title: Montmorillonite-Cu(II)/Fe(III) oxides magnetic material as adsorbent for removal of humic acid and its thermal regeneration.
abstract: In this work, the adsorption features of montmorillonite and the magnetic properties of Cu(II)/Fe(III) oxides were combined in a material to produce magnetic adsorbent, which can be separated from the medium by a simple magnetic process after adsorption. The magnetic material is effective for the removal of humic acid. At pH 6.1, 96% removal was observed from 4.4 mg l(-1) humic acid solution containing 0.02 M NaCl. The adsorption is pH and ionic strength dependent. Adsorption is favored at lower pH values and dissolved NaCl can enhance the adsorption. The adsorption mechanism of humic acid to the magnetic material was suggested to be the ligand exchange reaction between carboxylic groups of humic acid molecules and the magnetic material surface. The magnetic material can be thermally regenerated. The temperature and time required to achieve good regeneration efficiency were determined to be 300 degrees C and 3 h, respectively. The regenerated adsorbent is still magnetic and approximately has as high specific saturation magnetization and good adsorption capacities as the as-prepared adsorbent.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Xianjia
authors.initials: X
authors.lastname: Peng
authors.forename: Zhaokun
authors.initials: Z
authors.lastname: Luan
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D003300:Copper; D005290:Ferric Compounds; D006358:Hot Temperature; D006812:Humic Substances; D008280:Magnetics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods
chemical_list: D005290:Ferric Compounds; D006812:Humic Substances; D014874:Water Pollutants, Chemical; D001546:Bentonite; C000499:ferric oxide; D003300:Copper; C030973:cupric oxide