for both the raw groundwater (81.2 ± 13.5%) and EAOP-treated samples (84.7 ± 11.7%) as detected using the ATP bioassay showed no significant difference (p = 0.715). A mean reduction in the DNA damage (739 to 165 ng DOX-equivalency L-1 (ng DOX-EQ. L-1)) and inflammatory response levels (460 to 157 ng TNFα-equivalency L-1 (ng TNFα-EQ. L-1)) were observed for EAOP-treated samples subjected to p53 and NF-κB bioassays. Overall, the significances of the average degradation efficiency, DNA damage, and inflammatory response before and after groundwater with EAOP treatment was observed to be significant (p < 0.05). p53 and NF-κB bioassays might be applied to assess ecotoxic risk in the environment.
Assuntos
Monitoramento Ambiental , Água Subterrânea , Poluentes Químicos da Água , Água Subterrânea/química , Oxirredução , Poluição por Petróleo/análise , Taiwan , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Purificação da ÁguaRESUMO
BACKGROUND: Postoperative atrial fibrillation (POAF) is a common complication after coronary artery bypass grafting (CABG) and is associated with increased short-term and long-term mortality. While the precise etiology of POAF remains unclear, inflammation is a known contributing factor. Preliminary studies have suggested that an elevated preoperative platelet-to-lymphocyte ratio (PLR), an inexpensive and readily available novel inflammatory biomarker, may be associated with increased incidence of POAF after CABG. This study sought to further investigate this hypothesis. METHODS: The study cohort included all patients undergoing isolated CABG, with no prior history of arrhythmia, who were operated on between August 1, 2010, and December 31, 2018, at a major Australian tertiary center (n = 1457). Patients were divided into low (<86) or high (≥86) PLR groups based on an optimal cutoff derived from receiver-operating characteristic curve analysis. The incidence of POAF was then compared. Categorical variables were analyzed using the chi-square test and continuous variables using logistic regression. RESULTS: Of 1457 patients, 495 (34.0%) developed POAF. There was no statistically significant difference in the incidence of POAF between patients in the high-PLR and low-PLR groups (34.8% vs 31.0%; P = .22). Using multivariable logistic regression analysis, high PLR was not independently associated with POAF (odds ratio, 1.04; P = .78). CONCLUSIONS: Elevated preoperative PLR is not independently associated with POAF in patients undergoing isolated CABG. The findings of this study differ from those of 2 previous smaller studies.
Assuntos
Fibrilação Atrial/sangue , Fibrilação Atrial/epidemiologia , Ponte de Artéria Coronária/efeitos adversos , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/cirurgia , Complicações Pós-Operatórias/epidemiologia , Idoso , Austrália , Biomarcadores/sangue , Estudos de Coortes , Feminino , Humanos , Incidência , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Complicações Pós-Operatórias/sangue , Valor Preditivo dos TestesRESUMO
Previous studies have demonstrated that organochlorine pesticide (OCP) exposure has a negative impact on the neurological function of infants. Only a few reports have investigated the thyroid and growth hormones and their relationship to neurodevelopment after human exposure to OCPs, especially in the case of infants. Our goal was to determine whether breastmilk OCP residues were associated with negative impacts and/or alterations in the neurodevelopment of infants among specific southern Taiwanese mother-breastfed infant pairs. Our subjects (n = 55 pairs) were recruited from southern Taiwan between 2007 and 2010. The thyroid and growth hormone levels in the cord blood samples collected after childbirth were determined. The breastmilk was gathered within one month after childbirth for the determination of OCP levels using a high-resolution gas chromatograph with mass spectrometry, and the neurodevelopment of 10-12-month-old infants was examined using the Bayley Scales of Infant and Toddler Development®, Third Edition (Bayley-III). It was observed that 4,4'-dichlorodiphenyl-dichloroethylene (4,4'-DDE) (mean = 10.3 ng/g lipid) was the most predominant OCP compound in the breastmilk samples. At higher concentrations (>75th percentile), specific OCPs were associated with significantly lower levels of thyroid and growth hormones than at lower concentrations (<75th percentile). Significantly higher odds ratios (ORs) were observed for binary cognitive (OR = 8.09, p = 0.025 for 4,4'-DDT), language (OR = 11.9, p = 0.013 for 4,4'-DDT) and social-emotional (OR = 6.06, p = 0.01 for trans-CHL) composite scores for specific OCPs belonging to the lower exposure group as compared to the higher OCP exposure group. The five domain Bayley-III infant neurodevelopment outcomes were negatively associated with specific OCPs in the breast milk samples based on the redundancy analysis (RDA) test. Bayley-III scales, which include cognitive, language, motor, social-emotional, and adaptive behavior scales, could be predicted by 4,4'-DDT, endrin, endosulfan I, heptachlor, or heptachlor epoxide using multivariate linear regression models with adjustment for maternal age, pre-pregnant BMI, parity, and infant gender. In conclusion, although our study showed that postnatal exposure to breast milk OCPs may be associated with infant neurodevelopmental outcomes and that prenatal exposure, if extrapolated from breastmilk levels, is associated with changes in thyroid and growth hormones that may have effects on neurodevelopment, these associations are only suggestive; thus, further studies are recommended for confirmation.
Assuntos
Sistema Nervoso Central/crescimento & desenvolvimento , Sangue Fetal/química , Hidrocarbonetos Clorados/análise , Exposição Materna , Leite Humano/química , Resíduos de Praguicidas/análise , Hormônios Tireóideos/sangue , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lactente , Paridade , Parto , Gravidez , TaiwanRESUMO
Only few studies have focused on organochlorine pesticides (OCPs) in breast milk and the related health risks for women in Taiwan. Our goal is to examine breast milk OCPs and their associations with female reproductive function (infertility, gynecological diseases, and menstruation characteristics) as well as their correlation with sociodemographic parameters (age, pre-pregnant body mass index (BMI), annual incomes, population, birth year, and parity) and dietary habit. The breast milk samples were collected in southern Taiwan (n = 68) from 2013 to 2016 and the OCP residues were analyzed using high resolution gas chromatography with low resolution mass spectrometry (HRGC/LRMS). The results show that the most abundant OCP residues in the breast milk was ΣDDT with the geometric mean ± standard deviation of 9.81 ± 7.52 ng−1 lipid−1 followed by ΣHCH (0.539 ± 0.557 ng−1·lipid−1). In the principal component analysis, cis-chlordane (cis-CHL) and γ-HCH were found to be related to participants who received medical treatment for infertility, and 4,4′-DDT was associated with those who received gynecological surgery. The logistic regression showed that the odds ratio (OR) of log γ-hexachlorocyclohexane (γ-HCH) was higher for mothers who had received medical treatment for infertility than for the normal group (OR = 25.6, p = 0.035) after adjustments for age, pre-pregnant BMI, annual income, population (i.e., native-born Taiwanese), birth year, and parity. Cow milk and beef consumption as well as menstruation characteristics such as average menstrual period (>5 days), shortest menstrual period (<3 days), and women who had taken hormonal drugs were significantly associated to several OCP residues in the breast milk. In addition, ΣHCH including β-HCH and γ-HCH was correlated with annual family income and gravidity as well as cow milk and beef consumptions. Overall, γ-HCH exhibited a probable association with the infertility diseases of Taiwanese women, and dietary habit might play an important role in the female Taiwanese exposure to OCPs.
Assuntos
Hidrocarbonetos Clorados/análise , Leite Humano/química , Praguicidas/análise , Saúde Reprodutiva , Adulto , Fatores Etários , Animais , Índice de Massa Corporal , Bovinos , Dieta , Feminino , Hexaclorocicloexano/análise , Humanos , Infertilidade/epidemiologia , Paridade , Gravidez , Fatores Socioeconômicos , Taiwan , Adulto JovemRESUMO
This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44 pg WHO2005-TEQ/g lipid and 2810 pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (ß = 0.252) and 1,2,3,4,6,7,8-HpCDF (ß = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).
Assuntos
Dibenzofuranos Policlorados/análise , Monitoramento Ambiental/métodos , Éteres Difenil Halogenados/análise , Leite Humano/química , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análise , Adulto , Feminino , Humanos , TaiwanRESUMO
Few studies have been performed up to now on the emission factors and congener profiles of persistent organic pollutants (POPs) emitted from off-road diesel engines. This investigation elucidates the emission factors and congener profiles of various POPs, namely polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyl (PCBs), polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs) and polybrominated diphenyl ethers (PBDEs), in the exhausts of a diesel generator fueled with different waste cooking oil-based biodiesel (WCO-based biodiesel) blends. The PCDD/Fs contributed 87.2% of total dioxin-like toxicity (PCDD/Fs+PCBs+PBDD/Fs) in the exhaust, while the PCBs and PBDD/Fs only contributed 8.2% and 4.6%, respectively. Compared with petroleum diesel, B20 (20vol% WCO-based biodiesel+80vol% diesel) reduced total toxicity by 46.5% for PCDD/Fs, 47.1% for PCBs, and 24.5% for PBDD/Fs, while B40 (40vol% WCO-based biodiesel+60vol% diesel) reduced it by 89.5% for PCDD/Fs, 57.1% for PCBs, and 63.2% for PBDD/Fs in POP emission factors. The use of WCO-based biodiesel not only solves the problem of waste oil disposal, but also lowers POP emissions from diesel generators.
Assuntos
Poluentes Atmosféricos/análise , Biocombustíveis , Dibenzofuranos Policlorados/análise , Éteres Difenil Halogenados/análise , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análise , Culinária , Gasolina , ResíduosRESUMO
This study applies a thermal separation process (TSP) to recover Fe, Mn, and Zn from hazardous spent zinc-carbon and alkaline batteries. In the TSP, the batteries were heated together with a reducing additive and the metals in batteries, according to their boiling points and densities, were found to move into three major output materials: slag, ingot (mainly Fe and Mn), and particulate (particularly Zn). The slag well encapsulated the heavy metals of interest and can be recycled for road pavement or building materials. The ingot had high levels of Fe (522,000â mg/kg) and Mn (253,000â mg/kg) and can serve as an additive for stainless steel-making processes. The particulate phase had a Zn level of 694,000â mg/kg which is high enough to be directly sold for refinement. Overall, the TSP effectively recovered valuable metals from the hazardous batteries.
Assuntos
Poluentes Atmosféricos , Carbono/química , Fontes de Energia Elétrica , Gases/química , Material Particulado/química , Reciclagem , Zinco/química , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Metais Pesados/análise , Metais Pesados/químicaRESUMO
UNLABELLED: Valuable metal materials can be recovered from spent nickel-metal hydride (NiMH) batteries. However, little attention has been paid to the metal compositions of individual components of NiMH batteries, although this is important for the selection of the appropriate recycling process. In this study, NiMH batteries were manually disassembled to identify the components and to characterize the metals in each of these. A preliminary economic analysis was also conducted to evaluate the recovery of valuable metals from spent NiMH batteries using thermal melting versus simple mechanical separation. The results of this study show that metallic components account for more than 60% of battery weight. The contents of Ni, Fe, Co, and rare earth elements (REEs) (i.e., valuable metals of interest for recovery) in a single battery were 17.9%, 15.4%, 4.41%, and 17.3%, respectively. Most of the Fe was in the battery components of the steel cathode collector, cathode cap, and anode metal grid, while Ni (>90%) and Co (>90%) were mainly in the electrode active materials (anode and cathode metal powders). About 1.88 g of REEs (Ce, La, and Y) could be obtained from one spent NiMH battery. The estimated profits from recovering valuable metals from spent NiMH batteries by using thermal melting and mechanical processes are 2,329 and 2,531 USD/ton, respectively, when including a subsidy of 1,710 USD/ton. The findings of this study are very useful for further research related to technical and economic evaluations of the recovery of valuable metals from spent NiMH batteries. IMPLICATIONS: The spent nickel-metal hydride (NiMH) batteries were manually disassembled and their components were identified. The metals account for more than 60% of battery weight, when Ni, Fe, Co, and rare earth elements (REEs) were 17.9%, 15.4%, 4.41%, and 17.3%, respectively, in a single battery. The estimated profits of recovering valuable metals from NiMH batteries by using thermal melting and mechanical processing are 2,329 and 2,531 USD/ton, respectively, when including a subsidy of 1,710 USD/ton. These findings are very useful to develop or select the recovery methods of valuable metals from spent NiMH batteries.
Assuntos
Resíduo Eletrônico , Fontes Geradoras de Energia , Níquel/química , Reciclagem/economia , Eliminação de Resíduos/economia , Conservação dos Recursos Naturais/economia , Poluentes Ambientais/análise , Eliminação de Resíduos/métodosRESUMO
This investigation studied the size distributions of particulate matter (PM), particulate carbon, and polycyclic aromatic hydrocarbons (PAHs) that are emitted from a generator that is fueled by diesel that is blended with waste-edible-oil-biodiesel and water-containing acetone. PM samples were collected using a micro-orifice uniform deposit impactor (MOUDI) and a Nano-MOUDI (with aerodynamic diameters of 0.01-18 µm). The results reveal that waste-edible biodiesel blended with water-containing acetone (W5WA3 or W20WA3) at a load of 3 kW emitted lower ΣPM, ΣPM-EC, ΣPM-OC, ΣT-PAHs or ΣT-BaPeq concentrations than did D100, in all 13 particle size ranges, and these reductions of emissions of submicron particles exceeded 85%. Furthermore, W20WA3 emitted significantly lower concentrations of Total-PAHs and Total-BaPeq in four nano/ultrafine particle size ranges. Therefore, water-containing acetone biodieselhols can be utilized as alternatives to petroleum diesel as fuel to reduce the dangers to human health that are posed by emissions from diesel engines.
Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Tamanho da Partícula , Emissões de Veículos/análiseRESUMO
This study investigates the electrochemical degradation of N,N-diethyl-m-toluamide (DEET) on PbO2 and Bi-PbO2 anodes. The difference in electrode crystalline structure was responsible for the better DEET degradation and TOC removal on PbO2 than on Bi-PbO2. In 1 M Na2SO4, the degradation efficiency and apparent rate constant (kapp) of DEET oxidation on PbO2 increased with the increase in current density or temperature (activation energy=24.4 kJ mol(-1)). The kapp values in DEET-spiked environmental matrixes (municipal wastewater treatment plant secondary effluent (MWTPSE), groundwater (GW), and river water (RW)) were the same (6.05×10(-4) s(-1)), but significantly smaller than that in 1 M Na2SO4 (2.23×10(-3) s(-1)). The TOC removal efficiency was better in MWTPSE than in RW and GW; however, the mineralization current efficiencies in MWTPSE and RW were similar but higher than that in GW. During electrolysis, the aromaticity was lower in GW than in RW.
Assuntos
DEET/química , Eletrodos , Chumbo/química , Óxidos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Eletrólise , Oxirredução , TemperaturaRESUMO
This investigation examines the particulate matter (PM), particulate carbon, polycyclic aromatic hydrocarbons (PAHs), and nitrogen oxides (NOx) emitted from a generator fueled by petroleum diesel blended with waste-edible-oil-biodiesel and water-containing acetone. Experimental results show that using biodieselhols with water-containing (or pure) acetone as the fuel of generator, in comparison to using petroleum diesel, significantly reduces PM emission; roughly, this reduction increased as percentage of water-containing acetone increased. When the percentages of waste-edible-oil-biodiesel were ≤ 5 vol%, adding pure or water-containing acetone (1-3 vol%) to biodieselhols generated emission reductions of NOx, PM, particle-bound organic carbon (OC), total-PAHs, and total-BaPeq. Consequently, using water-containing acetone biodieselhols as an alternative generator fuel is feasible and helps recycle and reuse waste solvents containing water-containing acetone.
Assuntos
Acetona , Poluentes Atmosféricos/análise , Biocombustíveis , Óxidos de Nitrogênio/análise , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluição do Ar/prevenção & controle , Carbono/análise , Dióxido de Carbono/análise , Fontes Geradoras de Energia , Monitoramento Ambiental , Óleos , ÁguaRESUMO
Biodiesel is one of alternative energies that have been extensively discussed and studied. This research investigates the characteristics of particulate matter (PM), particulate carbon, and polycyclic aromatic hydrocarbons (PAHs) emitted from a generator fueled by waste-edible-oil-biodiesel with acetone and isopropyl alcohol (IPA) addition. The tested biodieselhols consisted of pure diesel oil (D100) with 1-3 vol.% pure acetone (denoted as A), 1-70 vol.% waste-edible-oil-biodiesel (denoted as W), and 1 vol.% pure isopropyl alcohol (the stabilizer, denoted as P). The results show that in comparison to W1D99, W3D97, W5D95, W10D90, and W20D80, the use of biodieselhols achieved additional reduction of PM and particulate organic carbon (OC) emission, and such reduction increased as the addition percentage of pure acetone increased. Regardless of the percentages of added waste-edible-oil-biodiesel, acetone, and isopropyl alcohol, the use of biodieselhol in place of D100 could reduce the emissions of Total-PAHs (by 6.13-42.5% (average = 24.1%)) and Total-BaPeq (by 16.6-74.8% (average = 53.2%)) from the diesel engine generator. Accordingly, the W/D blended fuels (W<20 vol.%) containing acetone (1-3 vol.%) and isopropyl alcohol (1 vol.%) are a potential alternative fuel for diesel engine generators because they substantially reduce emissions of PM, particulate OC, Total-PAHs, and Total-BaPeq.
RESUMO
This study investigates how reducing additives governed the vitrification of prepared specimens. In the experiments, pure CaO/CaCO3 and SiO2 served as the major components of glassy matrix (basicity = mass ratio of CaO/SiO2 = 2/3) with doping of hazardous metals (Cr Cu, and Ni). The substitution ratio of CaCO3 for CaO was used as an operating parameter. The specimens were vitrified at 1400 degrees C and a sequential extraction protocol was used to determine the phase distribution of Cr, Cu, and Ni. The volume fractions of crystalline and amorphous phases were measured using semiquantitative x-ray diffraction (XRD) analysis. A commercial software package (HSC Chemistry 6.0) was used to simulate the experiment to acquire additional information. The simulation results showed the addition of CaCO3 generated CO and CO2 at high temperature. This reducing atmosphere might enhance Cu and Ni to be easily separated from slags and elevated the levels of Cu and Ni in ingots. At higher CaCO3 mol(%), the polymerization of silicate (from sorosilicate to inosilicate) in slag rose and the CaSiO3 amount increased. In addition, the immobilization of metals and the acid resistance of slags were improved. The results indicate that CaCO3 addition is favorable for increasing the metal level in ingots and the metal encapsulation in slag in vitrification.
Assuntos
Resíduos Perigosos/análise , Eliminação de Resíduos/métodos , Simulação por Computador , Modelos Teóricos , VitrificaçãoRESUMO
This paper presents the electro-regeneration of Ce(IV) in real (hazardous) spent thin-film transistor liquid-crystal display (TFT-LCD) Cr-etching solutions. In addition to Ce(III)>Ce(IV) in diffusivity, a quasi-reversible behavior of Ce(III)/Ce(IV) was observed at both boron-doped diamond (BDD) and Pt disk electrodes. The Ce(IV) yield on Pt increased with increasing current density, and the best current efficiency (CE) was obtained at 2A/2.25 cm(2). The performance in terms of Ce(IV) yield and CE of tested anodes was in order BDD>Pt>dimensional stable anode (DSA). At 2A/2.25 cm(2) on Pt and 40 °C for 90 min, the Ce(IV) yield, CE and apparent rate constant (k) for Ce(III) oxidation were 81.4%, 21.8% and 3.17 × 10(-4) s(-1), respectively. With the increase of temperature, the Ce(IV) yield, CE, and k increased (activation energy = 10.7 kJ/mol), but the specific electricity consumption decreased. The Neosepta CMX membrane was more suitable than Nafion-117 and Nafion-212 to be used as the separator of the Ce(IV) regeneration process. The obtained parameters are useful to design divided batch reactors for the Ce(IV) electro-regeneration in real spent Cr-etching solutions.
Assuntos
Cério/química , Poluentes Químicos da Água/química , Cromo , Equipamentos e Provisões Elétricas , Eletroquímica , Resíduos Industriais , Cristais Líquidos , Reciclagem/métodos , Soluções , Eliminação de Resíduos Líquidos/métodosRESUMO
In this study, vitrification was applied to treat Ni-Cu electroplating sludge. The sludge was mixed with additives (limestone:cullet = 4:6) and then heated to 1450 °C. The cooled product could be separated into slag and ingot. An atomic absorption spectrometer was used to determine the metal levels of specimens and toxicity characteristic leaching procedure (TCLP) tests, whereas the crystalline and surface characteristics were examined using quantitative X-ray diffraction (XRD) analysis and scanning electron microscopy, respectively. With a glassy structure, the slag was mainly composed of Ca, Si, and Mg. The TCLP results of slags met the Taiwan regulated standards, suggesting that slag can be used for recycling purposes. With the aid of additives, the crystalline phase of slag was transformed form CaMgSiO4 into CsSiO3. The ingots were mainly composed of Ni (563,000-693,800 mg/kg), Cu (79,900-87,400 mg/kg), and Fe (35,000-43,600 mg/kg) (target metals) due the gravity separation during vitrification. At appropriate additives/sludge ratios (>0.2), >95% of target metals gathered in the ingot as a recoverable form (Ni-Fe alloy). The high Ni level of slag suggests that the ingot can be used as the raw materials for smelters or the additives for steel making. Therefore, the vitrification approach of this study is a promising technology to recover valuable metals from Ni-Cu electroplating sludge.
Assuntos
Galvanoplastia , Resíduos Industriais/análise , Metais Pesados/química , Reciclagem/métodos , Esgotos/química , Vitrificação , Gerenciamento de Resíduos/métodos , Microscopia Eletrônica de Varredura , Oxirredução , Relação Estrutura-Atividade , Taiwan , Difração de Raios XRESUMO
This study presents a simple electrochemical approach for preparing a poly(L-serine) film-modified glassy carbon electrode, which responds quickly and sensitively during the simultaneous determination of acetaminophen and ofloxacin in prepared, environmental, and pharmaceutical samples. The prepared electrode exhibited catalytic activities and promoted the oxidation of acetaminophen and ofloxacin. Acetaminophen and ofloxacin showed linear responses between 1.0 × 10(-5) and 1.0 × 10(-4) mol/L and their limits of detection were 1.2 × 10(-7) and 1.6 × 10(-7) mol/L, respectively. The average recoveries (± relative standard deviations) of acetaminophen and ofloxacin were 96.8 ± 3.5 % and 97.6 ± 3.2 %, respectively, indicating that the prepared electrode and detection method are very accurate and reproducible for the simultaneous determination of acetaminophen and ofloxacin.
Assuntos
Acetaminofen/análise , Técnicas Eletroquímicas/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Ofloxacino/análise , EletrodosRESUMO
This investigation studies the electro-regeneration of Ce(IV) from Ce(III) in 4 M HNO(3) in the presence/absence of NH(4)(+) and real spent thin-film transistor liquid-crystal display (TFT-LCD) Cr-etching solutions. On Pt, at 2 A and 70 °C for 100 min, the Ce(IV) yield and apparent rate constant of Ce(III) oxidation in 4 M HNO(3) without NH(4)(+) were 100% and 5.54 × 10(-4) s(-1), respectively (and the activation energy was 13.1 kJ mol(-1)). Cyclic voltammetric and electrolytic measurements consistently support the noticeable inhibition by NH(4)(+) of Ce(III) oxidation and lowering of the Ce(IV) yield, respectively. The apparent diffusion coefficients for 0.2 and 0.02 M Ce(III) oxidation in 4 M HNO(3) that contained 0-0.6 M NH(4)(+) were (0.38-0.25) × 10(-5) and (1.6-0.9) × 10(-5) cm(2) s(-1), respectively. Because of combined effects of NH(4)(+) and anion impurities, the 100 min Ce(IV) yield of a real spent TFT-LCD Cr-etching solution (with [NH(4)(+)]/[Ce(III)] = 0.74 M/0.39 M) was 82%, lower than that of 4 M HNO(3) without NH(4)(+), but higher than those of 4 M HNO(3) that contained anion impurities with/without 0.4 M NH(4)(+).
Assuntos
Césio/química , Eletroquímica/métodos , Compostos de Amônio Quaternário/química , Soluções/químicaRESUMO
This study investigated the particulate matter (PM), particle-bound carbons, and polycyclic aromatic hydrocarbons (PAHs) emitted from a diesel-engine generator fuelled with blends of pure fossil diesel oil (D100) and varying percentages of waste-edible-oil biodiesel (W10, 10 vol %; W20, 20 vol %; W30, 30 vol %; and W50, 50 vol %) under generator loads of 0, 1.5, and 3 kW. On average, the PM emission factors of all blends was 30.5 % (range, 13.7-52.3 %) lower than that of D100 under the tested loads. Substituting pure fossil diesel oil with varying percentages of waste-edible-oil biodiesel reduced emissions of particle-bound total carbon (TC) and elemental carbon (EC). The W20 blend had the lowest particle-bound organic carbon (OC) emissions. Notably, W10, W20, and W30 also had lower Total-PAH emissions and lower total equivalent toxicity (Total-BaP(eq)) compared to D100. Additionally, the brake-specific fuel consumption of the generator correlated positively with the ratio of waste-edible-oil biodiesel to pure fossil diesel. However, generator energy efficiency correlated negatively with the ratio of waste-edible-oil biodiesel to pure fossil diesel.
Assuntos
Poluentes Atmosféricos/análise , Carbono/análise , Monitoramento Ambiental , Gasolina/análise , Material Particulado/análise , Poluentes Atmosféricos/química , Biocombustíveis/análise , Carbono/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/químicaRESUMO
This study examines size-resolved particle-bound water-soluble ions and carbons (element carbon (EC) and organic carbon (OC)) collected near a busy road and at an urban site. The traffic-related fine and coarse particles were collected using two manual dichotomous samplers (Dichots) equipped with Quartz filters. The PM(2.5)/PM(2.5-10) value during rush hour (3.57) exceeded that during slack time (2.72). During weekdays and weekends, although the roadside PM(2.5) concentration correlated well with traffic flow (R(2)= 0.91 and 0.81, respectively), the roadside PM(2.5-10) concentration did not. The lowest second aerosol concentrations were observed from 19:00 to 21:00 during weekdays and weekends. The average content of total water-soluble ions in PM(2.5) was 30.7% and 35.7% for weekday and weekend samples, respectively (a total average of 33.2%). In PM(2.5), the content of NO(3)(-) (8.95-11.0%) exceeded that of SO(4)(2-) (7.08-8.10%) at the roadside site. Conversely, the content of PM(2.5)-bound SO(4)(2-) was higher than that of PM(2.5)-bound NO(3)(-) at the urban site. The mean content of PM(2.5)-bound TC was 35.8%, while that of PM(2.5-10)-bound TC was 15.9%. Moreover, the R(2) values of traffic flow versus PM(2.5)-bound EC concentration on weekdays and weekends were 0.89 and 0.56, respectively, and were 0.82 and 0.38, respectively, for those of traffic flow versus PM(2.5)-bound OC concentration.