Fourier Transform Infrared Spectroscopy Results Research Articles

Improved catalytic performance and resistance to SO2 over V2O5-WO3/TiO2 catalyst physically mixed with Fe2O3 for low-temperature NH3-SCR

A series of V2O5-WO3/TiO2 catalysts physically mixed with several Fe2O3 samples having different textural properties were prepared and applied to the selective catalytic reduction (SCR) of NOx with NH3. The physically mixed catalysts exhibited higher catalytic stability and SO2 resistance than the V2O5-WO3/TiO2 catalyst in the presence of SO2. The physicochemical properties of V2O5-WO3/TiO2 catalysts physically mixed with Fe2O3 were investigated by various analytical techniques, such as N2 adsorption-desorption, X-ray diffraction (XRD), Raman spectroscopy, temperature-programmed desorption with sulfur dioxide (SO2-TPD) and ammonia (NH3-TPD), and in situ Fourier-transform infrared spectroscopy (FT-IR) measurements. The formation of ammonium sulfate species was observed in the catalysts during the NH3-SCR reactions, leading to deactivation of the catalysts. SO2-TPD analyses revealed that Fe2O3 adjacent to V2O5-WO3/TiO2 suppressed the formation of ammonium sulfate species by generating iron sulfate species. In addition, the in situ FT-IR and NH3-TPD results indicated that the adsorption of SO2 on Fe2O3 could increase NOx conversion due to the additional production of Brønsted acid sites provided by iron sulfate. Among the catalysts tested, the mechanical mixture of V2O5-WO3/TiO2 and Fe2O3, with the highest surface area and pore volume, showed the best NH3-SCR activity and SO2 resistance at low temperature in the presence of SO2.

Piezoelectric and pyroelectric properties of ceramic nanoparticles-based nanostructured PVDF/PVC blend nanocomposites

BaZrO3 and BaTiO3 nanofillers were incorporated in pristine PVDF and pristine PVC blend matrix separately to prepare blend nanocomposites using the solution casting technique. The mass ratios of PVDF/PVC/BaTiO3 were chosen to be 80/16/4. The structure morphology of nanocomposites was analyzed by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and X-ray diffraction. The FTIR, AFM, XRD and pyroelectric results indicate the strong interaction between the nanofiller and PVDF/PVC blend matrix. The nanocomposite exhibits a high pyroelectric coefficient due to proper dispersion of nanofillers. The maximum piezoelectric coefficients (d33) were 39, 88, 79.72, 112pC N−1 for pristine PVC, pristine PVDF, PVDF/PVC/BaZrO3 and PVDF/PVC/BaTiO3 blend nanocomposites, respectively. The remnant polarization of blend nanocomposites is also measured by P–E loop. P–E loop shows that the polarization of the blend nanocomposites increases under influence of nanofiller. The pyroelectric coefficient for PVDF/PVC/nanofiller blend nanocomposite is very sensitive in the temperature range of 30 to 180 °C and greater than PVC (i.e. 351 µC m−2 K−1 > 15 µC m−2 K−1).

Evaluation of correlation between chemical modification state of pad and polishing rate in oxide chemical mechanical planarization

In the chemical-mechanical planarization of oxide films, the polishing rate (the rate of material removal) decreases if the polishing pad is not regularly conditioned. Pad brushing, which removed polishing debris but did not otherwise alter the pad surface, was unable to restore the original polishing rate. On the other hand, pad conditioning, in which the pad surface was scraped off, restored the original polishing rate. The morphological state and the chemical modification state of the pad surface were evaluated as factors affecting the polishing rate. FTIR (Fourier-Transform infrared spectroscopy) analysis showed that some of the polyurethane molecules of the pad surface were hydrolyzed. The degree of pad modification at each position in the pad radial direction was quantified based on the FTIR results, and the degree of pad modification was compared with the actual polishing profile within a wafer. The profile based on chemical modification of the pad matched the actual polishing profile. It was shown that not only the morphological factors of the pad but also the chemical modification factors greatly affected the polishing rate.

A Design of Experiment Approach for Optimization and Characterization of Clarithromycin Ternary System Using Spray Drying

The aim of present work was to characterize Clarithromycin (CLT), Polyvinyl pyrrolidone K30 (PVP K30) and Hydroxypropyl β-cyclodextrin (HPB) ternary system so as to check the effect of complexation on solubility of CLT. Physical mixtures of a drug and polymers in several weight ratios (1:1, 1:2) were prepared to check the effect of individual polymers on solubility of CLT. Spray drying method was accustomed investigate the combined effect of PVP K30 and HPB on Drug release (DR), Dissolution efficiency (DE) and mean dissolution time (MDT) of CLT. For the preparation and optimization of ternary system the Design of experiment (DoE) was used . Drug polymer interactions were analyzed with Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and particle size analysis. Results of solubility study suggested that there was significant increase in solubility of CLT with increase within the concentration of PVP K30 and HPB (*p<0.05). This may be thanks to the solubilizing effect of PVP K30 and sophisticated formation of CLT with HPB. Various combinations of PVP K30 and HPB prepared using DoE approach by spray drying method showed greater solubility of CLT than its physical mixtures (*p<0.05). Results of FTIR, DSC, XRD and particle size analysis revealed the interaction between CLT, PVP K30 and HPB. This suggested formation of amorphous ternary system with mean particle diameter within the range of 312±1.35 nm. Combine use of PVP K30 and HPB with DoE approach was an efficient tool for formulating ternary system of CLT.
 Keywords: Clarithromycin, Spray drying, polyvinyl pyrrolidone K30, Hydroxypropyl β-cyclodextrin, Design of experiments, Ternary system.

Adsorption of a poorly water-soluble drug onto porous calcium silicate by the sealed heating method

To improve the bioavailability of orally-administered drug, solubilization of poorly water-soluble drug is important. The solubility of a drug in its amorphous form is known to be higher than in its crystalline form. In this study, we attempted to adsorb a sublimable drug onto porous calcium silicate (Florite®, FLR) or non-porous calcium silicate (NPCS) by the sealed heating (SH) method and evaporated (EV) method. Ibuprofen (IBU) was used as the poorly water-soluble, sublimable drug. The physicochemical properties of samples were investigated using powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and dissolution test. From the PXRD and DSC results, IBU crystals were adsorbed and amorphized by the SH and EV methods with FLR. From the results of FTIR, the shift to a higher frequency by the carbonyl stretching vibration band of IBU suggests an intermolecular interaction between IBU and FLR. In SH with FLR, improved solubilization was observed. IBU adsorbed onto FLR showed a greater dissolution rate than the IBU crystals or NPCS. Thus, the petal-like structure of FLR may be an effective method to adsorb IBU onto FLR using the SH method.

Simultaneous FTIR and Raman Spectroscopy in Endometrial Atypical Hyperplasia and Cancer.

Currently, endometrial carcinoma (EC) is the most common genital cancer in high-income countries. Some types of endometrial hyperplasia (EH) may be progressing to this malignancy. The diagnosis of EC and EH is based on time consuming histopathology evaluation, which is subjective and causes discrepancies in reassessment. Therefore, there is a need to create methods of objective evaluation allowing the diagnosis of early changes. The study aimed to simultaneously asses Fourier Transform Infrared (FTIR) and Raman spectroscopy combined with multidimensional analysis to identify the tissues of endometrial cancer, atypical hyperplasia and the normal control group, and differentiate them. The results of FTIR and Raman spectroscopy revealed quantitative and qualitative changes in the nucleic acid and protein in the groups of cancer and atypical hyperplasia, in comparison with the control group. Changes in the lipid region were also observed in Raman spectra. Pearson correlation coefficient demonstrated a statistically significant correlation between Raman spectra for the cancer and atypical hyperplasia groups (0.747, p < 0.05) and for atypical hyperplasia and the controls (0.507, p < 0.05), while FTIR spectra demonstrated a statistically significant positive correlation for the same group as in Raman data and for the control and cancer groups (0.966, p < 0.05). To summarize, the method of spectroscopy enables differentiation of atypical hyperplasia and endometrial cancer tissues from the physiological endometrial tissue.

Controlling the Antioxidant Activity of Green Tea Extract through Encapsulation in Chitosan-Citrate Nanogel

Applying bioactive ingredients in the formulation of foods instead of artificial preservatives is problematic because bioactive ingredients are unstable and sensitive to environmental conditions. The present study aimed to control the antioxidant activity of green tea extract (GT) through encapsulating in chitosan nanoparticles (CS-NP). The synthesized nanoparticles were analyzed by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The encapsulation efficiency (EE), particle size, zeta potential, and polydispersity index (PDI) of GT-loaded CS-nanoparticles (CS-NP-GT) were assessed. Based on the results, the particle size and zeta potential related to the ratio of CS to GT of 1 : 0.5 were obtained as 135.43 ± 2.52 nm and 40.40 ± 0.2 mV, respectively. Furthermore, the results of FT-IR and XRD confirmed the validity of encapsulating GT in CS-NP. In addition, the antioxidant activity of GT increased after nanoencapsulation since the IC50 value of CS-NP-GT decreased to 6.13 ± 0.12 μg/ml. Finally, applying these particles for delivering GT polyphenols in foods is regarded as promising.

Study on the early cement hydration process in the presence of cationic asphalt emulsion

Cement-asphalt (CA) paste could be regarded as the Portland cement (PC) paste with enhanced flexibility due to the addition of asphalt emulsion (AE) and could be utilized as the semi-flexible pavement and repairing materials. In order to extensively explore the process of early cement hydration and the microstructure evolution of PC paste in the presence of cationic AE, various measurements including setting time, hydration heat, conductivity, compressive strength and ultrasonic pulse velocity, Fourier transform infrared spectroscopy (FTIR), chemically bound water, thermogravimetric (TG) and field emission scanning electron microscopy (FESEM) were adopted in the investigation. The experiment results showed that the setting process of PC paste was gradually prolonged with the increase of A/C, implying that the formation of microstructure of PC paste was inhibited by cationic AE, which is in agreement with the hydration heat and conductivity test. The compressive strength and pulse velocity of ultrasonic wave of cement mortar reduced with the incorporation of cationic AE, which thus implied the porosity increases with the addition of A/C, and in turn indicating the generation of microstructure of cement paste was suppressed gradually with the increase of cationic AE, this could also be confirmed by the chemically bound water, FTIR and FESEM results. Finally, the possible retardation mechanism of cement hydration, caused by the cationic AE, was proposed.

Argon and oxygen plasma treatment increases hydrophilicity and reduces adhesion of silicon-incorporated diamond-like coatings.

In this study, the structure, adhesion, and cell viability characteristics of silicon-incorporated diamond-like carbon (Si-DLC) coatings on fused silica substrates were investigated. The effects of argon and oxygen postprocessing plasma treatments on the Si-DLC coatings were also studied. The contact angle results showed that the Si-DLC coatings were more hydrophilic than the uncoated surfaces, and postprocessing plasma treatment increased the hydrophilicity of the Si-DLC coatings. Atomic force microscopy and profilometry confirmed that postprocessing plasma treatment increased the thickness and roughness of the Si-DLC coatings. The results of microscratch testing indicated that the plasma treatments reduced the adhesion of the coatings. The x-ray photoelectron spectroscopy (XPS) showed the presence of carbon, oxygen, and silicon in the Si-DLC coatings before and after the plasma treatments. These results show that the postprocessing plasma treatment significantly reduced the atomic percentage of the carbon in the Si-DLC coatings. XPS also confirmed the presence of carbon in the form of sp3(C-C), sp2(C=C), C-O, and C=O bonds in the Si-DLC coatings; it showed that postprocessing treatments significantly increased the percentage of oxygen in the Si-DLC coatings. Fourier transform infrared spectroscopy (FTIR) analysis showed features associated with C-OH stretching, C-H bending, as well as Si-CH2 and C-H bending in the Si-DLC coating. The XPS and FTIR results confirmed that the plasma treatment caused dissociation of the sp2 and sp3 bonds and formation of C-OH bonds. The contact angle data indicated that postprocessing treatment increased the hydrophilicity of the Si-DLC coating. Similar to the uncoated substrates, L929 cells showed no change in cell viability when cultured on Si-DLC coatings. These results of the study indicate the suitability of Si-DLC coatings as inert coatings for medical and biotechnology applications.

Enhancement on both phosphoric acid retention and proton conduction of polybenzimidazole membranes by plasma treatment

In this study, plasma treatment is designed to solve phosphoric acid (PA) leaching problem as well as enhance the proton conduction and tensile strength of PBI membranes at high temperature. The hydrophily of polybenzimidazole (PBI) membrane surface is remarkably improved during plasma process according to the water contact angle decreasing from 84.0° to 9.9°. The effect of plasma generating power, gas pressure, Ar/O2 gas proportion and exposure time on water contact angle was investigated. The optimized plasma treating condition was 350 W, 5 Pa, 50 % O2 and 7 min. Fourier transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the effects of plasma treatment on the chemical composition of PBI membranes. The results of FT-IR and XPS reveal the formation of oxygen groups and a progressive increase of oxygen content on the PBI membrane surface due to the plasma modification. Furthermore, the pristine-PBI and plasma-PBI membranes were doped into phosphoric acid (PA) for high temperature proton exchange membrane use. Compared with PA doped pristine-PBI, the PA doped plasma-PBI membranes were found to present higher PA doping levels, higher proton conductivity and better PA retention ability. This indicates plasma treatment could promote acid doping ability, maintain good mechanical strength and reduce PA leaching of PBI membranes.

Transient dynamics of cold‐rolled and subsequently thermally rejuvenated atactic‐polystyrene using broadband dielectric spectroscopy

AbstractThe effect of plastic deformation on the molecular dynamics of atactic polystyrene (a‐PS) was studied by broadband dielectric relaxation spectroscopy (BDRS), Fourier‐transform infrared spectroscopy (FTIR) and polarized‐light microscopy. Sheets of a‐PS have been subjected to cold rolling, that is, mechanical rejuvenation, followed by a quenching step and fast heating above its glass‐transition temperature, resulting in thermal rejuvenation. Cold rolling revealed, in addition to the known α‐ and γ(I)‐relaxations, four hitherto unknown relaxation processes (II, III, IV and V). Using the framework of craze formation and multiplicity of the glass transition (E. Donth, G. H. Michler, Colloid Polym. Sci. 1989, 267, 557–567), supported by an activation‐enthalpy/entropy analysis (Starkweather, W. Howard, Macromolecules 1981, 14, 1277–1281), the following physical picture emerges: (a) processes I and II represent local conformation transitions γ referring to chains of two different degrees of stretching (T/G‐ratio); and (ii) processes III and IV were identified as helix‐inversion processes of T2G2 helices as reported earlier for syndiotactic‐rich PS—an assignment supported by FTIR results. Finally, the relaxation V could be attributed to the onset of the fibrillar glass transition (within crazes), leading to stress release by collapse of the fibrils and hence dying out of process V. Polarized‐light microscopy confirmed the creation of oriented structures and internal stresses upon cold rolling, and their removal upon thermal rejuvenation.

Novel Biosynthesis of Copper Nanoparticles Using Zingiber and Allium sp. with Synergic Effect of Doxycycline for Anticancer and Bactericidal Activity.

Copper nanoparticles (CuNPs), due to their cost-effective synthesis, interesting properties, and a wide range of applications in conductive inks, cooling fluids, biomedical field, and catalysis, have attracted the attention of scientific community in recent years. The aim of the present study was to develop and characterize antibacterial and anticancer CuNPs synthesized via chemical and biological methods, and further synthesize CuNPs conjugated with doxycycline to study their synergic effect. During the chemical synthesis, ascorbic acid was used as a stabilizing agent, while Zingiber officinale and Allium sativum-derived extracts were used during the biological methods for synthesis of CuNPs. Characterization of CuNPs was performed by transmission electron microscopy (TEM), UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), and X-ray crystallography (XRD). Antimicrobial evaluation of the nanomaterials against Pseudomonas aeruginosa and Escherichia coli was performed by using disk diffusion method, while anticancer behavior against HeLa and HepG2 cell lines was studied by MTT assay. TEM revealed spherical-shaped nanoparticles with mean size of 22.70 ± 5.67, 35.01 ± 5.84, and 19.02 ± 2.41nm for CuNPs, Gin-CuNPs, and Gar-CuNPs, respectively, and surface plasmon resonance peaks were obtained at 570nm, 575nm, and 610nm for CuNPs, Gar-CuNPs, and Gin-CuNPs, respectively. The results of FTIR confirmed the consumption of biomolecules from the plant extracts for the synthesis of CuNPs. XRD analysis also confirmed synthesis of CuNPs. Doxycycline-conjugated NPs exhibited more antibacterial effects than doxycycline or CuNPs alone. Copper nanoparticles prepared by biological synthesis are cost-effective and eco-friendly as compared to their chemical counterparts. The chemically synthesized nanoparticles displayed more significant antimicrobial activity when capped with doxycycline than Z. officinale and A. sativum-mediated CuNPs; however, green-synthesized nanoparticles showed greater anticancer activity than their chemical counterparts.

Preparation of Ammonia Dealuminated Metakaolinite and Its Adsorption against Bixin

This study aims to prepare dealuminated metakaolinite which has a high surface area by using NH4OH as an activator. The natural kaolinite sample was treated at 600 °C for 6 h in order to obtain metakaolinite. A dealuminated metakaolinite was then prepared by the repeated activation method using concentrated ammonia (5 M NH4OH) at room temperature. Depending on the nature of each type of material, natural kaolinite, NH4OH treated kaolinite, metakaolinite and NH4OH treated metakaolinite were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET-N2) measurements. XRD and FTIR results confirmed that structural transformation from kaolinite to metakaolinite had occurred. According to SEM-EDS data, the activation of metakaolinite by NH4OH allowed the dealumination of metakaolinite. The increase in the Si/Al ratio was almost twice as high as in kaolinite. BET-N2 analysis showed that the specific surface area and the total pore volume increased significantly after activation. Its adsorption properties were tested against bixin. Bixin adsorption on dealuminated metakaolinite followed pseudo-second order kinetic where k2 = 0.20 g/mg min. The adsorption isotherm followed the Langmuir model where qm = 0.72 mg/g.

Preparation and thermal properties of colloidal mixtures of capric acid and Na2HPO4·12H2O as a phase change material for energy storage

This paper presents a colloidal binary composite phase change storage material prepared using inorganic–organic phase-change materials (PCMs) to improve the thermal conductivity of the organic PCM and solve the supercooling and phase separation problems associated with inorganic PCMs. Samples of disodium hydrogen phosphate dodecahydrate (DHPD)/capric acid (CA) were prepared using a sol-gel method. These samples were characterized by differential scanning calorimetry (DSC), thermal conductivity analyses, Fourier transform infrared (FTIR) spectroscopy, and X-Ray diffraction (XRD). First, the eutectic mixture ratio for a DHPD-CA binary system was theoretically predicted. An analysis of the DSC curve and the two-phase diagram of the eutectic system reveals that the colloidal mixture is close to the eutectic state when the DHPD/CA ratio is 7:3. The results of FTIR spectroscopy and XRD revealed that DHPD and CA in the colloidal mixture did not undergo a chemical reaction, indicating the occurrence of physical mixing. Second, the melting temperature of the composite material was 33.8 °C, the degree of supercooling was 0.9 °C, the melting enthalpy of phase change was 168.8 J g−1, and the thermal conductivity was 0.468 W m−1K−1 at 15 °C. Moreover, after 300 accelerated cold–hot cycles, the thermal properties and morphology of the colloidal binary composite were stable. The addition of CA reduced the degree of supercooling of the DHPD. Furthermore, the addition of DHPD improved the phase-change latent heat and thermal conductivity of CA, thereby reducing the cost of the composite material. The material presented can be used in passive solar energy applications.

Adsorption of dichromate ions from aqueous solution onto magnetic graphene oxide modified by β-cyclodextrin.

In this work, the β-cyclodextrin modified magnetic graphene oxide (β-CD/MGO) composite was fabricated by the in situ co-precipitation method and characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and particle size analysis. The adsorption behavior of dichromate ions on the β-CD/MGO was investigated, and the mechanism of adsorption was also studied using FT-IR and XPS. The results from SEM and TEM showed that the graphene oxide (GO) layer became rough, and many fine particles were attached after compounding with ferroferric oxide and β-cyclodextrin. The characterization results of FT-IR and XPS show that that β-cyclodextrin and ferroferric oxide have been perfectly compounded to the graphene oxide layer and β-CD/MGO has a particle size of about 460nm, a specific surface area of 252.3 m2g-1, and a saturation magnetization of 73.5emug-1. The adsorption amount of dichromate ions on the β-CD/MGO is affected by pH, adsorbent dosage, and adsorption time. Kinetic studies showed that the adsorption process followed a pseudo-second-order kinetic model. Equilibrium data agreed very well with the Langmuir model, the maximum adsorption amount of dichromate ions on the β-CD/MGO was 49.95mgg-1. After five successive adsorbent reuses, the reuse rate is still 73%, indicating the excellent potential reusability of β-CD/MGO adsorbent. β-CD/MGO exhibits excellent adsorption performance for dichromate ions. As an environmentally friendly magnetic adsorbent, β-CD/MGO is suitable for the treatment of dichromate-containing wastewater.

Characterization of New Cellulosic Fibers Obtained from Zingiber Officinale

ABSTRACT Zingiber officinale (known as ginger), a natural flowering plant of Zingiberaceae family, was taken to investigate its possible utilization in a textile material. Zingiber officinale fibers (ZOFs) were obtained from the plant root. The cellulose, hemicellulose, and lignin contents of ZOFs were determined. Elemental analysis of ZOFs was carried out with energy dispersive X-ray analysis (EDX) instrument. Surface morphology of fibers was investigated with a scanning electron microscope (SEM) instrument. The chemical functional groups of ZOFs were confirmed with Fourier transform-infrared spectroscopy (FT-IR). The crystalline structure of ZOFs was analyzed with X-ray diffraction (XRD), and then the crystallinity index was calculated as 78.81%. In addition to this, mechanical properties of ZOFs were investigated with Shimadzu Ag-X machine. The EDX and FT-IR results show that ZOFs have cellulosic structure. Furthermore, it was obtained that ZOFs have rough surface structure and the thickness is approximately 155 µm. The physical properties of ZOFs are substantial enough for its usage as a textile fiber.

Synthesis of Type A Zeolite from Rice Husk Ash and Its Application as a Builder on Effervescent Tablet Form Detergent

Abstract The application of phosphate compounds as a builder in a detergent formulation created eutrophication that encouraged industry to produce more eco-friendly detergents. To overcome that problem, phosphate can be substituted by zeolit that is more effective in cleaning and also biodegradable. In this study, zeolite was synthesized from rice husk ash using a melting method followed by hydrothermal processes. Effervescent detergent tablets were prepared with the following formulations: 3 formulations containing zeolite (F1–F3), 3 formulations containing sodium tripolyphosphate (STPP: P1–P3) and 1 control formulation. The synthesized zeolit was analysed by XRD (X-Ray Diffraction), FTIR (Fourier-Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and cation exchange capacity (CEC). Furthermore, all detergent formulas were characterized for flowability, compressibility, compatibility, disintegration time, pH, cleaning action and biodegradability. The results of FTIR, XRD and SEM characterization showed that the synthesized zeolite was an amorphous type-A crystal and the predominance of the amorphous phase with a cubic structure and CEC value of 95.71 cmol(+) kg−1. In this study the formulation F1 with 15-% zeolite was found to be the best formulation with granule flow rate parameters of 13.6 g/s, stationary angle of 22.0°, compressibility of 16.6-%, detergent tablet hardness accounted to 0.81 kgf/cm2, crushed time of tablet detergent of 1.5 min, pH 6.7, and biodegradability value of 70.3-% in BOD5 test. A higher concentration of zeolite provided a better cleaning effect of the detergent tablets.

Mechanisms of breakdown of Haematococcus pluvialis cell wall by ionic liquids, hydrochloric acid and multi‐enzyme treatment

SummaryThe robust cell wall structure of Haematococcus pluvialis (H. pluvialis) consists of polysaccharides and tough non‐hydrolysable sporopollenins, which makes it difficult to extract superpotent antioxidant, astaxanthin from these cells. Therefore, breakdown of cell wall is a key step in the overall process of astaxanthin recovery. In this study, the mechanism of three well‐established chemical techniques for cell disruption of H. pluvialis cysts [ionic liquids (IL), hydrochloric acid (HCl) and multiple enzymes (multi‐enzyme, ME)] on deconstruction of the cyst cell wall of H. pluvialis was explored and characterised by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC‐MS) analyses. The results demonstrated that the three cell wall breakdown techniques exhibited high extraction efficacies for the recovery of astaxanthin from H. pluvialis [IL (86.71 ± 2.06%), HCl (80.52 ± 2.28%) and ME (71.08 ± 2.49%)]. However, their performances on disrupting the trilayered cell walls of H. pluvialis were significantly different, which were confirmed by distinct morphologies of the treated cell walls visualised by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Meanwhile, the results of FTIR confirmed that, to some extent, cellulose, hemicellulose and lignin in the cell walls were hydrolysed by HCl, IL and ME treatments. However, ME exhibited a less hydrolytic effect on lignin than HCl and IL. Moreover, XRD and NMR analyses implied that the amorphous region of cell wall was susceptible to hydrolysis/breakdown by the three techniques.

Chemometric Analysis of Arbutin Derivatives from Paederia foetida and Vitis vinifera with Fourier Transform Infrared (FTIR)

Introduction: Paederia foetida and Vitis vinifera were reported to have antioxidant activities due to their polyphenolic phytochemical contents. Arbutin may be included as active compounds in the plants. The chemometric analysis is used to identify the similarity of functional groups found in arbutin and that are in Paederia foetida and Vitis vinifera. Materials and Method: The ethanol extracts of Paderia foetida and Vitis vinifera were subjected to compound partition and characterization. Then a liquid-liquid partition is carried out using n-hexan and water solvents, followed by ethyl acetate and water partitions. This procedure is carried out continuously until the top layer is cleared. Partitioned compounds were analyzed using FTIR spectroscopy to identify functional groups. Furthermore, it was analyzed using the chemometric method (Principal Component Analysis and Cluster Analysis). Results: From the results of FTIR spectroscopy, functional groups in Paederia foetida and Vitis vinifera were identical to functional groups found in arbutin. PCA Analysis was achieved using principal component accounting an eigenvelue about 99,3 % of the total variance. Conclusions: CA analysis showed that compounds in Paederia foetida (Euclidean distance 0.537) and Vitis Vinifera (Euclidean distance 1.157) may be similar with arbutin.

Cellulase modified waste biomass to remove sulfamethazine from aqueous solutions

The objective of this work is to find a simple and environmentally friendly way to prepare high efficiency adsorbent from maize stover by cellulase. The characteristics of the original maize cob (MC), maize husk (MH), maize straw (MS), and its cellulase modified form (MMC, MMH and MMS) were detected by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Batch adsorption experiments indicated that the adsorption followed the pseudo-second-order kinetic model, and the adsorption capacity of sulfamethazine (SMT) to adsorbents was in order of MMC > MMS > MMH > MC > MS > MH. The adsorption isotherm data of SMT on original materials were consistent with Freundlich models, while Henry models were more suitable for the modified materials. The adsorption was affected by pH and ionic strength which demonstrated the interaction between π-π EDA and H bonds might be an important factor in the adsorption of SMT on maize stover. The results of FTIR and two-dimensional correlation spectroscopy (2D-COS) analysis further demonstrated that oxhydryl and aromatic structures in the modified maize stover could interact with SMT via H bonds and π-π EDA interaction, respectively. This work provides a green way to remove SMT from aqueous solution, and new insights into the mechanisms of adsorption of SMT on stover materials.