Fourier Transmission Infrared Research Articles

The preliminary study of waste ash of Mpanau steam power plant (Mpanau PLTU)

Coal Steam Power Plan is nowadays very important because it serves electricity in certain areas in Indonesia. Mpanau Coal Steam Power Plan (Mpanau PLTU) located at Palu (Central Sulawesi, Indonesia) which is a source of electricity for the people who live in Palu and its surrounding area. The energy source of PLTU derived from coal which is a fossil fuel. The use of coal as an energy source creates some environmental problems such as the ash waste (bottom ash and fly ash). Characterization of waste ash from fly ash and bottom ash in qualitatively and quantitatively ways is the first step to evaluate the environmental impacts related to environmental and biological contamination risk. In this research, silica concentration (SiO2) has been determined after separation method by extraction of both ashes from Mpanau PLTU. Silica concentration of bottom ash and fly ash sample was 21.31% and 29.85% respectively. Furthermore, the extraction silica was characterized by using Fourier Transmission Infra-Red (FTIR), X-Ray Diffraction (XRD), and Scanning Electronic Microscope (SEM) to see morphology.

Effect of Cr3+ Substitution on the Structural, Electrical and Magnetic Properties of Ni0.7Zn0.2Cu0.1Fe2−xCrxO4 Ferrites

In this work, Ni0.7Zn0.2Cu0.1Fe2−xCrxO4 (x = 0.02, 0.04, 0.06, 0.08 and 0.1) ferrites were synthesized by using the solid state reaction method and how relevant properties of the samples were modified accordingly. The structural, morphological, magnetic and electrical features of the ferrites were evaluated by using X-ray diffraction, scanning electron microscopy, Fourier transmission infrared (FTIR) spectra, vibrating sample magnetometry, electron spin resonance and network analyser. The lattice constant decreases with increasing chromium concentration and the decrease in the lattice constant is attributed to the ionic radius of chromium being smaller than that of iron. The distribution of metal cations in the spinel structure was estimated from the X-ray diffraction data and showed that along with Ni2+ ions, most of the Zn2+ and the Cu2+ ions additionally occupied the octahedral [B] sites. The FTIR spectra revealed two prominent frequency bands in the wave number range 400–600 cm−1 which confirm the cubic spinel structure. The magnetic properties, such as the initial permeability, saturation magnetization and coercivity, were investigated at room temperature. The frequency-dependent dielectric constant was observed to decrease with increasing chromium concentration. This behavior was using Koops phenomenological theory.

Molecularly imprinted polymers based on zeolite imidazolate framework-8 for selective removal of 2,4-dichlorophenoxyacetic acid

Novel molecularly imprinted polymers (MIPs) based on zeolite imidazolate framework-8 (ZIF-8) stabilized Pickering emulsions polymerization were successfully prepared for the selective identification and separation of 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solutions. Experimentally, ZIF-8 of particle size of about 100 nm was successfully synthesized, which can be used as a stabilizer in Pickering emulsion. And then, with 2,4-D as the template monomer, 4-vinylpyridine (4-VP) as the functional monomer, the hollow spherical polymer microspheres were formed via Pickering emulsions polymerization. At last, after the removal of ZIF-8 and template, MIPs were obtained, which were characterized by Fourier transmission infrared (FT-IR) spectrometry and scanning electron microscopy (SEM). Through experiments, the results showed that the adsorption capacity of MIPs and NIPs had a good correlation with Langmuir isothermal model and the kinetic adsorption of MIPs was well suitable for the pseudo-second order kinetic model. The maximum adsorption capacity of MIPs was 108.10 mg/g, while that of NIPs was 28.22 mg/g. The imprinting factor (IF) was about 3.83. And the optimal adsorption equilibrium time was 60 min. The selective and regeneration adsorption experiments showed that MIPs had a high specific selectivity and stability. Also, MIPs revealed good selectivity for 2,4-D in complex water samples. On the basis, it could be proved that ZIF-8 is an excellent alternate for the traditional stabilizers and sacrificial materials, providing a new idea for separation and analysis of harmful substances in water environment.

Effect of initial concentration of chitosan on the particle size of chitosan nanoparticle

Various applications of chitosan lead to the growing interest of researchers to synthesise chitosan nanoparticles (CNP) which exhibit enhanced properties. However, it is very challenging to synthesise CNP due to the many parameters involved in the synthesis process which can affect the size of CNP. This work aims to synthesise CNP and investigate the effect of initial concentration of chitosan on the particle size of CNP. CNP was produced via ionic gelation process with varying initial concentration of chitosan (0.3, 0.6, 0.9, 1.2, 1.5, 1.8, and 2.1% w/v). Fourier transmission infrared (FTIR) analysis revealed the peak of amide shifted from 1629 cm-1 to 1635 cm-1, which confirmed the formation of CNP. Energy dispersive X-ray (EDX) elemental analysis revealed the presence of phosphorus in CNP. The particle sizes of CNP were measured using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was found that the average particle size of CNP increased from 46.7 nm to 225.33 nm with the increase in initial concentration of chitosan from 0.3 to 2.1% w/v due to the agglomeration of CNP, as proven from the TEM images.

Synthesis, characterization, and antibacterial potential of silver nanoparticles synthesized from Coriandrum sativum L.

IntroductionNanoparticles (NPs) have become very important owing to their various uses. In this research, an environmentally friendly biological technique was used to synthesize silver nanoparticles with Coriandrum sativum L. The objective of this research to use the source for the fabrication of silver NPs from C. sativum L., and to check the activity of the fabricated silver NPs was determined versus a couple of gram negative and a couple of gram positive bacteria in the presence of antibiotic viz. gentamicin to judge their impact. MethodologyA silver nitrate solution, which served as the reducing and capping agent, was mingled with coriander leaf extract. The solution’s temperature and pH were maintained at 75°C and 8.6, respectively. The observed mean particle size (z-average) and polydispersity index were 390.2nm and 0.452, respectively. The synthesized Ag NPs were characterized using different techniques, including scanning electron microscopy (SEM), X-ray diffraction, and Fourier transmission infrared (FTIR) analysis. The globular shape of the silver nanoparticles was depicted in SEM illustrations. ResultsXRD data revealed the mean size of the particles was 11.9nm. The FTIR analysis showed the existence of various functional groups, including CO and OH. When their antibacterial ability was tested, it was found that the fabricated Ag NPs inhibited Bacillus subtilis, Pasteurella multocida, Enterobacter aerogenes, and Staphylococcus aureus, with a greater effect against B. subtilis and P. multocida compared to E. aerogenes and S. aureus. ConclusionIt has been concluded small silver NPs benefited from a higher surface area ratio, as shown by the results of experiments where smaller particles had a better bactericidal proficiency than large silver-based NPs. Silver-based NPs infiltrate bacterial cells, as well as interfere with their exterior membrane. Silver ions also have the potential to interact with bacterial DNA, inhibiting the reproductive system of the cell.

Magnetism in BiFe1−xNixO3: studied through electron spin resonance spectroscopy

The effect of Ni doping in BiFe1−xNixO3 (BFNO) multiferroics are studied by X-ray diffraction (XRD), Fourier transmission infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), hysteresis loop (M–H), temperature dependent magnetization (FC-ZFC) measurements and electron spin resonance (ESR) techniques. The XRD and FTIR studies indicate that the BFNO compounds remain in rhombohedral (R3c) phase without appearance of any structural transformation due to Ni doping. The XPS studies show the oxidation states of Fe ions as 3+, whereas Bi is found to be in a mixed valence state of 2+ and 3+ in BFNO. The Ni ion doping enhances the saturation magnetization from 0.179 emu/g (x = 0.025) to 2.38 emu/g (x = 0.20), which is higher than the reported values found in literature. The FC-ZFC magnetization studies suggest the presence of a magnetic phase transition from a weak ferromagnetic to a spin glass state at low temperature. The ESR studies confirm the ferromagnetic state of BFNO samples.

Silver nanoparticles synthesized from Bacillus subtilis for detection of deterioration in the post-harvest spoilage of fruit

Global food shortage is mainly due to the post-harvest spoilage of food, rather than its under-production, especially in the sub-Saharan African countries. Rapid detection tools for the spoilage of fruit such as banana (Musa acuminata) would be a great resource in alleviating losses during post-harvest storage. In this study, silver-based colloidal nanoparticle (AgNPs) solution was synthesized using culture supernatant or wet biomass (cell pellets) of Bacillus subtilis. The synthesized silver nanoparticles solution was confirmed using UV–Vis Spectrophotometer and further characterized using Scanning Electron Microscope (SEM), X-ray Diffractometer (XRD) and Fourier Transmission Infrared (FT-IR), and then evaluated as a colorimetric sensor for the volatile compound released during the deterioration of Musa acuminata. The original reddish brown colour of the silver nanoparticle solution changed to light brown by the end of the fourth day and finally turned transparent on the tenth day. Simultaneous analysis carried out by UV–Vis spectroscopy corroborates our investigation of AgNPs as a colorimetric sensor displaying selectivity and specificity for 1,2-Benzenedicarboxylic acid, bis (2-methyl propyl) ester which was released during the deterioration of Musa acuminata. The use of colorimetric sensor as conducted in this study will help in easy detection for control of crop deterioration.

Application of a Polypyrrole/Carboxy Methyl Cellulose Ion Imprinted Polymer in the Electrochemical Detection of Mercury in Water

AbstractSulphur containing carboxy methyl ion imprinted polymers (S‐IIPs) were applied as an electrode modifier for the electrochemical detection of Hg(II). A bare glassy carbon electrode (GCE) was modified by electro‐polymerizing a layer of pyrrole and then drop coating with S‐IIPs. The bare GCE, GCE/polypyrrole (GCE/PPy), GCE/polyprrole/non‐ion imprinted polymers (GCE/PPy/NIPs) and the GCE/polypyrrole/sulphur ion imprinted polymers (GCE/PPy/S‐IIPs) electrodes were characterised with Fourier Transmission Infrared (FTIR) and electrochemical impendence spectroscopy (EIS). The square wave anodic stripping voltammetry (SWASV) optimised conditions for the GCE/PPy/S‐IIPs were: a pH of 3, deposition potential of −1.0 V, pre‐concentration time of 60 s and 0.1 M HCl supporting electrolyte. The developed ion imprinted polymer electrochemical sensor was applied in the detection of Hg(II) in water. A detection limit of 0.1 μg L−1 was calculated within a concentration range of 20–800 μg L−1. The sensor was selective in the presence of interfering ions and method was validated with inductively coupled plasma‐optical emission spectrometry (ICP‐OES) using real water and standard water samples.

Influence of calcination temperature on the activity of mesoporous CaO/TiO2\u2013ZrO2 catalyst in the esterification reaction

In the present study, the effect of calcination temperature on the structure and performance of mesoporous CaO/TiO2–ZrO2 catalyst fabricated by sol–gel method used in the esterification reaction was assessed. Then, CaO/TiO2 catalyst was also synthesized via the same method to evaluate the effect of zirconia cations on its properties and activity. The samples were characterized by X-ray Diffraction (XRD), Fourier transmittance infra-red (FT-IR), Brunauer–Emmett–Teller (BET)–Barrett-Joyner-Halenda (BJH), scanning electron microscope (SEM) and transmission electron microscopy (TEM) analyses. Moreover, Hammett indicator method was utilized to assess the acidity and basicity of the samples. It was found that zirconium was clearly incorporated in CaO/TiO2 lattice and transformed that from amorphous phase to crystalline structure. In addition, the basicity and acidity of CaO/TiO2 was clearly increased by zirconia loading. Evaluation of the samples’ activity presented that CaO/TiO2 catalyst exhibit no activity in the esterification reaction, while all CaO/TiO2–ZrO2 catalysts showed high ability to convert oleic acid to its ester. Moreover, the catalyst calcined at 400 °C showed the highest activity in the esterification reaction with desirable properties such as high crystallinity, acidity, basicity and surface area along with well-distribution of particle size and pore size. The best catalyst converted around 90% of oleic acid to ester at optimized conditions of 150 °C, 12:1 molar ratio of methanol/oleic acid, 3 wt% of catalyst for 4 h of reaction time. Moreover, the sample was successfully used for five runs without significant reduction in activity that makes it a suitable choice as a catalyst for industrial applications.Graphical abstract

Biodegradation of chlorpropham and its major products by Bacillus licheniformis NKC-1.

Chlorpropham [isopropyl N-(3-chlorophenyl) carbamate] (CIPC), an important phenyl carbamate herbicide, has been used as a plant growth regulator and potato sprout suppressant (Solanum tuberosum L) during long-term storage. A bacterium capable of utilizing the residual herbicide CIPC as a sole source of carbon and energy was isolated from herbicide-contaminated soil samples employing selective enrichment method. The isolated bacterial strain was identified as Bacillus licheniformis NKC-1 on the basis of its morphological, cultural, biochemical characteristics and also by phylogenetic analysis based on 16S rRNA gene sequences. The organism degraded CIPC through its initial hydrolysis by CIPC hydrolase enzyme to yield 3-chloroaniline (3-CA) as a major metabolic product. An inducible 3-CA dioxygenase not only catalyzes the incorporation of molecular oxygen but also removes the amino group by the deamination yielding a monochlorinated catechol. Further, degradation of 4-chlorocatechol proceeded via ortho- ring cleavage through the maleylacetate process. 3-Chloroaniline and 4-chlorocatechol are the intermediates in the CIPC degradation which suggested that dechlorination had occurred after the aromatic ring cleavage. The presence of these metabolites has been confirmed by using ultra-violet (UV), high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), Fourier transmission-infrared (FT-IR), proton nuclear magnetic resonance (1H NMR) and gas chromatography-mass (GC-MS) spectral analysis. Enzyme activities of CIPC hydrolase, 3-CA dioxygenase and chlorocatechol 1, 2-dioxygenase were detected in the cell-free-extract of the CIPC culture and are induced by cells of NKC-1 strain. These results demonstrate the biodegradation pathways of herbicide CIPC and promote the potential use of NKC-1 strain to bioremediate CIPC-contaminated environment with subsequent release of ammonia, chloride ions and carbon dioxide.

Preparation and Application of Carboxymethylated Xylan as a Flocculant for Ethyl Violet Dye in Aqueous Systems

Hemicellulose is one of the most abundant renewable biopolymers on earth. Xylan is the main hemicellulose of hardwood species, but it is under utilized. In this work, carboxymethylated xylan (CMX) with the maximum degree of substitution (DS) of 0.95 and charge density of −4.57 mmol/g was produced. Fourier transmittance infrared (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed the success of carboxylemthylation reaction. Thermogravimetric analysis confirmed that CMX was less thermo-stable than xylan. Furthermore, the CMX was applied as a coagulant for removing cationic ethyl violet dye from a simulated dye solution. The results showed that more than 95% of dye was removed from the solution. The theoretical and experimental values for the removal of the dye were close confirming that the charge neutralization was the main mechanism for interaction of dye and CMX. The impact of salt in the coagulation efficiency of CMX was also analyzed.

Integrated adsorption-solar photocatalytic membrane reactor for degradation of hazardous Congo red using Fe-doped ZnO and Fe-doped ZnO/rGO nanocomposites.

In this work, synergistic effect of solar photocatalysis integrated with adsorption process towards the degradation of Congo red (CR) was investigated via two different approaches using a photocatalytic membrane reactor. In the first approach, sequential treatments were conducted through the adsorption by graphene oxide (GO) and then followed by photocatalytic oxidation using Fe-doped ZnO nanocomposites (NCs). In the second approach, however, CR solution was treated by photocatalytic oxidation using Fe-doped ZnO/rGO NCs. These nanocomposites were synthesized by a sol-gel method. The NCs were characterized by X-ray diffraction (XRD), photoluminescence (PL), Fourier transmission infrared (FTIR), ultraviolet-visible (UV-vis) spectroscopy, and field emission scanning electron microscopy (FESEM). It was observed that Fe-doped ZnO could enhance the photoactivity of ZnO under solar light. When Fe-doped ZnO were decorated on GO sheets, however, this provided a surface enhancement for adsorption of organic pollutants. The photocatalytic performances using both approaches were evaluated based on the degradation of CR molecules in aqueous solution under solar irradiation. Nanofiltration (NF) performance in terms of CR residual removal from water and their fouling behavior during post-separation of photocatalysts was studied. Serious flux declined and thicker fouling layer on membrane were found in photocatalytic membrane reactor using Fe-doped ZnO/rGO NCs which could be attributed to the stronger π-π interaction between rGO and CR solution.

Porous Microparticles Containing Raloxifene Hydrochloride Tailored by Spray Freeze Drying for Solubility Enhancement.

Purpose: The goal of this study was to improve the solubility and dissolution behavior of Raloxifene Hydrochloride (RH) using Spray Freeze Drying (SFD) technique.Methods: For achieving this goal, series of samples containing RH with polyvinylpyrrolidone (PVP) or hydroxypropyl beta cyclodextrin (HPβCD) used as solubility enhancers were prepared and microparticles were formed via SFD. The resultant microparticles were physicochemically characterized. Morphology of the microparticles were observed using Scanning Electron Microscopy (SEM). High Performance Liquid Chromatography (HPLC) was used for analyzing the solubility and dissolution profile of the samples.Results: Fourier Transmission Infrared (FTIR) spectra showed that SFD processed compositions did not affect chemical structure of RH. SEM and Thermal Gravimetric Analysis (TGA) revealed that the fabricated spherical and highly porous microparticles were in amorphous state. SFD processed powders showed superior solubility and dissolution behavior; where, 80% of the drug was dissolved within 5 minutes.Conclusion: SFD method can be a promising alternative for enhancing the solubility of poorly water soluble compounds.

Characterizations of Polysulfone/Ferrihydrite Mixed Matrix Membranes for Water/Wastewater Treatment.

This study aimed to investigate the effects of ferrihydrite (Fh) nanoparticle loading on the physicochemical properties of polysulfone (PSf) membranes fabricated via the phase inversion method. The morphologies and physicochemical properties of prepared Fh and PSf/Fh mixed matrix membranes (MMMs) were characterized using transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), Fourier transmission infra-red (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), pure water flux analysis, contact angle measurement, and membrane porosity analysis. FTIR study indicated that a new O-H band was formed when Fh was added into the membrane matrix. SEM analysis showed the formation of typical asymmetric membrane structures with elongated fingerlike and looser porous layers. Increasing the loading of Fh significantly enhanced membrane pure water flux from 230.2 L/m2•h (M-Fh 0%) to 726.6 L/m2•h (M-Fh 15.3%), attributed to the improved membranes structures, membranes wettability, surface roughness, and overall porosity. The findings suggest incorporation of Fh into PSf membranes improves physicochemical properties of the membranes which are applicable for water/wastewater treatment.

A perspective on the hemolytic activity of chemical and green-synthesized silver and silver oxide nanoparticles

We report the hemolysis properties of silver and silver oxide nanoparticles (NPs) prepared by chemical and green-synthesis methods. The prepared silver and silver oxide NPs were analyzed using UV–vis spectroscopy to confirm their formation by characterizing their surface plasmon resonance (SPR) and absorption band peaks respectively. The Fourier transmission infrared (FTIR) spectra of the materials showed the characteristic functional groups corresponding to the molecules present in leaf extracts, which is proposed to be acted as reducing and capping agents that are also found on the surface of silver and silver oxide nanoparticles that synthesized via green-synthesis method. Zeta potential analysis revealed the surface charge and stability of the prepared NPs. HRTEM images showed almost spherical shape nanoparticles with an average size of 15.2 and 31.5 nm for wet chemical synthesized silver and silver oxide nanoparticles respectively. In the case of green synthesized silver and silver oxide nanoparticles, it was observed to be 19.4 and 30.4 nm respectively. The order of hemolysis efficacy of the materials is found to be as follows: chemically synthesized Ag2O> chemically synthesized Ag NPs followed by green-synthesized Ag2O and green-synthesized Ag NPs which showed almost similar hemolysis with respect to concentration. The relatively stable nature of the silver NPs could be attributed to their lower hemolysis efficacy, while the increased lysis properties of silver oxide could be attributed due to reductive/oxidative processes that give rise to the hemolysis through interfacial charge interactions with RBCs.

Synthesis of p-Cu2O/rGO composite films for enhancing photocurrent of p-Cu2O and H2 generation

Composites of p type cuprous oxide (p-Cu2O) and reduced graphene oxide (rGO) were prepared by depositing an rGO layer on top of nano-sized Cu2O particles prepared on a Cu substrate. These synthesized composites help to enhance the photocurrent over that of bare Cu2O, which means rGO acts as an excellent electron acceptor to separate electrons from Cu2O particles. Here the p-Cu2O layer was fabricated using thermal oxidation and the rGO layer was fabricated using electrophoretic deposition (EPD). The samples thus fabricated were characterized using diffuse reflectance spectra, Fourier transmission infrared (FTIR) spectra, scanning electron microscopy (SEM) images, time development of the photocurrent of photoelectrochemical cells, and electrochemical impedance spectroscopy (EIS) measurements. H2 evolution was observed using a gas chromatograph system.

Formulation and in-vitro evaluation of pantoprazole loaded pH-sensitive polymeric nanoparticles

The pH-sensitive polymeric nanoparticles are very efficient delivery systems for acid labile drugs. The main aim of the study was to formulate pantoprazole loaded pH-sensitive polymeric nanoparticles using pH-sensitive polymers to prevent degradation of acid labile drug and evaluate the effect of formation conditions on both nanoparticles characteristics and drug release patterns.Pantoprazole loaded nanoparticles were prepared using nanopercipitation method using pH-sensitive polymers Eudragit S100 or HPMC phthalate HP55. Nanoparticles were characterized for their micromeritic and crystallographic properties, drug content, in-vitro release and the ability to delay pantoprazole release in acidic medium to prevent its degradation.Physicochemical properties of nanoparticles, including particle size, loading capacity (LC), encapsulation efficiency (EE) and in-vitro drug release were significantly affected by formulation conditions. All formulas showed sub micronized size ranging from 299.3 ± 4.62 to 639.7 ± 9.71 nm and achieved delayed release to protect pantoprazole from degradation with different degrees, but generally Hydroxypropyl methyl cellulose phthalate HP55 loaded nanoparticles showed slower drug release than that of Eudragit S100 loaded nanoparticles. Release kinetics and morphological properties of nanoparticles with most delayed release pattern were investigated by Transmission Electron Microscope (TEM) and Compatibility between pantoprazole and polymer was proved by Fourier Transmission Infra Red (FT-IR) and Differential Scanning calorimetry (DSC). The formula stability was evaluated by measuring zeta potential value.Our results suggested that nanoprecipitation method is effective to produce pH-sensitive polymeric nanoparticles, which can be used as a delivery system for acid labile drug (Pantoprazole) to avoid its degradation in acidic medium of the stomach.

Novel Chitosan-poly(vinyl alcohol)/graphene oxide biocomposites 3D porous scaffolds

Abstract New porous Chitosan-Poly(vinyl alcohol)/graphene oxide (CHT-PVA/GO) biocomposites scaffolds were obtained by a freeze drying method. The structural and morphology properties of the scaffolds were investigated. Fourier transmission infrared (FTIR) spectra confirmed the presence of GO into the biopolymer matrices. Scanning Electron Microscopy (SEM) images show a highly interconnected porosity for the composites with GO incorporated within the polymer matrices. Further, the water uptake capacity and the enzyme degradation behavior were conducted. The biocomposite ability to form hydroxyapatite (HA) crystals and therefore bone regeneration potential was studied. SEM shows that all the samples are covered with a mineral phase made of micro globule needle type. The presence of HA crystals on the surface was proved by X-ray Diffraction (XRD) where a large number of the characteristic peaks of HA were observed, the average size of individual crystallite being dependent on GO amount.

Obtaining titanium dioxide nanoparticles with spherical shape and antimicrobial properties using M. citrifolia leaves extract by hydrothermal method

In this work, we synthesized titanium dioxide (TiO2) nanoparticles using leaf extract of Morinda citrifolia (M. citrifolia) by the advanced hydrothermal method. The synthesized TiO2 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transmission infrared (FT-IR), Ultraviolet-visible diffuse reflectance (UV–Vis DRS), Ultraviolet-visible spectroscopy (UV–Vis), Raman spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM with EDX) techniques. The XRD major peak at 27.3° corresponds to the (110) lattice plane of tetragonal rutile TiO2 phase and average crystalline size of nanoparticles is 10nm. The FT-IR result confirmed that TiO2 nanoparticles and the presences of very few amount of anthraquinone and phenolic compounds of the leaf extract. The obtained nanoparticles were also characterized by UV–Vis DRS absorption spectroscopy and an intense band at 423nm clearly reveals the formation of nanoparticles. SEM images with EDX spectra clearly reveal the size of the nanoparticles, between 15 and 19nm in excellent quasi-spherical shape, by virtue of stabilization (capping) agent. The presence of elements-titanium and oxygen was verified with EDX spectrum. Furthermore, the inhibitory activity of green synthesized TiO2 nanoparticles was tested against human pathogens like Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger by the agar well-diffusion method. The TiO2 nanoparticles exhibited superior antimicrobial activity against Gram-positive bacteria, demonstrating their antimicrobial value against pathogenic diseases.

Synthesis and Characterization of Microwave Absorber SiO2 by Sol-Gel Methode

In recent years, information technology is growing rapidly, such as communication devices. However, there are still many shortcomings, for example, confidential information leaks caused by the leakage of electromagnetic waves used. A coating of electromagnetic materials or formation composite of electromagnetic material with other materials such as SiO2 is needed to overcome these problems. For such needs, it is necessary to study the manufacture of SiO2 which is simple, cheap, and effective. In this research, manufacture of SiO2 by sol-gel method used a solution of sodium silicate (Na2SiO3) as precursors and H2SO4 as a catalyst. The parameters tested in this experiment is the effect of sintering temperature on the properties of the resulting SiO2. The purpose of this study was to obtain an amorphous SiO2 powder, which is in nano-sized and has a high surface area. The characterization of prepared samples were performed by using an X-ray Diffraction (XRD), Fourier Transmission Infra Red (FTIR), Scanning electron microscopy-energy dispersive spectrometer (SEM-EDS), Transmission Electron Microscopy (TEM), and Surface Area Analyzer (SAA). Based on the experimental results, the SiO2 amorphous structure was obtained with a particle size of 15-20 nm, the surface area of 298 m2/g, and sintering temperature of 100 °C.