•Tolerance limits of interference ions were very high.•Developed method has low LOD (0.25 ng L−1), low RSD (3.2%) and high enhancement factor (121).•The accuracy of method confirmed by the analysis ...of CRMs is above of 95.9%.•Quercetin as the complexing agents behaved highly selective for Se(IV).
A simple and green ultrasound liquid-liquid microextraction method based on low viscous hydrophobic deep eutectic solvent (ULLME-LV-HDES) was proposed for the preconcentration and separation of selenium prior to HG-AAS detection. Six different DESs were prepared for the extraction of selenium. Quercetin was used complexing agent for Se(IV) ions. Various analytical parameters such as pH, quercetin amount, DES type and its volume, sonication time, sample volume were optimized. Tolerance limits of anion, cation and transition metal ions were studied. Preconcentration and enhancement factor were found 62.5 and 121. Under the optimum conditions, limit of detection was found 0.25 ng L−1 with calibration range of 0.8–120 ng L−1. Relative standard deviation was found 3.2%. The accuracy of the method was confirmed with certified reference materials (NIST 1567a Wheat flour and NIST 1548a Typical diet). Finally, the developed method was successfully applied to food and water samples.
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•Graphene was modified with polyamide by interfacial polymerization.•The polyamide-graphene was evaluated for the removal of Sb(III).•The tests indicated high adsorption performance, ...high capacity and regeneration efficiency.
Graphene was modified with polyamide by using a facile interfacial polymerization method to obtain an effective composite. The produced polyamide-graphene (PAG) was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning Electron microscopy (SEM) equipped with Energy-Dispersive X-ray spectroscopy (EDX), Thermogravimetric analyzer (TGA), and Brunauer–Emmett–Teller (BET) analysis methods. The adsorption efficiency of the adsorbent for the removal of Sb(III) was evaluated under the effects of concentration, temperature, contact time, medium pH, and re-usability. The results of the study showed very good adsorption performance and high regeneration efficiency. The Langmuir modeling results revealed that the synthesized PAG sorbent had a considerably high adsorption capacity (158.2mg/g) for Sb(III) ions from aqueous solution. The adsorption data fitted well into pseudo-second order model. The exothermic enthalpy change of −65.6kJ/mol and negative Gibbs free energy change assured the viability of the adsorption process under the considered temperature conditions. Moreover, by taking into account all results it was concluded that the PAG composite material leverages its cheap source and ease of regeneration in combination with its high and fast uptake capacities to offer a great promise for the remediation of Sb(III) ions from aqueous solutions.
In this work, a new cloud point extraction (CPE) procedure was developed for the separation and preconcentration of lead(II), cobalt(II), and copper(II) in various water and food samples. Complexes ...of metal ions with 1-Phenylthiosemicarbazide (1-PTSC) were extracted into the surfactant-rich phase of octylphenoxypolyethoxyethanol (Triton X-114) from samples. After phase separation, the enriched analytes were determined by flame atomic absorption spectrometry (FAAS). Factors affecting cloud point extraction, such as pH, reagent and surfactant concentrations, temperature, and incubation time were evaluated and optimized. The interference effect of some cations and anions was also studied. After optimization of the CPE conditions, the preconcentration factor of 25 and the limits of detection (L.O.D.) obtained for lead(II), cobalt(II), and copper(II) based on three sigma (
n
=
20) were 3.42, 1.00, and 0.67
μg L
−1, respectively. The method presented precision (R.S.D.) between 1.7% and 4.8% (
n
=
7). The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap water, spring water, sea water, canned fish, black tea, green tea, tomato sauce and honey.
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•A linear polyethyleneimine modified activated carbon (PAF) was prepared as an effective sorbent.•The adsorption capacity of the PAF sorbent for U(VI) was determined to be ...115.31mgg−1.•The recovery yield was determined as 90–95%.
In this study, the polyethyleneimine modified activated carbon/Fe (PAF) was prepared and used as an effective magnetic adsorbent to remove uranium (U(VI)) ions from aqueous solution as a function of batch adsorption parameters. The developed magnetic adsorbent was investigated by FT-IR, SEM, EDX, TG/DSC and BET techniques. The effects of the adsorption parameters on the sorption amount were investigated by using factorial design. In order to study the sorption behavior for U(VI) ions, the Langmuir, and Freundlich isotherm models were applied to fit the equilibrium data. The monolayer adsorption capacity of the magnetic sorbent for U(VI) was determined to be 115.31mgg−1 at pH 5, 20°C and 60min. The kinetic results indicated that the pseudo-second-order kinetic modeling fits the equilibrium data well under employed temperature conditions. The thermodynamic examinations showed exothermic and spontaneous adsorption process. The reusability-cycling test indicated that the magnetic sorbent has good desorption performance. It was also concluded that the PAF magnetic material can be used as an effective adsorbent for the removal of U(VI) ions from wastewaters by taking into account its advantages such as being of cost effective, easy prepare and environmental friendly.
•New PHBvbNCl sorbent was synthesized for the simultaneous seperation and preconcentration of Pb(II) and Cd(II).•The adsorption capacity, selectivity, and operation efficiency were discussed.•FAAS ...was used for quantification of Pb and Cd in real samples.•Several factors affecting the extraction efficiency were investigated and optimized.
A green and efficient analytical approach was reported for simultaneous preconcentration, and separation of Pb(II) and Cd(II) in water, vegetables, and barbecue samples by dispersive solid-phase microextraction prior to their determination using flame atomic absorption spectrometry. A new poly-3-hydroxy butyrate-polyvinyl triethyl ammonium chloride comb-type amphiphilic cationic block copolymer (PHBvbNCl) was synthesized and characterized. Main variables such as pH, sorbent amount, adsorption time, eluent type, desorption time, and sample volume were optimized. Detection limits and working ranges for Pb(II) and Cd(II) were 0.03 μg L-1, 0.15 μg L-1, 0.1–250 μg L-1 and 0.5–375 μg L-1, respectively. Enhancement factor for Pb (II) and Cd (II) were 114 and 98. The adsorption capacity of PHBvbNCl for Pb(II) and Cd(II) was 175.2 mg g−1 and 152.9 mg g−1. After the accuracy of the method was confirmed by the analysis of certified reference materials, it was successfully applied to real samples. Finally, the analytical performance of the present method was compared with other methods.
•Simple, rapid and green ultrasound assisted liquid phase microextraction method was developed.•Non toxic deep eutectic solvents were used for extraction.•Very low limit of detection, low RSD and ...short extraction time were observed.•The developed method was applied to the food and water samples.•The developed method was sensitive and highly selective for Cd ions.
A simple, fast, green, sensitive and selective ultrasonic assisted deep eutectic solvent liquid-phase microextraction technique was used for preconcentration and extraction of cadmium (Cd) in water and food samples by electrothermal atomic absorption spectrometry (ETAAS). In this technique, a synthesized reagent (Z)-N-(3,5-diphenyl-1H-pyrrol-2-yl)-3,5-diphenyl-2H-pyrrol-2-imine (Azo) was used as a complexing agent for Cd. The main factors effecting the pre-concentration and extraction of Cd such as effect of pH, type and composition of deep eutectic solvent (DES), volume of DES, volume of complexing agent, volume of tetrahydrofuran (THF) and ultrasonication time have been examined in detail. At optimum conditions the value of pH and molar ratio of DES were found to be 6.0 and 1:4 (ChCl:Ph), respectively. The detection limit (LOD), limit of quantification (LOQ), relative standard deviation (RSD) and preconcentration factor (PF) were observed as 0.023 ng L−1, 0.161 ng L−1, 3.1% and 100, correspondingly. Validation of the developed technique was observed by extraction of Cd in certified reference materials (CRMs) and observed results were successfully compared with certified values. The developed procedure was practiced to various food, beverage and water samples.
► Performance of dry, wet and microwave digestion procedures was compared. ► Determination by ICP-OES. ► Application to dried fruit samples.
The aim of this study was used to investigate the level of ...trace metals (Ba, Pb, Cd, Mn, Cr, Co, Ni, Cu, Mn, Zn, Sr and Fe) in some dried fruits (Prunus domestica L., Ficus carica L., Morus alba L., Vitis vinifera L., Prunus armeniaca L., and Malus domestica) samples from Turkey. Trace elements were determined by ICP-OES after dry, wet and microwave digestion methods in dried fruit samples. Validation of the proposed method was carried out by using a NIST-SRM 1515-Apple Leaves certified reference material. Element concentrations in dried fruit samples were 0.33–1.77 (Ba), 0.12–0.54 (Cd), 0.25–1.03 (Co), 0.45–2.30 (Cr), 0.43–2.74 (Cu), 0.56–4.87 (Mn), 0.61–2.54 (Ni), 0.40–2.14 (Pb), 2.16–6.54 (Zn), 0.83–12.02 (Al), 11.82–40.80 (Fe) and 0.16–6.34 (Sr) μg/g. The analytical parameters show that the microwave oven digestion procedure provided best results as compared to the wet and dry digestion procedures. The results were compared with the literature values.
A novel and sensitive voltammetric nanosensor was developed for the first time for trace level monitoring of favipiravir based on gold/silver core–shell nanoparticles (Au@Ag CSNPs) with conductive ...polymer poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) and functionalized multi carbon nanotubes (F-MWCNTs) on a glassy carbon electrode (GCE). The formation of Au@Ag CSNPs/PEDOT:PSS/F-MWCNT composite was confirmed by various analytical techniques, including X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and field-emission scanning electron microscopy (SEM). Under the optimized conditions and at a typical working potential of + 1.23 V (vs. Ag/AgCl), the Au@Ag CSNPs/PEDOT:PSS/F-MWCNT/GCE revealed linear quantitative ranges from 0.005 to 0.009 and 0.009 to 1.95 µM with a limit of detection 0.46 nM (S/N = 3) with acceptable relative standard deviations (1.1-4.9 %) for pharmaceutical formulations, urine, and human plasma samples without applying any sample pretreatment (1.12–4.93%). The interference effect of antiviral drugs, biological compounds, and amino acids was negligible, and the sensing system demonstrated outstanding reproducibility, repeatability, stability, and reusability. The findings revealed that this assay strategy has promising applications in diagnosing FAV in clinical samples, which could be attributed to the large surface area on active sites and high conductivity of bimetallic nanocomposite.
Graphical abstract
The equilibrium, thermodynamics and kinetics of selenium(IV) biosorption from aqueous solution by dead green algae (
Cladophora hutchinsiae) biomass was investigated. Optimum biosorption conditions ...were determined with respect to pH, biomass concentration, contact time, and temperature. The equilibrium data were analyzed using the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. The maximum biosorption capacity of
C. hutchinsiae biomass for Se(IV) was found to be 74.9
mg/g at pH 5, biomass concentration 8
g/L, contact time 60
min, and temperature 20
°C. The biosorption percentage decreased from 96% to 60% as temperature was increased from 20 to 50
°C during the equilibrium time.
From D–R model, the calculated mean biosorption energy (10.9
kJ/mol) indicated that the biosorption of Se(IV) onto
C. hutchinsiae biomass was taken place by chemical ion-exchange.
The highest recovery (95%) was achieved using 0.5
M HCI. The high stability of
C. hutchinsiae permitted a slightly decrease about 20% in recovery of Se(IV) ions after ten times of adsorption-elution process. The calculated thermodynamic parameters, Δ
G° (between −18.39 and −16.08
kJ/mol at 20–50
°C) and Δ
H° (−45.96
kJ/mol) showed that the biosorption of Se(IV) onto
C. hutchinsiae biomass was feasible, spontaneous and exothermic, respectively. The experimental data was also fitted to the Lagergren's first-order and pseudo second-order kinetic models. The results revealed that the pseudo second-order reaction model provided the best description these data with coefficients of determination in range of 0.992–0.999. The biosorption rate constant was calculated as 24.9
×
10
−2
g/(mg
min).
Sepiolite was modified with polymer consisting of ethylenediamine(EDA)-trimesoyl chloride (TMC) to produce a highly effective sorbent for antimony (III) (Sb(III)) adsorption from aquatic solutions. ...The EDA-TMC polymeric branches were grafted onto the surface of sepiolite by polymerization. The surface morphology and the main adsorptive chemical groups of the developed S/EDA-TMC sorbent were characterized by SEM, EDX, BET, and FTIR, analysis methods. The impact of the batch adsorption conditions on the adsorption performance was systematically studied by conducting a factorial design analysis. While Langmuir and Freundlich isotherm models were employed with the non-linear equations to the removal data and the removal capacity of the prepared composite was estimated as 210.1 mg g−1 based on the Langmuir due to relatively high correlation. The kinetic investigation results displayed that the pseudo-second-order kinetic model was well appropriate for characterizing Sb(III) removal mechanism. Also, thermodynamic findings verified that the Sb(III) removal onto the composite adsorbent progressed exothermically and spontaneously with temperature increasing from 24° to 55°C. Besides, the produced adsorbent demonstrated still appreciated adsorption/desorption yield (80/76%) after the 7th cycle. Accordingly, the fabricated S/EDA-TMC material can be evaluated as a powerful sorbent in the cleaning of aqueous solutions containing Sb(III) pollutants.
•Polymer modified magnetic sepiolite adsorbent was synthesized.•Sb(III) adsorption conditions were optimized with factorial design analysis.•Adsorption/recovery performance was considerable high at 7th cycle.
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