Junshen Liu

Mussel-inspired polydopamine biopolymer decorated with magnetic nanoparticles for multiple pollutants removal

The polydopamine polymer decorated with magnetic nanoparticles (Fe3O4/PDA) was synthesized and applied for removal of multiple pollutants. The resulted Fe3O4/PDA was characterized with elemental analysis, thermo-gravimetric analyses, vibrating sample magnetometer, high resolution transmission electron microscope, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy. The self-polymerization of dopamine could be completed within 8h, and Fe3O4 nanoparticles were embedded into PDA polymer. Superparamagnetism and large saturation magnetization facilitated collection of sorbents with a magnet. Based on the catechol and amine groups, the PDA polymer provided multiple interactions to combine with pollutants. To investigate the adsorption ability of Fe3O4/PDA, heavy metal ions and dyes were selected as target pollutants. The adsorption of pollutants was pH dependent due to the variation of surface charges at different solution pH. The removal efficiencies of cation pollutants enhanced with solution pH increasing, and that of anion pollutant was just the opposite. Under the optimal solution pH, the maximum adsorption capacity calculated from Langmuir adsorption isotherm for methylene blue, tartrazine, Cu(2+), Ag(+), and Hg(2+) were 204.1, 100.0, 112.9, 259.1, and 467.3 mg g(-1), respectively. The Fe3O4/PDA shows great potential for multiple pollutants removal, and this study is the first application of PDA polymer in environmental remediation.

Biocompatible phosphatidylcholine bilayer coated on magnetic nanoparticles and their application in the extraction of several polycyclic aromatic hydrocarbons from environmental water and milk samples

In this work, phosphatidylcholine (PC) was coated on magnetic nanoparticles to form lipid bilayer as solid-phase extraction (SPE) sorbents for the enrichment of polycyclic aromatic hydrocarbons (PAHs) from environmental water and milk samples. The lipid bilayer was coated on Fe(3)O(4) nanoparticles using a modified dry lipid film hydration method. The resulted Fe(3)O(4)/PC could be readily isolated from solution with a magnet, and exhibited excellent adsorption performance to organic pollutants. Only 0.1g of sorbents was enough to extract PAHs from 500 mL aqueous solution, and 6 mL of acetonitrile was required to desorb them. The method was fast and relied on 10 min extraction time and 5 min magnetic separation. The proposed method was successfully applied to determine PAHs in some environmental water and milk samples. The detection limit was in the range of 0.2-0.6 ng L(-1). The recoveries of the spiked water samples ranged from 89% to 115% with relative standard deviations (RSD) varying from 1% to 8%. For spiked milk samples, RSD was satisfactory (1-9%), but the recoveries were relatively low (42-62%). We show the potentials of Fe(3)O(4)/PC sorbents in environmental water and biological sample analyses.

A facile route for preparation of magnetic biomass activated carbon with high performance for removal of dye pollutants

A novel and simple method for preparing magnetic biomass activated carbon (BAC) was developed. The BAC was prepared by decomposing fallen leaves, and magnetic nanoparticles were grown in situ on BAC using solvothermal method. The prepared magnetic BAC was characterized with FT-IR, XRD, vibrating sample magnetometer, thermo-gravimetric apparatus, SEM, and high-resolution transmission electron microscope, and results indicate that BAC and magnetic nanoparticles were combined together successfully. To investigate the adsorption ability of the composites, several dyes were selected as sample pollutants, and the sorbent showed high adsorption capacity for the dyes. The solution pH had no significant effect on the adsorption in the range of 5–9. The adsorption behavior of magnetic BAC for dyes followed the Langmuir isotherm model, and the adsorption capacity of congo red, neutral red, and methyl green were 396.8, 171.2, and 403.2xa0mg/g, respectively. The maximum adsorption capacity in natural water showed no obvious decrease, indicating the strong anti-interference ability of the sorbents. The Gibbs free energy calculated from the thermodynamics data was negative, demonstrating that the adsorption of these dyes on the magnetic BAC was spontaneous. The magnetic BAC showed a great potential for the removal of dye pollutants from environment water.