A review of the chemical modification and applications of starch

The modification of starch using esterification, etherification, oxidation, and Schiff base formation has garnered significant interest owing to its wide-ranging applications in different sectors. This overview delves into the various techniques utilized for modifying starch molecules and examines their utilization in adsorption, adhesive formulations, pharmaceuticals, nanoparticle synthesis, and film manufacturing. The article delves into the synthesis pathways associated with esterification, etherification, oxidation, and Schiff base formation, underscoring their influence on the physicochemical characteristics of starch. Furthermore, it thoroughly examines the application of modified starch in pollutant adsorption processes, as adhesive agents in industries, as excipients in pharmaceutical formulations, and as crucial elements in the creation of starch-based nanoparticles and films

Antimicrobial activity and molecular docking studies of some imidazo[2,1-b]thiazole derivatives

The synthesis of bioactive molecules is of major importance in the pharmaceutical industry. In this context, the study was conducted to determine the antimicrobial and antifungal potential of four chalcone-based imidazo[2,1-b]thiazole derivatives already synthesized by our research group. The synthetized compounds obtained in good yield were evaluated for their antibacterial and antifungal activities against E. coli, Staphylococcus aureus, Pseudomonas aeruginosa and Fusarium, the results obtained are compared with the standard. Molecular docking studies were utilized to forecast the potential of these molecules as antimicrobial agents, the results obtained in vitro antibacterial were well confirmed by this method

Synthesis of thermal insulator using chicken feather fibre in starch-clay nanocomposites

Incorporating chicken feather fibre (CFF) into natural based-nanocomposite comprising of glycerine plasticizedcassava starch binder with bentonite (BNT) as nanofiller, a thermal insulator (TIN) was synthesized. Central Composite Design (CCD) Response Surface Methodology was employed to carry out the experimental design using two factors (CFF and BNT) along with one response (thermal conductivity) to produce nine materials as insulators, comprising of 0%, 5%, and 10% BNT based on 8 g initial weight of CFF. A sample without CFF was used as the control. Developed thermal insulators were subjected to thermal conductivity tests using Lee's disc method at a steady state. The best insulator is TIN-4 with the lowest thermal conductivity of 0.0313 W/(mK) and the highest insulation property of 114.63 m2k/W, while TIN-10 with no CFF has the highest thermal conductivity of 0.0549 W/(mk) and lowest insulation property of 48.1603 m2k/W. Proportionate use of chicken feather fibre in starch-clay nanocomposite will help synthesize an effective thermal insulator with minimum cost

Adsorption of essential oil components of Lavandula angustifolia on sodium modified bentonite from Nador (North-East Morocco)

The analysis of essential oil has basically one technical goal: to achieve the best possible separation performance by using the most effective, available and current technology of chromatography. The present work aimed to study the formulation created by the adsorption of active components of Lavandula angustifolia essential oil on sodium modified bentonite. Essential oils were obtained from dried leaves of L. angustifolia; they were extracted by hydro distillation and were analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography flame ionization detector (GC-FID). The retention indices (RI) were calculated for each detected component. Besides, the characterization of the individual components making up the oils was performed with the use of a mass spectrometry (MS) library. The quantitative analysis was made by GC-FID. The identified components accounted for more than 95% for each essential oil. The results of these studies show that organic contaminant adsorption is dependent, to some degree, on solid-liquid ratio and the competition system of mixture. The adsorption amount of terpenics and the others components could be the results of many factors. The selectivity was affected by the abundance of each component in the crude essential dependent on the particle size fractions; the finer fractions adsorbed higher amounts. The selectivity of adsorption was affected by the polarity of terpenic components.Keywords: Clays, bentonite, essential oil, adsorption, Lavande angustifolia.African Journal of Biotechnology, Vol 13(31) 3413-342

Characterization and Adsorption Study of Thymol on Pillared Bentonite

peer reviewedPillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 Å, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg∙g−1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R² ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min

Ball-milling effect on Indonesian natural bentonite for manganese removal from acid mine drainage

The influences of mechanical milling on Indonesian Natural Bentonite (INB) characteristics and manganese (Mn) removal from acid mine drainage (AMD) were investigated. The INB characteristics were observed by scanning electron microscope (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption for specific surface area (SSA) and microporosity measurement, cation exchange capacity (CEC) and particle size distribution (PSD) analyzer. Four minutes milling with frequency 20 Hz on INB caused morphological change which showed more crumbled and destructed particle, lost the (001) peak but still retained the (100) peak that indicated delamination of montmorillonite mineral without breaking the tetrahedral-octahedral-tetrahedral (T-O-T) structure, rose the CEC from 28.49 meq/100g to 35.51 meq/100g, increase in the SSA from 60.63 m2/g to 104.88 m2/g, significant increase in microporosity which described in the t plots and decrease in the mean particle size distribution peak from 49.28 μm to 38.84 μm. The effect of contact time and effect of adsorbent dosage on Mn sorption was studied. Both unmilled and milled samples reached equilibrium at 24 hours and the pH rose from 4 to 7 in first 30 minutes. The Mn removal percentage increased significantly after milling. Using Langmuir isotherm, the maximum adsorbed metals (qmax) also increased from 0.570 to 4.219 mg/g

Use of chalky algae in the manufacturing of clayey ceramic membranes: Microstructural and dielectric behavior for electrochemical applications

International audienceNovel ceramic membrane filters were manufactured from kaolino-illitic clays and calcareous algae (up to 20 wt.%) as porogenic agent. The produced membranes were investigated using X-ray diffraction, thermogravimetric analysis, scanning electron microscope, impedance spectroscopy, and Fourier-transform infrared spectroscopy. All of the filtration suitability, electrical properties, and dielectric behavior were assessed and interrelated to the microstructure. It was found that the original clay minerals were involved in the mineralization development while the inclusion of large pores (8–12 μm) was observed at high magnification alongside porosity increase (up to 70%) due to the addition of the bio-based pore-former. Both electric and dielectric measurements revealed that the sintering process was governed by the densification phenomenon and was accompanied with lower activation energy. The order of magnitude of the values taken by electrical impedance was close to average Mega-Ohms suggesting the suitability of the produced ceramic membranes as an electrical insulator for typical electrochemical devices. The tests of filtration have shown that the ceramic membranes produced operate normally in the microfiltration range for a period of 50 min without clogging and at pressures up to 0.12 bar. Conclusively, the developed ceramic membranes could be considered for applications in industrial wastewater treatment and electrochemical media.In addition to this, a perspective has been proposed on the improvement paths or designs for ceramic membrane filters with good performance in wastewater treatment present in some electrochemical environments as well as methods to cope with the challenges regarding the performance of such materials

Synthesis, Characterization, DFT, and Thermogravimetric Analysis of Neutral Co(II)/Pyrazole Complex, Catalytic Activity toward Catecholase and Phenoxazinone Oxidation

The pyrazole-pyridin-2-amine, as a tridentate pyrazole ligand, and its neutral Co(II)/pyrazole complex were prepared using a direct method with a high yield. The desired pyrazole ligand and its complex were subjected to several physicochemical and thermal analyses; moreover, the DFT-like optimization of MEP, HOMO/LUMO, and TD-DFT correlated well with their experimental relatives. Additionally, the oxidation catalytic activities of the Co(II)/pyrazole complex, such as the catecholase of catechol to o-quinone and the phenoxazinone of 2-aminophenol to 2-aminophenoxazinone, were also evaluated under mild RT conditions and atmospheric oxygen

Synthesis, Characterization, DFT, and Thermogravimetric Analysis of Neutral Co(II)/Pyrazole Complex, Catalytic Activity toward Catecholase and Phenoxazinone Oxidation

The pyrazole-pyridin-2-amine, as a tridentate pyrazole ligand, and its neutral Co(II)/pyrazole complex were prepared using a direct method with a high yield. The desired pyrazole ligand and its complex were subjected to several physicochemical and thermal analyses; moreover, the DFT-like optimization of MEP, HOMO/LUMO, and TD-DFT correlated well with their experimental relatives. Additionally, the oxidation catalytic activities of the Co(II)/pyrazole complex, such as the catecholase of catechol to o-quinone and the phenoxazinone of 2-aminophenol to 2-aminophenoxazinone, were also evaluated under mild RT conditions and atmospheric oxygen