title: Optimization of factors affecting hexavalent chromium removal from simulated electroplating wastewater by synthesized magnetite nanoparticles.
abstract: Hexavalent chromium is a mutagen and carcinogen that is of significant concern in water and wastewater. In the present study, magnetite nanoparticles (n-Mag) were investigated as a potential remediation technology for the decontamination of Cr (VI)-contaminated wastewater. Synthesized n-Mag was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET-N2 technology. To screen and optimize the factors affecting Cr (VI) removal efficiency by synthesized nanoparticles, Plackett-Burman (PB) and Taguchi experimental designs were used respectively. The crystalline produced n-Mag was in the size range of 60-70 nm and had a specific surface area (SSA) of 31.55 m(2) g(-1). Results of PB design showed that the most significant factors affecting Cr (VI) removal efficiency were initial Cr (VI) concentration, pH, n-Mag dosage, and temperature. In a pH of 2, 20 mg L(-1) of Cr (VI) concentration, 4 g L(-1)of n-Mag, temperature of 40 °C, 220 rpm of shaking speed, and 60 min of contact time, the complete removal efficiency of Cr (VI) was achieved. Batch experiments revealed that the removal of Cr (VI) by n-Mag was consistent with pseudo-second order reaction kinetics. The competition from common coexisting ions such as NO₃(-), SO₄(2-), and Cl(-) were not considerable, unless in the higher concentration of SO₄(2-). These results indicated that the readily synthesized magnetite nanoparticles have promising applications for the removal of Cr (VI) from aqueous solution.
authors.affiliation: Soil Sciences Department, Islamic Azad University, Isfahan (Khorasgan) Branch, Isfahan, Iran (IR).
authors.forename: Mitra
authors.initials: M
authors.lastname: Ataabadi
authors.forename: Mehran
authors.initials: M
authors.lastname: Hoodaji
authors.forename: Arezoo
authors.initials: A
authors.lastname: Tahmourespour
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Kalbasi
authors.forename: Majid
authors.initials: M
authors.lastname: Abdouss
mesh_terms: D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D004595:Electroplating; D004784:Environmental Monitoring; D007700:Kinetics; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053758:Nanoparticles; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry*; D014867:Water; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D002857:Chromium; D058185:Magnetite Nanoparticles; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical; C074702:chromium hexavalent ion