title: Adsorption of microcystin-LR from water with iron oxide nanoparticles.
abstract: Adsorption of microcystin-LR (MC-LR) from water using iron oxide (alpha-Fe2O3) nanoparticles was investigated in this study. Adsorption of MC-LR adsorption was well-described by a pseudo second order kinetics model and Freundlich and Langmuir isotherm equations at 15 to 35 degrees C. Thermodynamic analysis showed that the Gibbs free energy was negative, whereas standard enthalpy and entropy changes were positive at this temperature range. These findings suggest that the adsorption of MC-LR on iron oxide nanoparticles was spontaneous and endothermic. The effects of initial pH, inorganic cations, and competing compounds with carboxyl groups on absorption of MC-LR were also evaluated. Typically, adsorption efficiency decreased with increasing pH from 2 to 11. Sodium ions did not appear to significantly affect MC-LR adsorption, whereas calcium ions slightly enhanced the MC-LR adsorption capacity of the iron oxide nanoparticles. Moreover, the inhibiting effect of competing organic compounds was increased with increasing numbers of carboxyl groups, as follows: citric acid (3)>oxalic acid (2)>benzoic acid (1).
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Yu-qiong
authors.initials: YQ
authors.lastname: Gao
authors.forename: Nai-yun
authors.initials: NY
authors.lastname: Gao
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
authors.forename: Jin-shan
authors.initials: JS
authors.lastname: Gu
authors.forename: Yi-chen
authors.initials: YC
authors.lastname: Shen
authors.forename: Shao-xiang
authors.initials: SX
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008387:Marine Toxins; D053768:Metal Nanoparticles / Q000737:chemistry*; D052998:Microcystins / Q000737:chemistry*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; C000499:ferric oxide; C057862:cyanoginosin LR