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Numerous fibers combinations are used in the construction industry for improving the fracture resistance of hybrid fiber-reinforced concrete (HyFRC). In this paper, the effects of fiber combination on the mechanical properties of FRC are studied. For this purpose, different volume percentages of the added fibers with different compositions are used to investigate their influences on the fracture toughness and tensile strength of the concrete. Different fiber compositions including the steel, carbon and polypropylene of different volume ratios can be added to the concrete specimens for measuring their tensile strength and critical stress intensity factor of the samples containing preexisting cracks. Therefore, some concrete specimens are prepared by adding 1% carbon fibers and different ratios of steel and polypropylene fibers. The direct tensile testing machine and the indirect Brazilian tensile test apparatus are used to measure the tensile strength of the HyFRC specimens in the laboratory. Some specimens are also used to measure the fracture toughness (Mode I) of the HyFRC by using the novel compression-to-tensile load converting device implemented in the universal tensile testing machine. The novelty of this paper is to render a new approach for the measurement of tensile strength and fracture toughness of hybridized fiber-reinforced concrete (HyFRC) by adding different kinds of fibers. These experimental results show that by changing the ratios of the carbon, steel and polyethylene fibers the tensile strength and fracture toughness of HyFRC specimens change accordingly.

In this study, an alternative application of supported liquid membranes (SLMs) containing specific ion carriers dissolved in supra molecular solvent (SUPRA) to the selective and simultaneous separation of Ag+ and Pb2+ ions from a dilute source solution is introduced. A two-membrane three-compartment cell was used. Two micro-porous polypropylene supported membranes loaded with dibenzyl-diaza-18-crown-6 (DBzDA18C6) and dicyclohexyl-18-crown-6 (DC18C6) dissolved in supra molecular solvent (SUPRA) were used for selective transport of silver (I) and lead (II) ions, respectively. At first, vesicles of decanoic acid (SUPRA), as green solvent, were synthesized. Then, each of two mentioned crown ethers was easily dissolved into the SUPRA phase and used as the selective membrane phase for facile and simultaneous transport of lead and silver ions through the designed cell. The DBzDA18C6-loaded membrane was placed between the first and the second compartments (MP1), whereas the DC18C6-loaded membrane was placed between the second and the third ones (MP2) of the transport cell. Using this cell assembly, simultaneous separation and transport of Ag+ and Pb2+ ions are possible from a 1.854 × 10–4 M picric acid source solution containing these two species and several other interfering ions into the two corresponding receiving compartments of the transport cell. The silver (I) and lead (II) ions quantitatively transport during 75 and 15 min of time into two individual receiving solutions, respectively. Sodium thiosulfate (0.6 M at pH 6.4) and sodium pyrophosphate (0.25 M at pH 7) were used as selective stripping agents for Ag+ and Pb2+ ions (RP1 and RP2), respectively.

In this research, hydrophobic task-specific room temperature ionic liquid (HTSRTIL) as a green modifier was synthesised and electrostatically in-situ immobilised on the magnetic multi-wall carbon n...

In this article, a highly efficient method based on coupling magnetic solid-phase extraction and dispersive microsolid-phase extraction was proposed to preconcentrate Hg2+. In this technique, extraction of Hg2+ was carried out by magnetic graphene-based bucky gel (MGBG). MGBG was prepared by dispersing magnetic graphene (MG) in a [Hmim][BF4]. Utilization of [Hmim][BF4] led to better dispersion of MG in aqueous solution and decreased the extraction time. In addition, MG was separable by an external magnet so filtration steps were omitted. The sorbent was characterized by X-ray diffraction, scanning electron microscopy, alternating gradient force magnetometer and Fourier transform infrared spectroscopy. The preconcentration conditions were optimized as pH value of 1 ± 0.2, dithizone concentration of 8 × 10−6 mol L−1, [Hmim][BF4] volume of 50 µL, MG amount of 5 mg, n-hexane volume of 200 µL and elution time of 5 min. The quantification of Hg2+ was carried out by UV–visible spectroscopy. Under the optimized conditions, limit of detection (2.11 μg L−1), relative standard deviation (2.59%), preconcentration factor (150) and linearity of dynamic range (7–100 μg L−1) were calculated which showed high reliability of sorbent to preconcentrate Hg2+. The effect of interference ions was investigated. The method was successfully applied to preconcentrate Hg2+ in fish and water samples. To better understand the adsorption of Hg2+ onto MGBG, thermodynamic of adsorption is reported.

The adsorptive removal of hazardous materials of organophosphorus insecticides by adsorbents with high adsorption capacities is highly desirable. In this work, we present the removal of two representative organophosphorus insecticides, Dichlorvos and Metrifonate by two exceptionally stable Zr-based MOFs of UIO-66 and UIO-67. The MOFs were characterized by TGA, FTIR, SEM, XRD, BET and XPS analyses. Effect of some parameters such as adsorbent dose, contact time, pH and ionic strength on the removal efficiency of Dichlorvos and Metrifonate were investigated. The mechanism of interaction was carefully investigated by XPS and FTIR. The isotherm and kinetic data were accurately described by the Langmuir and pseudo-second-order models. The adsorption capacities in UIO-67 approached as high as 571.43 mg g−1 for Dichlorvos and 378.78 mg g−1 for Metrifonate, which were much higher than UIO-66. Compared to other works this work has shown better adsorption capacity and cost efficient. The calculated removals for the samples are in the range from 97.8 to 99%, indicating that the UIO-67 can be applied for removal of Dichlorvos and Metrifonate in real samples.

Zwitterionic dispersive magnetic solid phase extraction (ZI-DMSPE) was developed through in situ binding of glycine on the magnetic graphene oxide, electrostatically. This highly selective sorbent was applied for the determination and preconcentration of trace levels of nitrite in soil, sausage, water samples (tap, mineral, and rain), and vegetables (potato, onion, spinach, radish, and lettuce) prior to its determination by UV–Vis spectrophotometry. The major advantage of the method is the analyte adsorption in both acidic and basic media. The sorbent was characterized by SEM, XRD, EDS, and FT-IR. Several parameters affecting ZI-DMSPE were optimized. Under the optimal conditions, LOD and RSD were obtained 17 ng L−1 and 1.3% respectively. Preconcentration factor and sorption capacity of the proposed method were 666 and 238 mg g−1 respectively. Accuracy was assessed by comparing results with those obtained by direct determination using ion chromatography and spiked real samples.

In this work, a highly selective method is presented for the preconcentration of cadmium. The developed magnetic solid-phase extraction is based on the adsorption of Cd(II)-N,N′-bis(salicylidene)ethylenediamine (BSE) complex on Fe3O4-embedded graphene oxide nanocomposite. The N,N′-bis(salicylidene)ethylenediamine ligand was used prior to extraction in order to increase the selectivity of the Cd(II) extraction process. Cd(II) concentrations were determined by flame atomic absorption spectroscopy. The π–π interaction between the Cd(II) and BSE complex and graphene oxide results in selective adsorption of the Cd complex compared to complexes of BSE with other heavy metal ions. The central composite design technique was performed to optimize the effective chemical parameters, including pH, amount of adsorbent, and ligand concentration. Under the optimum conditions, the method showed a linear concentration range of 1.0–130.0 ppb, limit of detection of 0.4 ppb with the relative standard deviation of 3.9% for blank solutions (n = 8), and a preconcentration factor of 50 for determination of Cd(II). The kinetics, thermodynamics, and isotherm of the adsorption process were also studied. The proposed method was successfully applied to water and vegetables samples.

In this work, a new magnetic nanocomposite was prepared for the specific isolation of CD45 positive cells. Acrolein (AC) and acrylated β-cyclodextrin (ACD) were used as monomers in order to polymerize on the surface of Fe₃O₄ magnetic nanoparticles (MNPs) via surface initiated radical polymerization. Polyacrolein-β-CD (PACD) functionalized Fe₃O₄ MNPs (Fe₃O₄@PACD) was achieved and subsequently, fluorescein conjugated IgG anti-human CD45 was immobilized onto Fe₃O₄@PACD. Antibody conjugation onto the latter nanocomposite was accomplished according to IgG encapsulation in cyclodextrin cavity and Schiff base formation between aldehyde groups of MNPs and primary amines of antibody. The characterization analysis of the bare Fe₃O₄, Fe₃O₄@PACD nanocomposite, and Fe₃O₄@PACD-Ab were investigated using XRD, VSM, FT-IR, H-NMR, TGA, SEM, TEM, and flow cytometry techniques. The results showed that the antibody has been successfully immobilized onto Fe₃O₄@PACD. Moreover, the fabricated nanocomposite was used for selective capturing of CD45+ cells among other peripheral blood mononuclear cells (PBMCs). The results of TEM and fluorescence microscopy confirmed the ability of the conjugated system for efficient cell capturing.

Cuminum cyminum is famous for its spicy fruits used for culinary and therapeutic properties worldwide. Brine shrimp test was performed for detecting cytotoxic fractions and subfractions. Ethyl acetate (EA) and hexane (HE) fractions demonstrated LC50 of 52.40 and 60.77 µg/ml against Artemia salina while other fractions showed no toxicity (LC50> 500 µg/ml). Bioguided elucidation of EA and HE fractions were carried out and cytotoxicity of pure compounds were investigated against breast cancer cell lines (MCF-7 and MDA-MB-231) and normal cell line (NIH/3T3) by MTT assay. Four flavone structures as luteolin, apigenin, luteolin-7-O-glucoside and apigenin-7-O-glucoside from EA and cuminoid A from HE were purified and identified. Luteolin-7-O-glucoside demonstrated potent anticancer activities against MCF-7 cell line (IC50 of 3.98 µg/ml) with selectivity index of 8.0. In conclusion, flavonoids especially luteolin-7-O-glucoside play a significant role in cytotoxic effect of C. cyminum fruits and can be introduced as candidate for chemopreventive and chemotherapeutic drugs.

A new class of polymeric sorbents based on deep eutectic solvents (DESs) is introduced. These materials are obtained from simple and inexpensive precursors via an energy-efficient process. The primary benefit of these sorbents is that they possess the unique characteristics of DESs and porous materials simultaneously. Moreover, the possibility of tailoring deep eutectic solvents allows designing a specific polymer for a desired analyte, based on its physical and chemical properties. In this work, the deep eutectic solvent of tetrabutylammonium bromide and acrylic acid (1:2 molar ratio) was prepared and then polymerized under solventless condition. The synthesized polymer was characterized by FT-IR spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and Brunauer, Emmett and Teller analysis (BET) to evaluate the properties of the sorbent. The poly (TBAB-2AA DES) was applied as a selective sorbent for preconcentration of lead from food and water samples prior to its quantification by flame atomic absorption spectroscopy (FAAS). Variable factors affecting the extraction were optimized, and under the optimum conditions, the calibration plot was linear in the range 5.0–250.0 μg L−1. The relative standard deviation was (for n = 5) (RSD)

In this work, we evaluated the applicability of hydrophobic carboxylic acid-based deep eutectic solvents (DESs) as environmentally friendly alternatives to common organic solvents in microextraction methods based on solidification of floating drop (SFD). Due to the limited number of solvents that can be used in SFD, the introduction of new solvents can help in the development of these attractive methods. Deep eutectic solvents consisting of tetra-n-butyl ammonium bromide (TBAB) and carboxylic acids were prepared and used as extraction solvent. They had the desirable characteristics such as low density, suitable freezing point and proper hydrophobicity which make them suitable alternatives to conventional organic solvents for SFD. With the help of the synthesized hydrophobic DESs, a simple, fast, efficient and environmentally friendly microextraction method was developed based on solidification of deep eutectic solvent (SFDES) without using any organic solvent. The proposed organic solvent-less microextraction method based on SFDES was applied in the analysis of polycyclic aromatic hydrocarbons (PAHs) as model compounds in environmental water samples. By coupling this method with high-performance liquid chromatography–fluorescence detection, we achieved low LOD values which is a necessity in the ultra-trace analysis of PAHs in environmental water samples. Under the optimized conditions, good linearity and low limits of detection of 0.7–6.6 ng L−1 were obtained. The analysis of six PAHs in real water samples gave acceptable relative recoveries ranging from 83 to 117% with 5.4–10.5% intra-day relative standard deviations (RSD) and 4–7.1% interday RSD.

Polymeric compounds are main types of advanced materials to prepare antibacterial coating as well as water treatment system hence this work was aimed to prepare a polymeric nanostructure with excellent bacteria capture efficiency. Dendronized melamine – resorcinol was synthesized by a condensation reaction. To simplify polymer collection from aqueous solutions, a magnetic nanocomposite of the polymer was also prepared. For this purpose, CoFe2O4 nanoparticles were synthesized by solid-state combustion route using cellulose as fuel. Bacteria removal efficiency was studied by uptake of Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria from water, milk and fruit juice samples. Effective parameter on the capturing efficiency including; solution pH, contact time and nanocomposite dosage were optimized. Results confirmed the positive role of presented nanostructure for fast capturing of bacterial pathogens with high efficiency (more than 99%).

Magnetic MnFe2O4 and CuFe2O4 - 2- aminobenzoic acid – phenylenediamine nanocomposite was prepared using the catalytic activity of the magnetic ferrites as an efficient oxidizer. Antimicrobial activity of nanocomposite has been studied by capturing of Bacillus subtilis as sample pathogenic contaminant. Moreover, the nanocomposite was applied for selective adsorption of copper ions as well as methylene blue removal from aqueous solution. Dye and metal adsorption equilibrium time were 1 and 5 min and adsorption followed the second-order model. Moreover, the sorbent can be considered as dye super – adsorbent with a capacity of 7089 mg of methylene blue per gram of adsorbent.

This study presents a new and novel technique for the determination of the tensile strength of concrete specimens. A prismatic concrete specimen with a hole at its centre is placed in a new device, called seesaw, and with the use of a conventional loading machine in compression mode, a tensile stress is applied to the specimen for the determination of the indirect tensile strength. In this study, two types of concrete mixes were used for preparation of specimens. The mixes were made of gravel, sand, cement, water, polypropylene fibre, and admixtures. Concrete specimens were subjected to tensile loading using a new load convertor device and a universal loading machine was used for the application of the load to the specimen. The load was applied at the rate of 0.02 MPa/s. The two dimensional finite element code FRANC2D/L was used for numerical modelling of the specimens and the loading conditions to determine the stress concentrations around the hole as a function of the hole diameter and the specimen width. Based on the results of experiments and numerical modelling efforts, a new formula for determination of the tensile strength of concrete is proposed in this study. Concurrent with indirect tensile tests using this new device, splitting test were performed to confirm the observed tensile strength values for concrete specimens. Both experimental and numerical modelling results show that the tensile failure occurs around the sides of the hole along the horizontal axis.

In this research an efficient ionic liquid based ferrofluid system was developed for efficient adsorption/preconcentration of cadmium using magnetic mesoporous carbon – chitosan nanohybrid. Mesoporous CMK - 3 was synthesized using MCM – 48 as ordered template. Then magnetic CMK was combined with chitosan through reaction with epichlorohydrin. The nanohybrid was characterized with FESEM, TEM, XRD, SEM mapping, FTIR, BET and VSM techniques. Effective parameters on cadmium adsorption was optimized with response surface methodology (RSM) using Box – Behnken design. Solution pH, contact time, adsorbent dosage and ionic strength were four studied variables on cadmium adsorption. Results showed that all studied variables are significant on cadmium adsorption. Isotherm study was performed at optimum conditions (pH = 8, time 3 min, adsorbent dosage 13 mg and ionic strength of 0.15%) based four isotherm models and results showed that cadmium adsorption followed the order of Redlich–Peterson > Freundlich > Langmuir > Dubinin–Radushkevich with maximum adsorption capacity of 251.9 mg g − 1 . Results for kinetic study confirmed that pseudo second order model can better describe cadmium adsorption. Regeneration of the sorbent was performed with HNO 3 solution (1.0 mol L − 1 ). Finally developed adsorption process was employed for cadmium preconcentration from real samples.

A facile headspace single drop microextraction method was developed using deep eutectic solvent-based magnetic bucky gel as the extraction solvent for the first time. The hydrophobic magnetic bucky gel was formed by combining choline chloride/chlorophenol deep eutectic solvent and magnetic multiwalled carbon nanotube nanocomposite. Magnetic susceptibility, high viscosity, high sorbing ability, and tunable extractability of organic analytes are the desirable advantages of the prepared gel. Using a rod magnet as a suspensor in combination with the magnetic susceptibility of the prepared gel resulted in a highly stable droplet. This stable droplet eliminated the possibility of drop dislodgement. The prepared droplet made it possible to complete the extraction process in high temperatures and elevated agitation rates. Furthermore, using larger micro-droplet volumes without any operational problems became possible. These facts resulted in shorter sample preparation time, higher sensitivity of the method, and lower detection limits. Under the optimized conditions, an enrichment factor of 520-587, limit of detection of 0.05-0.90 ng/mL, and linearity range of 0.2-2000 ng/mL (coefficient of determination = 0.9982-0.9995) were obtained. Relative standard deviations were

Non-modified molybdenum disulfide (MoS2) is known to adsorb various compounds. However, in case of very small particle sizes and high dispersibility, ordinary centrifugation and filtration fail to separate MoS2 from aqueous media limiting, its applicability to solid-phase extraction. To overcome this shortcoming, we have prepared a nanohybrid consisting of MoS2 and nanoparticles of CaFe2O4. Detailed characterizations through field emission scanning electron microscopy, vibrating sample magnetometer, X-ray diffraction and energy-dispersive X-ray techniques confirmed the formation of the hybrid. The adsorption behavior was systematically accessed through kinetic, equilibrium and thermodynamic experiments. The nanohybrid was applied to the adsorption of paclitaxel. The adsorption capacity was 68.96 mg g−1. Also, the method was successfully applied to the preconcentration of the analytes in (spiked) injection vial of paclitaxel and water samples.

This article investigates the applicability of an environmentally friendly and energy efficient deep eutectic solvents (DES) for indigotin blue dye (IBD) preconcentration prior to its quantification by a UV–Visible spectrophotometer. The adsorbent (UT-mGO) is made of Fe3O4, graphene oxide, urea and tetramethylammonium chloride. It was prepared via dispersing magnetic graphene oxide in a DES. The adsorbent was prepared fast and easy, without consumption of dangerous reagents. X-ray diffraction patterns show pure structures of components. FT-IR spectra show strong interaction between DES and mGO. In addition, a scanning electron microscope confirms that DES covered the surface of mGO homogeneously. Magnetic amount and surface property were characterized by an alternating gradient force magnetometer and Brunauer-Emmett-Teller, respectively. High surface area and enough magnetic property, as well as π-π and electrostatic interactions among analyte and adsorbent propose UT-mGO as a qualified candidate to preconcentrate IBD. Effective parameters including pH, adsorbent amount, adsorption time, eluent and desorption time were optimized. Under the optimized conditions, the method has the following figures of merit: (a) limit of detection of 1.5 × 10-6 g L-1, (b) relative standard deviation (n = 7) of 3.49%, (c) preconcentration factor of 50 and (d) linearity of dynamic range of 1.0 × 10-5 to 45 × 10-5 g L-1. The adsorbent is not reusable but durable in six months. Isotherm model of Langmuir and kinetic model of pseudo-second-order fitted for the system. ΔH (-13.2 × 103 J mol−1), ΔS (5.38 J K−1 mol−1) and ΔG (-3.69 × 103 - +10.9 × 103 J mol−1) were calculated as thermodynamic parameters. The method was successfully applied for IBD preconcentration from three samples of fruit juices and three samples of jelly powders.

In this work, amine riched MnFe 2 O 4 -cellulose was employed to remove toxic Cr (VI). To find out the optimum conditions R (3.3.1) software was used. The results of Cr (VI) adsorption onto three-step adsorbents were compared by interpreting kinetic and isotherm studies. The kinetic studies reveal that the adsorption of Cr (VI) onto cellulose and magnetic cellulose (MC) followed pseudo-first order model whereas the adsorption of Cr (VI) onto amine modified cellulose (AFMC) followed pseudo-second order kinetic model. From the obtained intraparticle diffusion model results it is evident that the adsorption is an external surface process. The adsorption isotherm parameters for Cr (VI) adsorption onto MC and AFMC showed that the correlation coefficient (R 2 : 0.96, 0.88) of Freundlich isotherm is more than that of Langmuir isotherm (R 2 : 0.50, 0.76); hence, it is suggested that the adsorption of Cr (VI) onto these sorbents occurs in multilayer possessing heterogeneous sorption sites whereas the adsorption onto cellulose followed Langmuir model. The maximum adsorption capacities of cellulose, MC and AFMC under optimum conditions were found to be 25, 125 and 250 mg/g, respectively; thus, it is confirmed that adsorption efficiency has been improved after modification steps.

Focus of this research is on employment of a green route to prepare magnetic CuFe2O4@polysaccharide resin for environmental remediation purpose. The method is including solvent free solid state synthesis of copper ferrite nanoparticles by combustion route using cellulose as fuel. Then polysaccharide resin as well as its magnetic composite was prepared by using glucose, citric acid and copper ferrite as solid raw materials. Characterization study using FESEM and TEM images showed that as synthesized resin possesses graphene like structure as ferrite nanoparticles are dispersed in the matrice of resin. Methylene blue (MB) adsorption study of the nanohybrid showed that maximum removal efficiency obtained at pH = 8 with very fast equilibrium time of 1 min. Kinetic study confirmed pseudo – second order model is dominant kinetic model for dye removal. Moreover isotherm study revealed dye adsorption followed Freundlich model with maximum adsorption capacity of 366.6 mg g−1. Antibacterial activity of resin and magnetic composite was examined and result confirmed high efficiency of them in coping with E. coli as sample pathogen. Effect of solution pH, contact time and adsorbent dosage on E. coli capturing efficiency was also studied. Results showed bacteria capturing is more than 99% within equilibrium time of 20 min and dosage of 20 mg which confirmed high efficiency of the nanosystem in bacteria removing.

In this work, we developed dispersive solid-phase extraction method with the use of carbon nanotube based magnetic bucky gels. The hydrophilic carbon nanotube (CNT)-based magnetic bucky gels (M-BGs) were developed with the features of magnetic susceptibility to permit fast injection of sorbent, rapid retrieval of the sorbent and high dispersion of MWCNT in the aqueous sample. We combined magnetic multi-wall carbon nanotube nanocomposite (MMWCNTs) with hydrophilic ionic liquids in order to prepare highly stable carbon nanotube-based magnetic bucky gels. The hydrophilic ILs act simultaneously as modifier and disperser for MMWCNTs and reduce the agglomeration of sorbent in water .Consequently they enhance the extraction efficiency. We used the unique features of this responsive gel (fluidity, stability, magnetic properties, and strong sorbing ability) in developing a new, fast, sensitive, simple, and environmental-friendly magnetic bucky gel-based dispersive solid-phase extraction method (M-BG-dSPE) combined with fibre optic linear array detection spectrophotometer (FO-LADS) for preconcentration and speciation of Cr(VI) and Cr(III) in water samples. The properties of MMWCNT and magnetic bucky gels were characterised by scanning electron microscopy (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Fourier transform infrared spectrophotometer (FT-IR). Under the optimised conditions, the enrichment factor of the method was 318, the limit of detection was 0.1 ng mL−1 and the repeatability of the method, expressed as the relative standard deviation (RSD, n = 5), varies between 3.2% and 2.5% in different concentrations. The proposed procedure has been applied for speciation of Cr(VI) and Cr(III) in water samples with good recoveries in the range from 90 to 105%. Validation of the method was carried out by comparison of the obtained results with results obtained by the ET-AAS and spiking-recovery method.

In the present study, to extract the residue of seven pesticides (diazinon, chlorpyrifos, ethion, permethrine, cypermethrin, fenvalerate RR and fenvalerate SS) from raisin samples, reduced graphene oxide—Fe3O4 magnetic nanocomposite is applied as an adsorbent and then the preconcentrated pesticides were determined by GC–MS. The application of high adsorption capacity magnetic graphene oxide sheets in pesticides solid phase extraction, provides a fast and easy procedure without filtration or centrifugation. The extraction conditions were optimized by analyzing spiked raisin samples (80 ng mL−1). The parameters affecting the performance of the extraction such as nanoparticles concentration, extraction time, solution pH and desorption conditions were investigated using a univariate optimization process. The maximum adsorption was observed within 15 min at pH 7–8 using 0.4 mg mL−1 of adsorbent with the sample ionic strength of 0.02 M NaCl. Limits of detection and quantification were about 14 and 40 µg kg−1, respectively, for all of pesticides. The validated method was successfully applied for the determination of pesticides in raisin samples.

Novel deep eutectic solvent (DES) magnetic bucky gels (MBG) were formed by choline chloride/urea deep eutectic solvent and magnetic multi-walled carbon nanotube nanocomposite (MMWCNT) and were used in developing dispersive solid-phase extraction (dSPE) method. The hydrophilic DES based MBGs were developed with the features of magnetic susceptibility to permit fast injection of sorbent into the aqueous sample, rapid retrieval of the sorbent, high dispersion of MWCNT in water and compatibility with GC. In this work we investigated the application of DESs as a new class of carriers for CNT based nanofluids. In this gel DES acts simultaneously as a carrier and stabilizer for MMWCNT nanoparticles. By combining the MWCNT nanocomposite and DES, a highly stable (stability against sedimentation) viscous magnetic bucky gel or soft material was prepared without any additional stabilizer. This gel possesses fluidity, stability, magnetic properties and the unique strong sorbing properties of MWCNT simultaneously. We used the advantages of this magnetic DES based soft material in developing a new DES magnetic bucky gel based dispersive solid phase extraction. By coupling this method with GC- micro ECD and using large-volume-injection technique we achieved low LOD values which is a necessity in the ultra trace analysis of organochlorine pesticides (OCPs) in environmental water samples. Under the optimized conditions, the enrichment factors were in the range of 270-340. The limits of detection were between 0.04 and 0.27ng/L and the relative standard deviations were

This article describes a useful sorbent for separation and preconcentration of trace amounts of gold(III), palladium(II) and silver(I) ions. Graphene oxide (GO) nanoparticles were synthesized by a modified Hummers method and magnetized by MnFe2O4 nanoparticles to give a sorbent referred to as mag-GO. Addition of sodium dodecyl sulfate creates admicelles on the surface of the mag-GO. Then the metal chelating agent 2-mercaptobenzothiazole (MBT) was immobilized on mag-GO to give a mag-GO-MBT type material. This adsorbent was applied to the preconcentration of gold(III), palladium(II) and silver(I) ions. Following ion desorbed with a solution of thiourea, the ions were quantified by flow injection coupled to ICP-OES. Effect of sample pH value, type and volume of eluent, amount of adsorbent, sample volume, time of adsorption and desorption were optimized. Under optimized condition, the calibration plots are linear in the 2.5 to 25,000 μg.L−1 concentration range. The limits of detection range from 0.045 to 0.076 μg.L−1, and enhancement factors are 160, 160 and 140 for gold, palladium and silver ions, respectively. Precisions, expressed as relative standard deviation for 100 μg.L−1 of each ion are

Objectives Diabetes mellitus is a common metabolic disorder with high global prevalence. It is characterized by a decrease in insulin secretion or a decrease in insulin sensitivity or both. The aim of the present study was to investigate the effects of resveratrol treatment on the expression of the genes involved in insulin signalling cascade, such as Forkhead box protein O1 (FoxO1), 3-phosphoinositide-dependent protein kinase 1 (PDPK1) and mammalian target of rapamycin (mTOR). Methods HepG2 cells were cultured in serum-free medium with high concentrations of glucose and insulin and then were treated with resveratrol (5, 10 and 20 µM) for 24 and 48 hours. Complementary deoxyribonucleic acids (cDNAs) were synthesized followed by RNA extraction. Real-time quantitative reverse transcription polymerase chain reaction was used to analyze the expression of FoxO1, PDPK1 and mTOR. Results Resveratrol increased the expression of PDPK1, mTOR and FoxO1. No significant difference was seen among differing dosages of resveratrol, but treatments for 48 hours exerted the greatest effectiveness. Conclusions Our results were consistent with other studies showing the beneficial effects of resveratrol on diabetes. However, considering the effects of resveratrol in increasing FoxO1 and gluconeogenic gene expression, long-term usage of resveratrol should be investigated in greater depth in future studies.

In the present work, synthesis of polymer wrapped flower-like MgAl layered double hydroxide was done through condensation of 1,4 phenylenediamine and resorcinol by p-formaldehyde. The nanocomposite was characterised with X-ray diffraction analysis, fourier transform infrared spectroscopy, thermogravimetric analysis and field emission scanning electron microscopy techniques and employed for effective adsorption of Cr(VI) from aqueous solution prior to flame atomic absorption spectrometer determination. Optimum level of effective parameters (pH, reaction time and adsorbent dosage) and their interaction was determined by response surface methodology. To investigate applicability of method for trace heavy metal adsorption, the method was employed for preconcentration of Cr(VI) in water samples. At the optimum conditions, pH = 4.5, shaking time of 15 min and adsorbent dosage of 20 mg, analytical performance of the method was evaluated and results showed that calibration curve is linear in the concentra...

Polylysine–resorcinol coated alumina nanotube has been synthesized based on Mannich reaction. Synthetic polymer has been obtained using lysine and resorcinol as monomer and p-formaldehyde as linker by condensation reaction. The nanosorbent was employed for cadmium adsorption from aqueous samples. Effective parameters on sorption process have been optimized with Box–Behnken design (BBD). Equilibrium time was 11 min as well as adsorption capacity was 220 mg g−1. Regeneration of the sorbent was performed with HNO3 solution (0.5 mol L−1). The accuracy of the method was evaluated by determination of cadmium in various real samples.

Fluoride is an essential compound in drinking water for preventing the dental caries, however excess intake of fluoride leads to various diseases. If amount of fluoride in drinking water exceeds the permissive limit, it is essential to remove fluoride from water. The aim of this study was to investigate the removal of fluoride from drinking water by nano- alumina coated on multi-walled carbon nanotubes (MWCNTs). The impact of various parameters, such as, pH, contact time, adsorbent dose, and initial fluoride concentration was investigated in the solution. The results of this research showed that, with decreasing pH from 9 to 3, removal efficiency increased, meanwhile the time for fluoride ion adsorption to reach equilibrium was 60 min. Also, increasing the adsorbent dosage from 0.5 to 1.5 g/L with fluoride concentration of 4 mg/L, resulted in increasing the removal from 70.5 to 97.1. The results for the adsorption were fitted to the model of the Freundlich with value (R-2 = 0.997 at 25 degrees C). Therefore, the combined nano- alumina/MWCNTs process was shown to be an excellent option for the removal of fluoride from drinking water.

This article describes a method for highly selective preconcentration of Cd(II) via magnetic Mn2O3 coated by N,N′-bis(salicylidene)ethylenediamine (BSED). The metal oxide components were prepared via combining sol-gel and precipitation methods. Then, BSED was added as the third component of the composite. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometry, and Fourier transform infrared spectroscopy were applied to characterize the materials. BSED selectively forms a complex with Cd(II), and the sorbent can then be magnetically separated. The preconcentration conditions were optimized as pH value (4.0 ± 0.5), sorbent amount (30 mg), adsorption time (20 min), eluent 2 M HNO3), eluent volume (1.5 mL) and desorption time (4 min). The quantification of Cd(II) was done by flame atomic absorption spectroscopy. The method has the following figures of merit: (a) a detection limit of 320 µg L−1, (b) a relative standard deviation of 1.1%, (c) an enhancement factor of 36, (d) a preconcentration factor of 33, and (e) a linear dynamic range that extends from 10 to 120 μg L−1. Other features include the use of safe reagents, fast and simple preparation, high selectivity and reliable analytical performance. The effects of potentially interfering ions were examined. The Dubinin–Radushkevich model and the pseudo second-order model are found to fit the adsorption behavior. The absorption is spontaneous and exothermic. The method was successfully applied to the determination of Cd(II) in (spiked) fruit samples.

Ionic liquids (ILs) are a class of fluids with unique physicochemical properties employing polymeric substances emerging new materials. Solidification of ILs into porous materials generates porous ionic liquid polymers that combine the unique characteristics of ILs with common porous materials and polymers. In this study, it’s the first time the porous ionic liquid polymer was chosen as a sorbent for extraction and speciation of nitrite and nitrate. Porous IL was prepared through polymerization of 1-allyl-3-methylimidazolium bromide monomers in the presence of azobisisobutyronitrile (AIBN) and crosslinking of ethylene glycol dimethyl acrylate (EGDMA). Parameters affecting the adsorbent performance were optimized. Under the optimal conditions, correlation coefficient (R2) was 0.9996 and LOD was 0.1 µg L−1. This method presented the linearity in the concentration range between 0.1–100 µg L−1 and the relative standard deviation was 3.2%. Finally, the adsorption behavior of the obtained sorbent for nitrate and nitrite determination in various real samples was evaluated. The result indicates that the porous ionic liquid polymer showed high adsorption capacity (233 mg g−1). The convenient preparation of the porous ionic liquid material, as well as high adsorption capacity for anionic pollutants predicted its broad application potential in anion removal materials.

In this work, a simple thermal method was used to synthesize carbon dots from citric acid and glycine precursors. It was found that Hg(II) ions can selectively quench the fluorescence emission of these carbon dots. Subsequently, a sensor was designed and optimized for the determination of Hg(II) ions. The limit of detection and quantification of the sensor were found to be 38 and 112 ppb, respectively. The sensor showed good selectivity toward Hg(II) ions and was successfully used for the determination of Hg(II) ions in mineral water samples.

Non-modified molybdenum disulfide (MoS2) is known to adsorb heavy metal ions. However, in case of very small particle sizes and high dispersibility, ordinary centrifugation and filtration fail to separate MoS2 from aqueous media, and this limits its applicability to solid-phase extraction. To overcome this shortcoming, the authors have prepared a nanocomposite consisting of MoS2 and sheets of reduced graphene oxide (r–GO). The material was obtained by a hydrothermal reaction between sodium molybdate and L-cysteine in the presence of GO sheets. The results of characterizations show the MoS2 nanosheets to be well dispersed on the surface of r-GO sheets. The nanocomposite was applied to the preconcentration of Pb(II) and Ni(II) ions as representative examples of heavy metal ions. The adsorption capacities are 322 and 294 mg.g−1 for Pb(II) and Ni(II), respectively. The ions were quantified by atomic absorption spectrometry, and the respective detection limits are 0.71 and 0.21 μg⋅L−1, respectively. The relative standard deviations are ±2.2 % for both ions. The method was successfully applied to the preconcentration of the analytes in (spiked) urine, saliva and water samples.

In the present work, titanium dioxide nanowires (TNWs) were synthesised via hydrothermal method. Insertion of ZnFe2O4 nanoparticles to the surface of TNWs was done by sol gel combustion synthesis of the nanoparticles in the presence of the nanowires. The surface of prepared magnetic TNWs was modified by p-phenylendiamine and then it was used in preconcentration of Cu2+ ion prior to their determination by flame atomic absorption spectroscopy. The sorbent was characterised by Fourier transform infrared spectra, EDX, FE-SEM and VSM techniques. We investigated and optimised various parameters influencing the preconcentration efficiency, such as the media pH, adsorbent quantity, contact time, sample volume and elution conditions. Under optimum conditions, the analytical performance of the method was evaluated. The calibration curve was found to be linear from 10.0 to 150 μg L−1 (R2 = 0.996). Calculated limit of detection was 0.43 μg L−1 (n = 5). The estimated relative standard deviation was 2.50% (n = ...

Ionic liquids are considered to be a class of environmentally friendly compounds as combination of them with bioresource polymeric substances such as; cellulose, constitute emerging coating materials. Biosorption by polymeric ionic liquids exhibits an attractive green way that involves low cost and irrespective of toxicity. As a result, a novel polymeric ionic liquid has been developed by the reaction of one step synthesized Fe3O4-cellulose nanohybrid, epichlorohydrin and 1-methylimidazole and employed as a green sorbent for efficient biosorption of Congo red dye. Effective parameters on dye removing as well as their interactions were determined with response surface methodology (RSM). Congo red adsorption showed fast equilibrium time (11 min) with maximum uptake of 131 mg g−1. Isotherm study revealed that Langmuir adsorption model can better describe dye adsorption behavior. Regeneration of the sorbent was performed with a mixture of methanol–acetone–NaOH (3.0 mol L−1) solution.

In this research, magnetic BaFe 2 O 4 nanoparticles (NPs) have been synthesized via the sol-combustion process using triethanolamine as fuel. Thereinafter, the silica coated NPs have been reacted with carbon disulfide and melamine to prepare magnetic polytriazine-thiourea dendronized nanohybrid. Prepared materials have been characterized by XRD, FT–IR, VSM, EDX, TGA, BET and FE–SEM techniques. In view of potential application, the nanohybrid was employed for rhodamine B (RB) preconcentration as well as Pb(II) adsorption from aqueous solutions. Results showed that equilibrium time for both analytes obtained within 5 min as RB and lead adsorption followed second order adsorption mechanism. Moreover, adsorption process followed the Freundlich isotherm model for the target analytes. Adsorbed RB and lead have been released from the sorbent surface with ethanol and HNO 3 solution (0.1 mol L − 1 ), respectively. Moreover, the sorbent showed good reusability after 5 cycles of sorption and desorption.

A novel, bio-based 8-hydroxyquinoline (8-HQ) anchored magnetic chitosan using Co(II) as imprinted ions was prepared and applied for selective removal of Co(II) from aqueous solutions. At first, γ-Fe2O3 has been synthesized by solvent free precipitation route and then combined with 8-hydroxyquinoline anchored chitosan using epichlorohydrin (EPH) as crosslinking agent. The FT- IR spectra showed that 8-HQ has been successfully anchored onto chitosan structure. Moreover, TEM analysis confirmed that the nanocomposite has core-shell structure. The experimental results showed that equilibrium time was 10min moreover, the maximum adsorption capacity of Co(II) with non-imprinted and surface imprinted polymer at pH 8 were 66.6 and 100mgg(-1), respectively. The selectivity coefficient of Co(II) ions relative to Cd(II), Ni(II) and Pb(II) were 11, 42 and 2, respectively. Prepared biosorbent represented good stability and good repeatability after three cycle of sorption and desorption using 0.5molL-(1) of HNO3 as eluent. Kinetic and thermodynamic behavior were also investigated and result showed that cobalt adsorption followed second order model and endothermic path.

The selective and efficient surfactant assisted transport of Pb2+ ions using a bulk liquid membrane composed of dicyclohexyl-18-crown-6, as a highly selective carrier, in chloroform solution is reported. In the presence of 6.0 × 10−2 M P2O7 4− ions and 10−3 M sodium dodecylsulfate, as suitable stripping agent and membrane/receiving phase interface modifier, respectively, in the receiving phase and 2.4 × 10−3 M picric acid, as a counter ion in the source phase, the amount of lead transported across the liquid membrane after 5 h is 100.0 ± 1.1. The designed transport system was successfully applied to the removal of lead from sea water and blood serum samples.

The article describes a magnetic nanocomposite (mag-NC) that was obtained by oxidative polymerization of thionine in the presence of Fe3O4 nanoparticles. The mag-NC was characterized by FTIR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. It is shown that the mag-NC represents a useful sorbent for magnetic solid-phase extraction of cobalt(II) at trace levels from water and foodstuff samples prior to its determination by FAAS. The effect of pH value, sorbent dose, shaking time and interfering ions on extraction efficiency were optimized. Figures of merits include (a) preconcentration factor of 50, (b) good linearity in the concentration range from 1.3 to 140.0 ng mL−1, (c) a 0.3 ng mL−1 detection limit; and (d) the intra- and inter-day relative standard deviations (for n = 6) of 1.9 and 2.8 %, respectively. Appropriate recovery values, ranging from 96.0 to 104.9 %, were also obtained for real samples analyses.

Supported liquid membranes (SLM) using organic solvents are limited by their relative instability and high volatility. The use of supramolecular solvents (SUPRASs) as a liquid membrane phase could overcome these disadvantages due to their negligible vapor pressure and high viscosity. In the present study, a highly facile and selective transport of silver ions through a SLM using a SUPRAS composed of vesicles of decanoic acid was developed. The SLM used was a thin porous membrane impregnated with dibenzyl-diaza-18-crown-6 (DBzDA18C6), as a selective ion carrier, dissolved in the SUPRAS. Effective parameters including the concentration of picric acid, as a counter ion, in the source phase (SP), nature of solvent and amount and type of carrier in the membrane phase and nature and concentration of stripping agent in the receiving phase (RP), and nature and amount of stripping agent in the RP were investigated. In the presence of 8.85 × 10−5 M, picrate ion as a suitable bulky ion pairing agent in the S...

The authors describe the synthesis of core-shell structured Fe3O4@graphene oxide nanospheres (denoted as Fe3O4@GO NSs) via a chemical (covalent) bonding method. A chemical method was applied to cutting graphene oxide flakes into GO nanosheets. These were then covalently immobilized onto the surface of magnetite (Fe3O4) nanoparticles. The material was characterized by TEM, SEM, EDX, FTIR, vibrating sample magnetometry and Raman spectroscopy. The data confirmed the coexistence of Fe3O4 and GO nanosheets with a core-shell structure. The Fe3O4@GO NSs were applied to ferrofluid-based dispersive solid phase extraction of cadmium(II) as a model analyte using an ionic liquid carrier. This sorbent possesses as large contact surface area and a high density of polar groups on its surface. The nanoparticles, when finely dispersed in the sample solution, result in almost complete extraction of Cd(II) within a few seconds. Cd(II) was then quantified by FAAS. Under optimized conditions, the assay has the following features: (a) A detection limit of 0.12 ng mL−1, (b) a preconcentration factor of 250, (c) a relative standard deviation of 1.4 % (at a level of 50 ng mL−1; for n = 10); (d) a linear analytical range extending from 0.4 to 150 ng mL−1, (e) a maximal adsorption capacity of 33.7 mg g−1, and (e) a well expressed Langmuir adsorption isotherm.

A magnetic Fe3O4@CuS nanohybrid has been successfully prepared by a rapid polyol route. The synthetic procedure includes refluxing a mixture of Fe3O4, CuSO4 and sodium thiosulfate in ethylene glycol at 150 °C for 90 min. The prepared composite has been characterized using XRD, VSM, FE – SEM and Raman techniques. Gold adsorption properties of the nanostructure were investigated using flame atomic absorption spectroscopy (FAAS). The results indicate that the adsorption process is very fast as equilibrium is obtained within one minute with a maximum capacity of 333 mg g−1. The isotherm study and error analysis showed that the adsorption process followed the Freundlich model. The regeneration study was also performed and the adsorbed ions were eluted with 0.5 mol L−1 of thiosulfate solution. The limit of detection (LOD) was calculated as three times the standard deviation of the blank signal (n = 6) and it was 0.92 μg L−1. Moreover, the relative standard deviation in the determination of 100 μg L−1 of gold ions was found to be 3.4%.

A magnetic ion-imprinted polymer (Fe3O4@TiO2@SiO2-IIP) functionalized with -NH groups for the selective determination of Co(II) ions from environmental and biological samples is presented. This sorbent was synthesized by surface imprinting technique combined with sol-gel process using 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS) as a functional ligand, tetraethyl orthosilicate as across-linking agent, and Co(II) ion as the template. The prepared magnetic ion-imprinted polymer was characterized by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Fe3O4@TiO2@SiO2-IIP showed higher capacity and selectivity than that of Fe3O4@TiO2@SiO2-NIP. The important parameters influencing the recovery such as pH, the volume and eluent concentration, contact time, and the amount of sorbent on extraction percentage of Fe3O4@TiO2@SiO2-IIP were studied and optimized. The linear range (LR), relative standard deviation(RSD) and limit of detection (LOD=3 S(b)/m) for flame atomic absorption spectrometric determination of Co(II) ion, after its selective extraction by the prepared IIP polymer, were evaluated as 1-130 µg L(-1), 1.22% and 0.15 µg L(-1), respectively. The maximum capacity of Fe3O4@TiO2@SiO2-IIP and Fe3O4@TiO2@SiO2-NIP is 35.21 mg g(-1) and 10.34 mg g(-1), respectively. The separation factor of Fe3O4@TiO2@SiO2-IIP for Co(II)/Pb(II), Co(II)/Ni(II), and Co(II)/Cd(II) are 41.17, 79.74, and 56.48, respectively. In addition, the spent magnetic ion-imprinted polymer can be refreshed by simply washing with an aqueous HNO3 solution, and there is no significant decrease in adsorption capacity after a test of upto seven cycles, demonstrating that the Fe3O4@ TiO2@SiO2-IIP is stable and reusable.

A graphene based bucky gel-coated stainless steel fiber was prepared and applied to headspace solid phase microextraction of volatile organic compounds. Graphene was mixed with an ionic liquid to produce a bucky gel that displays the attractive features of both compounds. It can be directly deposited on an etched stainless steel wire to give the fiber for use in extraction of benzene, toluene, ethylbenzene and xylene (BTEX) isomers. The presence of graphene favors the π-interaction between the sorbent and aromatic analytes. The sorbent is thermally stable up to 300 °C and can be used more than 50 times. It was characterized by field emission scanning electron microscopy, FT-IR spectroscopy and thermogravimetric analysis. Under optimized conditions, linear responses were found in the range of 0.11–5000 μg L−1 for toluene, 0.15–5000 for benzene and o-xylene, 0.17–5000 for m- and p-xylene and 0.20–5000 for ethylbenzene. Limits of detection are between 0.03 and 0.06 μg L−1 (at an S/N ratio of 3). The run-to-run RSDs are

New developed method based on official American Society for Testing and Materials (ASTM) standard method was used for determining phenolic compounds in water by using homogeneous liquid–liquid extraction (HLLE) and fiber optic-linear array detection spectrometers (FOLADS). HLLE is a method based on phase separation in a ternary solvent system (water-tetrabutylammonium ion, TBA +-chloroform). The phase separation phenomenon occurred by an ion-pair formation of TBA + and perchlorate ion. The aim of using this method was decreasing volume of extraction solvent used in ASTM standard method. After centrifugation the sediment phase was transferred to a 50-μL cylindrical micro-cell and absorbance was measured at 480 nm. Under the optimum conditions, linearity was obtained in the range of 5.0 to 80.0 μg/L for phenol. Coefficient of correlation (r 2) was 0.992. The relative standard deviation was 1% for the analysis of 5 samples with concentration of 50 μg/L of phenol. The limit of detection was 2.0 μg/L. The relative recoveries of phenol in water samples were in the range of 97–104%. The proposed method was successfully applied for determination of phenolic compounds in real water samples.

L-Threonine (L-thr) as a general chiral selector anchored on the surface of magnetic multi-wall carbon nanotube (MMWCNT) was prepared using an in situ electrostatic adsorption and studied as a new magnetically chiral selector for the separation of chiral DL-mandelic acid (DL-MA) as a model sample. By varying the pH, DL-MA was adsorbed on the surface of magnetic chiral selector through hydrogen bonds. It is recognized that MMWCNT with chiral ligands on its surface simultaneously possesses both magnetic property and direct chiral recognition ability. The successful immobilization of L-thr onto the surface of MMWCNT was confirmed by infrared spectra (FT-IR), X-ray diffraction patterns (XRD) and transmission electron microscopy (TEM). The FT-IR and mass spectra of supernatant and elution solutions also confirmed the immobilization of L-thr onto the surface of MMWCNT. The analysis results of specific rotation, HPLC and ultraviolet-visible spectroscopy reveal that the L-thr-MMWCNT show stronger complexation of (+)-enantiomer than (-)-enantiomer. The functional magnetic nanotubes were easily separated from the racemic solution using an external magnetic field which demonstrated its feasibility of recycling the adsorbent. All processes including in situ immobilization, enantioseparation (enantioenrichment) and magnetic separation were done by single process in a short time (only 10min).

This study presents a method to synthesize magnetic expanded perlite composite through a co-precipitation method using single iron source and yellow pea as a reducing agent. The suggested method is environment friendly, easy, and biogenic. The combination of magnetite nanoparticles with expanded perlite and its modification with ibuprofen resulted in a new, cost-effective, and eco-friendly magnetic adsorbent for dye removal from contaminated streams. The prepared composite was characterized by point of zero charge (pHzpc), X-ray diffraction, scanning electron microscopy, vibration sample magnetometer, and Fourier transforms infrared spectroscopy (FT-IR). The prepared adsorbent was used to remove Direct Red-81 as a target pollutant to test the feasibility of this idea, UV–vis spectroscopy was used to follow the adsorption process. The maximum adsorption was observed within 1 min at pH 4–6 using 30 mg of adsorbent. The experimental data were analyzed by the Langmuir and Freundlich adsorption models....