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An eco-friendly efficient supramolecular solvent-based method was developed for extraction and determination of selected non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac sodium, caffeine and paracetamol in water samples followed by detection with high-performance liquid chromatography. Supramolecular solvent (SUPRAs) with composition of 400 μL of 1-undecanol as reverse micelles in dispersing solvent of 15% tetrahydrofuran (THF) solution in water at pH 4 used as extracting solvent for selected NSAIDs. Various factors affecting the extraction efficiency of NSAIDs like amount of 1-undecanol, percentage of THF, composition of SUPRA, pH, vortex time and sample amount were studied. Limit of detection (S/N = 3) and quantification (S/N = 10) were 0.02 and 0.08 μg mL-1 for paracetamol, 0.006 and 0.02 μg mL-1 for caffeine, 0.06 and 0.2 μg mL-1 for diclofenac sodium with linear range of 0.1-12 μg mL-1. The inter-day relative standard deviation (RSD) values were 3.1%-5.2%, 3.3%-4.2% and 2.2%-3.6%, while for intra-day the RSD values obtained were 2.4%-4.1%, 1.4%-3.1% and 1.5%-4.1% for paracetamol, caffeine and diclofenac sodium, respectively. The proposed method has been applied successfully to the spiked water samples and recoveries were found in the range of 89.5%-94.6% for tape water, 88.5%-92.8% for canal water and 90.0%-95.2% for industrial wastewater samples was obtained. [ABSTRACT FROM AUTHOR]

A comparative study of Cu-impregnated ZnO and Ag-impregnated ZnO for the sonophotocatalytic degradation of cefpodoxime proxetil in aqueous solution under visible light irradiation were carried out. Optimum conditions for degradation of cefpodoxime proxetil using Cu-ZnO and Ag-ZnO was investigated. The effect of enhancers and scavengers were investigated using optimum conditions and hydrogen peroxide as enhancers. 100% degradation was achieved using Cu-ZnO and Ag-ZnO. Furthermore, total organic carbon analysis was carried out and 89% using Cu-ZnO and 93% using Ag-ZnO removal of total organic compounds were observed. The sonophotocatalytic degradation of cefpodoxime proxetil using Cu-ZnO and Ag-ZnO followed pseudo-first-order kinetic and the rate of degradation of cefpodoxime proxetil using Ag-ZnO was found higher (k1 = 0.228) than the Cu-ZnO photocatalyst (k1 = 0.185). The method has also been successfully applied in samples for sonophotocatalytic degradation. [ABSTRACT FROM AUTHOR]

Orange peel powder was impregnated with magnetic nanoparticles through co-precipitation with Fe3O4 nanoparticles and used for the removal of Ni(II) from aqueous solutions. The adsorbent magnetic nanoparticles orange peel powder (MNP-OPP) was characterized by Fourier-transform infrared spectroscopy for surface functional group and scanning electron microscope for the surface morphology. The effectiveness of Ni(II) removal was studied systematically as a function of solution pH 2-7, amount of adsorbent 20-220 mg, contact time 20-60 min, initial metal ion concentration 200-120 mg L-1 and temperature 303-363 K. Maximum uptake of Ni(II) (98.12%) was observed at pH 7 with 60 min agitation time. The kinetic studies showed that the data followed second-order kinetics with a correlation coefficient of 0.9948. Adsorption isotherms show that the data fitted to Langmuir adsorption isotherm (R² = 0.9954) with the monolayer adsorption capacity (Q0) of 110.12 mg g-1. The thermodynamic study revealed that the adsorption of Ni(II) ions onto the MNP-OPP composite was spontaneous and endothermic. The effect of different coexisting ions like alkali, alkaline earth metals and transition metals was studied and the results revealed that orange peel with magnetic nanoparticle composite can be used for removal of Ni(II) from water samples as an alternative adsorbent. The method was successfully applied to real environmental water like tap water, canal water and river water with quantitative % adsorption results. [ABSTRACT FROM AUTHOR]

An efficient microextraction method was developed for extraction and determination of phenylurea herbicides (monuron, linuron and isoproturon) in water and rice samples followed by analysis with high performance liquid chromatography (HPLC). The proposed method based on microextraction of herbicides in supramolecular solvent (SUPRAs, 400 mg decanoic acid; 15% THF) for 1.0 min of centrifugation. Factors affecting the extraction efficiency of herbicides like pH, amount of decanoic acid (DeA), volume of tetrahydrofuran (THF), composition of SUPRA, centrifugation time and sample amount were studied. Limit of detection (LOD) and quantification (LOQ) were 30 ngmL-1 and 10 ngmL-1 for monuron, 10 ngmL-1 and 30 ngmL-1 for linuron, 30 ngmL-1 and 100 ngmL-1 for isoproturon with linear range of 0.3-20 (10³) ngmL-1. The inter-day RSD values were 2.5-3.7%, 4.2-5.5% and 5.2-7.2, while for intra-day the obtained RSD values were 3.2-4.1%, 4.3-5.2% and 5.2-6.5% for 5,10, 15 (10³ ngmL-1), respectively. The proposed method has been applied successfully to the spiked water and rice samples and recoveries in the range of 91.1-99.0 % for tape water, 82.5-94.0% for canal water and 80.0-85.5% for rice samples were obtained. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop simple, efficient, and environmental friendly adsorbent, polyaniline (PANI)-modified magnetic nanoparticles (Fe3O4@PANI) for the removal of 2,4-dichlorophenol and 2,4,6-trichlorophenol from wastewater. Magnetic nanoparticles were synthesized by co-precipitation method and coated with PANI through oxidative polymerization of aniline monomers. The morphology, elemental composition, and crystallinity of (Fe3O4@PANI) were determined using scanning electron microscopy, energy dispersion X-ray, X-ray diffraction spectroscopy, and Fourier-transform infrared spectroscopy for functional group analysis, respectively. The parameters effecting the adsorption efficiency such as pH, temperature, contact time, adsorbent dosage, and initial concentration of 2,4-dichlorophenol and 2,4,6-trichlorophenol were studied. The experimental adsorption results were evaluated by different isotherms, and the Freundlich isotherm model was found to best fit the data. Three kinetics models were applied to the data and the pseudo-second-order kinetic model was found leading the kinetics of adsorption process. Thermodynamics evaluation of the adsorption parameters showed that the adsorption is exothermic and spontaneous at low temperature. This research elucidated that (Fe3O4@PANI) is efficient, low cost, and environmental friendly adsorbent to remove to 2,4-dichlorophenol and 2,4,6-trichlorophenol from wastewater. [ABSTRACT FROM AUTHOR]

In this study, silica-coated magnetic nanoparticles with mixed hemimicelles were used for the solid-phase extraction of chlorophenols such as 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol from aqueous samples. Magnetic nanoparticles (Fe3O4) were prepared by coprecipitation method, modified with silica (SiO2) and characterized using different techniques. The effect of various parameters including solution pH, contact time, amount of adsorbent and volume of surfactant (cetyltrimethylammonium bromide [CTAB]) was evaluated in batch experiments for the maximum adsorption of chlorophenols. The results showed that the percentage removal of 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol was 85%, 87%, 95% and 96%, respectively, achieved by using Fe3O4@SiO2 at neutral pH 7 with 150 mg/g of CTAB amount in 60 min. For the extraction of chlorophenols, type of eluent, volume of eluent and extraction time were optimized. The limit of detections of chlorophenols ranged from 0.02 to 0.07 μg/L using high-pressure liquid chromatograph with UV detector. The proposed method was applied for the determination of chlorophenols in real water samples including groundwater, river water, wastewater and tap water. The percentage recovery of 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol was in the range of 95%–99%, respectively. [ABSTRACT FROM AUTHOR]

Solid phase extraction method for the preconcentration of Pb(II) from real water samples was developed by using magnetic nanoparticles impregnated banana peel, magnetic nanoparticle and banana peels as adsorbents. The adsorbents were characterized by using scanning electron microscope, energy dispersive X-ray and surface area analyzer. Parameters that influencing % recovery of Pb(II) such as solution pH, adsorbent dose, sample volume, concentration and volume of eluent and matrix effect were determined and optimized. Analytical parameters such as limit of detection, limit of quantification, preconcentration factor, enhancement factor and relative standard deviation were determined under optimized experimental condition. Kinetic data show that this adsorption study follow pseudo-second-order kinetics and the equilibrium data fit to Langmuir adsorption isotherm. The positive values of ΔH, ΔS and negative values of ΔG show that the adsorption process is endothermic, feasible and spontaneous in nature. The method was validated by applying the method to three real water samples with satisfied percent recoveries. [ABSTRACT FROM AUTHOR]

In the present study synthesis of magnetic nanoparticle (MNPs) and silica coated magnetic nanopar)ticle SiMNPs were carried using co-precipitation method and used for the sold phase extraction of Cd (II) from environmental water samples. MNPs and SiMNPs were characterized using FTIR for surface functional group, SEM for surface morphology, EDX for elemental analysis and SAA for surface area, pore volume and pore size. For quantitative percent recovery various analytical parameter like solution pH, adsorbent dose, volume of sample, eluent type and volume and matrix effect were optimized. Limit of detection (LOD) like 0.30 µg L–1 and 0.31 µg L–1 for SiMNPs and MNPs values shows that the method is highly sensitive. The kinetic data shows that the adsorption of Cd (II) on MNPs and SiMNPs follows pseudo second order kinetics. Values of ΔHº, ΔSº and ΔGº show that these adsorption processes are exothermic and feasible in nature. For equilibrium studies different isotherms like Langmuir, Freundlich, Temkin and D-R adsorption isotherms were applied. The method was successfully applied to environmental water samples like Tap water and River water with satisfied recovery results. [ABSTRACT FROM AUTHOR]

Removal and recovery of Cd(II) was studied on sawdust modified with magnetic nanoparticles, Fe3O4(MNP), from aqueous solution. MNP were prepared, loaded on sawdust, and characterized using scanning electron microscopy and surface area analyzer. The parameters for removal percentage of Cd(II) from aqueous solutions were studied such as pH, contact time, and concentration of Cd(II). Results for kinetics studies revealed that Cd(II) removal followed pseudo-second-order kinetics and theqecalculated values (22.17 mg g−1) were in close agreement with experimental values (22.45 mg g−1) with a high value of correlation coefficient (R2 = 0.9994). The adsorption isotherm data were followed by Langmuir isotherm model adsorption studies. The adsorption capacity (Qo) was found to be 1,000 mg g−1, 588.5 mg g−1, and 403.7 mg g−1for SD-MNP, MNP, and SD, respectively. [ABSTRACT FROM PUBLISHER]