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Background Streptococcus thermophilus were considered one of probiotic bacterial strain; found in milk, cheese, and yogurt, that providing health benefits to humans. Due to their probiotic potentiality, S. thermophilus can be very helpful in replacing chemicals preservatives. This study came out to investigate the probiotic activity of ten S. thermophilus isolates obtained from raw cow milk in eastern Morocco against multidrug-resistant bacteria (MDR) bacteria: Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC: 25922 and 35218). Besides their antioxidant potential, bile salts tolerance as well as their antibiotic susceptibility, were evaluated Result The results showed remarkable in vitro inhibitory ability of the studied S. thermophilus isolates against the tested multidrug-resistant bacteria, as reported for S. thermophilus CFS and supernatant against Staphylococcus aureus (ATCC29213), confirming their potential as antibacterial agents. The mixtures of NaOH, catalase and proteinase K showed no inhibition zones against all tested multidrug-resistant bacteria; suggesting the main antibacterial effect of all isolates based on acids, hydrogen peroxide and/or proteins. For the antioxidant activity, the DPPH inhibition values varied between 18.97% and 44.44%, for the bacterial isolate ST9 and ST5, respectively. Notably, S. thermophilus isolates were able to survive up to 6h of incubation with a concentration of 0.1% of bile salt at 37°C. Thus, ST5 could be considered as the most promising bacterial isolate in terms of antioxidant activity. All isolates of S. thermophilus exhibited sensibility to all tested antibiotics except for rifampicin and trimethoprim-sulfamethoxazole compared to the standards proposed by the European committee on antimicrobial susceptibility testing. Conclusions The tested isolates were exhibited excellent antibacterial and potential antioxidant activities. In addition to that, these isolates were reported to resist rifampicin and trimethoprim-sulfamethoxazole antibiotics. These findings presage the use of S. thermophilus isolates as good probiotics.

Volatile organic compounds (VOCs) are considered a major public health concern in industrial location areas. The presence of exposure to (VOCs) has raised concern regarding the health effects caused by chronic human exposure as this will increase cancer diseases in the village. An analytical method has been developed and modified to help us detect 38 VOCs in the blood of 38 volunteers who are related to a carpentry shop at the parts-per-trillion level. To measure and evaluate the potential risk, several devices, such as portable passive monitors and air-collected samples, in addition to blood concentration, were used to study three different occupational groups. Ten of the volunteers are employees at the shop, 10 volunteers live very close to the shop, and 10 of them are students in an elementary school very close to the shop. In this study, we developed an automated analytical method using headspace (HS) together with solid-phase microextraction (SPME) connected to capillary gas chromatography (GC) equipped with quadrupole mass spectrometry (MS). The detection limits for the method used were measured in the range from 0.001 to 0.15 ng/L, using linear calibration curves that have three orders of magnitude. The detected concentrations ranged from 3 ng L−1 for trichloroethene to 91 ng L−1 for toluene and 270 ng L−1 for 2,4-diisocyanate, which was derived from the paint solvents used for the wood in the carpentry shop and the paints on the walls. More than half of all assessed species (80%) had mean concentration values less than 50 ng L−1, which is the maximum allowed for most VOCs. The major chemical types among the compounds quantified will be those we found in our previous study in the surrounding air of a carpentry workshop in Deir Ballout in Palestine, which were toluene diisocyanate and butyl cyanate. Some were found to be highly present air. Most of the measurements were below the guidelines of the World Health Organization (WHO). Despite the fact that this study only involved a small number of smokers, smoking was found to be connected with several blood and breath components. This group includes unsaturated hydrocarbons (1,3-butadiene, 1,3-pentadiene, 2-butene), furans (2,5-dimethylfuran), and acetonitrile. The proposed classification of measured species into systemic (blood-borne) and exogenous volatiles is strictly hypothetical, as some species may have several origins.

In this work, we have studied and optimized the technique of the synthesis of hydroxyapatite by a new method called "dissolution/reprecipitation", with the aim of finding the appropriate operating conditions for the synthesis of apatitic nanoparticles. The optimum value of the size of the apatitic nanoparticles being 65 nm. The theoretical results presented by this experimental design have been verified: the experimental results are similar to the results estimated by this model. Scanning electron microscopy images confirm the morphology of apatitic nanoparticles and verify the validity of our mathematical modeling. Analysis by infrared spectroscopy and X-ray diffraction of the products obtained by the method shows that the final phases are pure and stoichiometric. The method of dissolving-reprecipitating apatitic nanoparticles has several advantages over other methods, such as purity and nanoscale sizes of the final phase. The new dissolution / reprecipitation method is a synthesis technique which makes it possible to prepare very pure hydroxyapatite nanoparticles without the intervention of precursors (salts) which generally generate impurities in the final product. The new method can then be used in the synthesis of apatitic biocomposites using biopolymers.

The rheological behaviors of four aromatic amine-based epoxy monomers for were evaluated and compared. The four epoxy monomers are useful for making cross-linked epoxy resin, the monomers are triglycidyl-2 aminophenol (TGAP), triglycidyl-2-aminothiophenol (TGATP), tetra-functional tetraglycidyl-1,2-phenylenediamine (TGPDA), and tetraglycidyl-4-methyl-1,2-phenylenediamine (TGMPDA). The monomers were cured with 4, 4’-methylene dianiline (MDA). The rheological behaviors of the cured products were also evaluated. The cured epoxy monomers were characterized by FT-IR and the curing process was monitored using a Haake Mars rheometer equipped with a cone-plate geometry. During the curing process, the change in the viscosity was monitored as a function of time at various temperatures. The temperatures ranged from 120 °C to 150 °C. The curing process was temperature dependent; at 150 and 120 °C, a sharp rise in the viscosity was observed. The viscosity of TGPDA-MDA and TGMPDA-MDA (tetra-functional) showed a higher increase in the viscosity compared to other matrices an indication of faster formation of the 3D network. The storage moduli G’ and the loss moduli and G” conditions of the macromolecular matrix structures of TGMPDA-MDA was higher than that of the macromolecular matrix structures of TGAP-MDA, TGATP-MDA and TGPDA-MDA. Quantum chemical calculations were performed using the density functional theory (DFT) to investigate the influence of electronic and molecular structure of the investigated compounds before and after cross-linking with MDA unit(s) of the examined epoxy resins.

Iron phosphate, Fe2 (HPO4)3*4H2O, is synthesized at ambient temperature, using the inorganic sol–gel method coupled to the microwave route. The experimental conditions for the gelling of Fe (III)-H3PO4 system are previously defined. Potentiometric Time Titration (PTT) and Potentiometric Mass Titration (PMT) investigate the acid–base surface chemistry of obtained phosphate. Variations of surface charge with the contact time, Q a function of T, are examined for time contact varying in the range 0–72 h. The mass suspensions used for this purpose are 0.75, 1.25 and 2.5 g L−1. The point of zero charge (PZC) and isoelectric point (IEP) are defined using the derivative method examining the variations $$\frac{{{\text{dpH}}}}{{{\text{d}}t}} = f\left( {{\text{pH}}} \right)$$ dpH d t = f pH , at lower contact time. A shift is observed for PZC and IEP towards low values that are found to be 2.2 ± 0.2 and 1.8 ± 0.1, respectively. In acidic conditions, the surface charge behavior of synthesized phosphate is dominated by $$\overline{{ > {\text{POH}}}}$$ > POH ¯ group which pKa = 2.45 ± 0.15. Q against T titration method is performed for synthesized Fe2 (HPO4)3*4H2O in NaCl electrolytes. The maximal surface charge (Q) is achieved at the low solid suspension. Hence, for m = 0.75 g L−1, Q value of 50 coulombs is carried at μ = 0.1 and pH around 12, while charge value around 22 coulombs is reached in the pH range: 3–10. The effect of activation time, Q and pH on sodium insertion in iron phosphate, were fully evaluated. To determine the optimal conditions of the studied process, mathematical models are used develop response surfaces in order to characterize the most significant sodium interactions according to the variation of the pH, Q, the contact time and the contents of the synthesized material.

Corrosion inhibition propriety of (2E)-3-phenylprop-2-enal, known as trans-cinnamaldehyde (TCA) for mild steel in 1 M HCl medium was investigated by weight loss technique (WL), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and density functional theory approach, using the B3LYP/6-31G(d,p) basis level. It was shown that the inhibition efficiency augmented with TCA concentration. The potentiodynamic polarization was revealed that TCA acted as a mixed type inhibitor with prevalence cathodic. The adsorption isotherm of TCA on the mild steel surface was found to obey to El-Awady, Temkin and Florry–Huggins. The scanning electron microscope analysis was confirming that a protective adsorbed film of the studied inhibitor showed on the metal surface. Moreover, the most relevant global and local quantum chemical parameters according to the inhibition effect were demonstratedthat the adsorption of the studied compound on the steel surface is mostly associated to its active electrophile and nucleophile sites.

This study aims to explore the inhibitory action of certain derivatives of Schiff’s base, namely 4-(pyridin-2-ylimino) pentan-2-one (CE5),4-(pyrimidin-2-ylimino) pentan-2-one (CE4) and 4-((1H-tetrazol-5-yl) imino) pentan-2-one (CE20) against mild steel (MS) corrosion in 1 M HCl by the gravimetric, stationary and transient method. For additional information on the inhibitory properties of the studied compounds, scanning electron microscopy (SEM) and functional density theory (DFT) calculations were also performed. The effectiveness of the Schiff’s base derivatives studied follows the order: CE20 > CE4 > CE5. The electrochemical impedance curves show that the corrosion reaction is controlled by a charge transfer process, while the potentiodynamic polarization curves indicate that the synthesized compounds act as a mixed-type inhibitor. The adsorption process follows the Langmuir isotherm. Kinetic, as well as thermodynamic parameters, were calculated and discussed. The increase in EHOMO and decrease in gap energy ΔEgap lead to an increase in the inhibition efficiency. Results obtained from quantum chemical studies are in good agreement with quantum chemical parameters and experimental inhibition efficiencies.

Film directing toward applications in food packaging and counter top coating with ability of inhibiting antimicrobial growth is important for maintaining food freshness and reducing bacteria transmittance. In this work, cellulose-based fatty amine with antimicrobial functionality covalently attached to cellulose backbone was synthesized. The synthesis was performed in a three-step process that involves cellulose oxidation, amination of oxidized cellulose using fatty amine and reduction. Films composites with various proportions of cellulose-based amine and cellulose triacetate were prepared. The films morphologies, tensile strengths, percent of elongation and contact angle were evaluated. The cellulose-based amine showed excellent antimicrobial activity against gram positive and moderate activity toward gram-negative bacteria. The films prevented the growth of gram-positive bacteria by 99.99%. Results indicate a good mechanical properties and bioactivities of produced film which makes it suitable for use in food wrapping application.

Recently, there were reported investigations in the field of corrosion prevention, about finding effective environment-friendly alternative inhibitors, to replace toxic and harmful compounds. In the present review, the corrosion inhibition of some materials in various corrosive media, using imidazole derivatives, is summarized. Several organic compounds reported by many researchers are herein presented. This review considers previous studies conducted on various inhibitors, and provides an overview of some experimental techniques performed in order to investigate their corrosion properties.

Two pyrimidine-pyrazole derivatives have been investigated as corrosion inhibitors for mild steel in acidic medium using weight loss measurement, polarization curve and electrochemical impedance spectroscopy (EIS). The results obtained reveal that these compounds perform as corrosion inhibitors for mild steel in 1 M HCl. The values of inhibition efficiency calculated from three experimental techniques are reasonably in good agreement. The adsorption process of these compounds on surface of mild steel obeys to El Awady isotherm. Also, the adsorption process of inhibitors studied explaining by surface analysis (EDX). This work followed by in silico approach studies. Firstly, we used Marvinsketch.18 program in order to detect predominant form of inhibitors in electrolytic solution and then computed by Gaussian 09 based on the DFT method at B3LYP/6-31G (d,p).The results obtained theoretically are in good correlation with those obtained experimentally.

In the last decade calcium phosphate composites and other related biomaterials, were commercially used for bone substitution or allogrefts. In this study, a method was developed for purpose. In thi...

BackgroundHuman and veterinary antibiotics are typically discharged as parent chemicals in urine or feces and are known to be released into the environment via wastewater treatment plants (WWTPs). Several research investigations have recently been conducted on the removal and bioremediation of pharmaceutical and personal care products (PPCPs) disposed in wastewater. ResultsSiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), and nitrogen adsorption-desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the experimental and theoretical of different adsorption coefficients. The Langmuir and Freundlich adsorption models were used and the study showed better match with Fruendlich model. The removal capacity was depending on pH and increased by increasing pH The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94 %. The sample was simply regenerated by soaking it for a few minutes in 1N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. Thermodynamic study also showed endothermic, increasing randomness and not spontaneous in nature. The findings of the DFT B3LYP/6-31+g (d,p) local reactivity descriptors revealed that nitrogen atoms and p-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The negative values of the adsorption energies obtained by molecular dynamic simulation indicated the spontaneity of the adsorption process. ConclusionThe global reactivity indics prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indices concluded that the active centers for the adsorption process are the nitrogen atoms and the p-electrons of the pyrimidine and benzene rings. Furthermore, the positive value of the maximum charge transfer number (DN) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

Water purification from toxic metals was the main objective of this work. A composite in film form was prepared from the biomaterials hydroxyapatite, chitosan and glycerol using the dissolution/recrystallization method. A nanoparticle-based film with a homogenous and smooth surface was produced. The results of total reflectance infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA/DTA) demonstrated the presence of a substantial physical force between composite components. The composite was tested for its ability to absorb Cd2+ and Zn2+ ions from aqueous solutions. Cd2+ and Zn2+ adsorption mechanisms are fit using the Langmuir model and the pseudo-second-order model. Thermodynamic parameters indicated that Cd2+ and Zn2+ ion adsorption onto the composite surface is spontaneous and preferred at neutral pH and temperatures somewhat higher than room temperature. The adsorption studies showed that the maximum adsorption capacity of the HAp/CTs bio-composite membrane for Cd2+ and Zn2+ ions was in the order of cadmium (120 mg/g) > Zinc (90 mg/g) at an equilibrium time of 20 min and a temperature of 25 °C. The results obtained on the physico-chemical properties of nanocomposite membranes and their sorption capacities offer promising potential for industrial and biological activities.

The expanding amount of remaining drug substances in wastewater adversely affects both the climate and human well-being. In the current investigation, we developed new cellulose acetic acid derivation/zeolite fiber as an effective technique to eliminate erythromycin (ERY) from wastewater. The number of interchangeable sites in the adsorbent structures and the ratio of ERY to the three adsorbents were identified as the main reasons for the reduction in adsorption as the initial ERY concentrations increased. Additionally, for all adsorbents, the pseudo–second-order modeling showed better fitting for the adsorption than the pseudo–first-order modeling. However, the findings obtained in the pseudo–first-order model were still enough for explaining the sorption kinetics of ERY, showing that the surface displayed all chemisorption and physi-sorption adsorption processes by both adsorbents. TheR2for the second order was very close to 1 for the three adsorbents in the case of pseudo–second-order. The adsorption capacity reached 17.76 mg/g. The three adsorbents showed negative values of ΔH, and these values were −6,200, −8,500, and −9600 kJ/mol for zeolite, CA, and ZCA, respectively, and this shows that the adsorption is exothermic. The desorption analysis shows no substantial loss of adsorption site after three trials, indicating higher stability and resilience of the three adsorbents, indicating a strong repeatability of their possible use in adsorption without contaminating the environment. In addition, the chemical attitude and possible donor–acceptor interactions of ERY were assessed by the quantum chemical parameters (QCPs) and NBO analysis performed, at the HF/6-311G** calculations.

The experimental design strategy is applied to study and model the preparation of oxygenated apatite obtained by the dissolution-reprecipitation of hydroxyapatite in a hydrogen peroxide. The oxygenated apatite obtained is characterized by infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The characterization by analyzes (IR, DRX, SEM) shows that the dissolution-repricipitation method gives better results for oxygenated apatite containing molecular oxygen. For this, we studied the influence of the four factors such as the temperature of the reaction medium, the pH, the concentration of hydrogen peroxide and the mass of the attacked hydroxyapatite. As well as their interactions whose goal is to increase the molecular oxygen insertion rate in apatitic tunnel. The orthogonal centered composite plane allowed us to establish an equation that links the insertion rate according to the factors studied, and we obtained an optimum of introduction of 5.06%.

A cellulose derivative with multiple coordination sites for metals composed of cellulose powder and 1,2-pheneylnediamine was synthesized and evaluated as an adsorbent for metal ions from wastewater. The cellulose powder was generated from the solid waste of the olive industry. The adsorption efficiency of the cellulose amine polymer toward Fe(III) and Pb(II) was investigated as a function of adsorbent dose, temperature, pH, and time. The adsorption parameters that lead to excellent adsorption efficiency were determined. In addition, the polymer showed an excellent extraction efficiency toward approximately 20 metal ions present in a sewage sample. The cellulose amine derivative had several coordination sites that included amine, hydroxyl, and aromatic groups. The diversity and frequency of the coordination sites explained the high efficiency of the polymer for metal ions. The thermodynamic analysis results supported the spontaneous adsorption efficiency of the polymer at room temperature. The adsorption process fit well with the Langmuir adsorption isotherm model.

This research was aimed to assess the photosynthetic activities of barley (Hordeum valgare L.), clover (Trifolium repens L.), and pearl millet (Pennisetum glaucum (L.) R. Br.) under different salin...

In latest years, industrial development, intended using agricultural fertilizers and inappropriate treatment of wastewater have risen poisonous contaminants like metal ions, organic and inorganic ions such as nitrate in water and soil. The adsorption which consists of multiwall carbon nanotubes (MWCNTs) functionalized with chitosan have been synthesized in a composite to produce a magnetic adsorbent. Composites of MWCNT/nano-iron oxide were characterized by Transmission Electron Micrograph, Vibrating Sample Magnetometry, Thermogravimetric analysis and Fourier transform infrared spectroscopy. To investigate the adsorption efficiency for the adsorption of nitrate onto magnetic multiwalled carbon nanotubes functionalized with chitosan, the effect of solution conditions on each adsorption process were studied. These conditions involve the effect of contact time, pH value, temperature, adsorbent dose and the initial concentration of adsorbate. The best equilibrium isotherm model for each adsorption process was studied and the results showed the data follows Langmuir adsorption model with capacity (qm) more than 322 (mg/g). The kinetics of adsorption was also investigated, and the data were best fitted to pseudo-second order. In addition, Van’t Hoff plot was used to measure thermodynamics parameters to study the adsorption process which showed the spontaneous process. The synthesized adsorbent was also regenerated, and the percentage removal before and after adsorbent recovery was determined and showed high-efficiency removal. In conclusion, results showed that the resulting product has high adsorption efficiency and it showed strong complexation properties with nitrate ions.

The present study aimed to evaluate the inhibition effect of an organic compound, namely, (E -N'-(2-hydroxybenzylidene) isonicotinohydrazide (BIH), for carbon steel corrosion in a 1.0 M HCl solution, by using weight loss (WL), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results show that BIH is a good inhibitor, and the percentage of inhibition efficiency increases on its higher concentrations. The maximum inhibition efficiency of 94% was obtained at 5×10-3 M. Polarization studies revealed that the BIH compound acts as a mixed type inhibitor. EIS showed that increasing the concentration of the inhibitor led to an increase in the charge transfer resistance and a decrease in the double layer capacitance. It was found that the adsorption of this compound obeyed the Langmuir adsorption isotherm. The associated activation energies and thermodynamic parameters of the adsorption process were evaluated and discussed. The temperature effect was studied in the range from 303 to 333 K. In addition, quantum chemical calculations based on the density function theory (DFT) and Monte Carlo simulations were done to support the experimental results.

The present study is based on the investigation of performance of C,N-bipyrazole receptor grafted onto silica surface (SG2P) of adsorption Arsenic (AS) from aqueous solutions. The effects of operating parameters that include pH, contact time, concentration of As and dosage of adsorbent on adsorption were accomplished. The results clearly showed that the removal efficiency of As was decreased with an increasing of As concentration, pH, and temperature, while it was continuously increasing with time and adsorbent dose. Moreover, the removal efficiency of Cr (VI) adsorption was 75% corresponding to pH; temperature (°C), initial concentration (ppm) and weight of dose (g) were 6, 25, and 0.04 respectively at 24 hours. The adsorption capacity of the synthesized sorbent (SG2P) for arsenic at pH < 7 from pseudo second order in batch experiments was efficient at 20 minutes. Furthermore, the results obtained in this study presented that the antimicrobial activity was limited where the Escherichia coli (ATCC25922) and Staphylococcus aureus (ATCC25932) were as a reference strains, while, the SG2P was able to inhibit growth only at high concentration (MIC = 1.5625 mg/ml).

The goal of this work was to develop polymer-based heterocycle for water purification from toxic pesticides such as difenoconazole. The polymer chosen for this purpose was cellulose nanocrystalline (CNC), two cellulose based heterocycles were prepared by crosslinking with 2,6-pyridine dicarbonyl dichloride (Cell-X), and derivatizing with 2-furan carbonyl chloride (Cell-D). The synthesized cellulose-based heterocycles were characterized by SEM, proton NMR, TGA and FT-IR spectroscopy. To optimize adsorption conditions, the effect of various variable such as time, adsorbent dose, pH, temperature, and difenoconazole initial concentration were evaluated. Results showed that, the maximum difenoconazole removal percentage was about 94.7%, and 96.6% for Cell-X and Cell-D, respectively. Kinetic and thermodynamic studies on the adsorption process showed that the adsorption of difenoconazole by the two polymers is a pseudo-second order and follows the Langmuir isotherm model. The obtained values of ∆G ° and ∆H suggest that the adsorption process is spontaneous at room temperature. The results showed that Cell-X could be a promising adsorbent on a commercial scale for difenoconazole. The several adsorption sites present in Cell-X in addition to the semi crown ether structure explains the high efficiency it has for difenoconazole, and could be used for other toxic pesticides. Monte Carlo (MC) and Molecular Dynamic (MD) simulation were performed on a model of Cell-X and difenoconazole, and the results showed strong interaction.

The main objective of this study to develop an epoxy resin that is stable and does not homopolymerizes on storage. A series of di- and tetra-glycidyls of aromatic amines and alcohols were prepared. Diglycidyl of 4,4 '-dihydroxydiphenyl sulfone (DGEDDS) was prepared in a one step process by condensation with epichlorohydrin. The tetra-glycidyl of 4,4′-methylenedianiline (TGEDA) and 4,4′-(propane-2,2-diyl) diphenol, Tetraglycidyl 4-amino benzene sulfonamide (TGABSA) were obtained in satisfactory yields. The structures of the epoxy monomers were confirmed by FTIR, 1H NMR and 13C NMR spectroscopy. The viscosimetric study of the synthesized epoxy monomers showed that the bifunctional aromatic phenolic resins (DGEBA and DGEDDS) exhibited high thermostability making it possible to avoid homopolymerizing and self-crosslinking during storage. Unlike the tetra-glycidyl resins of aromatic amines (TGMDA, TGABSA and TGEDA) showed the disadvantage of self-crosslinking under the effect of temperature. The results indicate that the storage temperature for the tetra-glycidyl resins should not excess 5 °C. The bifunctional aromatic DGEDDS, should exceptional thermal stability and high fire resistance upon hardening it showed a Td of about 220 °C with a residual percentage of 40% at 500 °C. Hardened DGEBA which was used as a reference showed a Td of about 212 °C. The high thermal stability could be attributed to the presence of the sulfone group. The bifunctional aromatic amine resin TGEDA, when it is hardened with MDA it showed a Td equal of 296 °C. The increase in density of crosslinking in the case of bifunctional aromatic amine resin (TGEDA) cured with MDA enhanced the thermal resistance compared to those bifunctional aromatic phenolic resins and bifunctional aromatic amine resin (TGMDA and TGABSA). The Heteroskedasticity and autocorrelation Consistent Covariance, HAC was performed on the epoxy resins to explain the results of the thermal degradation of the examined epoxy resins as a function of the EHOMO and ELUMO, which are obtained from the optimized structure of the epoxy resins using the density functional theory. Consequently, the HAC model was validated by comparing the predicted theoretical results to experimental of thermal degradation of the studied epoxy monomers.

In our study, we prepared three adsorbents to extract the emergent drug (ibuprofen) from an aqueous solution, such as cellulose nanocrystalline (CNC), magnetic cellulose nano-crystalline (MNC), and silver cellulose nanocrystalline (AgNC)). The cellulose was con-verted into CNC and then it was converted to MNCs and AgNCs. However, the NCs and AgNCs showed excellent extraction efficiency toward ibuprofen (IBP) compared to MNCs. Five variables were monitored and evaluated during the extraction process: time, pH, temperature, dosage, and IBP concentrations. The adsorption process followed Langmuir isotherm model and pseudo-second order. The negative ∆G° values indicate that the adsorption is favorable and spontaneous at different temperatures.

In recent years, concerns have been raised about the occurrence of active raw materials and pharmaceutical ingredients that may be present in water, including wastewater, in the pharmaceutical industry. Wastewater treatment methods are not enough to completely remove active pharmaceuticals and other waste, thus, this study aims to assess the use of a multiwall carbon nanotube after derivatization and magnetization as a new and renewable absorbent for removing ibuprofen from an aqueous medium. The adsorbents were prepared by first oxidizing a multiwall carbon nanotube and then deriving the oxidized product with hydroxyl amine (m-MWCNT&ndash, HA), hydrazine (m-MWCNT&ndash, HYD), and amino acid (m-MWCNT&ndash, CYS). Adsorbents were characterized by Raman spectroscopy, Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM and TEM), Brunauer&ndash, Emmett&ndash, Teller surface area analysis (BET), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Batch adsorption studies were conducted to study the effects of pH, temperature, time, and initial concentration of the adsorbate. Adsorption isotherm, kinetics, and thermodynamics studies were also conducted. The results show that the optimal pH for nearly complete removal of Ibu in a short time at room temperature was 4 for three adsorbents. The adsorption followed the Langmuir isotherm model with pseudo-second-order kinetics. The percentage of removal of ibuprofen reached up to 98.4%, 93%, and 61.5% for m-MWCNT&ndash, CYS, m-MWCNT&ndash, HYD, and m-MWCNT&ndash, HA respectively. To the best of our knowledge, the grafted MWCNTs presented in this work comprise the first example in the literature of oxidized MWCNT modified with such functionalities and applied for ibuprofen removal.

In this work, we have studied, formulated, prepared, and characterized the rheological and electrical behavior of a composite material based on an epoxy resin Diglycidyl Ether of Bisphenol A (DGEBA) reinforced with hexaglycidyl cyclotriphosphazene (HGCP). The epoxy system was cured with 4,4&rsquo, methylene dianiline (MDA). DGEBA-HGCP-MDA epoxy composite materials with reinforced HGCP which varied from 5% to 10% by weight were prepared by mixing in the molten state. The morphology was evaluated by SEM. The rheological behavior was studied using small deformation rheology. The electrical characterization was carried out with a frequency variation range from 1 Hz to 100 KHz at room temperature. These measurements revealed that the rheological and electrical behaviors strongly depend on the quantity of HGCP in the DGEBA matrix. The linear viscoelastic properties study reveals that the modulus of elasticity G&rsquo, is dependent on the amount of HGCP present in the epoxy resin DGEBA. The capacitance-frequency measurements suggest a distribution of localized states in the band gap of the blends.