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Powder Quartz/Nano-TiO2 Composite: Mechanochemical Preparation and Photocatalytic Degradation of Formaldehyde
摘要： Powder quartz (PQ)/nano-TiO2 composite was prepared by a mechanochemical method. Based on as-prepared PQ/nano-TiO2 composite, we prepared interior paints and investigated the degradation efficiency of formaldehyde (DEF). Scanning electron microscopy showed that nano-TiO2 got well dispersed by the adding of PQ. Thermogravimetric analysis indicated that the mass ratio of 4:1 was a relatively good proportion for the most production of PQ/nano-TiO2 composite. Fourier transform-infrared spectrometry showed that the peak position of Ti-O-Si bond varied with the milling time. At the early stage, no characteristic peak of Ti-O-Si bond was observed, while at the later stage, new peaks at 902 cm-1 and 937 cm-1 appeared. Meanwhile, PQ/nano-TiO2 composite-based interior paint exhibited significant DEF of 96.3% compared to that consisting of sole nano-TiO2 of 92.0% under visible light illumination. As an abundant mineral resource, PQ would make interior paints with HCHO purifying effect much more efficient and cheaper.
关键词： powder quartz,formaldehyde,interior paint,nano-TiO2
更新于2025-11-21 11:18:25
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Photocatalytic properties of TiO2@Polymer and TiO2@Carbon aerogel composites prepared by atomic layer deposition
摘要： Monolithic structured TiO2/aerogel composites were prepared from resorcinol-formaldehyde polymer aerogel (RFA) and its carbon aerogel (RFCA) derivative. A resorcinol-formaldehyde hydrogel was synthesized in a sol-gel reaction and transformed into polymer aerogel by supercritical drying. The RFA was converted to carbon aerogel by pyrolysis at 900 °C in dry N2. Amorphous and crystalline TiO2 layers were grown from TiCl4 and H2O precursors by atomic layer deposition (ALD) at 80 °C and 250 °C, respectively, on both RFA and RFCA. The substrates and the composites were studied by N2 adsorption, TG/DTA-MS, Raman, SEM-EDX and TEM techniques. Their photocatalytic activity was compared in the UV catalyzed decomposition reaction of methyl orange dye.
关键词： ALD,photocatalysis,carbon aerogel,TiO2,resorcinol-formaldehyde polymer aerogel
更新于2025-11-20 15:33:11
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A Turn-on Fluorescence Probe For Rapid, Sensitive And Visual Detection of Formaldehyde
摘要： The sensitive and selective determination of formaldehyde is very significant in food safety and environmental protection. In this paper, a novel perylenediimide based fluorescent probe for formaldehyde has been constructed. The probe can be used to detect formaldehyde rapidly, facilely and sensitively, and it exhibited an obvious fluorescence enhancement (at 582 nm) within 1 minutes, and the enhanced yellow fluorescence can be easily observed by the naked eyes. Importantly, the probe showed strong anti-interference abilities to protons and other small molecules. Moreover, the density functional theory was performed to understand the Turn-On process and the probe was successfully used to detect formaldehyde in living cells.
关键词： turn-on,anti-interference,perylenediimide,formaldehyde,fluorescence
更新于2025-09-23 15:23:52
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Rapid and sensitive detection of formaldehyde using portable 2-dimensional gas chromatography equipped with photoionization detectors
摘要： We developed an automated and highly portable device for rapid and sensitive formaldehyde detection based on heart-cutting 2-dimensional gas chromatography. In this design, the air sample was first absorbed by a preconcentrator before it is injected into the 1st-dimensional column (Rtx?-VMS). The partial elution from the 1st-dimensional column containing formaldehyde was re-injected into the 2nd-dimensional column (Rt? Q-BOND column) for further separation. The detection of formaldehyde was achieved by using a micro-helium dielectric barrier discharge photoionization detector that is able to ionize formaldehyde (ionization potential = 10.88 eV). Due to the use of many miniaturized components, the entire system has a weight of only 1.3 kg (excluding the helium cartridge) and dimensions of only 27 cm x 24 cm x 12 cm. It is capable of detecting formaldehyde down to 0.5 ppb (V/V) with a signal-to-noise ratio of 6 in only 11 min (including 6 min of sampling). Meanwhile, simultaneous separation and detection of other air pollution related toxic compounds, such as benzene, toluene, ethylbenzene, and xylene, was also demonstrated by the 1-dimensional column and a flow-through micro-photoionization detector. The device developed here should have a broad range of applications in environmental protection, industries, space exploration, and battlefield.
关键词： Gas chromatography,Air quality control,Indoor air analysis,Photoionization detector,2D GC,Formaldehyde detection
更新于2025-09-23 15:23:52
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The photocatalytic degradation kinetics of gaseous formaldehyde flow using TiO2 nanowires
摘要： A high performance TiO2 nanowires photocatalyst was successfully prepared by a hydrothermal method to decompose gaseous formaldehyde into CO2 and H2O in a homemade tube reactor without secondary pollution under UV irradiation. The photocatalytic oxidization (PCO) kinetics fit well with the traditional Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. Multiple parameters including formaldehyde concentration, flow rate, and light intensity were monitored online and proved to be key factors affecting the rate in the photocatalytic reactions. The crystallinity of photocatalyst and its surface reactive site density determined the adsorption equilibrium constant (KHCHO) of formaldehyde on TiO2. The experimental results show that the degradation kinetics of mobile gas-phase formaldehyde by TiO2 nanowires did not strictly conform to the first-order reaction kinetics, and its photocatalytic degradation rate increases with the increase of ultraviolet LED irradiation intensity. It takes only 8.6 minutes to completely degradate formaldehyde at a flow rate of 50 ml/min by 50 mg 700TiO2, and the reaction performance remains unchanged during the decomposing process of 1200 minutes.
关键词： reaction kinetics,formaldehyde,Titanium oxide nanowires,photocatalyst,photocatalytic oxidization
更新于2025-09-23 15:22:29
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Determination of formaldehyde in single cell by capillary electrophoresis with LIF detection
摘要： As a small molecule gas, formaldehyde (FA) is the simplest carbonyl active material and plays an important role in the carbon cycle of metabolism. However, due to the volatile nature of the gas, it is difficult to accurately quantify its content, which limits the study of the mechanism of action in life activities. Thus, an efficient approach to quantitative detection of FA in cells especially in single cell is urgent needed. Nevertheless, no method for quantifying FA in single cell has been reported to date. In this work, a fluorescent probe N-propyl-4-hydrazino-naphthalimide (NPHNA), which has highly desirable attributes and has been applied to living biological samples, was chosen as labeling reagent to detect endogenous FA at single cell level. After optimization of separation conditions, fast baseline separation of the FA derivative N-propyl-4-hydrazone-naphthalimide product (NPHNA-FA) and NPHNA was achieved in about 5 min by capillary electrophoresis with laser-induced fluorescence detection. The detection limit for FA was 5 amol (signal-to-noise ratio of 3). The developed method was validated by the measurements of intracellular levels of FA in single cell.
关键词： Capillary electrophoresis,Endogenous formaldehyde levels,Single cell
更新于2025-09-23 15:22:29
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CH<sub>2</sub>O Adsorption on M (M = Li, Mg and Al) Atom Deposited ZnO Nano-Cage: DFT Study
摘要： The structural and electronic properties of Li, Mg and Al deposited ZnO nano-cages and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory (DFT) computations. To understand the behavior of the adsorbed CH2O molecule on the ZnO nano-cage, results of DFT calculations of the M-deposited nano-cages (M=Li, Mg and Al), as well as complex systems consisting of the adsorbed CH2O molecule on M-deposited ZnO nano-cage were reported. The results presented include adsorption energies, bond lengths, electronic configurations, density of states and molecular orbitals. It was found that, the most energetically stable adsorption configurations of CH2O molecule on the bare ZnO leads to 12% dilation in C=O bond length of CH2O and 14% decrease in HOMO-LUMO gap of ZnO cluster. The most energetically stable adsorption configurations of CH2O molecule on Li, Mg and Al-deposited ZnO lead to 4%, 4% and 11% dilation in C=O bond length of CH2O and -0.66, -45 and , +66% change in HOMO-LUMO gap of ZnO nano cages, respectively. The interaction between CH2O with bare ZnO and M-deposited ZnO nano-cages is attributed to charge transfer mechanism. These results may be meaningful for CH2O degradation and detection.
关键词： ZnO,Adsorption,nanomaterials,Formaldehyde,DFT
更新于2025-09-23 15:21:21
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A new formaldehyde optical sensor: detecting milk adulteration
摘要： A sensor consisting of an optic fibre with the exposed tip coated with a the polyoxometalate salt [(C4H9)4N]4H[PMo10V2O40], specially designed to be insoluble in water, which UV-Vis spectrum changed in contact with formaldehyde, is presented. The sensor limit of detection for formaldehyde was 0.2 mg L-1, and the limit of quantification was 0.6 mg L-1, which were close to the conventional spectrophotometric method values of 0.2 mg L-1 and 0.5 mg L-1, respectively, and lower than the tolerable limit for ingested food. The sensor was tested for formaldehyde quantification in milk, as its deliberate addition is a matter of concern. The results obtained analysing formaldehyde in milk samples by the optical sensor and by the conventional method were not statistically different (α=0.05).
关键词： acetylacetone method,milk,formaldehyde,polyoxometalate,food adulteration,optical fibre sensor
更新于2025-09-23 15:21:01
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Surface-plasmon-enhanced optical formaldehyde sensor based on CdSe@ZnS quantum dots
摘要： For the first time, a reproducible surface-plasmon-enhanced optical sensor for the detection of gaseous formaldehyde was proposed by depositing the mixture of CdSe@ZnS quantum dots (QDs), fumed silica (FS) and gold nanoparticles (GNs) on the surface of silica spheres array to meet the urgent requirement of a rapid, sensitive, and highly convenient formaldehyde detection method. Due to the spectra overlap between QDs and GNs, plasmon-enhanced fluorescence was observed in the film of QDs/FS/GNs. When exposing to formaldehyde molecules, the enhanced fluorescence was quenched linearly with the increase of formaldehyde concentration in the range of 0.5-2.0 ppm. The reason is attributed to the nonradiative electron transfer from QDs to the carbonyl of formaldehyde molecules with the assistance of amino groups. Our results demonstrate that the designed sensors are capable of detecting ultralow concentration gaseous formaldehyde at room temperature with a fast response-recovery time, excellent selectivity, stability and reproducibility. This work provides a simple and low-cost approach for optical formaldehyde sensor fabrication and shows promising applications in environmental detection.
关键词： plasmon-enhanced fluorescence,Quantum dots,reproducibility,Optical formaldehyde sensors,fluorescence quenching
更新于2025-09-23 15:19:57
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A new laser-based and ultra-portable gas sensor for indoor and outdoor formaldehyde (HCHO) monitoring
摘要： In this work, a new commercially available, laser-based, and ultra-portable formaldehyde (HCHO) gas sensor is characterized, and its usefulness for monitoring HCHO mixing ratios in both indoor and outdoor environments is assessed. Stepped calibrations and intercomparison with well-established laser-induced fluorescence (LIF) instrumentation allow a performance evaluation of the absorption-based, mid-infrared HCHO sensor from Aeris Technologies, Inc. The Aeris sensor displays linear behavior (R2 > 0.940) when compared with LIF instruments from Harvard and NASA Goddard. A nonlinear least-squares fitting algorithm developed independently of the sensor’s manufacturer to fit the sensor’s raw absorption data during post-processing further improves instrument performance. The 3σ limit of detection (LOD) for 2, 15, and 60 min integration times are 2190, 690, and 420 pptv HCHO, respectively, for mixing ratios reported in real time, though the LOD improves to 1800, 570, and 300 pptv HCHO, respectively, during post-processing. Moreover, the accuracy of the sensor was found to be ± (10 % + 0.3) ppbv when compared against LIF instrumentation sampling ambient air. The aforementioned precision and level of accuracy are sufficient for most HCHO levels measured in indoor and outdoor environments. While the compact Aeris sensor is currently not a replacement for the most sensitive research-grade instrumentation available, its usefulness for monitoring HCHO is clearly demonstrated.
关键词： outdoor monitoring,gas sensor,ultra-portable,HCHO,indoor monitoring,formaldehyde,laser-based
更新于2025-09-23 15:19:57