Fourier Transform Infrared Spectrometer Research Articles

Real-Time In Vivo Human Skin Testing Using a Handheld Fourier Transform Infrared Spectrometer with a Three-Bounce Two-Pass Attenuated Total Reflection Interface.

Attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FT-IR) is used to characterize a vast array of materials at the molecular level in various industry types. Here we compare the performance of a portable spectrometer with a novel three-bounce-two-pass (3B2P) ATR scanning interface to the same device with a standard one-bounce (1B) ATR, and to a benchtop spectrometer with a 10-bounce (10B) ATR, in ideal sample-interface conditions and an applied dermatological study setting. In both application settings, the benchtop 10B ATR interface showed the highest signal-to-noise ratio (SNR), however, the novel 3B2P produced a six-fold increase in the sensitivity of the portable spectrometer when analyzing isopropanol and showed the greatest consistency of SNR of all devices when analyzing isopropanol and in vivo skin samples. Spectral data were sourced from a recently undertaken dermatological study involving a cohort of 180 healthy, full-term babies, using both 1B and 3B2P interfaces. Use of the 3B2P interface resulted in a 55% greater successful high-quality spectrum collection rate, compared to the 1B, and showed significantly superior SNR at both observed study time points, i.e., birth (1B: 68.37; 3B2P: 77.37), and at four weeks (1B: 74.53; 3B2P: 80.22). The utility of ATR FT-IR spectrometers as a dermatological clinical tool was also exemplified here, by quantifying the moisture level of newborn skin. By gathering rich spectroscopic data on the molecular structure of the skin, this technique holds great promise for the quantification of skin disease-specific biomarkers.

Understanding the role of sodium lignosulphonate on obstructing the aggregation of fine serpentine particles on to the hydrophobized pyrite surface

The slime coatings of serpentine via its hydrophobic Si-O layers significantly weaken the floatability of the hydrophobized sulfide minerals. In this paper, sodium lignosulphonate (SLS) was adopted to avoid the aggregation of fine serpentine particles on to the hydrophobized pyrite surface. The micro-flotation findings indicated that for the artificial mixture of pyrite and serpentine (2:1 mass ratio), 1.0 × 10-4 mol/L sodium isobutyl xanthate (SIBX) only floated out ∼22% pyrite at pH ∼9.0, while, after extra addition of 70 mg/L SLS, the floatability of pyrite was restored and its recovery reached ∼90%. In situ AFM (Atomic Force Microscope), contact angle, zeta potential, fourier transform infrared spectrometer (FTIR) and optical microscope deduced that the strong affinity of SIBX to pyrite rendered it replace the most part of the pre-aggregated SLS from pyrite surface, thus to restore the hydrophobicity of pyrite and further decrease the zeta potential. In addition, SLS attached on the positively-charged Mg sites of serpentine through its carboxyl and phenolic hydroxyl groups reduce the hydrophobicity and zeta potential of serpentine. While, the hard base O atom/anion exhibited much stronger affinity to hard acid Mg cation than that of the soft base S atom/anion, SIBX hardly replaced the adsorbed SLS from serpentine surface. Therefore, the increased electrostatic repulsion and weakened hydrophobic attraction between the SLS-adsorbed serpentine and SIBX-hydrophobized pyrite avoided their aggregation. The combination of SLS and SIBX realized the selective flotation separation of pyrite from serpentine.

Impact of biochar prepared at different pyrolysis temperatures on the methane production and microbial community structure of food waste anaerobic digestion

Biochars were prepared through the pyrolysis of sawdust at 300 °C, 500 °C, and 700 °C, respectively, under oxygen-limited conditions. The basic physicochemical properties of biochars were explored by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), surface area and porosity analyzer (BET), and Fourier-transform infrared spectrometer (FTIR). The effects of biochar addition on the methane yield and microbial community structure of anaerobic digestion of food waste were also investigated. SEM images showed that biochar had a honeycomb-like pore structure, EDS analysis showed that the C content in the biochar tended to increase, and the O contents tended to decrease with the increasing temperature. The specific surface area of biochars increased from 1.2014 m2/g (300 °C) to 326.8435 m2/g (700 °C). FTIR analysis showed that the number of different surface functional groups decreased with the increasing temperature. The addition of biochar could increase the cumulative methane volume by 11.63%–25.18%. High-throughput sequencing results showed that biochar addition could increase the relative abundance of Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, and Spirochaetota, which were associated with the degradation of refractory organic matters. Meanwhile, biochar addition could enrich the relative abundance of methanogens participating in direct electron transfer (Methanosaeta and Methanosarcina), and methanogens producing methane through multiple pathways (Methanobacterium and Methanosarcina). The addition of biochar derived at 700 °C significantly increased the relative abundance of Methanobacterium and Methanosarcina from 1.96% and 0.70% (control group) to 32.68% and 64.69%, respectively and improved methane production by transforming acetoclastic/hydrogenotrophic methanogenic pathways to more metabolically diverse methanogenic pathways.

Mixed surfactants with solubilization behaviors: Separation of feldspar and quartz by self-assembly flotation

This study designed a mixed surfactant with solubilization behavior for selective flotation separation of feldspar and quartz. By optimizing the compounding ratio and dosage of reagents, the optimal mixed surfactants, dodecylamine (DDA), sodium dodecyl sulfate (SDS), and dodecane with the concentrations of 1.75, 0.58, and 3.5 mmol/L, used in flotation separation of feldspar and quartz has the maximum flotation difference of 91.36 % at pH 3 for single mineral. The result of flotation experiments of artificial-mixed-ore shows that the Al2O3 grade was maintained at 14.23 %, and Al2O3 recovery was achieved at 69.21 % for the froth product with a selectivity index (SI) of 1.59. The bench-scale flotation tests confirmed a better effect by using mixed surfactants with Al2O3 grades of 14.72 % and the Al2O3 recovery of 66.62 %. The separation mechanism of quartz and feldspar was proposed through analyses of critical micelle concentration (CMC), fourier transform infrared spectrometer (FTIR), contact angle, zeta potential, microscopy image, and X-ray photoelectron spectroscopy (XPS) measurements, and indicated that the flotation difference between quartz and feldspar mainly originated from the selective adsorption of anions on feldspar and the aggregation and subsidence of quartz in mixed surfactants.

Polymerization of acrylonitrile in dimethyl carbonate: A kinetic and mechanistic study

For the first time, a new polymerization medium, dimethyl carbonate (DMC), was used for the polymerization of acrylonitrile (AN), and polyacrylonitrile (PAN) powder was obtained successfully. The effects of polymerization factors, including monomer concentrations, temperature and initiator concentrations on the structures and properties of PAN powders were investigated by nuclear magnetic resonance spectroscopy (NMR), total internal reflectance Fourier transform infrared spectrometer (FTIR), wide-angle X-ray diffractometer (WXRD) and thermal gravimetric analyzer (TGA). The polymerization kinetic and mechanistic study of PAN with DMC as the polymerization medium were discussed in details. There are three key achievements in this paper. First, the kinetic equation of PAN polymerization with DMC as a medium was established: Rp = K[ABVN]0.92[AN]6.78. This result shows that the Rp is highly dependent on the AN concentrations. Second, the chain transfer constant of DMC was measured to be 4.57 × 10−4 at 60 °C, and the chain transfer constant increases with polymerization temperature. Lastly, the structures and properties of PAN powders prepared with H2O, tetrahydrofuran (THF) and DMC as media were compared. The results showed that the PAN prepared with DMC as a medium by free radical polymerization had a higher conversion, molecular weight and better crystalline property compared to THF. These findings indicate that DMC is a promising medium for manufacturing high quality PAN powder by free radical polymerization.

Fast Dissolution of Chitin in Amino Acids Based Deep Eutectic Solvents Under the Assistance of Microwave.

Due to the abundant hydrogen bond networks, high crystallinity, and high molecular weight of chitin, it is difficult to dissolve chitin in most solvents. Meanwhile, most of the existing solvent systems have the disadvantages of high toxicity, low solubility, and high cost. Therefore, the efficient and rapid dissolution of chitin using green solvents is urgently needed. In this work, ternary DES with amino acids, urea, and 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) is prepared at first. Then chitin can be dissolved fastly with the assistance of a microwave. Compared with the conventional heating process (110°C, 6-8h), the microwave process can be shortened to only 3-10min. The successful dissolution of chitin is verified by means of fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), rheology studies, and optical light microscope, and the dissolution mechanism contributed to the synergistic destroying of the hydrogen bond networks of chitin by amino acids and DBU. The DES solvent can be well recovered with the remaining of its dissolving ability to chitin.

Atmospheric propane (C3H8) column retrievals from ground-based FTIR observations in Xianghe, China

Abstract. Propane (C3H8) is an important trace gas in the atmosphere, as it is a proxy for oil and gas production and has a significant impact on atmospheric chemical reactions related to the hydroxyl radical and tropospheric ozone formation. In this study, solar direct absorption spectra near 2967 cm−1 recorded by a ground-based Fourier transform infrared spectrometer (FTIR) were applied to retrieve C3H8 total columns between June 2018 and July 2022 in Xianghe in north China. The systematic and random uncertainties of the C3H8 column retrieval are estimated to be 18.4 % and 18.1 %, respectively. The mean and standard deviation of the C3H8 columns derived from the FTIR spectra in Xianghe are 1.80 ± 0.81 (1σ) × 1015 molec. cm−2. Good correlations are found between C3H8 and other non-methane hydrocarbons, such as C2H6 (R=0.84) and C2H2 (R=0.79), as well as between C3H8 and CO (R=0.72). However, the correlation between C3H8 and CH4 is relatively weak (R=0.45). Moreover, the FTIR C3H8 measurements in Xianghe are also compared against MkIV measurements at several sites around the world. The new FTIR measurements in Xianghe provide us with insight into C3H8 column variations and the underlying processes in north China.

Auricularia Auricula Polysaccharide-Mediated Green Synthesis of Highly Stable Au NPs

Polysaccharide-functionalized gold nanoparticles (Au NPs) exhibit a promising application in biomedical fields due to their excellent stability and functional properties. The Au NPs from Auricularia auricula polysaccharide (AAP) were successfully synthesized using a straightforward method. By controlling the mass fraction of AAP, pH, reaction temperature, reaction time, and concentration of gold precursor, the highly dispersed spherical AAP-functionalized Au NPs (AAP-Au NPs) were prepared. The Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS) indicated that the synthesis mechanism of AAP-Au NPs was as follows: the molecular chain of AAP undergoes a glycosidic bond breakage to expose the reduction terminus in the presence of gold precursor, which reduced Au(III) to Au(0), and itself was oxidized to carboxylate compounds for maintaining the stability of AAP-Au NPs. Additionally, based on the electrostatic interactions and steric forces, as-prepared AAP-Au NPs exhibit excellent stability at various pH (5–11), temperature (25–60 °C), 5 mmol/L glutathione, and 0.1 mol/L Na+ and K+ solutions. Furthermore, AAP-Au NPs retained the ability to scavenge DDPH and ABTS radicals, which is expected to expand the application of Au NPs in biomedical fields.

Study on the sound absorption characteristics and noise reduction mechanism of coconut-shell-activated carbon particles and coconut fiber composite biomass sound-absorption materials

Abstract Sound-absorbing materials are widely used in the field of automotive industry. Biomass materials are abundant in the nature, some of which have natural sound absorption and noise reduction properties. Biomass sound-absorption materials are green and pollution-free, which have obvious noise reduction effect on middle- and high-frequency noises, a large specific surface area, a light weight and strong sound absorption effect. The purpose of this paper is to prepare new types of biomass composite sound absorbing material. In order to analyze the sound absorption and physical properties of biomass sound-absorbing materials, the noise reduction performance of different structures of biomass sound-absorbing materials was analyzed. In this paper, the biomass sound-absorbing materials coconut-fiber- and coconut-shell-activated carbon particles were used to make samples. A coconut-shell-activated carbon sound-absorption material (CSAC) was made. The cylindrical holes were made and filled with coconut fiber materials to form composite sound-absorbing materials (CSAC-F). The acoustic performance of an impedance tube was tested based on the acoustic absorption coefficient, whose physical performance was studied by means of a scanning electron microscope (SEM), Brunauer, Emmett and Teller (BET), x-ray diffraction (XRD), a Fourier transform infrared spectrometer (FTIR), thermogravimetric analyzer (TGA) and other detection methods. In contrast, the sound absorption effect of CSAC-F was better in the middle- and low-frequency range, whose microstructure was analyzed and its mechanism of noise reduction was studied. This study will provide a new way for the research and development of sound-absorbing materials in the automotive industry, and biomass sound-absorbing materials have potential applications in the noise absorption and vibration control of automotive interior.

Rationally tailored configuration of multifunctional scavengers by encapsulating nanoscale Fe0 and FeS into zeolite imidazole framework–8 with reinforced perrhenate/pertechnetate confinement

In order to probe into the potential application prospects of multifunctional scavengers in remediating nuclear wastewater, we combined versatile functionality of nanoscale Fe0 and FeS with tailorable porosity of zeolitic imidazole frameworks–8 (ZIF–8) to manufacture two multifunctional scavengers for ReO4– confinement i.e., NZVI@ZIF–8 by reduction approach and FeS@ZIF–8 by coprecipitation approach. Batch approaches unveiled that as–manufactured scavengers illustrated an reinforced performance towards ReO4– confinement. The pseudo-second-order model was well simulated with the kinetic of ReO4– confinement. Thermodynamic analysis unraveled that ReO4– confinement was endothermic and spontaneous. The mechanism was explored via characterization alters of structure and composition of NZVI@ZIF–8 and FeS@ZIF–8 before and after ReO4– confinement. Specifically, fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) indicated that NZVI and FeS were successfully encapsulated into ZIF–8, and NZVI@ZIF–8 and FeS@ZIF–8 remained stable after ReO4– confinement. X–ray absorption fine structure (XAFS) unveiled that various Fe mineral phases were formed on the scavenger surfaces under various reaction conditions. X-ray photoelectron spectroscopy (XPS) unraveled existence of Re(VI)/Re(IV) on scavengers surfaces, unveiling ReO4– was initially enriched NZVI@ZIF–8 and FeS@ZIF–8 surfaces with subsequent reduction into Re(VI)/Re(IV). This work proposed an innovative perspective to tailored multifunctional scavengers in nuclear waste management.

Comparative adsorption of selected pesticides from aqueous solutions by activated carbon and biochar

ABSTRACT This work aimed to determine activated carbon (AC) and hard wood derived biochar (BC) adsorption capacity for the uptake of four pesticides atrazine, chlorothalanil, α-endosulfan and β-endosulfan from aqueous solution by conducting batch experiments under different experimental conditions. Structural properties of AC and BC were determined through ‘SEM (Scanning Electron Microscope), FTIR (Fourier Transform Infrared Spectrometer) and XRD (X-ray Powder Diffraction Spectroscopy)’. The optimized pH, particle size, contact time, agitation speed and initial pesticides concentration for the maximum adsorption rates were found to be 7, 250 μm, 60 min, 180 rpm and 12 μgL−¹ respectively. Pesticides adsorption were enhanced by increasing pH to 7 while slight decrease were noted when pH increases from 7 to 9. The adsorption equilibrium data were well described by the Langmuir isotherm model having a significant correlation coefficient value from 0.9999 to 1. Adsorption kinetic data were well fitted with the Lagergren's Pseudo-Second-Order kinetic model. The standard Gibb's free energy (ΔG) negative value at every temperature shows the practicability and spontaneity of the adsorption process. While the negative value for enthalpy change (ΔH) indicated the collective impact of exothermic adsorptions process with randomness intensifying due to positive entropy change.

Preparation of the fluorinated graphene/epoxy resin anti-corrosion composite coating

In order to enhance the corrosion resistance of epoxy resin (EP) coating system, we put forward a facile approach to prepare hydrophobic fluorinated graphene (FG) filler for the EP coating by one-pot hydrothermal reaction in this work. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle measuring instrument and scanning electron microscopy (SEM) were employed for the FG characterization. The SEM images of fracture morphology revealed that FG uniformly dispersed in epoxy resin matrix. Additionally, the excellent water resistance and the lower coefficient of friction of FG/EP coating was confirmed through the water absorption test and friction and wear test machine. The electrochemical impedance spectroscopy (EIS) demonstrated that the impedance value at the low frequency (|Z|0.01Hz) of 0.50 wt% FG/EP was 3.49 × 107 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 60 days, which was about 2 orders of magnitude higher than that of the pure EP coating (4.74 × 105 Ω·cm2). The 0.50 wt% FG/EP coating exhibited the superior anti-corrosion performance due to the FG with the two-dimensional sheet structure, uniform dispersion and hydrophobicity properties.

Hyperthermia and biological investigation of a novel magnetic nanobiocomposite based on acacia gum-silk fibroin hydrogel embedded with poly vinyl alcohol

The design and synthesis of biocompatible nanostructures for biomedical applications are considered vital challenges. Herein, a nanobiocomposite based on acacia hydrogel, natural silk fibroin protein, and synthetic protein fibers of polyvinyl alcohol was fabricated and magnetized with iron oxide nanoparticles (Fe3O4 MNPs). The structural properties of the hybrid nanobiocomposite were investigated by essential analyses such as Fourier Transform Infrared Spectrometer (FTIR), Field emission scanning electron microscopy (FE-SEM), and X-ray powder diffraction)XRD(analyses, Thermogravimetric and Differential thermogravimetric analysis (TGA-DTG), Vibrating-sample magnetometry (VSM), and Energy Dispersive X-Ray Analysis (EDX). The biological activities and functional properties of the prepared magnetic nanobiocomposite were studied. Results proved that this nanobiocomposite is non-toxic to the healthy HEK293T cell line. In addition, the synthesized nanobiocomposite showed an approximately 22 % reduction in cell viability of BT549 cells after 72 h. All results confirmed the anti-cancer properties of nanobiocomposite against breast cancer cell lines. Therefore, the prepared nanobiocomposite is an excellent material that can use for in-vivo application. Finally, the hyperthermia application was evaluated for this nanobiocomposite. The SAR was measured 93.08 (W/g) at 100 kHz.

Synthesis and Characterisation of Cellulose Acetate/Polyethylene Glycol Membrane from Pineapple Hump by Phase Inversion Method

Cellulose is a natural polymer contained in growing fibres, such as pineapple fibres. Cellulose can be modified into cellulose acetate, a modified polymer that can be used in the synthesis of a cellulose acetate/polyethylene glycol (CA/PEG) membrane. The phase inversion method was used in this study to produce CA/PEG membranes. Variations in polyethylene glycol (PEG) concentration with a ratio of 1:1 to cellulose acetate, where variations in PEG concentrations used are 2%, 5% and 8%. Acetone and dimethylformamide are used as organic solvents. Membrane morphological analysis using scanning electron microscopy (SEM) and functional group analysis using a Fourier transform infrared (FTIR) spectrometer were performed for membrane characterisation. The result of the synthesis of the CA/PEG membrane is in the form of a thin white layer. The characterisation results of the FTIR spectrometer showed the vibration of the carbonyl bond at wavenumber 1729 cm−1 and the vibration of the hydroxyl bond torque at the wave number 648 cm−1, where the vibration intensity decreased with each addition to the concentration. The results of SEM characterisation show that the increase in PEG concentration increases the percentage porosity of the membrane. The membranes with 2%, 5% and 8% PEG have porosity percentages of 51.54%, 68.70% and 73.50%, respectively. As the membrane with 2% PEG has the lowest percent porosity, it has more potential in removing or filtering solutes from a fluid.

Estimated of Pomegranate Peel Waste for Biosorption of Cu (II) & Pb(II) Ions From Aqueous Solutions

This study intends to explore the waste natural materials’ adsorption capability. The use of pomegranate peels was investigated to see the chances of eradicating Pb(II) and Cu(II) ions from the aqueous solutions. Adsorption capability was evaluated using batch adsorption experiments, which also evaluated the impact of solution pH and initial metal concentration. The ideal biosorption conditions included a pH of 6.0, a dose of 0.1 g of biomass, and an equilibrium duration of 90 minutes. The adsorption data fit in a way that was comparable to the isotherm models by Freundlich and Langmuir. Pomegranate peel (PGP) was tested for its affinity and adsorption capability. Based on the values of the separation factor (RL) and Freundlich constant (n), it seems that the metal ions were taken up onto biosorbents in a preferred manner. According to this study's conclusions, the equilibrium data suit the Freundlich and Langmuir isotherms rather nicely. According to correlation coefficient data, the maximal sorption capacity of the produced pomegranate peel is 5000 mg/g. The Fourier Transform Infrared Spectrometer (FTIR), Energy Dispersive X-ray Spectrometer (EDX), and Scanning Electron Microscope (SEM) were utilised in the characterisation examinations. As a result, distinct aggregates formed on the surface of the biosorbent. In the characterisation experiments, an energy-dispersive X-ray spectrometer (EDX) and a scanning electron microscope (SEM) were employed. Different aggregates developed on the biosorbent surface as a result of contact with metal ions. On the surface of the biosorbent, distinct aggregates formed as a result of interaction with metal ions. Either via complexation or electrostatic attraction, the metal ions attached themselves to the biosorbents' active sites.

Идентификация цефалоспориновых антибиотиков с использованием ИК-спектроскопии и хемометрических алгоритмов

The use of mid-field infrared spectroscopy in combination with chemometric algorithms for the identification of cephalosporin antibiotics in the form of injectable powders is demonstrated. III generation cephalosporins have been selected as objects of the study: ceftriaxone, ceftazidime, cefotaxime, which are widely used in pharmaceutical practice. IR spectra of the medical preparations have been recorded using an FT-801 Fourier transform IR spectrometer with an attenuated total reflection (ATR) attachment. The results have been processed in the Microsoft Excel computer package with the XLSTAT add-in using the principal component analysis (PCA), the k-means method and agglomerative hierarchical clustering (AНC). It has been shown that using these algorithms it is possible to identify the studied cephalosporin antibiotics from different manufacturers. In the PCA method, points corresponding to samples are located in separate quadrants depending on the nature of the antibiotic. The k-means method has been used to divide antibiotics into classes; differences are also visible in the classes themselves, depending on the manufacturer. The clearest separation of cephalosporins is observed when data are presented using the AHC method in the form of a dendrogram.

Antibacterial and Antibiofilm Potential of Chlorophyllin Against Streptococcus mutans In Vitro and In Silico.

Streptococcus mutans is a leading causative agent of dental caries and exerts pathogenicity by forming biofilms. Dental caries continues to be a significant public health issue worldwide, affecting an estimated 2.5 billion people, showing a 14.6% increase over the past decade. Herein, the antibacterial potential of Chlorophyllin extracted from Spinacia oleracea was evaluated against biofilm-forming S. mutans via in vitro and in silico studies. The antimicrobial activity of chlorophyllin extract against S. mutans isolates was tested using the agar well diffusion method. Chlorophyllin extract was also tested against biofilm-forming isolates of S. mutans. Chlorophyllin was docked with the antigen I/II (AgI/II) protein of S. mutans to evaluate its antimicrobial mechanism. The chemical structure and canonical SMILES format of Chlorophyllin were obtained from PubChem. Additionally, adsorption, distribution, metabolism, excretion, and toxicity (ADMET) analyses of Chlorophyllin were performed using ADMETlab 2.0 to assess its pharmacokinetic properties. An agar well diffusion assay revealed that all S. mutans isolates were susceptible to Chlorophyllin extract and showed a variety of inhibition zones ranging from 32 to 41 mm. Chlorophyllin reduces the biofilm strength of four isolates from strong to moderate and six from strong to weak. The antibiofilm potential of Chlorophyllin was measured by a reduction in the number of functional groups observed in the Fourier Transform Infrared Spectrometer (FTIR) spectra of the extracellular polymeric substance (EPS) samples. Chlorophyllin showed binding with AgI/II proteins of S. mutans, which are involved in adherence to the tooth surface and initiating biofilm formation. The ADMET analysis revealed that the safety of Chlorophyllin exhibited favorable pharmacokinetic properties. Chlorophyllin stands out as a promising antibacterial and antibiofilm agent against biofilm-forming S. mutans, and its safety profile highlights its potential suitability for further investigation as a therapeutic agent.

Optimal development and performance evaluation of electrolytic graphene oxide synergistic all-solid waste cementitious grouting material

The low-carbon and friendly alkali-activated cementitious (AACM) grouting material has a broad application potential in the field of grouting engineering due to its excellent workability and higher early strength and is expected to replace cement grouting material in the future. In this study, an AACM grouting material using electrolytic graphene oxide (EGO) synergistic ground granulated blast-furnace slag (GGBS)-fly ash (FA)-rice husk ash (RHA) solid waste was proposed. The optimal ratio was 0.025 % EGO, 8.13 % FA, 26.6 % RHA, and 65.27 % GGBS, which determined by the Analytic Hierarchy Process (AHP), Entropy Weight Method (EWP), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) methods. A systematic evaluation of the mechanical properties and impermeability of the proposed AACM grouting material was conducted by macro experiments (compressive strength, flexural strength and permeability) and micro experiments (XRD, SEM-EDS, Fourier Transform Infrared Spectrometer (FTIR) and Thermogravimetry Analysis (TG)). The results show that the increment of compressive strength and flexural strength for AACM grouting material with 0.025 % EGO compared to the cement water-glass grouting material were 161.2 % and 2.9 %, respectively, at 7-day. While the permeability coefficient compared to AACM grouting material without EGO decreased by 43.9 %. The XRD results show that the EGO reduced the intensity of AACM grouting material diffraction peaks, and FTIR analysis reveals that EGO increased the visibility of O-C-O characteristic peaks. These confirmed that EGO could enhance the degree of alkali activation reaction. The TG results indicate that the addition of EGO promoted the formation of carbonates, which strengthen the mechanical properties of AACM grouting material. The SEM-EDS results demonstrate that EGO increased the Ca/Si ratio, promoted the formation of highly polymerized hydration products.

Heat and mass transfer visualisation of an exothermic acid-base microfluidic reactor using infrared thermospectroscopy

ABSTRACT Here, a microfluidic reactor that is transparent in the mid-wave infrared spectrum with an effective path length of 38 µm is developed for characterisation via operando Fourier-transform Infrared (FTIR) thermospectroscopy. This imaging technique couples an infrared (IR) camera with an FTIR spectrometer to quantify heat and mass transfer in the exothermic acid-base reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH). The absorbance fields of the reaction are used to simultaneously derive the molar concentration fields of the reactants (HCl and NaOH) and products (sodium chloride [NaCl]) at the microscale through a linear inverse method. The heat generated at the reaction interface is visualised through a thermal field captured from the measured proper emission. Concentration and thermal fields are then compared to an advection-diffusion model for validation. The results proposed in this work present a refined contactless calorimetry process for characterising the heat and mass transport in an acid-base reaction. Further refinement of this work will enable accurate and non-invasive measurements for the enthalpy of reaction in chemical reactions.

Fabrication of a macro-micro porous structure on PEEK surface by ultrasound-assisted sulfonation

A multiscale porous surface can significantly improve the osseointegration of biomedical implants, but it cannot be facilely achieved on the Poly-ether-ether-ketone (PEEK) surface. In this work, a macro-micro porous structure was prepared on the PEEK surface by ultrasound-assisted sulfonation. The surface morphologies, chemical compositions, functional groups, surface roughness, and wettability of the porous structures at different sulfonation times were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectrometer (FTIR), laser scanning confocal microscope (LSCM), and contact angle measurement, respectively. The results demonstrate that a macro-micro porous structure is formed on the PEEK surface, with macropore sizes ranging from 50 to 250 μm and micro-sized pore sizes ranging from 0.2 to 1.5 μm. Moreover, the results of in vitro cellular experiments demonstrate that the macro-micro porous structure can promote cell adhesion and proliferation of BMCSc. The formation mechanism of the multiscale porous structures has also been discussed. This novel approach may provide a simple and effective strategy for surface modification of PEEK to improve its mechanical and biological response.