Journal of Applied Research in Chemistry
Year:2021 | Volume:14 | Issue:4|Papers Count:12

Although the membrane technology has advantages such as the high capability of separation, flexibility of operation, efficiency, etc. compared to conventional methods, fouling is the main limitation for the further use of membrane technology, mainly because of the inherent hydrophobicity of membrane materials. To overcome this drawback, nanocomposite membranes are used. Among membrane processes, nanofiltration has applications in groundwater, surface water and wastewater treatment as well as pre-desalination operations. Since NF process is performed at a lower pressure, it is a much more energy efficient process. In this review, modification of polysulfone/polyatersulfone membranes is investigated with regards to anti-fouling performance. The mechanism of fouling reduction clearly shows that surface hydrophilicity improves at the polysulfone/polyatersulfone membranes, based on different membrane modification methods. In addition, the fabrication of nanocomposite membranes resulting from the participation of nanoparticles in the polymeric matrix mixed membrane, their properties and applications using organic fillers (such as graphene and carbon nanotubes) have been thoroughly studied. Furthermore, the characterization techniques applied for modified membranes have been discussed. This comprehensive study concludes with some recommendations for future research and development of NF membranes.

One of the most important factors affecting membrane formation via phase inversion method is the viscosity of the polymer solution. In this research, with the aim of providing a solution to predict the performance of polymeric membranes based on viscosity data, the influence of dope solution temperature and casting speed on the viscosity of PVDF solution were investigated. For this purpose, the viscosity of PVDF/DMAc solution with LiCl and PEG additives was measured at the temperature range of 10-50 ° C and atmospheric pressure with a precise rheometer. The performance of PVDF ultrafiltration membrane with composition of PEG 3 wt. % and LiCl 7 wt. % was evaluated and an empirical model using response surface methodology and central composite design was developed to predict membrane permeability and rejection based on viscosity data and two variables of solution temperature and casting speed. Scanning electron microscopy, pure water permeability, and membrane rejection tests were used to characterize the membranes. The results show that the model is in good agreement with the experimental data and based on the results, the casting speed of 1. 2 m/min and the temperature of the polymer solution at 50 ° C are the optimum conditions for membrane fabrication to obtain the membrane with maximum flux and rejection.

Zinc oxide is an important industrial material used in different industries, in particular rubber industries. This compound like the other industrial materials has amounts of impurities and thus removal of those due to their undesirable influences on rubber compounds curing and environment, is taken into consideration. In this study, chemically bonded chlorosulfonylcalix[4]arene to silica gel was synthesized by using the methods in literature reports, afterwards it was used as an absorbent to remove cadmium ions from zinc oxide solution. The adsorption of metal ions from aqueous solution was investigated by atomic absorption spectroscopy. Sorption percentage and adsorption capacity were calculated by using the ions concentration in each level. The results showed that cadmium ions were removed from zinc oxide solution effectively by tetrachlorosulfonylcalix[4]arene-silica while silica gel without any reactive agent, could not remove the ions from the solution.

The main purpose of food packaging is to prevent it from being destroyed by physical, chemical, and microbial contamination. A new strategy that has recently been considered for this aim is the use of smart-active food packaging. In this study, ethylene-vinyl acetate copolymer (EVA) was used as an abundant, flexible, and nontoxic polymer for the preparation of packaging films. Anthocyanin extracted from red cabbage was stabilized on the montmorillonite and was added to the film as a timetemperature indicator. Furthermore, other materials such as ZnO, rosemary essential oil, and modified montmorillonite were used in order to achieve antimicrobial, antioxidant, and air barrier activity in the fabricated smart-active food packaging films. The nanoparticles and prepared films were characterized by XRD and FESEM analysis. The performance of the prepared films was investigated by antioxidant capacity test by DPPH, in vitro test, minimum bactericidal concentration (MBC), minimum inhibition concentration (MIC), antibacterial test and capacity of oxygen absorbance. Results showed that those film which contained additives such as rosemary, ZnO, and modified montmorillonite exhibited remarkable antibacterial and antioxidant activity compared to pristine EVA film.

In this article, silver nanoparticles capped with 4- benzenesulfonamideaminothiophenol (BSATP-AgNP) were synthesized. The formation of synthesized nanoparticles was characterized by UV– Vis spectroscopy, FTIR, TEM, and NMR. The interactions between the silver nanoparticles with calf-thymus DNA, human serum albumin (HAS) and bovine serum albumin (BSA) were investigated by UV-Vis spectroscopy, fluorescence spectroscopy, circular dicroism (CD) spectroscopy, viscosity measurements, and molecular docking studies. Circular dicroism data showed that binding of BSATP-AgNPs to DNA resulted in changes in the structure and conformation of DNA. This indicates a minor groove mode of binding. Fluorimeteric studies showed a decrease in fluorescence intensity of the BSATP-AgNPs in the presence of increasing amounts of DNA solution. The results of CD data indicate that the conformation of HSA and BSA molecules is changed signifi cantly in the presence of BSATP-AgNPs. The negative Δ H and Δ S values indicate that the main interactions between BSATP-AgNPs and HSA were hydrogen bonding and weak van der Waals forces. The results of the site marker competitive experiment confirmed that the BSATP AgNPs can bind to HSA located within site I (subdomain IIA) and BSA within site II. The experimental results were in agreement with the results obtained via a molecular docking study. This study provided important insight into the interaction of BSATPAgNPs with DNA and serum albumin, facilitating further investigation on the pharmacological behavior of BSATP-AgNPs.

A new biodesulfurization method has been considered using Pseudomonas aeruginosa supported on polyethylene (PE) for biodesulfurization (BDS) of dibenzothiophene (DBT) as heavy fuel oil sulphur compound model. The obtained results according to Spectrophotometric analysis at 325 nm showed that 90. 54 % of DBT at the primary concentration about 5 (mg. L ), pH=7, biocatalyst dosage of 0. 1 g, in 37 ° C and after 90 min of contact time has been removed. These optimum conditions have been applied for heavy fuel oil (mazut) samples and the biodegradation of their total sulphur content (TSC) has been investigated by X-ray fluorescence spectrometer (XRF). The obtained results revealed that 33. 075 % of total sulphur content from mazut sample has been removed. Kinetic study predicted the chemisorption process as the rate determining step, as it followed the pseudo-second-order rate equation. The data for DBT adsorption on biocatalyst fitted to the Freundlich isotherm model. Morphology and surface functional groups of the biocatalyst have been investigated by SEM and FTIR, respectively.

Because of ever-increasing demand for the use of biodegradable lubricants and additives, it is necessary to design and synthesize new additives. In the present study, two ionic liquids with imidazole cations were synthesized and characterized by H NMR and FTIR spectra. The use of ionic liquids based on the imidazolium cation and anion bis(trifluoromethylsulfonyl)amide (TFSA) and tris(tetrafluoroethyl)trifluorophosphate (FAP) has been investigated. These additives are known to be green additives as these compounds lack zinc, an element prohibited by environmental protection organizations. These materials were used as an additive to ISO 32 grade hydraulic oil. Their lubricating properties, such as cinematic viscosity at 40° C, copper corrosion, 4-ball weld point test, sulfated ash, oil/water separating test, and air release from oil were examined, which showed better results than the ordinary additive zinc dialkyldithiophosphate (ZDDP).

Acetanilide is one of the most important intermediate chemicals in the pharmaceutical industry, which is used as an antiseptic and analgesic, and so far no research has been done to treat and destroy the effluent containing this contaminant. In this study, for the first time, synthetic wastewater containing Acetanilide has been treated with ozonation process and the effect of process variables was investigated using BoxBehnken design method in semi− batch reactor. The optimum condition was achieved at 15 mg/l of ozone, the pH at 9 and the initial concentration of Acetanilide at 50 mg / l, and in 30 minutes 100% of the Acetanilide and 61. 5% of Chemical Oxygen Demand (COD) were removed. The most important influencing factor was pH, and due to the formation of hydroxyl radical, the efficiency of pollutant degradation in alkaline environment was higher. Due to the production of intermediate carboxylic acid, the rate of destruction of Acetanilide was much higher than the rate of mineralization and removal of COD. The rate equation of pollutant degradation was of the pseudo− first order type and the rate constant and half− life of the degradation reaction were determined to be as 152. 2×10-3 min-1 and 4. 55 min, respectively.

In this study, new derivatives of (2-chloro-5-(trifluoromethyl)phenyl)carbamic acid phenyl ester, were synthesized using cysteine, tryptophan, aspartic acid, and isoleucine amino acids as well as their methyl esters. These compounds were selected from the four main classes of amino acids: (polar without charg), (nonpolar and aromatic), (polar with negative charge), and (nonpolar and aliphatic), respectively. The molecular structures of all products were identified and confirmed using HNMR and FT-IR spectroscopic methods. Finally, pure compounds ((2-chloro-5-(triflouromethyl)phenyl)carbamoyle)-D-tryptophan and 1-(2-chloro-5-(triflouromethyl)phenyl)-2, 6-dioxohexahydropyrimidine-4-carboxylic acid, were tested for their effects on the pheochromocytoma cells’ morphology using microscopic imaging. The calculated lethal dose was 10  M and the assay time was 48 h. Visual inspection of invert microscope images revealed acceptable lethal effect of synthetic products.

The aim of this study was to investigate the loading and release conditions of quercetin using a pH-sensitive nanocarrier. Initially, tin oxide nanoparticles and magnetic nanocomposites were synthesized; then, chitosan biopolymer functionalized with folic acid was used to coat the magnetic nanocomposite. In order to optimize the nanocarrier, loading times (4, 3, 2, 1 and 5 hours), the amount of nanocarrier (10. 5 and 15 mg), drug concentration (15, 25, 35, and 50 ppm), and solvent (methanol and Ethanol) were investigated with an iron to tin ratio of 0. 2. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size distribution were used to investigate the properties of nanoparticles, and according to the results, synthesized nanocomposites had a homogenous structure with particle size between 5 to 25 nm, the amount of carrier was 10 mg, the concentration of the drug was 15 ppm with methanol solvent and the loading time was 4 hours with a maximum loading efficiency of 85% and was selected as the optimal nanocarrier. The maximum adsorption capacity was obtained based on the Langmuir model and Sips were 36. 2322 mg / g and 37. 3915 mg / g, respectively. Absorption synthetic studies have shown that quercetin adsorption has followed second-degree synthetics. In order to evaluate the intelligent release of the drug, its release in laboratory conditions using phosphate salt solution with buffer properties in different pHs was investigated and the synthesized nanocarrier showed complete release in the acidic pH of 2. 5.

In this research, the reinforcing effect of calix[4]arene macrocycle on the green strength in the rubber matrix is investigated for the first time. The calixarene derivative is mixed into raw rubber compounds before the vulcanization process. The bead and ply rubber compounds used in the motorcycle tire are selected for the tests. Due to the rawness of the rubber compounds and the absence of crosslinks to measure the green strength, elongation at break values of the raw compounds were considered as the indicator. Calixarene molecules can connect; this connection is through H-bonding between two calixarene moiety. These molecules pair each other two by two and make colonies. Paired calix molecules act as a bridge between rubber chains. Therefore, they reinforce the compounds and behavior similar to composites could be seen. Consequently, when they hold the chains, the green strength of the compounds increases.

Metal corrosion represents a significant cost to the industry. Detection and prevention are possible by use of various methods including electrochemical technics and corrosion inhibitors. In the present study, the performance of two types of inhibitors, 5bromo-2-(((1-hydroxybutan-2-yl)imino)methyl)phenol (C11H14BrNO2) and 2-((2-((2hydroxybenzylidene)amino)ethyl)amino)phenol C15H16N2O2, was investigated in reducing corrosion rate of A106 Gr. b alloy steel used in oil pipelines in corrosive medium of 1M sulfuric acid. The comparison between these two inhibitors and the role of nitrogen in their performance and their life span were investigated by cyclic voltammetric electrochemical technique and fast Fourier transform method for data processing. It was found that the C11H14BrNO2 inhibitor by having a slower kinetics in the decomposition process can stand longer and was more effective than the other corrosion inhibitor. This C11H14BrNO2 inhibitor also has a much better performance in preventing carbon corrosion, despite having a lower nitrogen element in the structure because of its favorable spatial structure and better placement of “ N” on the corroded metal surface.