title: Shellac-coated iron oxide nanoparticles for removal of cadmium(II) ions from aqueous solution.
abstract: This study describes a new effective adsorbent for cadmium removal from aqueous solution synthesized by coating a shellac layer, a natural biodegradable and renewable resin with abundant hydroxyl and carboxylic groups, on the surface of iron oxide magnetic nanoparticles. Transmission Electron Microscopy (TEM) imaging showed shellac-coated magnetic nanoparticle (SCMN) adsorbents had a core-shell structure with a core of 20 nm and shell of 5 nm. Fourier Transform Infrared Spectroscopic analysis suggested the occurrence of reaction between carboxyl groups on the SCMN adsorbent surface and cadmium ions in aqueous solution. Kinetic data were well described by pseudo second-order model and adsorption isotherms were fitted with both Langmuir and Freundlich models with maximum adsorption capacity of 18.80 mg/g. SCMN adsorbents provided a favorable adsorption capacity under high salinity conditions, and cadmium could easily be desorbed using mild organic acid solutions at low concentration.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China. jilaigong@gmail.com
authors.forename: Jilai
authors.initials: J
authors.lastname: Gong
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.forename: Fei
authors.initials: F
authors.lastname: Long
authors.forename: Jiuhua
authors.initials: J
authors.lastname: Deng
authors.forename: Qiuya
authors.initials: Q
authors.lastname: Niu
authors.forename: Xun
authors.initials: X
authors.lastname: He
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000302:isolation & purification*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D012116:Resins, Plant / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D005290:Ferric Compounds; D012116:Resins, Plant; D014874:Water Pollutants, Chemical; D002104:Cadmium; C000499:ferric oxide; D012965:Sodium Chloride; C003934:shellac