Colorimetric Detection of Acenaphthene and Naphthalene Using Functionalized Gold Nanoparticles.

Polycyclic aromatic hydrocarbons are a class of chemicals that occur naturally. They generally demonstrate a high degree of critical toxicity towards humans. Acenaphthene and naphthalene contain compounds that are commonly found in the environment as compared to other PAHs. Consequently, a reliable method of detecting PAHs is crucial for the monitoring of water quality. A colorimetric method based on sodium nitrite-functionalized gold nanoparticles was developed in this study for acenaphthene and naphthalene detection. Different functionalized parameters are determined for the optimization of assay conditions. A linear relationship was found in the analyte concentration range of 0.1-10 ppm with the limit of detection for acenaphthene and naphthalene being 0.046 ppm and 0.0015 ppm, respectively, under the optimized assay conditions. The method's recovery rate for actual samples falls within the range of 98.4-103.0%. In selective and anti-interference tests, the presence of cations and anions has minimal impact on the detection of the analyte. The colorimetric detection method proposed in this study effectively determines the presence of the analyte in real water samples and has a high recovery rate.

Preparing Copper Nanoparticles and Flexible Copper Conductive Sheets.

Nanotechnology is used in a wide range of fields, including medicine, cosmetics, and new material development, and is one of the most popular technologies in the field of flexible electronic products. For the present work, the chemical reduction method with environmentally friendly reducing agents was used to synthesize copper nanoparticles (CuNPs) with good dispersibility. The CuNPs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and ultraviolet-visible spectrophotometry (UV-vis). After the CuNPs were formed, the solvent, polymers, and additives were added to form copper ink. Finally, the prepared copper inks were applied to flexible polyethylene terephthalate (PET) substrate under low sintering temperature and the effects of sintering time and different concentrations of sintering agent on resistivity were investigated. The results show that the copper nanoparticles synthesized by secondary reduction were smaller, more uniform, and better dispersed than those formed by primary reduction. Ethylene glycol has reducing effects under high temperatures; therefore, the CuNPs formed using the mixed solvent were small and well dispersed. The copper ink was applied on the PET substrate, treated with a formic acid aqueous solution, and sintered at 130 °C for 60 min, and its resistivity was about 1.67 × 10-3 Ω cm. The proposed synthesizing method is expected to have potential applications in the flexible electronic products field.

Facile Synthesis of Silver Nanoparticles and Preparation of Conductive Ink.

In the scientific industry, sustainable nanotechnology has attracted great attention and has been successful in facilitating solutions to challenges presented in various fields. For the present work, silver nanoparticles (AgNPs) were prepared using a chemical reduction synthesis method. Then, a low-temperature sintering process was deployed to obtain an Ag-conductive ink preparation which could be applied to a flexible substrate. The size and shape of the AgNPs were characterized by ultraviolet-visible spectrophotometry (UV-Vis) and transmission electron microscopy (TEM). The experiments indicated that the size and agglomeration of the AgNPs could be well controlled by varying the reaction time, reaction temperature, and pH value. The rate of nanoparticle generation was the highest when the reaction temperature was 100 °C within the 40 min reaction time, achieving the most satisfactorily dispersed nanoparticles and nanoballs with an average size of 60.25 nm at a pH value of 8. Moreover, the electrical resistivity of the obtained Ag-conductive ink is controllable, under the optimal sintering temperature and time (85 °C for 5 min), leading to an optimal electrical resistivity of 9.9 × 10-6 Ω cm. The results obtained in this study, considering AgNPs and Ag-conductive ink, may also be extended to other metals in future research.

Association of long-term indoor exposure to fine particles with pulmonary effects in Northern Taiwan.

An association between short-term indoor exposure to fine particles (PM2.5) and acute respiratory effects has been reported. It is still unclear whether long-term indoor exposure to PM2.5 is associated with pulmonary events. This study recruited 1023 healthy adult homeworkers to conduct a prospective observational study from 2010 to 2021. Four repeated home visits per year were conducted for each participant to measure 24-hour PM2.5 and peak expiratory flow rate (PEFR) and to collect blood samples for absolute eosinophil count (AEC) and carcinoembryonic antigen (CEA) analysis. Additionally, a questionnaire related to personal characteristics, health status and home characteristics was conducted for each participant. The mixed-effects models showed a significant association of PM2.5 with increased CEA and AEC and decreased % predicted PEFR. No significant association between low-level PM2.5 exposure (10-year mean level < 10 µg/m3) and adverse pulmonary effects was observed. The present study concluded that long-term indoor exposure to PM2.5 at a concentration higher than 10 µg/m3 was associated with adverse pulmonary effects among healthy adult homeworkers.

Colorimetric detection of polycyclic aromatic hydrocarbons by using gold nanoparticles.

The existence and content of polycyclic aromatic hydrocarbons (PAHs) in the environment have gradually received attention because PAHs are widely detected in many sources. Therefore, an effective detection method for PAHs is necessary for further treatment. This study proposes a novel colorimetric detection method based on AuNPs to determine the contents of phenanthrene (Phe) and pyrene (Pyr). Trisodium citrate was used as a reducing agent to synthesize gold nanoparticles, and ammonium nitrate (NH4NO3) was added as a reactant to detect the analyte content. Some assay parameters, such as the concentration of NH4NO3 solution, the volume of NH4NO3 solution, the concentration of MES buffer solution, the volume of MES buffer solution, and the reaction time influenced the analyte detection ability of AuNPs and were optimized. The limits of detection for Phe and Pyr are 0.06 mg/L and 0.087 mg/L, respectively. In addition, the detection method has good selectivity and anti-interference ability for the target analytes. This colorimetric method was used to detect target analytes in real water (tap water and mineral water) with acceptable results.

Enhancement of plasticizer adsorption by utilizing a rice bran-derived adsorbent.

Bis(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) are commonly used plasticizers in many countries and are detected at significant levels in the environment. Wastewater treatment plants are currently unable to completely treat wastewater discharges containing plasticizers. Rice bran was used to prepare magnetic-activated biochar (MAB) as a reusable adsorbent for enhanced adsorption of DEHP and DBP. The influence of the adsorbent dose, temperature, and adsorption time on the removal efficiency of MAB was studied using response surface methodology (RSM). An analysis of the results indicated that the optimum conditions were a MAB dose of 3.6 g/L, a temperature of 49 °C, and an adsorption time of 454 min for DEHP removal; and a MAB dose of 3.7 g/L, a temperature of 36 °C and an adsorption time of 312 min for DBP removal. The adsorption isotherm data were well fitted by the Langmuir isotherm model, and the adsorption kinetic data were reasonably described by the pseudosecond-order model. MAB is a potential adsorbent for DEHP and DBP removal because of good removal efficiency and reusability.

Husk of Agarwood Fruit-Based Hydrogel Beads for Adsorption of Cationic and Anionic Dyes in Aqueous Solutions.

Hydrogel beads based on the husk of agarwood fruit (HAF)/sodium alginate (SA), and based on the HAF/chitosan (CS) were developed for the removal of the dyes, crystal violet (CV) and reactive blue 4 (RB4), in aqueous solutions, respectively. The effects of the initial pH (2-10) of the dye solution, the adsorbent dosage (0.5-3.5 g/L), and contact time (0-540 min) were investigated in a batch system. The dynamic adsorption behavior of CV and RB4 can be represented well by the pseudo-second-order model and pseudo-first-order model, respectively. In addition, the adsorption isotherm data can be explained by the Langmuir isotherm model. Both hydrogel beads have acceptable adsorption selectivity and reusability for the study of selective adsorption and regeneration. Based on the effectiveness, selectivity, and reusability of these hydrogel beads, they can be treated as potential adsorbents for the removal of dyes in aqueous solutions.

Performance Evaluation and Optimization of Dyes Removal using Rice Bran-Based Magnetic Composite Adsorbent.

Although several studies have explored green adsorbent synthesized from many types of agriculture waste, this study represents the first attempt to prepare an environmentally friendly rice bran/SnO2/Fe3O4-based absorbent with economic viability and material reusability, for the promotion of sustainable development. Here, rice bran/SnO2/Fe3O4 composites were successfully synthesized and applied for adsorption of reactive blue 4 (RB4) and crystal violet (CV) dyes in aqueous solutions. The adsorption data were well-fitted by the Langmuir isotherm model and the pseudo-second-order kinetic model. The maximum adsorption capacities of the RB4 and CV dyes as indicated by the Langmuir isotherm model were 218.82 and 159.24 mg/g, respectively. As results of response surface methodology (RSM) showed, the quadratic model was appropriate to predict the performance of RB4 dye removal. The findings exhibited that an optimum removal rate of 98% was achieved at 60 °C for pH 2.93 and adsorption time of 360 min. Comparative evaluation of different agricultural wastes indicated that the rice bran/SnO2/Fe3O4 composite appeared to be a highly promising material in terms of regeneration and reusability, and showed that the composite is a potential adsorbent for dye removal from aqueous solutions. Overall, the study results clearly suggest that an adsorbent synthesized from rice bran/SnO2/Fe3O4 magnetic particle composites provides encouraging adsorption capacity for practical applications for environmental prevention.

In-vehicle carbon dioxide and adverse effects: An air filtration-based intervention study.

Drowsiness is considered a potential risk for traffic accidents. Exposure to high carbon dioxide (CO2) levels in vehicles may result in unpleasant feeling, fatigue, drowsiness or lethargy among drivers and passengers. However, little is known about whether reducing CO2 levels in vehicles by air filtration can relieve adverse effects among human subjects during driving. We recruited a panel of 84 healthy participants to drive a vehicle equipped with a CO2 filtration system for 1 h on a coastal road in a Northern Taiwan rural area. The operation modes of the CO2 filtration system, including fresh air from open windows without a CO2 filtration system (Control-mode), fresh air from an air conditioning (AC) system with closed windows and a false CO2 filtration system in operation (Off-mode) or a true CO2 filtration system in operation (On-mode), were examined. The repeated measurements of heart rate (HR), blood pressure (BP), CO2, total volatile organic compounds (TVOCs), particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) and a simple question about drowsiness were obtained for each participant in three different modes. We found that decreased HR, systolic BP (SBP) and diastolic BP (DBP) and increased drowsiness were associated with increased levels of in-vehicle CO2. The effects of in-vehicle CO2 on adverse effects were highest in the Off-mode during driving. In the On-mode, the participants showed slight decreases in HR, SBP and DBP and slight increases in drowsiness. We concluded that the utilization of a CO2 filtration system can reduce in-vehicle CO2 levels and modify the effect of in-vehicle CO2 on HR, BP and drowsiness among human subjects during driving.

Houseplant, indoor air pollution, and cardiovascular effects among elderly subjects in Taipei, Taiwan.

Previous studies have documented the linkage between houseplant usage and indoor air quality (IAQ) improvement. However, the effect of houseplant on the association between indoor air quality and cardiovascular health is still unknown. We recruited 100 elderly subjects from 100 houses with (50) or without houseplants (50) in Taipei and conducted six 24-hour house visits for each elderly subject between 2015 and 2016. The particulate matter less than or equal to 2.5 µm in diameter (PM2.5), total volatile compounds (TVOCs), heart rate (HR) and blood pressure (BP) were continuously measured in each house visit. The association between indoor air pollution, BP and HR was investigated by mixed-effects. We found that the elderly subjects in houses without houseplants were exposed to higher indoor PM2.5 and TVOCs levels compared to the elderly subjects' exposures in houses with houseplants. Also, the elderly subjects' HR, systolic BP (SBP) and diastolic BP (DBP) were higher in houses without houseplants than those in houses with houseplants. Moreover, high indoor air pollution levels were associated with elevated BP and HR, especially among subjects in houses without houseplants. Accordingly, we concluded that indoor air pollution was associated with cardiovascular effects. Houseplant could improve IAQ and cardiovascular health among elderly subjects in Taipei, Taiwan.

Indoor ozone levels, houseplants and peak expiratory flow rates among healthy adults in Taipei, Taiwan.

The association between houseplants and indoor air quality improvement has been reported in previous studies. However, the effect of houseplant-emitted isoprene on the association between ozone (O3) formation and respiratory health remains unclear. We recruited 60 adult subjects from 60 houses with or without houseplants (1:1) in Taipei; twelve house visits were conducted in each home throughout 2014. The indoor air pollutants that were measured consisted of particulate matter less than or equal to 2.5 µm in diameter (PM2.5), O3 and isoprene. Peak expiratory flow rate (PEFR) was measured in each study subject during each house visit. Household information was collected by a questionnaire. Mixed-effects models were used to explore the association between indoor air pollution levels and PEFR. We found that the concentrations of O3 and isoprene in houses with houseplants were higher than those in houses without houseplants. In contrast, PM2.5 levels and % predicted PEFR were higher in houses without houseplants than in those with houseplants. Moreover, increased levels of O3 and PM2.5 in houses with houseplants were associated with a decreased % predicted PEFR, especially in the summer. We concluded that increased levels of indoor O3 and PM2.5 were associated with decreased PEFR. The presence of houseplants was associated with indoor O3, isoprene and PEFR variations in the summer.

Investigation of the Antioxidant Capacity, Insecticidal Ability and Oxidation Stability of Chenopodium formosanum Seed Extract.

To maximize the extraction of antioxidants from Chenopodium formosanum seeds, the process factors, such as the ethanol concentration (0⁻100%), extraction time (30⁻180 min) and temperature (30⁻70 °C), for the extraction of the bioactive contents as well as the antioxidant capacity are evaluated using response surface methodology (RSM). The experimental results fit well with quadratic models. The extract was identified by GC/MS, and it was found that some active compounds had antioxidant, repellency and insecticidal activities. Various concentrations of the extract were prepared for the evaluation of the insecticidal activity against Tribolium castaneum, and the toxicity test results indicated that the extract was toxic to Tribolium castaneum, with an LC50 value of 354.61 ppm. The oxidative stability of the olive oil determined according to the radical scavenging activity and p-anisidine test demonstrates that the extract obtained from the Chenopodium formosanum seeds can retard lipid oxidation.

Biosynthesis of SnO2 Nanoparticles Based on Response Surface Methodology and the Study of Their Dye Removal.

Litsea cubeba is an evergreen tree from the Lauraceae family, with the common name of mountain pepper in Taiwan. The extracts from different parts such as the bark, leaf, root and fruit have various medicinal properties and have been extensively used in traditional Chinese medicine. SnO2 nanoparticles (NPs) were synthesized using an extract of Litsea cubeba fruit based on response surface methodology (RSM). The phytochemicals present in the extract of Litsea cubeba fruit played a crucial role in the NP formation, which could be confirmed by Fourier-Transform Infrared Spectrometer (FTIR). Analysis of variance (ANOVA) was used to evaluate the validation of the RSM models and indicated that the quadratic model was highly significant and suitable to represent the response of the NP formation yield. The optimum parameters were determined using the Design Expert Program and were as follows: extract volume ratio 30.0%, pH 6.3 and reaction temperature 44.4 °C. Using the optimal reaction conditions from the central composite design (CCD) of RSM, the SnO2 NPs were prepared and characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The FE-SEM results showed that the SnO2 NPs were spherical, and XRD results showed that the NPs had a tetragonal crystal structure. Furthermore, the photodegradation kinetics of malachite green by the SnO2 NPs was represented well with a pseudo first-order model.

Adsorption Behavior of Recyclable Magnetites with N-Components for Adsorption of Copper Ion.

Recyclable magnetites with thioureido group (poly-allyl-thiourea/oleic acid/magnetite, PAT-adsorbent) and amine functional group (ethylenediamine/methyl methacrylate/oleic acid/magnetite, EDA-adsorbent) were synthesized by modifying magnetite with oleic acid, methyl methacrylate, allyl thiourea and ethylenediamine. PAT-adsorbent and EDA-adsorbent were used and compared for adsorption of copper ions in a batch system due to the existence of amino group (-NH2) both on thioureido group and amine functional group. The kinetics of both PAT-adsorbent and EDA-adsorbent were evaluated utilizing pseudo-first-order and pseudo-second-order kinetic models. The equilibrium data was analyzed and compared using the Langmuir and Freundlich isotherm models. The maximum adsorption capacity (Qm) of PAT-adsorbent (19.126 mg g-1) was higher than that of EDA-adsorbent (7.096 mg g-1). As compared to EDA-adsorbent the magnetic adsorbent (PAT-adsorbent) with good desorption performance (>85% desorption efficiency) and easily reuse (>85% recovery by magnetic force) was the important factors for its potential practical application.

Antioxidant capacity, insecticidal ability and heat-oxidation stability of Tagetes lemmonii leaf extract.

The aim of this study was to examine the effect of process factors such as ethanol concentration, extraction time and temperature on the extraction yield and the bioactive contents of Tagetes lemmonii leaf extracts using response surface methodology (RSM). ANOVA results showed that the response variables were affected by the ethanol concentration to a very significant degree and by extraction temperature to a lesser degree. GC/MS characterization showed that the extract is rich in bioactive compounds and those present exhibited important biological activities such as antioxidant, insect repellence and insecticidal activities. The results from the toxicity assay demonstrate that the extract obtained from the leaves of Tagetes lemmonii was an effective insect toxin against Tribolium castaneum. The radical scavenging activity and p-anisidine test results of olive oil spiked with different concentrations of leaf extract showed that the phenolic compounds can retard lipid oxidation.

Long-term indoor air conditioner filtration and cardiovascular health: A randomized crossover intervention study.

The association of short-term air pollution filtration with cardiovascular health has been documented. However, the effect of long-term indoor air conditioner filtration on the association between air pollution and cardiovascular health is still unclear. We recruited 200 homemakers from Taipei and randomly assigned 100 of them to air filtration or control intervention; six home visits were conducted per year from 2013 to 2014. The participants under air filtration intervention during 2013 were reassigned to control intervention in 2014. The air pollution measurements consisted of particulate matter less than or equal to 2.5µm in diameter (PM2.5) and total volatile organic compounds (VOCs); blood pressure was monitored for each participant during each visit. The following morning, blood samples were collected after air pollution monitoring. The blood samples were used to analyze biological markers, including high sensitivity-C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and fibrinogen. Household information, including cleaning, cooking, and air conditioning, was collected by a questionnaire. Mixed-effects models were used to investigate the associations among air pollution measurements, blood pressure and biological markers. The results showed that increased levels of PM2.5 and total VOCs were associated with increased hs-CRP, 8-OHdG and blood pressure. The health variables were higher among participants in the control intervention phase than among those in the air filtration intervention phase. We concluded that air pollution exposure was associated with systemic inflammation, oxidative stress and elevated blood pressure. The long-term filtration of air pollution with an air conditioner filter was associated with cardiovascular health of adults.

Characterization of pulmonary protein profiles in response to zinc oxide nanoparticles in mice: a 24-hour and 28-day follow-up study.

Although zinc oxide nanoparticles (ZnONPs) are recognized to cause systemic disorders, little is known about the mechanisms that underlie the time-dependent differences that occur after exposure. The objective of this study was to investigate the mechanistic differences at 24 hours and 28 days after the exposure of BALB/c mice to ZnONPs via intratracheal instillation. An isobaric tag for the relative and absolute quantitation coupled with liquid chromatography/tandem mass spectrometry was used to identify the differential protein expression, biological processes, molecular functions, and pathways. A total of 18 and 14 proteins displayed significant changes in the lung tissues at 24 hours and 28 days after exposure, respectively, with the most striking changes being observed for S100-A9 protein. Metabolic processes and catalytic activity were the main biological processes and molecular functions, respectively, in the responses at the 24-hour and 28-day follow-up times. The glycolysis/gluconeogenesis pathway was continuously downregulated from 24 hours to 28 days, whereas detoxification pathways were activated at the 28-day time-point after exposure. A comprehensive understanding of the potential time-dependent effects of exposure to ZnONPs was provided, which highlights the metabolic mechanisms that may be important in the responses to ZnONP.

Carbon dioxide adsorption on amine-impregnated mesoporous materials prepared from spent quartz sand.

Mesoporous MCM-41 was synthesized using cetyltrimethyl ammonium bromide (CTAB) as a cationic surfactant and spent quartz sand as the silica source. Modification of the mesoporous structure to create an absorbent was then completed using 3-aminopropyltrimethoxysilane. Amine-Quartz-MCM (The A-Q-MCM) adsorbents were then characterized by N2 adsorption/desorption, elemental analysis (EA), X-ray fluorescence (XRF), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), as well as the carbon dioxide (CO2) adsorption/desorption performance. In this study, spent quartz sand was utilized to synthesize Quartz-MCM (Q-MCM) and the amine functionalized material, A-Q-MCM, which exhibited a higher uptake of CO2 at room temperature compared with the nongrafted material. The results showed that Q-MCM is similar to MCM-41 synthesized using commercial methods. The surface area, pore volume, and pore diameter were found to be as high as 1028 m2/g, 0.907 cm3/g, and 3.04 nm, respectively. Under the condition of CO2 concentration of 5000 ppm, retention time of 50 cc/min, and the dosage of 1 g/cm3, the mean adsorption capacity of CO2 onto A-Q-MCM was about 89 mg/g, and the nitrogen content of A-Q-MCM was 2.74%. The adsorption equilibrium was modeled well using a Freundlich isotherm. Implications: In this study, spent quartz sand was utilized to synthesize Q-MCM. The amine functionalized material exhibited a higher uptake of CO2 at room temperature compared with the nongrafted material. The results showed that Q-MCM is similar to MCM-41 synthesized using commercial methods. The adsorption equilibrium was modeled well using a Freundlich isotherm.

Study on particulates and volatile organic compounds removal with TiO2 nonwoven filter prepared by electrospinning.

UNLABELLED: In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The wires of titanium dioxide and the nonwoven binding titania nanofibers were formed using 14 kV voltage and a distance of 15 cm. A single-factor experimental method was used to investigate the effects of parameters such as initial concentration, retention time, and light source on acetone removal by nonwoven binding titania nanofibers. Furthermore, the effects of parameters such as gas pressure, particle size, initial concentration, and retention time on the removal of particulates were also assessed. The results showed that the degradation efficiency increased with decreasing initial concentrations and increasing retention time. The best operational conditions during this study for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and ultraviolet (UV) light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained. In addition, 90% particulate matter removal efficiency was reached when the particulate size was greater than 200 nm and the reaction time was longer than 5 minutes. The prepared TiO2/nanofiber has good performance for volatile organic compounds (VOCs) and particulate removal at the same time. IMPLICATIONS: In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The results showed that the optimum operating conditions for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and UV light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained.

Study on the methylene blue adsorption from wastewaters by pore-expanded calcium fluoride sludge adsorbent.

The adsorption of methylene blue (MB) onto pore-expanded calcium fluoride sludge (ECF) by the batch adsorption technique was investigated. The results showed that the adsorption capacity increased with increasing MB concentration but decreased as pH was increased. In order to investigate the adsorption mechanisms, three simplified isotherm models and kinetic models were used in this study. The best-fit adsorption isotherm was achieved with the Temkin model. Furthermore, the pseudo-second-order kinetic model agreed very well with the dynamical behavior for the adsorption of MB onto ECF. Thermodynamic studies revealed that the adsorption process of MB onto ECF was spontaneous and exothermic. The results indicated that ECF adsorbed MB efficiently and could be used as a waste adsorbent for the removal of cationic dyes in wastewater treatment.