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.

Chromium removal from contaminated waters using nanomaterials – A review

“…Most of the removal experiments have been tested at temperature between 20 and 25ºC, presumably to be more practical and reduce associated costs with cooling and heating. Other studies were performed approximately at 30ºC [39,48,49,51,[58][59][60][61][62][63], at 35ºC [37], and even at 40ºC [64,65] most likely ajusting to the natural conditions existing in warmer countries. Apart from the cases described by [8,9,39,66,67], efficiency of chromium sorption increases with temperature.…”

Reduction of Hexavalent Chromium and Detection of Chromate Reductase (ChrR) in Stenotrophomonas maltophilia

“…Hexavalent chromium is used in a variety of industrial applications such as leather tanning, metallurgy, electroplating, petroleum refining, textile dyeing, paints, pigment production, steel making and thermonuclear weapons manufacturing [ 11 , 12 , 13 ]. Similar to some organic pollutants, chromium tend not to be degraded and accumulated into the environment, chromium compounds may enter to food chain and could cause different effects [ 14 ].…”

Effective adsorption of Cr(VI) on mesoporous Fe-functionalized Akadama clay: Optimization, selectivity, and mechanism

“…7 Table 1 Data for optimization operation: experimental range and levels of independent process 8 variables. The adsorption selective experiments were conducted using commonly coexisting 10 anions in Cr(VI)-containing wastewaters [22,23]. The concentrations of coexisting ions 11 in real wastewater are usually several hundred ~ thousand mg L -1 [24,25], thus different A c c e p t e d M a n u s c r i p t 11 represented univalent Cl -, bivalent SO 4 2-, and trivalent PO 4 3-.…”