Ultraviolet-visible Spectrometer Research Articles

Improving the performance of glucose oxidase biofuel cell by methyl red and chitosan composite electrodes

This research aims to improve the output power of self-pumping glucose enzymatic biofuel cell (EBFC) and modifying the anode. Adding a fixed ratio of methyl red-chitosan (MR-CS) can effectively improve the EBFC efficiency and stability. In addition, chitosan can be obtained from discarded crustacean fishery waste objects such as shrimp and oysters, are also significant to the use of environmentally friendly materials. The catalyst was immobilized on pyrenecarboxaldehyde (PCA), polyethyleneimine (PEI) and multi-wall carbon nanotubes (MWCNT) and combined with glucose oxidase (GOx). Finally, the [PCA/GOx]/PEI/Nafion solution/MWCNT/[MR-CS] catalyst was immobilized on the carbon cloth. Experimental analysis was progressed under the preparation of enzyme-supported electrode to observe the feasibility of the anode electrode. Experiment including Fourier transform infrared spectroscopy (FTIR) to analyze the distribution of functional groups after modification of the carbon cloth electrode, and through the comparison of the ultraviolet–visible spectrometer (UV–Vis), it can be known that the concentration ratio of [MR-CS] is 1:5, the glucose oxidase load can be maximized. Electrochemical analysis (Cyclic Voltammetry, CV) measures the activity of the maximum reaction of the anode material and the corresponding redox peak, and scanning electron microscope (SEM) observes the surface morphology of the modified electrode. Self-pumping glucose enzymatic biofuel cell module was assembled and examined, the results showed that the maximum output power density (MPD) was 2.64 mW/cm2.

Selective detection of MnO4- in non-standard explosives by nitrogen-doped carbon quantum dots-copper complexes (NCQDs@Cu)

Nitrogen-doped carbon quantum dots (NCQDs) with bright yellow fluorescence (quantum yield of 27.3 %) were synthesized via a solvothermal method using 2,3-diaminopyridine as the carbon and nitrogen source and ethanol as the solvent. Subsequently, the NCQDs were reacted with Cu2+ in an aqueous solution, forming nitrogen-doped carbon quantum dots-copper complexes (NCQDs@Cu) with great potential for selective determination of MnO4- ions. The aqueous solution of NCQDs@Cu exhibiting a very weak fluorescence (quantum yield of 2.2 %) demonstrated a significant enhancement (quantum yield of 10.0 %) upon interaction with MnO4-(Turn-on). Furthermore, this enhancement remained unaffected by the interfering conventional or unconventional explosives, inorganic ions, and oxidants. Moreover, a good linear relationship existed between the fluorescence intensity of the NCQDs@Cu and the concentration of the permanganate ions in a range of 0 to 5 μmol/L with a detection limit of 32.4 nmol/L. Additionally, the study investigated the underlying principles of the detection mechanism using advanced technologies such as X-ray photoelectron spectroscopy(XPS), The Fourier-transform infrared (FTIR), ultraviolet visible spectrometer (UV–Vis), fluorescence spectrometer and other methods. Finally, the NCQDs@Cu were successfully applied for detecting MnO4- in simulated and actual unconventional explosives, demonstrating a good correlation with standard methods. Therefore, the developed NCQDs@Cu can be used for rapid on-site inspection in explosive incident scenarios. This new method of using carbon dots-metal complexes as fluorescent probes will also provide new ideas for researchers.

Construction and antibacterial activities of walnut green husk polysaccharide based silver nanoparticles (AgNPs)

In this paper, the size-controllable nano‑silver particles (AgNPs) were synthesized from walnut green husk polysaccharide, and its cytotoxicity and antibacterial activity were evaluated. Firstly, acidic polysaccharide WGHP2 was extracted from walnut green husk, and then the silver ion in AgNO3 was reduced in WGHP2 aqueous solution using NaBH4, so as to synthesize the nano‑silver composite. The nano‑silver composite was characterized by transmission electron microscope, Fourier infrared spectroscopy, ultraviolet-visible spectrometer, scanning electron microscope, inductively coupled plasma mass spectrometry and X-ray photoelectron spectroscopy. The results show that AgNPs stabilized by WGHP2 are mainly regular spheres with an average particle size distribution of 15.04–19.23 nm. The particle size distribution and morphology of AgNPs changed with the concentration of silver precursor, which is related to the dispersion of silver precursor in polysaccharide aqueous solution and the formation of AgO coordination bond between silver precursor and polysaccharide molecules. These coordination bonds changed the ability of nanoparticles to produce and release Ag+, and thus regulated their antibacterial activity and cytotoxicity, as evidenced by the experimental result of the cytotoxicity of the nano‑silver particle against PC12 cells and the bacteriostatic effect on E.coli and S.aureus. Conclusively, WGHP2-Ag has good stability, antibacterial activity and low cytotoxicity.

Efficient extraction of Au(Ⅲ) by a piperidine-based ionic liquid and exploration of the mechanism driving force

Efficient gold extraction is of paramount importance, but how to improve the extraction efficiency and enhance the driving force of the extraction process is still to be explored. This study introduces an innovative approach using versatility ionic liquids (ILs) to overcome existing challenges. A tailored IL was synthesized and employed computational tools, including the Interaction Region Indicator, to predict its effectiveness in gold extraction. Quantum chemical calculations elucidated the interplay between hydrogen bonding capability and ion exchange properties of the ILs. Subsequent optimization of experimental conditions (0.1 mol/L HCl, 10.6 mg IL) yielded a remarkable 98.4 % extraction efficiency at 45 °C. Molecular dynamics simulations affirmed the IL's exceptional selectivity for Au(III) extraction, with analysis revealing that the extraction mechanism primarily hinged on electrostatic attraction and van der Waals interactions between ionic liquid cations and [AuCl4]−. This mechanism aligns with the established anion exchange mechanism, validated through Ultraviolet–visible spectrometer (UV–Vis), Nuclear Magnetic Resonance spectrometer (NMR), and Liquid Chromatograph Mass Spectrometer (LC-MS) analyzes. To complete the extraction cycle, 1.0 mol/L K2C2O4 was employed as a stripping agent for efficient Au(III) recovery from the loaded IL phase, facilitating repeated extraction cycles. This study underscores the sustainability of the IL-based Au(III) extraction process, maintaining consistently high extraction rates even after five cycles. In summary, this method does not use solvent, enabling environmentally friendly Au(III) extraction.

Synthesize Iron Oxide and Zinc Oxide Nanoparticles Using Plant Extracts

Recently, a plant-mediated approach to synthesizing nanoparticles via unconventional, eco-friendly technique-based techniques involving natural materials was developed. In this work, the microwave method has been used, where Hibiscus rosa sinensis flower extract and Myristica Fragrans have been used as reducers and stabilizers to synthesize iron oxide nanoparticles (α-Fe2O3) and zinc oxide nanoparticles (ZnO), respectively. The melting point and ultraviolet-visible spectrometer (UV-Vis) have been utilized to investigated and characterized the synthesized iron oxide and Zinc oxide nanoparticles. The results showed that the melting point of Fe2O3-NPs and ZnO-NPs were above ~300 °C, which indicated the melting of nanoparticle. Nanoparticles exhibit a significant in melting point as their size goes below ≈10 nm. in addition, the UV-Vis absorption spectra of the synthesized iron oxide NPS show peak surface plasmon resonance (SPR) band around 320 nm and Zinc oxide NPS shown peak surface plasmon resonance (SPR) band around 370 nm. The microwave method has been successfully used in this study, which has advantages over the other methods.

Chicken Meat and Beef Identification in UV-Vis Absorbance Spectrum by Applying Savitzky-Golay Method

Spectroscopy is one of the techniques suitable for validation of the quality, safety, and hygiene of meat due to some advantages, such as rapid detection capability, ease of use, and non-destructive measurement. Utilizing an ultraviolet-visible (UV-Vis) spectrometer, with a wavelength range of 200 nm to 1100 nm, this paper proposes a method for processing spectrum data profiling of chicken meat and beef. A 360-time reflectance spectrum was acquired from each chicken breast and beef loin at the optimum integration time of 60 ms. Subsequently, the spectrum was converted into an absorbance spectrum, and the apparent noise was excluded by applying the Savitzky-Golay (SG) method. The result shows the difference in spectrum between chicken meat and beef in which the chicken meat has two peaks at the wavelength of 284.79 nm and 422.69 nm, meanwhile, the beef shows three peaks at wavelengths of 282.46 nm, 419.03 nm, and 577.97 nm. It was found that the SG method enhanced the absorbance spectrum, showing the difference in spectrum behaviors in the wavelength range of 450∼600 nm. Consequently, to shorten the computational time, building a light, cheap, and compact prototype reading device within this specific wavelength range will be the next target in the near future.

Exploring the emulsification potential of chitosan modified with phenolic acids: Emulsifying properties, functional activities, and application in curcumin encapsulation

This study successfully grafted caffeic acid and 3,4-dihydroxybenzoic acid into chitosan through a coupling reaction, yielding grafting ratio of 8.93 % for caffeic acid grafted chitosan (CA-GC) and 9.15 % for 3,4-dihydroxybenzoic acid grafted chitosan (DHB-GC) at an optimal concentration of 4 mmol phenolic acids. The characterization of modified chitosans through ultraviolet visible spectrometer (UV–vis), Fourier transform infrared spectrometer (FTIR), proton nuclear magnetic resonance (1H NMR), and x-ray photoelectron spectrometer (XPS) confirmed the successful grafting of phenolic acids. In the subsequent step of emulsion preparation, confocal laser scanning microscope images confirmed the formation of O/W (oil-in-water) emulsions. The phenolic acid-grafted chitosans exhibited better emulsification properties compared to native chitosan, such as reduced droplet size, more uniform emulsion droplet distribution, increased ζ-potential, and enhanced emulsifying activity and stability. Moreover, the modified chitosans demonstrated increased antioxidant activities (evidenced by DPPH and β-carotene assays) and displayed greater antimicrobial effects against E. coli and S. aureus. Its efficacy in curcumin encapsulation was also notable, with improved encapsulation efficiency, sustained release rates, and enhanced storage and photostability. These findings hint at the potential of modified chitosans as an effective emulsifier.

Naked-eye rapid recognition of tyrosine enantiomers using silver triangular nanoplates as colorimetric probe

Recognizing and quantifying enantiomers of chiral molecule is of great importance in chemical, biological and pharmaceutical fields. Herein, we presented one simple-yet-efficient method of sensing tyrosine (Tyr) enantiomers. In this sensing, silver triangular nanoplates (AgTNPs) were used as colorimetric probes. L-Tyr quickly induced the color of AgTNPs solution to change from dark blue to light gray, whereas D-Tyr induced no change of the AgTNPs solution color. The obvious color change enables the naked eye to recognize Tyr enantiomer. The visual method was used to detect the enantiometric excess value of L-Tyr in the whole range (−100 % ∼ 100 %). This chiral sensing can be finished within 5 min using one simple ultraviolet–visible spectrometer or naked eye. Furthermore, the mechanism of this chiral sensing was explored. It was confirmed that this chiral sensing was based on AgTNPs’ intrinsic chirality. This chiral sensing is rapid, simple, and low-cost, and has great potential for chiral determination of Tyr.

Highly ordered structure and susceptibility to light absorption of ZnO/calcium phosphate (5%) to enhance the stability of charge diffusion as a methylene blue bond breaker

The composite Zinc oxide/calcium phosphate was successfully prepared using the sol–gel method. The structural and optical properties are observed by using x-ray Diffraction and Fourier Transform Infra-Red, respectively. The degradation of MB dye is analyzed by using Ultraviolet-Visible spectrometer. The maximum MB degradation is achieved 92.61 2.7% and shows the linear correlation to a high optical longitudinal position and enlarged d spacing. Superior photocatalytic activity is demonstrated by ZnO/CP_240 which has a consistent band gap due to its highly ordered structure and susceptibility to light absorption ability, thus triggering better charge diffusion stability. The empirical findings suggest that the introduction of CP at the atomic level into the crystal lattice of ZnO buffer generates a surplus of oxygen vacancies, thereby diminishing the strength of the MB bonding. This, in turn, facilitates the activation of lattice oxygen.

Effect of synchronous surface grafting and intercalation bentonite on properties of SBS modified bitumen

To better enhance the improvement effect of natural bentonite on the comprehensive performance of styrene-butadiene-styrene thermoplastic elastomer modified bitumen (SMB), in this study, 3-(trimethoxysilopropyl) dimethyl octadecyl ammonium chloride (DC5700) was used for synchronous surface grafting and intercalation of bentonite (DC5700-Bentonite). Meanwhile, γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560) surface grafting bentonite (KH560-Bentonite) and octadecyldimethylbenzylammonium chloride (ODBA) intercalation bentonite (ODBA-Bentonite) were used as comparison samples. The structure and properties of the bentonite and organic bentonites (DC5700-Bentonite, KH560-Bentonite and ODBA-Bentonite) were tested by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), ultraviolet-visible spectrometer and contact angle measurement. The effects of bentonite and organic bentonites on physical, rheological and aging properties of SMB were investigated. FTIR and XRD results showed that KH560 was chemically grafted onto the surface of bentonite, ODBA was organically intercalated into the bentonite, while DC5700 achieved synchronous surface grafting and intercalation on the bentonite. Compared with KH560-Bentonite and ODBA-Bentonite, DC5700-Bentonite had the best lipophilicity and ultraviolet shielding ability. When the bentonite content was 4 wt%, KH560-Bentonite, ODBA-Bentonite and DC5700-Bentonite could increase the rutting factor of SMB by 2.9 ℃, 4.9 ℃ and 6.5 ℃, respectively, and reduce the ductility of SMB by 6.5 cm, 4.2 cm and 3.1 cm. Meanwhile, compared to SMBs containing KH560-Bentonite or ODBA-Bentonite, the SMB containing DC5700-Bentonite had the smallest creep stiffness at − 12 ℃, − 18 ℃, and − 24 ℃. The results indicated that DC5700-Bentonite was more conducive to increasing high-temperature performance of SMB than KH560-Bentonite and ODBA-Bentonite, and its adverse effects on low-temperature ductility and low-temperature cracking resistance of SMB were also significantly reduced. After thermal and ultraviolet aging, the deterioration extent of physical and rheological properties of SMB containing DC5700-Bentonite was significantly smaller than that of SMB containing KH560-Bentonite and ODBA-Bentonite. FTIR revealed that DC5700-Bentonite was more beneficial than KH560-Bentonite and ODBA-Bentonite in inhibiting the increase of carbonyl index and the decrease of butadiene index in SMB during aging. The comprehensive results revealed that compared to KH560 surface grafting bentonite and ODBA intercalation bentonite, DC5700 synchronous surface grafting and intercalation bentonite were more conducive to improving the physical and rheological properties, and aging resistance of SMB.

Architecture of a dual biocompatible platform to immobilize genistin: fabrication with physio-chemical and in vitro evaluation

The design of biocompatible cell culture substrates and electrospun nanofibers can improve cell proliferation and behavior in laboratory conditions for tissue engineering applications in medicine. In this research, genistin was obtained by extracting from soybean meal powder, and then by adding polycaprolactone (PCL), genistin nanocapsules were prepared. For the first time, we used a lipophilic nanophase (encapsulated genistin) coated in a hydrophilic nanophase (gelatin /polyvinyl alcohol) as a dual nanosystem by the electrospinning method. In the approach, the nanofibers mimic the natural extracellular matrix, interact favorably with cells being cultured from one side, and raise the local concentration of a bioactive compound at the cell surface. The encapsulated drug which was inserted in fibers with a loading percentage of 92.01% showed appropriate and significant controlled release using high-performance liquid chromatography (HPLC). To prove the experiments, analysis using an ultraviolet–visible spectrometer (UV–Vis), 1H NMR spectrometer, Fourier transforms infrared spectrometer (FTIR), mechanical test, scanning electron microscope (SEM) and microscope transmission electron microscopy (TEM) was performed. The sample synthesized with 40% drug using the MTT method exhibited remarkable biological effects, viability, and non-toxicity. Additionally, significant proliferation and adhesion on the mouse fibroblast cell line L929 were observed within a 72-h timeframe.

A practical green synthesis method of Ag NPs using rosy periwinkle plant leaves for solar panel coating

Coated silver nanoparticles (Ag NPs) are currently receiving interest because of their numerous uses in various fields of electronics, antimicrobials, manufacturing sectors, optical science, and pharmaceuticals. Among others, it gained significant attention in the power electronic system. The goal of the proposed study is to use a cost-effective coating material for solar panels; to accomplish this, silver nanoparticles were synthesized from the leaves of the Rosy Periwinkle plants. Green synthesis and characterization, such as Ultraviolet Visible Spectrometer (UV–Vis) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR), were carried out after the silver nanoparticles have been collected prior coating. As a consequence, the effectiveness is determined based on the conductivity test, and the resulting Ag NPs are then applied to the c-si layer of the solar panel. Additionally, a modelling and experimental analysis are performed in this study to ascertain the suggested framework's ability to measure energy before and after coating panels with Ag NPs. Specifically, the Voltage Current (VI) and Power Voltage (PV) characteristics were validated in this study for analyzing the effectiveness and the obtained results revealed that the coating of green synthesized Ag NPs generated 2 % more power than the reference solar panel under the same conditions. Further, hardware testing and simulation were both used to confirm the outcomes and effectiveness of the suggested method. The open circuit voltage (Voc), short circuit current (Isc), maximum peak voltage (Vmp), maximum peak current (Imp), and efficiency are taken into account when assessing how well the suggested system performs at tracking. Moreover, the current density characteristics were evaluated with respect to various irradiation conditions for both the typical solar as well as Ag NPs coated panels. From the observation, it is noted that the efficiency level of coated panel was improved up to 19.20 %, 18 %, and 17.20 % for the irradiations of 200 W/m2, 500 W/m2, and 1000 W/m2 respectively.

A SIMPLE 3D TOOLBOX-BASED SMARTPHONE COLORIMETER: THE ABILITY TO DETECT THE STOICHIOMETRIC EQUIVALENT OF A CHEMICAL REACTION

The simple 3D toolbox is constructed and used with a smartphone for detecting the stoichiometric equivalent of chemical reactions. The reaction between salicylic acid and iron(III) ion to form a purple complex is chosen. The captured image of the purple product is measured for RGB color intensities. The color intensities of the solutions depends on concentration of the colored product, and the constant color intensities were observed after the reaction reached its stoichiometry. Several smartphones have been tested for capturing the images and measuring the color intensities. It revealed that all smartphones can be used but the white balance mode is required tuning up to get clear enough picture for color intensity measurement. This smartphone spectrometer provides a comparable results to those obtained from a commercial ultraviolet-visible spectrometer. This work can be a guideline for creation of portable devices in chemical analysis using a smartphone. Moreover, the developed device and method can be practically repeated in chemistry laboratory class for teaching stoichiometry and chemical reaction using a smartphone.

Effect of TiO2/ZnO nanofillers on structural, optical and nonlinear optical properties of PVA

Polyvinyl alcohol (PVA)/(x)Titanium dioxide (TiO2) (15-x) Zinc oxide (ZnO) nanocomposites for x = 0, 1, 5, 7.5, 10, 14 and 15 wt% concentration was prepared using solution casting method with the help of an ultrasonicator. The XRD spectra of films validate the formation of nanocomposites, as evidenced by the presence of peaks corresponding to both PVA and TiO2/ZnO nanoparticles. FTIR spectroscopy reveals the formulation of complexes between the PVA main chain and nano fillers. The homogeneous distribution of nano fillers in PVA nanocomposites was observed using SEM and EDAX. The optical studies conducted using an ultraviolet–visible spectrometer reveals that PVA/(x)TiO2(15-x) ZnO shows minimum energy gap of 2.66 eV at x = 15 wt%. The photoluminescence measurements carried out at an excitation wavelength of 370 nm using spectrophotometer exhibits unique strong emission band at 680 nm in the visible region for all the films. The open aperture (OA) Z-scan traces of PVA filled TiO2–ZnO nanocomposites at various filling levels were explored by means of Z-scan technique with DPSS continuous wave laser at 532 nm wavelength and 200 mW output power reveals that the absorption coefficient (β) of PVA nanofilms rises from 3.19 × 10−5 cm/W (for pure) to 1.17 × 10−3 cm/W (for x = 14 wt %) with rise in filling level. The closed-aperture (CA) z-scan analysis gives the nature of third order nonlinear refractive index (NRI) (n2) of PVA nanofilms. The value of nonlinear refractive index (NRI) increases from −1.57 × 10−9cm2/W (pure PVA) to −3.24 × 10−8 cm2/W for x = 14 wt% filling level. The observed enhancement in Nonlinear absorption (NLA) coefficient (β), NRI (n2) and third order nonlinear susceptibility (χ3) of prepared nanocomposites is due to added nanofillers to the PVA matrix. The improved third order nonlinear optical properties make these PVA nanocomposites as good candidates for optical switching device and optoelectronic device applications.

Biosynthesis of Zinc oxide nanorods using Agaricus bisporus and its antibacterial capability enhancement with dodeciltriethoxyl on cotton textiles

ZnO nanorods (ZnO-NRS) were synthesized using bioactive compounds from the fungus champignon (Agaricus bisporus) via sol–gel – hydrothermal methods. The purpose of this research is to modify the morphology and dimensions of ZnO-NRS with pH variations and increase the antibacterial properties of ZnO-NRS through the dodecyltriethoxysilane (DTES) hydrophobization process. The obtained ZnO-NRS was characterized using Ultraviolet Visible (UV–Vis) spectrometer, Fourier Transform Infra-Red (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDX). Meanwhile, the hydrophobicity was measured based on the water contact angle (WCA) = 148°-150°. The antibacterial test was carried out using Gram-positive (+) Staphylococcus aureus and Gram-negative (-) Pseudomonas aeruginous bacteria, each of which has an inhibition zone of 19-30 mm and is categorized as a strong inhibitory compound when compared to the commercial antibiotic chloramphenicol of 20–28 mm.

Discovery and experimental verification of the spectral characteristics at different growth stages of Aurelia

Under the dual pressure of human activities and global changes, jellyfish outbreaks have occurred frequently in China's offshore waters in recent years, with serious impacts on marine fisheries, coastal tourism, marine ecology and cooling water systems for coastal industries. In order to accurately identify the origin of Aurelia and to be more proactive in the prevention and control of Aurelia outbreaks, this article proposed the use of ultraviolet (UV) and fluorescence spectroscopy to detect the polyps, ephyrae and larvae of Aurelia at different growth stages. The AvaSpec-2048 UV visible fibre spectrometer and the F-7000 fluorescence spectrophotometer were used to focus on studying the UV absorption spectrum and three-dimensional fluorescence spectrum of the polyps, ephyrae, and larvae of Aurelia cultured under laboratory conditions. The research results showed that the three-dimensional fluorescence spectrum of the three different growth stages of Aurelia, namely polyps, ephyrae and larvae of Aurelia, had relatively similar fluorescence distributions, and the fluorescence intensity was different from each other. However, the absorption peaks of the three UV absorption spectrum appeared in different UV light bands and there were absorption peaks of different intensities. The different spectral characteristics at different growth stages of Aurelia provide new ideas and methods for exploring the birthplace of Aurelia.

Triangular silver nanoplates-BiVO4 composite for the photocatalytic CO2 reduction under irradiating LED light source

In this study, triangular silver nanoplates (TagNPts)/BiVO4 nanomaterials were prepared by hydrothermal method and are used as a photocatalyst in a photoreaction system to convert carbon dioxide into methane and carbon monoxide. The as prepared material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and ultraviolet–visible spectrometer (UV–vis). The absorbance increases in the visible light region due to the incorporation of nano-silver (triangular plate) metal and pulls electrons, reduces the recombination rate of electron-hole pairs, and improves the photoreduction activity. The transmittance ratio is measured and the specific wavelengths of blue LED 412–505 nm and green LED 427–622 nm are measured. It shows that the irradiation of targeted wavelength bands will increase the absorbance and effectively reduces the recombination of electron-hole pairs. The best performance in this study was achieved after irradiating blue light source with 0.9% TAgNPts/BiVO4. The cumulative production of photoreduced carbon monoxide is 30.11 μmol g−1 and the quantum yield is 0.07%. After a green light source, the cumulative carbon monoxide yield using 0.9 wt% TAgNPts/BiVO4 is 24.77 μmol g− and the quantum yield is 0.06%.

An Experimental Study on the Properties of β-Keratin as Dust Suppressant for Gravel Roads

This study aimed to investigate the suitability of β-keratin, produced from chicken feathers, as a surface sealant to suppress dust on gravel roads, in terms of mechanical, chemical, and physical properties. This study used High-Performance Thin Layer Chromatography (HPTLC) chemical tests, Ultraviolet-Visible Spectrometer (UV-ViS) physical tests, and the standard testing procedures of the American Society for Material Testing (ASTM) and American Association of Highway and Transportation Officials (AASHTO) for mechanical tests. For testing its mechanical properties, β -keratin was mixed with gravel at 0, 1.5, 2.0, 2.5, and 3.0% proportions of dry weight. The wavelength and absorbance of a β-keratin water solution (1:10) were 275.4nm and 0.4295 respectively. β -keratin is a hydrocarbon with the chemical formula C28H48N2O32S4 and easily melts and burns under fire. 1 liter of Keratin mixed with the carboxymethyl cellulose (CMC) emulsifier at 55 and 65g/liter yielded acceptable results between 30-60kg/m·s viscosity at 60°C according to ASTM D2170 and AASHTO T201. The optimal percentage mix of β-keratin in the gravel mixture was found to be 2.0%, providing a CBR value of 57%, least swell of 0.3%, MDD of 1850kg/m3, and OMC of 15.8%, all acceptable according to BS 1377:2-1990. For better dust suppressant results, 1 liter of pure β-keratin should be mixed with 55-65g of CMC.

Optical properties and molecular composition of wintertime atmospheric water-soluble organic carbon in different coastal cities of eastern China

To evaluate the optical properties and molecular composition of water-soluble organic carbon (WSOC) in the atmosphere of coastal cities, particle samples were collected in Tianjin, Qingdao and Shanghai, three coastal cities in eastern China. Subsequent analysis by ultraviolet visible and fluorescence spectrometer and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry were performed. The results showed that the concentration levels and light absorption ability of WSOC decreased from the north to south cities, ranking as Tianjin > Qingdao > Shanghai. Three major fluorescent components including less‑oxygenated humic-like substances (52–60 %), highly‑oxygenated humic-like substances (15–31 %) and protein-like substances (17–31 %) were identified in WSOC based on the fluorescence spectroscopy and parallel factor analysis, which might be closely related to anthropogenic emissions and continental sources as well as secondary formation processes. Five subgroups of molecular components were further identified in WSOC, including the predominant CHON compounds (35–43 %), sulfur-containing compounds (i.e., CHONS and CHOS compounds, 24–43 %), CHO compounds (20–26 %) and halogen-containing compounds (1–7 %). Compared to marine air masses influenced samples, WSOC affected by continental air masses exhibited higher light absorption coefficients and generally had a higher degree of aromaticity and unsaturation, as well as contained more molecular formulas of WSOC, especially enriched with sulfur-containing compounds. In contrast, relatively more abundant halogen-containing compounds were identified in the marine air masses influenced samples. Overall, this study provided new insights into the light-absorbing and chemical properties of WSOC in coastal cities, especially under the influences of continental and marine air masses.

Developing a Portable Spectrometer to Detect Chemical Contaminants in Irrigation Water

Water pollution is a critical issue since it can severely affect health and the environment. The purpose of the study is to develop a portable spectrometer (ESP32-based spectrometer) to detect chemical contaminants in irrigation water by observing the light absorbance of contaminants. ESP32 and a light sensor (photodiode) were respectively, used as the main controller and detector of the portable spectrometer. It was developed based on optical dispersion and Beer–Lambert law theory. The light absorbance of different types of contaminants was displayed in a Blynk application for real-time monitoring. The samples were also tested using a lab-based spectroscopy method, ultraviolet-visible (UV-Vis) spectrometer. The spectral range of the measurement is from 350 nm to 700 nm and the standard error of the ESP32-based spectrometer is from 0.01 to 0.05. Five water samples were tested, consisting of ammonium nitrate, organic pesticide, zinc oxide and two different reservoirs used for irrigation. The absorption peaks of the ammonium nitrate and organic pesticide are 363 nm and 361 nm, respectively. Zinc oxide shows the absorbance peak at 405 nm, whereas both reservoirs show absorbance peaks lie in the region from 300 nm to 370 nm. Therefore, this study shows that different types of contaminants can absorb light only at specific wavelength regions by considering the concentration of samples. The developed ESP32-based spectrometer can be applied for on-site water quality monitoring as it is portable, light, simple and can be monitored in real time using multiple devices.