Volume 7, Issue 2

Natural laterite can be regarded as a strong adsorbent due to its special structure and composition. In this study, the laterite was modified by manganese oxide (MnO 2 ) to create a new good adsorbent for treating phosphate and fluoride in water environment. Under the optimized conditions of the adsorbent dose (pH 6, temperature 20°C, and the contact time 180 min), laterite, doped manganese, with diameter of grains from 0.1 to 0.5 mm has maximum adsorption capacity of 31.25 mg/g and 10.99 mg/g for phosphate and fluoride, respectively. The characteristics of the manganese doping laterite were confirmed using various techniques like SEM, BET, XRD, EDX. The adsorption process of the material was investigated by both kinetic models (pseudo-first and second orders) and isotherm models (Freundlich and Langmuir). This new material was tested for treatment of wastewater taken from the superphosphate fertilizer factory, with the results obtained showing high potential for application in reality.

Silver nanoparticles (AgNPs) were biologically synthesized in an eco-friendly manner using aqueous leaf extract of Origanum majorana plant and silver nitrate (AgNO 3 ) solution. Size, shape, and crystallinity of the biosynthesized AgNPs were determined by using a transmission electron microscope (TEM). Zeta potential analyzer was used to prove the stability of the metallic nanoparticles, while Fourier transform infrared spectroscopy was used to identify the bioreducing and capping agents. AgNPs were electrochemically investigated using cyclic voltammetry (CV), while the optical properties of the metallic nanoparticles were studied using UV-Vis and fluorescence spectroscopies. According to TEM images, AgNPs are spherical with an average size of 35 nm. TEM also refers to the presence of mono and polycrystalline AgNPs. The value of zeta potential (−39 mV) proved the stability of AgNPs caused by capping molecules of O. majorana plant. CV studies showed that AgNPs were electrochemically investigated at 0.39 mV. AgNPs showed a surface plasmon resonance peak at 440 nm, while the emission peak was detected at 466 nm. These nanoparticles are promising for many industrial and medical applications.

The activity of the α-amylase enzyme incubated in aqueous solutions with a high concentration (80.2% w/v) of imidazolium ionic liquid, [C 4 C 1 im]Br, has been studied. Contrary to the complete deactivation hitherto reported in the literature, a way is found to preserve the enzyme, by adding the appropriate salt, so that the activity is saved for a long grace period. Different salts are studied and the concentration is optimized in view of the enzyme hydration. Due to the limited amount of free water available to the enzyme at higher salt concentrations, the activity decreases. The best results are obtained by adding potassium acetate, 0.200 mol dm −3 . Some 90% of the activity is saved in a 2-week incubation, and a half activity remains in a month. Precipitates are observed in the samples of the solution without salt. No precipitation is noticed when acetate is present. Regardless of the fluorescence quenching, the activity is saved. The effect of the acetate on the α-amylase preservation is probably related to the ability of the acetate anion to interact with the imidazolium cation thus shielding the enzyme from being salted out and precipitated. Compared with potassium bromide, which does not interact with [C 4 C 1 im]Br, precipitation and fast inactivation are observed.

Zinc oxide nanoparticles (ZnO NPs) were synthesized using barberry ( Berberis vulgaris ) extract via heating method. The effects of the amount of barberry extract (15–35 ml) and the reaction time (30–90 min) on the antibacterial (clear zone diameter, mm) and antioxidant (%) activities of the synthesized ZnO NPs were investigated by response surface methodology. Main reducing and stabilizing compounds of barberry extract were identified by gas chromatography and Fourier transform infrared spectroscopy. Spherical ZnO NPs with an average size of 20 nm were successfully fabricated at optimal synthesis conditions using 35 ml of barberry extract and 30 min reaction time. ZnO NPs were determined to have a zeta potential of –15.3 mV and an antioxidant activity of 28.8%. The antibacterial activity of fabricated ZnO NPs was tested against Staphylococcus aureus and found to possess significant (p<0.05) inhibitory effect against this microorganism.

In this research, 80 wt.% hydroxyapatite (HA)/20 wt.% calcium aluminate (CA) bioceramic nanocomposites were synthesized by using three liquid phase green methods. X-ray diffraction, energy dispersive X-ray spectroscopy, and field emission-scanning electron microscopy were conducted for the characterization of nanocomposites. To study the mechanical (compressive strength, flexural strength, and hardness) and physical (density, porosity, and water adsorption) properties of nanocomposites, these materials were sintered by spark plasma technique, after which the desired properties were measured. To study the bioactivity of samples, SBF vitro test was used. After reviewing the obtained data, results showed that the bioactivity and mechanical properties of the synthesized HA/NA nanocomposites were improved compared with those of the nano-components that form them and those of similar micro-scale composites. The measured maximum compressive strength, flexural strength, and hardness of the synthesized nanocomposites were 440 MPa, 137 MPa, and 202 H V , respectively. The corresponding amounts for hydroxyapatite nanoparticles were 350 MPa, 115 MPa, and 124 H V , respectively.

Chitosan-silver nanoparticles (Ag@CS) as a novel drug delivery system have been developed for fungicide drug. In this study, the synergistic effect of silver nanoparticles (AgNPs), chitosan (CS), and fungicide zineb (Zi) was investigated as antifungal materials against Neoscytalidium dimidiatum in dragon fruit. More specifically, Ag@CS were prepared by embedding of AgNPs in CS polymer and then combined with Zi. Transmission electron microscopy was used to confirm the morphology and size of Ag@CS. The diameter of spherical nanoparticles is around 4.11±0.37 nm. Furthermore, the formation of Ag@CS was characterized by Fourier transform infrared and X-ray diffraction analysis. The thermostability properties of these nanoparticles were also determined by thermogravimetric analysis. Especially the antifungal activity of Ag@CS has shown antifungal ability better than each component alone, analyzed by zone of inhibition method against N. dimidiatum . These results suggest the potential applications of Ag@CS in the development of nanomaterials for antibiotic application.

Calcium sulfate dihydrate (CaSO 4 ·2H 2 O) was prepared from the chemical reaction between calcium carbonate from duck eggshell and sulfuric acid at 25°C. The CaSO 4 ·2H 2 O was dried in an oven at 110°C and transformed into calcium sulfate hemihydrate or plaster of Paris (CaSO 4 ·0.5H 2 O). The CaSO 4 ·0.5H 2 O was calcined at 700, 800 and 900°C and transformed into anhydrite or anhydrous calcium sulfate (CaSO 4 ). The raw material used in this research was the duck eggshell, the waste eggshell generated from food processing industries. The obtained anhydrous calcium sulfate or anhydrite has true density, color, specific surface area, pore diameter and particle size equal to 2.95 g/cm 3 , white powder, 3.57 m 2 /g, 96.98 Å and 3.983 μm, respectively. In addition, other characteristics, microstructures, phase transformation and physical properties of raw materials and calcium sulfates were investigated and reported here using X-ray fluorescencemeter, Fourier transform infrared spectrometer, differential thermal analyzer, thermogravimetric analysis, scanning electron microscope, X-ray diffractometer, pycnometer method and Brunauer-Emmett-Teller.

The present work deals with the production of nanocapsules containing a natural corrosion inhibition component. Azadirachta indica was encapsulated in urea-formaldehyde polymeric shell using ultrasound-assisted and conventional approaches of in situ polymerization. Subsequently nanocapsules were incorporated into clear epoxy polyamide to develop the green self-healing corrosion inhibition coating. The actual performance of the coating was evaluated based on the studies involving the repair of the crack of high solid surface coating. Corrosion inhibition of the healed area has been evaluated using the electrochemical impedance spectroscopy and immersion test based on the use of standard epoxy coating. The obtained results confirmed better corrosion protection in terms of the electrochemical impendence spectroscopy data and Tafel plot. It was found that current density decreases from 0.0011 A/cm 2 (for standard epoxy coating) to 5.22 E −7 A/cm 2 as 4 wt% nanocapsules incorporated in coating.

The purpose of this study was to formulate and validate a new green high-performance liquid chromatography-ultraviolet (HPLC)-UV method for quick quantification of rosuvastatin calcium (ROC) in standard drugs. The results showed a combination of ethanol:methanol:ethyl acetate (6:3:1 v/v) at a rate of 1.0 ml/min to be the best for identifying ROC and its separation from its breakdown products. The identification of ROC was achieved using a NUCLEODUR 150 mm×4.6 mm RP C8 column packed using 5 μm filler as the stationary phase and detection was performed at 254 nm. The technique developed was checked for linearity, selectivity, accuracy, precision, robustness and sensitivity as well as specificity. The usefulness of the proposed process was confirmed by analyzing ROC in a prepared self-nanoemulsifying drug delivery system (SNEDDS) and over-the-counter products. The amount of ROC in SNEDDS was found to be 98.38%. The HPLC-UV system we developed effectively determined the ROC peak along with its breakdown products which confirmed the stability-indicating property of the projected system. The system could also be used to compare the solubility of rosuvastatin nanoparticles in standard drugs. These outcomes indicated that the developed HPLC could be effectively used for the regular investigation of ROC in standard drugs, various pharmaceutical formulations and drug release samples.

The costs associated with the production of biodiesel fuel (BDF) are directly affected by the nature of the feedstock material and the methods used during the production process. In Southeast Asia, many non-edible oils are used to produce BDFs, as exemplified by the recent use of the non-edible oil derived from Vernicia montana Lour. in Laos and Vietnam for the production of BDF. In this work, we developed an improved procedure for the production of BDF from Vernicia montana oil consisting of 80.3%±0.5% α-eleostearic acid moiety (C18:3) using a co-solvent method. Furthermore, the stability of the BDF was evaluated based on its iodine value and unsaturated ester content. The optimized production conditions were determined to be as follows: methanol/oil molar ratio of 6:1, 1% (wt/wt) KOH, 20% (wt/wt) acetone as a co-solvent, and a reaction temperature of 40°C. Under these conditions, we achieved a BDF conversion efficiency of 99%±0.3% within 30 min of initiating the transesterification process. Notably, the BDF produced from Vernicia montana oil showed good stability to air at temperatures ≤30°C for 1 month, showing similar stability properties to the BDF produced from rapeseed oil.