Fourier Transform Infrared Spectroscopy Method Research Articles

An Investigation of RNA Methylations with Biophysical Approaches in a Cervical Cancer Cell Model

RNA methylation adds a second layer of genetic information that dictates the post-transcriptional fate of RNAs. Although various methods exist that enable the analysis of RNA methylation in a site-specific or transcriptome-wide manner, whether biophysical approaches can be employed to such analyses is unexplored. In this study, Fourier-transform infrared (FT-IR) and circular dichroism (CD) spectroscopy are employed to examine the methylation status of both synthetic and cellular RNAs. The results show that FT-IR spectroscopy is perfectly capable of quantitatively distinguishing synthetic m6A-methylated RNAs from un-methylated ones. Subsequently, FT-IR spectroscopy is successfully employed to assess the changes in the extent of total RNA methylation upon the knockdown of the m6A writer, METTL3, in HeLa cells. In addition, the same approach is shown to accurately detect reduction in total RNA methylation upon the treatment of HeLa cells with tumor necrosis factor alpha (TNF-α). It is also demonstrated that m1A and m6A methylation induce quite a distinct secondary structure on RNAs, as evident from CD spectra. These results strongly suggest that both FT-IR and CD spectroscopy methods can be exploited to uncover biophysical properties impinged on RNAs by methyl moieties, providing a fast, convenient and cheap alternative to the existing methods.

Evolution of activation energy for boron dissolution in the borosilicate glass during the initial leaching stage

Borosilicate glass is widely used for immobilizing high-level radioactive waste. In this study, two types of borosilicate glasses, Na-borosilicate and Zr-Na-borosilicate, were subjected to leaching within a temperature range of 50-90°C, at 10°C intervals. The rate of boron consumption was measured by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) and Fourier-Transform infrared spectroscopy (FTIR) techniques, and the boron activation energy was determined through the Arrhenius equation. The boron activation energies for Na-borosilicate and Zr-Na-borosilicate glasses are approximately 46 kJ/mol and 42 kJ/mol, respectively. The activation energy, which FTIR calculated, was consistent with that obtained by ICP-OES during the initial leaching time and decreased as the leaching time increased. The decrease in activation energy of boron is because the [BO3] structure was replaced by molecular water. The FTIR method offers an alternative approach for calculating the boron activation energy and contributes to understanding the leaching mechanism in the initial leaching stage.

Mechanical properties of low calcium alkali activated binder system under ambient curing conditions

These days, the construction industry is facing sustainability issues, leading to the selection of greener, low-carbon, alkali-activated materials. This study examines a low calcium alkali activated system composed of three constituents (ceramic brick, metakaolin waste, and phosphogypsum). The AAB compositions consist of the primary precursor, waste ceramic brick, which is increasingly (20–100 wt%) replaced with waste metakaolin. The alkaline solution was made of sodium hydroxide and water; dosage depended on the Na2O/Al2O3 ratio (1.00–1.36). The AAB specimens were inspected by using XRD (X-ray diffraction) and FT-IR (Fourier transform infrared spectroscopy) methods for the evaluation of mineral composition, accompanied by SEM–EDS (scanning electron microscopy & energy dispersive X-ray spectroscopy) for the analysis of the microstructure. The compressive strength after 7, 28 and 90 days, along with water absorption and softening coefficient were determined. Also, mixture calorimetry was established. The results have shown that the initial materials are suitable for producing medium-strength alkali-activated binder under ambient temperature. The maximum compressive strength was reached by using the combination of 80% CBW and 20% MKW (13.9 and 21.2 MPa after 28 and 90 days respectively). The compressive strength development was linked with the formation N–A–S–H gel and faujasite type zeolite. A higher level of geopolymerization in composition with metakaolin waste led to lower compressive strength. Consequently, binding materials with low demand of high final and especially early compressive strength could be produced under ambient temperature curing, making them more sustainable.

Investigation of Fourier Transform Infrared (FT-IR) Spectroscopy and Chemometric Analysis Method as an Alternative Method in the Diagnosis of Prostate Cancer

Prostate cancer is one of the most common types of cancer in men. It usually grows slowly and may not show obvious symptoms at first. Prostate cancer can be diagnosed by symptoms or by a doctor performing certain tests during routine health checkups. These tests include physical examination, PSA (Prostate Specific Antigen) Test, biopsy, imaging techniques, and Gleason score. In addition, Fourier transform infrared spectroscopy (FT-IR) is an analysis method used for prostate cancer diagnosis. This study aims to demonstrate FT-IR spectroscopy as an alternative method to other diagnostic methods in the diagnosis of prostate cancer. The FT-IR spectroscopy method is used to examine the molecular structure of samples. For prostate cancer diagnosis, FT-IR spectroscopy can be used to identify molecular changes in prostate tissue and identify characteristics by which cancerous cells differ from healthy cells. FT-IR spectroscopy is based on spectral data obtained by exposing samples to infrared radiation. These spectral data are based on properties associated with the movements of the molecules contained in the samples, such as vibration, rotation and bending. Molecular changes caused by diseases such as prostate cancer may be evident in these spectral data. These changes can provide information about the presence or stage of cancerous cells. Data obtained using FT-IR spectroscopy is processed with statistical analysis methods. These analyses are used to identify molecular differences between cancerous and healthy prostate tissues. In this way, FTIR spectroscopy can help obtain sensitive and accurate results in the diagnosis of prostate cancer.

Honey differentiation with FTIR-ATR spectroscopy – Comparison with physicochemical parameters of a Polish honey sample set

The varietal discrimination of honey is important because its bioactive properties, as well as specific characteristics, depend on the botanical origin. The present study aimed to verify the discriminatory power of Fourier-transform infrared spectroscopy (FT-IR) for differentiating Polish honeys and compare the results with the discrimination power of a model built on the basis of selected physicochemical parameters. For this purpose, buckwheat, rape, acacia, heather, goldenrod, and coniferous honeydew honeys were collected from trustworthy apiaries in different regions of Poland. The samples were further authenticated using pollen analysis and tested by means of FT-IR and the attenuated total reflection (ATR) technique. Basic psychochemical parameters were also assessed. The obtained data were analyzed by means of principal component analysis (PCA) and linear discriminant analysis (LDA). The obtained models were validated with a leave-one-out cross-validation (LOOCV) procedure. PCA analysis confirmed the usefulness of the ATR FT-IR method as a honey differentiation tool. The LDA for the FT-IR model allowed to correctly classify 26 out of 32 samples (81.3% accuracy), which was only slightly lower than for data the model based on the physiochemical characteristics (27 out of 32 samples and 84.4% accuracy), revealing a certain potential of FT-IR as fast evaluation method.

Ekstraksi senyawa tanin dalam ampas kopi sebagai sumber daya tanin terbarukan

The increase in global coffee consumption causes an increase in the amount of waste. One of the components of coffee grounds waste that is thrown into the environment is tannin. Tannins are applied in various industries, including the textile, pharmaceutical, cosmetic and food industries. The research aims to observe the effect of temperature and extraction time on tannin content using the ultrasonic extraction method. Extraction was carried out using 80% ethanol solvent with 2 variations, namely, variations in extraction temperature (40, 45, 50, 55, and 60) ˚C and extraction time (10, 20, 30, 40, 50, and 60) minutes. Extracts containing tannins were then analyzed qualitatively and quantitatively. Tannin levels were tested qualitatively using FeCl3 and Gelatin, and quantitative analysis was carried out using a UV-VIS Spectrophotometer. The functional groups contained in the tannin extract were tested using the FTIR (Fourier Transform Infra Red) Spectroscopy method. The highest tannin content was obtained at an extraction temperature of 55°C and an extraction time of 10 minutes, amounting to 215.85 mg/g-1. The tannins contained in coffee grounds extract are condensed tannins.

Diagnosis of Cutaneous Leishmaniasis Using FTIR Spectroscopy and Machine Learning: An Animal Model Study.

Cutaneous leishmaniasis (CL) is a polymorphic and spectral skin disease caused by Leishmania spp. protozoan parasites. CL is difficult to diagnose because conventional methods are time-consuming, expensive, and low-sensitive. Fourier transform infrared spectroscopy (FTIR) with machine learning (ML) algorithms has been explored as an alternative to achieve fast and accurate results for many disease diagnoses. Besides the high accuracy demonstrated in numerous studies, the spectral variations between infected and noninfected groups are too subtle to be noticed. Since variability in sample set characteristics (such as sex, age, and diet) often leads to significant data variance and limits the comprehensive understanding of spectral characteristics and immune responses, we investigate a novel methodology for diagnosing CL in an animal model study. Blood serum, skin lesions, and draining popliteal lymph node samples were collected from Leishmania (Leishmania) amazonensis-infected BALB/C mice under experimental conditions. The FTIR method and ML algorithms accurately differentiated between infected (CL group) and noninfected (control group) samples. The best overall accuracy (∼72%) was obtained in an external validation test using principal component analysis and support vector machine algorithms in the 1800-700 cm-1 range for blood serum samples. The accuracy achieved in analyzing skin lesions and popliteal lymph node samples was satisfactory; however, notable disparities emerged in the validation tests compared to results obtained from blood samples. This discrepancy is likely attributed to the elevated sample variability resulting from molecular compositional differences. According to the findings, the successful functioning of prediction models is mainly related to data analysis rather than the differences in the molecular composition of the samples.

Diagnosis of common intraosseous lesions of the dentomaxillofacial region by chemometry-assisted FT-IR spectroscopy in dental tissue samples

PurposesThis study aimed to determine the differential diagnosis of three intraosseous lesions (odontogenic keratocyst (OKC), central giant cell granuloma (CGCG), and dentigerous cyst (DC)) of the dentomaxillofacial region with very similar radiological and clinical features by using chemometrics assisted FT-IR (Fourier transform infrared) spectroscopy in tissue samples. MethodsTissue samples (exposed to formaldehyde for a similar time) of 20-micron thickness belonging to 19 intraosseous lesions diagnosed histopathologically were obtained from the pathology laboratory. The samples were analyzed by FT-IR spectroscopic method using the 400–4000 cm−1 wavenumber range, and the obtained spectra of the samples were evaluated using the orthogonal partial least squares discriminant analysis (OPLS-DA) algorithm. ResultsThe intraosseous lesions with different histopathological diagnoses were accurately and precisely clustered with different FT-IR bands corresponding to the main molecular vibrations, especially the phosphodiester region, of the tissue components using the proposed model with 3 latent variables. ConclusionsThe model showed high sensitivity and specificity. The present study is the first to report the elucidation of clear spectral differences between similar lesions in the maxillofacial region. In the future, the FT-IR method may be used in the non-destructive classification of similar lesions in the maxillofacial region as an alternative to histopathological evaluation.

Characterization of functionalized multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) are functionalized to determine structural and chemical changes occurred due to oxidation at room temperature in presence of an aqueous solution of concentrated HNO3. The raw and processed (functionalized) MWCNTs were investigated with FTIR and FESEM spectroscopy methods. The surface morphology was examined by FESEM and presence of carboxylic group were identified with Fourier Transform Infrared Spectroscopy (FTIR). The multi walled carbon nanotube of 8 nm, 10–30 nm & 50 nm were taken for experimentation. The FTIR spectra revealed that the broad peak @3450 cm-1 corresponds to O–H bond and peak at @ 1630 cm-1 corresponds to C = O bond. The intensity of both raw and functionalized MWCNTs peak signifies presence of COOH group. Likewise, FESEM images shows, agglomeration of MWCNTs due to Van der Waals forces in raw MWCNTs but after functionalization, unbundled CNTs with reduction in length due to breakage of C = C bond and presence of carboxyl group at end of CNTs.

The bottom line: Exploring analytical methods for assessing bioapatite preservation in archaeological bone using FTIR-ATR

We conducted a meta-content analysis of FTIR (Fourier Transform Infra-red) spectroscopy methods and application throughout five journals, and evaluated variation present in FTIR-ATR spectra across original data sets from bone samples from distinct archaeological contexts. The meta-analysis revealed a lack of standardization and consistency in methodology and reporting for FTIR practices. Results suggest wavenumbers used for calculating IRSF and C/P in addition to baseline correction impact interpretations of bioapatite preservation. We recommend that FTIR spectra should always be baseline corrected and analyzed in absorbance (A). We also recommend consistent reporting of methods to demonstrate data fidelity prior to interpretation.

Ultrasound-Promoted preparation and application of novel bifunctional core/shell Fe3O4@SiO2@PTS-APG as a robust catalyst in the expeditious synthesis of Hantzsch esters

In this work, D-(–)-α-phenylglycine (APG)-functionalized magnetic nanocatalyst (Fe3O4@SiO2@PTS-APG) was designed and successfully prepared in order to implement the principles of green chemistry for the synthesis of polyhydroquinoline (PHQ) and 1,4-dihydropyridine (1,4-DHP) derivatives under ultrasonic irradiation in EtOH. After preparing of the nanocatalyst, its structure was confirmed by different spectroscopic methods or techniques including Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and thermal gravimetric analysis (TGA). The performance of Fe3O4@SiO2@PTS-APG nanomaterial, as a heterogeneous catalyst for the Hantzsch condensation, was examined under ultrasonic irradiation and various conditions. The yield of products was controlled under various conditions to reach more than 84% in just 10 min, which indicates the high performance of the nanocatalyst along with the synergistic effect of ultrasonic irradiation. The structure of the products was identified by melting point as well as FTIR and 1H NMR spectroscopic methods. The Fe3O4@SiO2@PTS-APG nanocatalyst is easily prepared from commercially available, lower toxic and thermally stable precursors through a cost-effective, highly efficient and environmentally friendly procedure. The advantages of this method include simplicity of the operation, reaction under mild conditions, the use of an environmentally benign irradiation source, obtaining pure products with high efficiency in short reaction times without using a tedious path, which all of them address important green chemistry principles. Finally, a reasonable mechanism is proposed for the preparation of polyhydroquinoline (PHQ) and 1,4-dihydropyridine (1,4-DHP) derivatives in the presence of Fe3O4@SiO2@PTS-APG bifunctional magnetic nanocatalyst.

Analysis of changes on substrates filling constructed wetland systems after landfill leachate treatment - FTIR study

A rapid and inexpensive method, Fourier transform infrared spectroscopy (FTIR), can be used to identify impurities and determine the functional groups responsible for the sorption of specific ions. The FTIR method has already been used in research. However, there is a lack of research on constructed wetland (CW) infill materials used to treat landfill leachate (LL). Therefore, the aim of this study was to verify the changes occurring in selected substrates (zeolite, expanded clay and bark) constituting vertical flow CW infill (VFCW) supplied with municipal LL. The principal component analysis carried out mainly showed differences in the results between the variants of the experiment with an infill of expanded clay and the others (for the values obtained at wave numbers in the range 1600-400 cm−1, in which most changes occurred). All peaks of the FTIR spectra of the pine bark filling the CW differ in location and intensity between the samples. In most cases, the stripes were elongated at exposure to 25% and 100% LL (compared to tap water). In all CW variants infill made of zeolite, peaks occurred at wave numbers within 1049-1012 cm−1, which were most likely caused by the presence of inorganic substances corresponding to clay minerals, and to silica. The FTIR spectra for zeolites, do not show large differences between the different infill samples used for LL treatment (100% LL and 25% LL). In all CW variants with expanded clay infill, peaks in the 1250-900 cm−1 wave number region, possibly indicating the presence of polysaccharides and phosphodiesters. FTIR spectroscopy has proven to be a very useful tool for rapid grade assessment determination of changes occurring on selected substrates and the identification of contaminants that remained after treatment in VFCWs fed with LL.

Screening of Native Trichoderma Species for Nickel and Copper Bioremediation Potential Determined by FTIR and XRF

Soil pollution with heavy metals is a serious threat to the environment. However, soils polluted with heavy metals are considered good sources of native metal-resistant Trichoderma strains. Trichoderma spp. are free-living fungi commonly isolated from different ecosystems, establishing endophytic associations with plants. They have important ecological and biotechnological roles due to their production of a wide range of secondary metabolites, thus regulating plant growth and development or inducing resistance to plant pathogens. In this work we used indigenous Trichoderma strains that were previously isolated from different soil types to determine their tolerance to increased copper and nickel concentrations as well as mechanisms of metal removal. The concentrations of bioavailable metal concentrations were determined after extraction with diethylene-triamine pentaacetate (DTPA)-extractable metals (Cd, Cr, Co, Cu, Pb, Mn, Ni, and Zn) from the soil samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). Two indigenous T. harzianum strains were selected for copper tolerance, and three indigenous T. longibrachiatum strains were selected for nickel tolerance tests. Strains were isolated from the soils with the highest and among the lowest DTPA-extractable metal concentrations to determine whether the adaptation to different concentrations of metals affects the mechanisms of remediation. Mechanisms of metal removal were determined using Fourier-transform infrared spectroscopy (FTIR) and X-ray fluorescence spectroscopy (XRF), non-destructive methods characterized by high measurement speed with little or no need for sample preparation and very low costs. Increased DTPA-extractable metal content for nickel and copper was detected in the soil samples above the target value (TV), and for nickel above the soil remediation intervention values (SRIVs), for total metal concentrations which were previously determined. The SRIV is a threshold of metal concentrations indicating a serious soil contamination, thus confirming the need for soil remediation. The use of FTIR and XRF methods revealed that the presence of both biosorption and accumulation of metals in the Trichoderma cells, providing good bioremediation potential for Ni and Cu.

Monitoring surface dynamics of electrodes during electrocatalysis using in situ synchrotron FTIR spectroscopy.

Monitoring the surface dynamics of catalysts under working conditions is important for a deep understanding of the underlying electrochemical mechanisms towards efficient energy conversion and storage. Fourier transform infrared (FTIR) spectroscopy with high surface sensitivity has been considered as a powerful tool for detecting surface adsorbates, but it faces a great challenge when being adopted in surface dynamics investigations during electrocatalysis due to the complication and influence of aqueous environments. This work reports a well designed FTIR cell with tunable micrometre-scale water film over the surface of working electrodes and dual electrolyte/gas channels for in situ synchrotron FTIR tests. By coupling with a facile single-reflection infrared mode, a general in situ synchrotron radiation FTIR (SR-FTIR) spectroscopic method is developed for tracking the surface dynamics of catalysts during the electrocatalytic process. As an example, in situ formed key *OOH is clearly observed on the surface of commercial benchmark IrO2 catalysts during the electrochemical oxygen evolution process based on the developed in situ SR-FTIR spectroscopic method, which demonstrates its universality and feasibility in surface dynamics studies of electrocatalysts under working conditions.

Acid and Base modified Pectin from Orange Peel as an Effective Bio-adsorbent for Pb(II) and Cr(VI) from Textile Industry Wastewater

Modifying the methoxyl group on pectin from Siam orange peel (Citrus nobilis) has been done. Pectin was obtained from the peel of Siam orange by extraction method. The modified pectin obtained were analyzed using the FT-IR (Fourier Transform-Infra Red Spectroscopy) method, the XRD (X-Ray Diffractometry), and surface appearance images using SEM (Scanning Electron Microscopy). Pb(II) and Cr(VI) metals which can be adsorbed by the adsorbent then analyzed by UV-Visible Spectrophotometer. The results of the FT-IR analysis was found that the modification of the methoxyl group was successful. XRD analysis showed that the modified pectin adsorbent produced amorphous properties. The maximum pH for Pb(II) adsorption was obtained, namely pH = 6 and the maximum pH for Cr(VI) adsorption was pH =7. The best adsorption time variation for Pb(II) was 240 min and for Cr(VI) was 500 min. The best adsorbent for adsorption of Pb(II) was base-modified pectin adsorbent, while the best adsorbent for adsorption of Cr(VI) was base-modified pectin adsorbent. It could be proven that base-modified pectin was able to adsorb Pb(II) and acid-modified pectin was able to absorb Cr(VI) better (Pb(II) 80% adsorption percentage and 90% Cr(VI) adsorption percentage) than previous studies, namely pectin without modification (adsorption percentage obtained 60-70%).

Characterization of PLA/PCL/Nano-Hydroxyapatite (nHA) Biocomposites Prepared via Cold Isostatic Pressing.

Hydroxyapatite has the closest chemical composition to human bone. Despite this, the use of nano-hydroxyapatite (nHA) to produce biocomposite scaffolds from a mixture of polylactic acid (PLA) and polycaprolactone (PCL) using cold isostatic pressing has not been studied intensively. In this study, biocomposites were created employing nHA as an osteoconductive filler and a polymeric blend of PLA and PCL as a polymer matrix for prospective usage in the medical field. Cold isostatic pressing and subsequent sintering were used to create composites with different nHA concentrations that ranged from 0 to 30 weight percent. Using physical and mechanical characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and density, porosity, tensile, and flexural standard tests, it was determined how the nHA concentrations affected the biocomposite's general properties. In this study, the presence of PLA, PCL, and nHA was well identified using FTIR, XRD, and SEM methods. The biocomposites with high nHA content showed intense bands for symmetric stretching and the asymmetric bending vibration of PO43-. The incorporation of nHA into the polymeric blend matrix resulted in a rather irregular structure and the crystallization became more difficult. The addition of nHA improved the density and tensile and flexural strength of the PLA/PCL matrix (0% nHA). However, with increasing nHA content, the PLA/PCL/nHA biocomposites became more porous. In addition, the density, flexural strength, and tensile strength of the PLA/PCL/nHA biocomposites decreased with increasing nHA concentration. The PLA/PCL/nHA biocomposites with 10% nHA had the highest mechanical properties with a density of 1.39 g/cm3, a porosity of 1.93%, a flexural strength of 55.35 MPa, and a tensile strength of 30.68 MPa.

Клінічне значення ідентифікації сечових каменів пацієнтів, мешканців промислового регіону методом Mid-FTIR Spectroscopy

Introduction. Physico-chemical, biological and biochemical processes that occur during the formation of urinary stones determine the peculiarities of their composition and structure, as evidenced by modern methods of analysis: spectral, X-ray, polarization, optical, immersion, infrared spectrometry, etc. Modern Fourier Transform Infrared (FTIR) spectroscopy is a powerful instrument for identifying organic and inorganic substances by measuring the infrared (IR) absorption spectrum. It provides qualitative information about the molecular composition of the target material. The aim of the study. To determine the possibilities and improve the results of identification of urinary stones of patients, residents of the industrial region by the method of Mid-FTIR Spectroscopy. Materials and methods. To carry out the work, a comparative analysis of the chemical composition, morphology and structural features of 85 urinary stones of patients, residents of the Dnipropetrovsk region, was carried out. The analysis of the mineral composition of all urinary stones was carried out by a hardware and software complex that combined a Nicolet iS10 FTIR spectrometer and μ-FTIR Continuum microscope from the American company Thermo Scientific, ATR-Smart Golden Gate prefix with a diamond crystal from the English company Specac, OMNIC FTIR Software and Spectral Library NICODOM IR Kidney Stones, which contains 1668 transmission spectra. Research results and their discussion. Most of the stones in 48% of patients were oxalates, 43% of the stones belonged to the oxalatecontaining mixed type. Conditionally pure urate and phosphate stones were 4% and 5%, respectively. The registered spectra generally showed a satisfactory agreement with the library analogues. The capabilities of the hardware and software complex make it possible to map and visualize the spatial distribution of organic substances and minerals in rock samples. The μ-FTIR method makes it possible to reasonably understand the cause of the microstructural heterogeneity of stones and the triggering mechanism of the layer-by-layer deposition of constituent substances during the growth of the stone mass. Conclusion. The analysis of the results of the identification of urinary stones of patients, residents of the industrial region by the Mid- FTIR Spectroscopy method showed advantages among similar methods of studying urinary stones and proved the feasibility of its use in the complex examination of patients with urolithiasis. Accurate analysis of the primary and secondary chemical composition and spatial distribution of stone components will lead to an understanding of the physicochemical processes that form the basis of the pathogenesis of stone formation. Spectral monitoring of the chemical composition of urine is important for early diagnosis, effective personalized treatment and prevention of stone recurrence in patients with urolithiasis.

Composite Cement Materials Based on β-Tricalcium Phosphate, Calcium Sulfate, and a Mixture of Polyvinyl Alcohol and Polyvinylpyrrolidone Intended for Osteanagenesis

The primary purpose of the study, presented in this article, was to obtain a composite cement material intended for osteanagenesis. The β-tricalcium phosphate powder (β-TCP, β-Ca3(PO4)2) was obtained by the liquid-phase method. Setting and hardening of the cement system were achieved by adding calcium sulfate hemihydrate (CSH, CaSO4·1/2H2O). An aqueous solution of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and a PVA/PVP mixture were used as a polymer component. The methods of capillary viscometry and Fourier-transform infrared spectroscopy (FTIR) revealed the formation of intermolecular hydrogen bonds between polymer components, which determines the good miscibility of polymers. The physicochemical properties of the synthesized materials were characterized by X-ray diffraction (XRD) and FTIR methods, and the added amount of polymers does not significantly influence the processes of phase formation and crystallization of the system. The size of crystallites CSD remained in the range of 32-36 nm, regardless of the ratio of polymer components. The influence of the composition of composites on their solubility was investigated. In view of the lower solubility of pure β-TCP, as compared to calcium sulfate dihydrate (CSD, CaSO4·2H2O), the solubility of composite materials is determined to a greater degree by the CSD solubility. Complexometric titration showed that the interaction between PVA and PVP impeded the diffusion of calcium ions, and at a ratio of PVA to PVP of 1/1, the smallest exit of calcium ions from the system is observed. The cytotoxicity analysis results allowed us to establish the fact that the viability of human macrophages in the presence of the samples varied from 80% to 125% as compared to the control.

Identification and classification of PAH in asphalt binders with FTIR spectroscopy and multivariate analysis methods

Reclaimed asphalt pavements (RAP) with increased contents of polycyclic aromatic hydrocarbons (PAH) are restricted for reuse due to their harmful effects on humans and the environment. This work investigated whether Fourier transform infrared (FTIR) spectroscopy is suitable for a fast and simple identification and quantification of PAH in binders recovered from reclaimed asphalts. For this, the binders from 34 RAP samples were recovered using a rapid procedure developed at the Universität Kassel and were examined with infrared spectroscopy. The obtained spectra were pre-processed (Standard Normal Variate transformation, 1st derivative) and evaluated using a combination of factor analysis and linear discriminant analysis. The results showed that various PAH groups with differently pronounced aromatic structures are present in the binders. However, with FTIR spectroscopy combined with the multivariate methods, a statistical model was developed allowing for the differentiation between the PAH groups and also for the distinction between PAH contents below or above the threshold of 25mg/kg valid in Germany.

NiFe2O4/ZnO nanoparticles and its composite with flat 2D rGO sheets for efficient degradation of colored and colorless effluents photocatalytically

For photocatalytic degradation of organic pollutants, ZnO and NiFe2O4 nanoparticles are synthesized via co-precipitation method. ZnO/NiFe2O4 and composite with reduced graphene oxide (ZnO/NiFe2O4@rGO) is synthesized via ultra-sonication method. Reduced graphene oxide is used because of its excellent behaviour in photocatalysis such as high stability, huge surface area and rapid transfer of electrons. The physicochemical properties of synthesized nanoparticles are studied using X-ray diffraction technique (XRD), Field emission-scanning electron microscopy (FE-SEM), Fourier transform-infrared spectroscopic method (FT-IR) and UV–Visible spectroscopic analysis. Electrochemical measurements are also done to investigate electrical properties of synthesized samples. Photo-degradation efficiency of fabricated photocatalysts was studied using crystal violet as coloured and phenol as colourless dye. When similar conditions are applied, these synthesized nanoparticles degrade 80.5% crystal violet and 42% phenol in 140 min in sunlight. Combination of ZnO and NiFe2O4 boost separation of charges and also diminishes the chances of recombination of charge carrier species, which as a result enhance photocatalytic activity. Photocatalytic activity of ZnO/NiFe2O4@rGO is greater than bare ZnO and NiFe2O4. Due to magnetic nature of nickel ferrite, sample is not agglomerated and it can be recycled easily. It is observed that ZnO/NiFe2O4@rGO is used as a potential photocatalyst in treatment of polluted water.