FTIR Peaks Research Articles

Carbazole derivatives: Synthesis, spectroscopic characterization, antioxidant activity, molecular docking study, and the quantum chemical calculations

A various carbazole derivatives were synthesized for the synthesis 2,3-Dihydro-1H-carbazol-4(9H)-one O-acetyl oxime (3), ethyl 2-(2,3,4,9-tetrahydrospiro[carbazole-1,2′-[1,3]dithiolane]-2-yl)acetate (5), 2- hydroxyethyl {2,3,4,9-tetrahydrospiro[1H-carbazole-1,2′[1,3]dithiolane-4-one]-2-yl}-acetamide (7). These products (3, 5, and 7) were characterized by the spectroscopic techniques (IR, 1H NMR, 13C NMR and elemental analysis). Then, the observed FT-IR and NMR peaks of the studied compounds were compared with the calculated values. The FMO analyses disclosed that the (5) would prefer intermolecular interactions more than intramolecular interactions because of its higher energy gap. NBO analyses displayed that the n → П* and П → П* interactions were responsible for the lowering of the stabilization energy. The molecular docking studies showed that (5) exhibited highest binding affinity with the human glutathione reductase at binding site (−7.21 kcal/mol). Also, the antioxidant activities were investigated using the CUPRAC method, and TEAC coefficient implied that compound (3) have an antioxidant property. In addition, docking calculations of the compound (3), (5), and (7) were performed on bacterial tyrosinase enzyme and human glutathione reductase protein.

Probing the interaction of glutathione with different shape of silver-nanoparticles by optical spectroscopy

To understand the influence of the shape of the particles on assay sensitivity using surface plasmon resonance phenomenon (SPR), three different types of silver nanoparticles spherical (SAgNPs), triangular (TAgNPs), and octahedral (OAgNPs) of around 20 nm in size and similar aspect ratio were analyzed after interaction with glutathione (GSH). FTIR peak of Ag-S peak at 2312 cm−1and 2305 cm−1, 2312 cm−1 in SAgNPs, TAgNPs, and OAgNPs respectively confirming interactions. DLS and TEM studies agglomeration of SAgNPs and TAgNPs but not in OAgNPs due to the interaction. Detailed SPR analysis showed interaction of GSH with nanoparticles resulted in alteration of three characteristic features namely changes a decrease in peak height at (506 nm and 398 nm) an increase in peak height (987 nm and 987 nm) and bathochromic shift of absorption peak in 600−700 nm range in the case of SAgNPs and TAgNPs, but no such changes were observed for OAgNPs. To understand the physical phenomenon Marquardt-Levenberg algorithm based non-linear curve fitting analysis where done. In the fitting analysis, GSH concentration-dependent changes of the AS characteristics were fitted to polynomials of different orders, and from the weighted residuals and 95 % prediction interval of the fits, the best models are suggested that describe the changes in the AS of the triangular AgNPs (TAgNPs). The probable reason for the phenomenon lies in surface protection and accessibility of the interaction surface. Unlike SAgNPs, in TAgNPs and OAgNPs the edges of each side are loosely protected with Polyvinylpyrrolidone (PVP) allowing enhanced interaction with GSH from the edges and linear joining. Further, the majority of the ridge of the surface of OAgNPs are not accessible to the other particles which reduce the stability of interaction and joining. As a cumulative result TAgNPs are the best choice for GSH titration among these 3 types of particles.

Characterization of Physico-chemical, Thermal, and Mechanical Properties of Ethiopian Sisal Fibers.

ABSTRACT The objective of this paper was to examine the effectiveness of extraction methods (retting, chemical, and scraping) on physico-chemical, thermal, and mechanical properties of sisal (Agave sisalana) fibers. Thermal analysis (TGA), FT-IR spectroscopy, SEM, XRD, and mechanical strength tests were used to trace back the influence of extraction methods on physico-chemical, thermal, and mechanical properties of sisal fibers. Interestingly, sisal fibers extracted by chemical method (15% NaOH) have shown the highest amount of cellulose (78%) while lignin content (2.5%) is very small compared to the results from other extraction methods, retting, and scraping. The FT-IR peak around 1240 cm−1 confirmed the presence of lignin and hemicellulose which indicates the inefficiency of all extraction methods. Thermal analysis (TGA) showed two degradation peaks representing the evolution of adsorbed moisture and glycosidic cleavage of chemical components of sisal fibers. The chemical method has shown superior tensile strength (387 MPa) relative to similar fibers from retting (278 MPa) and scraping (362 MPa). To sum up, the chemical method can be recommended as a more suitable extraction technique for further engineering applications of sisal fibers.

In-situ Production and Collection of Bacterial Cellulose on Jute and Flax Mats by Static Cultivation

ABSTRACT In this study, jute and flax mats were used as a support material to deposit bacterial cellulose (BC) on its surface produced by Gluconacetobacter liquefaciens (MTCC 3135) through fermentation process under static condition. Amount of BC produced during the study indicates that type of mats as support material affects the production of BC at the air-liquid interface. About 2.45 g/l and 1.85 g/l of BC was produced in presence of jute and flax mats as support, respectively. Neat BC obtained under static cultivation was found to be brittle in nature. In order to prevent brittleness in BC, mat hanging method has been proposed to deposit BC directly on the surface of the mat. FTIR peaks obtained at 3337 and 3350 cm−1 as well as at 1647 and 1654 cm−1 indicated the presence of cellulose in form of BC on both the mats. Microscopic observation, water uptake behavior and antibacterial studies of neat mats, unadhered BC and BC deposited on mats were also carried out and the results were compared. The proposed in-situ method of collecting BC on the cellulosic mats will help in fabrication of biocomposite sheets that can be further explored in packaging, medical and biomedical applications.

Investigating the effects of calcination time on Α-alumina synthesis from aluminum waste can

Several countries around the world are confronted solid waste management most especially from aluminum beverage containers. The recycling process is seen as an effective approach since it is energy saving, cost effective and reduced emission. In this study, the Sol-gel method was used to process the aluminum wastes and to consequently synthesize them into aluminum oxide (α-Al2O3) and presented in several crystalline structures. The result from this study indicated that the synthesized α-alumina at lower calcination time exhibited a lower FTIR peak intensity which indicated a more crystallinity. However, the synthesized α-alumina exhibited higher and sharper FTIR bands at higher calcination time. Moreover, the morphological characteristic shows that exhibited almost similar features with a non-spherical heterogeneous particle sizes. The results of the elemental analysis suggest a direct proportionality between the calcination time, and atomic percentage of aluminum among the samples. Conclusively, this study shows that the waste aluminum can be converted into economical value-added products.

Hydrophobic development and mechanical properties of cellulose substrates supercritically impregnated with food-grade waxes

Supercritical impregnation may be used to impart specific functional properties into porous substrates such as wood, textiles, or paper. In the current study, food-grade beeswax (BW), carnauba wax (CW) and vegetable wax (VW) were impregnated into paper substrates to improve their hydrophobicity and mechanical strength. The contact angle of impregnated and annealed samples was approximately 110–120° when annealed at 140 °C, and 130° when annealed at 160 °C. SEM analyses revealed that dual micro- and nano-scale roughness was generated in impregnated paper substrates that also underwent annealing. FTIR analysis showed evidence of H-bonding between the waxes and cellulose, but this was more dominant with BW/CW compared with VW due to the different chemical structures of the waxes. Annealed samples showed lower intensity FTIR peaks, tentatively confirming a phase transition of the waxes as a result of the annealing. A reduced tan delta signal up to the secondary alpha transition temperature for paper was observed with BW/CW impregnated samples, indicating the formation of additional chemical bonds between cellulose and wax. Compared with untreated paper substrates, the sharp decrease in storage modulus during degradation occurred at temperatures up to 10 °C higher for wax-impregnated papers, and up to 40 °C lower for baseline papers impregnated and annealed without wax. It is believed that the H-bonds between the waxes and cellulose were able to withstand higher temperatures in the degradation region, thus offsetting the effects of sample preparation.

Effects of the degree of oxidation of pitch fibers on their stabilization and carbonization behaviors

The stabilization of isotropic pitch (IP)-derived pitch fibers (PFs) and mesophase pitch (MP)-derived PFsin air was performed at different heating rates and with different final stabilization temperatures. The stabilized fibers (SFs) and carbon fibers (CFs) were characterized by elemental analysis, FT-IR, TG-MS and SEM to investigate the influence of the degree of oxidation of the SFs on the microstructures and mechanical properties of the CFs. Results showed that a slow heating rate during stabilization was beneficial to the oxidative cross-linking of PFs, and the corresponding CFs had a higher carbonization yield and tensile strength at the lower heating rate. When both IPF and MPF were stabilized at 270 oC, the two resulting CFs all reached their optimal performance. In addition, the FTIR peak intensity ratio of the C=O band at about 1700 cm–1 to the C=C band at 1600 cm–1 of the SFs had a good relationship to the carbonization yield and tensile strength of the CFs, and thiscan beusedto optimize the degree of oxidation of the SFs. Moreover, insufficiently stabilized fibers released a great deal of H2 and CH4, causing some porosity in the resulting CFs with a low tensile strength, especially forthe insufficiently stabilized IPCF. While over-stabilized fibers released a large amount of CO and CO2, causing cracked textures in the corresponding CFs, especially inthe over-stabilizedMPCF. Therefore, this research into the stabilization and carbonization behaviors of pitch fibers has great significance for improving the mechanical properties of pitch-based CFs.

Antioxidant and antidiabetic properties of biocompatible ceria oxide (CeO2) nanoparticles in mouse fibroblast NIH3T3 and insulin resistant HepG2 cells

This work synthesized the ceria oxide nanoparticles (CeO2 NPs) using the plant extract of Stachys japonica Miq and determined their antioxidant and antidiabetic activities. The characterization results demonstrated the successful formation of spherical shaped CeO2 NPs with average size of 21 nm with PDI of 0.121. The FTIR peak of CeO2 NPs revealed the capping of phyto-molecules and a peak at 470.92 cm−1 indicated the formation of Ce–O of CeO2 NPs. The CeO2 NPs scavenged the free radicals of ABTS+ and DPPH, with IC50 of 12.16 ± 0.12 μg. mL−1 and 109.5 ± 0.26 μg. mL−1 respectively. The 50 μg mL−1 of CeO2 NPs showed the maximum inhibitory effect on α-glucosidase (19.78 ± 0.95%) and α-amylase (43.24 ± 1.14%). The cellular assay revealed the non-toxicity of CeO2 NPs in NIH3T3 and HepG2 cells. Cell antioxidant assay demonstrated that CeO2 NPs attenuated the staurosporine (STS) induced-oxidative stress in NIH3T3 cells through preventing the MMP loss and nucleus damage. The treatment of CeO2 NPs was broken the insulin resistance in IR-HepG2 cells and increased the glucose uptake through strengthening the mitochondria from oxidative stress. These antioxidant and antidiabetic properties of CeO2 NPs have opened a new avenue for extending future study on CeO2 NPs regulated glucose metabolism and its underlying molecular mechanism for beneficial therapy of diabetes.

Peroxynitrite-Mediated Structural Changes in Histone H2A: Biochemical and Biophysical Analysis.

Peroxynitrite, a nitrating and oxidizing agent, is formed by the interaction between nitric oxide and superoxide radicals. H2A histone is a basic nucleoprotein and is one of the major core histones responsible for packaging DNA. It has been shown that they are highly sensitive to oxidizing and nitrating agents. Nitration of tyrosine residues in proteins by peroxynitrite is regarded as a marker of nitrosative damage. The dityrosine bond, an oxidative covalent cross-link between two tyrosines in protein, is increasingly identified as a marker of oxidative stress, aging and neurodegerative diseases. Peroxinitrite-mediated nitration and dinitration in H2A histone was assessed by various biophysical techniques. The data presented in this study showed that the dityrosine content was found to be elevated in H2A histone modified with peroxynitrite. The formation of dityrosine showed a decrease in fluorescence intensity, generation of a new peak in FT-IR, increase in hydrodynamic size, and loss of secondary and tertiary structure of H2A resulting in a partially folded structure. We report that H2A may undergo conformational and structural changes under nitrosative and oxidative stress from the deleterious effects of peroxynitrite.

Synthesis and physicochemical characterization of rhamnolipid-stabilized carvacrol-loaded zein nanoparticles for antimicrobial application supported by molecular docking

Carvacrol is a phenolic monoterpenoid obtained from the genera of Origanum, Thymus, Satureja, and Lippia. It is a hydrophobic phytoconstituent that readily tends to decay while processing leading to restricting its potential application. In the current study, zein/rhamnolipid (ZRL of 306 nm) complex nanoparticles were loaded with carvacrol successfully (CRZRL of 271 nm) to explore its antimicrobial activity and obtained the MIC value of 135 μg/ml and 270 μg/ml against P. syringae (bacterial canker) and F. oxysporum (Fusarium wilt) respectively. These complex nanoparticles were further characterized by DLS, FE-SEM, DSC, FT-IR, H1NMR, docking, and HPLC studies. The strong interaction of carvacrol with zein and rhamnolipid complex nanoparticles which showed characteristic peaks in FTIR as well as H1NMR were also supported by our docking studies. This strong interaction resulted in higher EE (95%) as well as LE (42%), confirmed by HPLC studies. Docking studies further revealed the presence of stronger Π-Π interaction within binding and active sites of zein through which rhamnolipid and carvacrol interact. The developed nano-formulation could be exploited for controlling different plant diseases and other foodborne pathogens.

One-pot synthesis and characterization of in-house engineered silver nanoparticles from Flacourtia jangomas fruit extract with effective antibacterial profiles

Nanobiotechnology is an emerging field among researchers. Currently the development of plant-mediated biogenic nanoparticles is gaining much attention. It is notable that the biogenic nanoparticles particularly silver nanoparticles are therapeutically more effective than its chemically synthesized form. Thus, here in, the development of silver nanoparticles (Fj-AgNPs) using aqueous extract of ripe fruit of Flacourtia jangomas as a reducing agent is investigated. The developed Fj-AgNPs were additionally compared with ammine modified silver nanoparticles (Am-AgNPs), developed through chemical route using the reported approach and confirm the phyto-reduction of Ag+ to Ag0.UV–visible spectrum has exhibited a peak at 418 nm and FTIR peak profile (at 1587.6, 1386.4, and 1076 cm−1 with corresponding compounds) in addition to the diffraction peak at 38°, 44°, 64°,78° in PXRD spectrum confirmed the synthesis of Fj-AgNPs with 8.29 nm average crystallite size. Enhanced anti-bacterial effect is observed in the case of Fj-AgNPs as compared to Am-AgNps. These results refer to the idea that the use of the aqueous extract of ripe fruit of Flacourtia jangomas could be a good replacement of EDTA in the synthesis of silver nanoparticles.

Acute and Sub-Acute Toxicity Studies and Pharmacodynamic Studies of Standardized Extract of Trachyspermum ammi (L.) Sprague (Fruits) Against Chemically Induced Inflammation in Rats.

Nowadays, researchers have been attempting to use herbal products as medicines which have proven to cause lesser side effects. The fruit part of Trachyspermum ammi (L.) - Ajwain has been an integral part of the Indian medicine system with much importance in Ayurveda and Unani medicine system and is prescribed by Vaidya gurus and Hakim in raw form or as a major constituent in the powdered formulations. This research aimed to evaluate acute and sub-acute toxicity of standardized T. ammi fruit and its anti-inflammatory property using experimental models. The extract of herbs was spectroscopically analyzed for the estimation of the number of bioactive compounds. Then acute and sub-acute toxicity analysis of the herbal extract was performed to ensure the toxic effects, if any. Biochemical parameters like ALT, AST, ALP, etc. and histopathological analysis were determined to study the toxicity of the extract. Then, the anti-inflammatory activity of the T. ammi fruit extract employing Carrageenan and formalin-induced edema model in rats was studied. Ajwain seeds have a pungent smell and a characteristic odor. The powder microscopy clearly showed endosperm, unicellular warty trichomes, striated cuticle in surface view, vittae, endodermis, and vascular strand. Phytochemical tests reported the presence of carbohydrates, alkaloids, tannins, etc. and characteristic peaks in UV, Mass, NMR, FTIR and HPLC were observed for the extract. Acute and sub-acute toxicity studies did not report any toxicity, and significant anti-inflammatory action was recorded. The spectroscopic and pharmacognostic analysis has shown the strong presence of flavonoids, mineral matter, protein, phenols, saponins, carbohydrates, volatile oils, fiber, glycosides and fat. Spectroscopic study interpretations have shown the presence of compounds like thymol, para-cymene, γ-terpinene, α- and β-pinene, carvone, limonene, saponins,, β-phellandrene, βfenchyl alcohol, α-thujene, β-phellendrene, α-thujene, etc. No signs of toxicity were recorded in acute and sub-acute toxicity studies assessing the relative weight and histopathological analysis. Significant anti-inflammatory potential of T. ammi fruit extract was found and LD50 was found to be beyond 3000 mg/kg. The results of this study could be useful; in setting the quality parameters for further identification of the crude herb and preparation of the monograph.

Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder

This study investigated the changes in camel milk powder on spray and freeze drying by preparing spray dried whole camel milk powder (SDW), spray dried skimmed camel milk powder (SDS) and freeze-dried whole camel milk powder (FDW). All the powder variants showed significant changes (P < 0.05) in their composition, water activity and color values. Freeze dried powder (FDW) showed higher retention of calcium (15.33 g/kg) and iron (0.012 g/kg) while SDS possessed highest L* (94.83 ± 0.74) values. FDW sample had highest interstitial air (80.84 ± 0.66 mL/100 g), occluded air (119.47 ± 1.08 mL/100 g) and porosity (50.59 ± 0.56%) followed by SDS which was further reinforced by their SEM images. The water binding capacity was highest for FDW (5.21 g/g protein) and lowest for SDW which is attributed to highest porosity and presence of surface fat, respectively. Freeze-dried camel powder had porous sheet like structure while the spray dried samples were agglomerates of individual spherical particles. FTIR peak differences between whole camel milk powder samples (FDW and SDW) and skimmed powder sample (SDS) in wavenumber range 2850–3000 cm−1 was due to milk fat. Fitted with BET and GAB model, the moisture sorption isotherm showed lowest monolayer moisture content for SDW, thereby highlighting its better storage stability.

Development of Thermoplastic Starch (TPS) Including Leather Waste Fragments.

A thermoplastic starch (TPS) material is developed, based on corn starch plasticized with glycerol and citric acid in a 9:3:1 ratio and further bonded with isinglass and mono- and diglycerides of fatty acids (E471). In TPS, leather fragments, in the amount of 7.5 15 or 22.5 g/100 g of dry matter, were also introduced. The mixture was heated at a maximum temperature of 80 °C, then cast in an open mold to obtain films with thickness in the range 300 ± 50 microns. The leather fragments used were based on collagen obtained from production waste from shoemaking and tanned with tannins obtained from smoketree (Rhus cotinus), therefore free from chromium. Thermogravimetric (TGA) tests suggested that material degradation started at a temperature around 285 °C, revealing that the presence of leather fragments did not influence the occurrence of this process in TPS. Tensile tests indicated an increase in tensile properties (strength and Young’s modulus) with increasing leather content, albeit coupled, especially at 22.5 wt%, with a more pronounced brittle behavior. Leather waste provided a sound interface with the bulk of the composite, as observed under scanning electron microscopy. The production process indicated a very limited degradation of the material after exposure to UV radiation for eight days, as demonstrated by the slight attenuation of amide I (collagen) and polysaccharide FTIR peaks. Reheating at 80 °C resulted in a weight loss not exceeding 3%.

&lt;p&gt;Biocompatibility, Cytotoxicity, Antimicrobial and Epigenetic Effects of Novel Chitosan-Based Quercetin Nanohydrogel in Human Cancer Cells&lt;/p&gt;

BackgroundPrevious studies have reported that quercetin (Q) has a potential antibacterial and anticancer activity. However, its application is limited by many important factors including high hydrophobicity and low absorption.MethodologyIn the current study, we synthesized and characterized (Patent) a novel chitosan-based quercetin nanohydrogel (ChiNH/Q). Encapsulation efficiency was confirmed by UV/VIS spectrophotometer. Physicochemical characterization of ChiNH/Q was assessed by PDI, DLS, SEM, FTIR, and XRD. The toxicity of the ChiNH/Q against five strains of the pathogen and HepG2 cells was examined. Moreover, the quantification of ChiNH/Q on genomic global DNA methylation and expression of DNMTs (DNMT1/3A/3B) in HepG2 cancer cells were evaluated by ELISA and real-time PCR, respectively.ResultsUnder the SEM-based images, the hydrodynamic size of the ChiNH/Q was 743.6 nm. The changes in the PDI were 0.507, and zeta potential was obtained as 12.1 mV for ChiNH/Q. The FTIR peak of ChiNH/Q showed the peak at 627 cm−1 corresponded to tensile vibrational of NH2-groups related to Q, and it is the indication of Q loading in the formulation. Moreover, XRD data have detected the encapsulation of ChiNH/Q. The ChiNH/Q showed a potent antimicrobial inhibitory effect and exerted cytotoxic effects against HepG2 cancer cells with IC50 values of 100 µg/mL. Moreover, our data have shown that ChiNH/Q effectively reduced (65%) the average expression level of all the three DNMTs (p<0.05) and significantly increased (1.01%) the 5-methylated cytosine (5-mC) levels in HepG2 cells.ConclusionOur results showed for the first time the bioavailability and potentiality of ChiNH/Q as a potent antimicrobial and anticancer agent against cancer cells. Our result provided evidence that ChiNH/Q could effectively reduce cellular DNMT expression levels and increase genomic global DNA methylation in HepG2 cancer cells. Our results suggest a potential clinical application of nanoparticles as antimicrobial and anticancer agents in combination cancer therapy.

Synthesis and characterization of nitrogen-doped carbon dots as fluorescent nanoprobes with antimicrobial properties and skin permeability

Nitrogen doped carbon dots (N-doped C-dots) were prepared using polyethyleneimine (PEI) and citric acid (CA) as precursors via the hydrothermal method. Various weight ratios of PEI and CA, 1:0.5, 1:1, and 1:2, were used in the synthesis of N-doped C-dots. The N-doping of prepared C-dots was confirmed with an FT-IR peak that was observed at 1652 cm−1 assigned to N–H bending. The hydrodynamic diameters of prepared N-doped C-dots were 70.2 ± 6.9, 32.2 ± 4.7, and 11.5 ± 3.1 nm by DLS measurements, and surface charges values were 1.32 ± 0.8, 0.14 ± 0.2, and −1.57 ± 0.7 mV, for 1:0.5, 1:1, and 1:2 wt ratio based on PEI of CA, respectively. A high quantum yield 53 ± 4.8% according to quinine sulfate standard was determined for 1:1 C-dot prepared from 1:1 wt ratio of PEI:CA. The C-dots were found to inhibit growth of both Gram-negative and Gram-positive bacteria with no noted toxicity to mammalian cells in vitro. Skin permeation studies indicate that the particles permeate into and through the dermis within hours, indicating their potential use for topical administration.

SYNTHESIS OF SOME 2,3-DIHYDRO-1,3,4-OXADIAZOLES AND 4,5-DIHYDRO-1,2,4-TRIAZOLES AS ANTICANCER AGENTS

Objective: The main objective of this work was to synthesize and evaluate the novel 2,3-dihydro-1,3,4-oxadiazole and 4,5-dihydro-1,2,4-triazole derivatives for cytotoxic activities.&#x0D; Methods: The 2,3-dihydro-1,3,4-oxadiazole derivatives 4a-h were synthesized by cyclization of N'-(substituted-benzylidene) isonicotinohydrazide 3a-e in refluxing acetic anhydride. The 2,3-dihydro-1,3,4-oxadiazole derivatives 4a-h were converted into the corresponding 4,5-dihydro-1,2,4-triazoles 5a-h using ammonia. All the synthesized compounds were identified, depending on the physical and spectral data. Title compounds were assessed for their cytotoxic activity against human cancer cell line (MCF-7) by using Sulforhodamine B (SRB) colorimetric assay.&#x0D; Results: All the synthesized compounds showed characteristic peaks in FTIR, 1HNMR and Mass spectral analysis. The results of the in vitro cytotoxic activity revealed that the compound 4c exhibited equipotent cytotoxic activity with an IC50 value of 8.04 µM when compared with that of standard drug doxorubicin (IC50= 8.02 µM). The reminder compounds have shown good to moderate cytotoxic activities when compared with that of a reference standard.&#x0D; Conclusion: We synthesized a series of title compounds in quantitative yields. Most derivatives showed moderate to good cytotoxic activity.&#x0D;

Iron and zirconium modified luffa fibre as an effective bioadsorbent to remove arsenic from drinking water

Porous luffa plant fibre (LF) was grafted with Fe and Zr, and the ability of the fabricated adsorbents to remove arsenate (As(V)) from water was investigated in batch and column adsorption experiments. The Langmuir adsorption capacity (mg g−1) at pH 7 of LF was found to be 0.035, which increased to 2.55 and 2.89 after being grafted with Fe (FLF-3) and Zr (ZLF-3), respectively. Grafting with Fe and Zr increased the zeta potential and zero point of charge (ZPC) of LF (from pH 3.9 to 7.4 for Fe grafting and to 7.6 for Zr grafting), due to chemical bonding of the metals, possibly with the hydroxyl and carboxylic groups in LF as indicated in FTIR peaks. Zeta potential and ZPC decreased after As adsorption owing to inner-sphere complexation mechanism of adsorption. The increase of pH from 3 to 10 progressively reduced the adsorbents’ adsorption capacity. Co-existing anions weakened the As(V) removal efficiency in the order, PO43− > SiO32− > CO32− > SO42−. Adsorption kinetics data fitted well to the Weber and Morris model, which revealed initial fast and subsequent slow rates of intra-particle As diffusion into the bigger pores and smaller pores, respectively. Column adsorption data fitted well to the Thomas model with the predicted adsorption capacities in the same order as in the batch adsorption experiment (ZLF-3 > FLF-3 > LF).

Visible light photo-Fenton catalytic properties of starch functionalized iron oxyhydroxide nanocomposites

The photocatalytic properties of nanocomposites of akageneite and goethite have not been explored in literature. The present communication uses a green synthesis protocol to produce rod-shaped akageneite/goethite nanocomposites. The functionalization of these nanocomposites by starch changed their shapes to rice grain-like, improved the hydrophilicity of the surfaces of the nanoparticles, blue-shifted the Fe-O bond FTIR peak, and also altered their band structure to make them better visible light photocatalysts. The Mott–Schottky plots of (both starch functionalized and non-functionalized) thenanocomposites exhibited positive and negative slope parts, confirming the formation of a p-n heterojunction. Starch functionalization changed not only the band gap but also the band positions and the relative band alignments of the components making the nanocomposites. Degradation of p-nitrophenol (PNP) and methyl orange (MO) were efficiently photocatalyzed by these nanocomposites under visible light photo-Fenton conditions. The degradation of PNP and MO followed zero-order kinetics under photo-Fenton conditions. Starch functionalization of the nanocomposite led to significant improvement in the photo-Fenton activity of this catalyst in comparison to that exhibited by the non-functionalized counterpart. The photo-Fenton activities of both nanocomposites for PNP and MO degradation are among the best reported in literature till date.

Development and Evaluation of Mucoadhesive Tablets of Cinnarizine Using Carboxymethylated Guar Gum by Compression Coating Technique

The e study was designed to perform carboxymethylation of guar gum and to develop mucoadhesive tablets of cinnarizine by compression coating technology. Carboxymethyl guar gum was synthesized and characterized by FTIR, SEM, XRD and DSC techniques. Inner core tablets of cinnarizine were compression coated with guar gum and carboxymethylated guar gum. The formulated mucoadhesive tablets were evaluated for various tablet parametric tests viz. hardness, friability, content uniformity, thickness. Ex vivo mucoadhesion strength and in vitro drug release studies were also conducted. Appearance of new FTIR peaks, surface morphology analysis by SEM, reduction in crystallinity by XRD and appearance of the endothermic peak in DSC thermogram point out towards successful carboxymethylation of guar gum. Mucoadhesive strength of F1CGG to F4CGG batches of mucoadhesive tablets prepared with carboxymethyl guar gum found higher than F1GG to F4GG batches of tablets prepared with guar gum. Carboxymethyl guar gum exhibited sustained release effect on in vitro release cinnarizine from compression coated mucoadhesive tablets. The study confirms that carboxymethylation of guar gum improves the mucoadhesive properties of pure guar gum. Also, the compression coating of carboxymethylated guar gum enhances the gastric retention time and sustained release of cinnarizine. Carboxymethyl guar gum can be used as mucoadhesive polymer for developing different mucoadhesive drug delivery systems.