a b s t r a c tFe 3 O 4 magnetic nanoparticles (MNPs) with diameters about 10 nm were synthesized successfully and used to remove phenol and aniline from aqueous solution. The results showed that phenol and aniline could be eliminated easily from solution under acidic and neutral conditions in the presence of MNPs and H 2 O 2 . When the concentrations of Fe 3 O 4 MNPs and H 2 O 2 were 5 g L −1 and 1.2 M, respectively, phenol and aniline could be removed completely after 6 h of reaction at 308 K, and the total organic carbon (TOC) abatement efficiency for phenol and aniline were 42.79% and 40.38%. Some intermediates such as formic acid, acetic acid, fumaric acid and hydroquinone were detected during reaction. Fe 3 O 4 MNPs exhibited good stability and reusability, also showed excellent catalysis ability to eliminate some substituted phenolic and aniline compounds from solution. Fe 3 O 4 MNPs had good superparamagnetism and was readily separated from solution by applying an external magnetic field. Finally we proposed that phenol and aniline might be degraded by the hydroxyl free radicals (·OH) released from H 2 O 2 in the presence of Fe 3 O 4 MNPs as catalysts.

No abstract

No abstract

a b s t r a c tThe carbon coated Fe 3 O 4 nanoparticles (Fe 3 O 4 /C) were synthesized by a simple hydrothermal reaction and applied as solid-phase extraction (SPE) sorbents to extract trace polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. The Fe 3 O 4 /C sorbents possess high adsorption capacity and extraction efficiency due to strong adsorption ability of carbon materials and large surface area of nanoparticles, and only 50 mg of sorbents are required to extract PAHs from 1000 mL water samples. The adsorption attains equilibrium rapidly and analytes are eluted with acetonitrile readily. Salinity and solution pH have no obvious effect on the recoveries of PAHs, which avoids fussy adjustment to water sample before extraction. Under optimized conditions, the detection limits of PAHs are in the range of 0.2-0.6 ng L −1 . The accuracy of the method was evaluated by the recoveries of spiked samples. Good recoveries (76-110%) with low relative standard deviations from 0.8% to 9.7% are achieved. This new SPE method provides several advantages, such as high extraction efficiency, high breakthrough volumes, convenient extraction procedure, and short analysis times. To our knowledge, this is the first time that Fe 3 O 4 /C nanoparticles are used for the pretreatment of environmental water samples.

No abstract

No abstract

No abstract

a b s t r a c tThe hydrophobic octadecyl (C 18 ) functionalized Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 @C 18 ) were caged into hydrophilic barium alginate (Ba 2+ -ALG) polymers to obtain a novel type of solid-phase extraction (SPE) sorbents, and the sorbents were applied to the pre-concentration of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) pollutants from environmental water samples. The hydrophilicity of the Ba 2+ -ALG cage enhances the dispersibility of sorbents in water samples, and the superparamagnetism of the Fe 3 O 4 core facilitates magnetic separation. With the magnetic SPE technique based on the Fe 3 O 4 @C 18 @Ba 2+ -ALG sorbents, it requires only 30 min to extract trace levels of analytes from 500 mL water samples. After the eluate is condensed to 0.5 mL, concentration factors for both phenanthrene and di-n-propyl-phthalate are over 500, while for other analytes are about 1000. The recoveries of target compounds are independent of salinity and solution pH under testing conditions. Under optimized conditions, the detection limits for phenanthrene, pyrene, benzo [a]anthracene, and benzo[a]pyrene are 5, 5, 3, and 2 ng L −1 , and for di-n-propyl-phthalate, di-n-butyl-phthalate, di-cyclohexyl-phthalate, and din-octyl-phthalate are 36, 59, 19, and 36 ng L −1 , respectively. The spiked recoveries of several real water samples for PAHs and PAEs are in the range of 72-108% with relative standard deviations varying from 1% to 9%, showing good accuracy of the method. The advantages of the new SPE method include high extraction efficiency, short analysis time and convenient extraction procedure. To the best of our knowledge, it is unprecedented that hydrophilic Ba 2+ -ALG polymer caged Fe 3 O 4 @C 18 magnetic nanomaterial is used to extract organic pollutants from large volumes of water samples.