Removal of arsenate by cetyltrimethylammonium bromide modified magnetic nanoparticles.
Cetyltrimethylammonium bromide (CTAB) modified magnetic nanoparticles (Fe(3)O(4)@CTAB) were synthesized and used to remove arsenate from water. Fe(3)O(4)@CTAB was prepared by a modified simple co-precipitation process with cheap and environmental friendly iron salts and cationic surfactant CTAB. Powder X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infra-red spectroscopy were utilized to characterize the prepared adsorbent (Fe(3)O(4)@CTAB). Transmission electron microscopy (TEM) image showed that Fe(3)O(4)@CTAB particles were approximately spherical with the core size of 10 nm. With a saturation magnetization of 67.2 emu g(-1), the Fe(3)O(4)@CTAB nanoparticles could be easily separated from solutions with a simple magnetic process in very short time (within 5 min). Adsorption of arsenate on Fe(3)O(4)@CTAB reached equilibrium within 2 min at pH 6. Arsenate adsorption agreed well with pseudo-second order kinetic model and two-site Langmuir isotherm model with the arsenate adsorption capacity of 23.07 mg g(-l), which was twice greater than that of pure Fe(3)O(4). Arsenate removal rate was over 90% at a wide pH range from 3 to 9 and the removal of arsenate was not obviously affected by the presence of dissolved natural organic matter (up to 10 mg L(-1) as TOC) and competitive anions (sulfate, bicarbonate, and silicate up to 20 mg L(-1), and phosphate up to 5 mg L(-1)) in solutions. Fe(3)O(4)@CTAB could be regenerated in alkali solutions and more than 85% As(V) was removed even in fifth regeneration/reuse cycle.
The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, PR China.
Yinjia
Y
Jin
Fei
F
Liu
Meiping
M
Tong
Yanglong
Y
Hou
D000327:Adsorption; D001149:Arsenates / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D001149:Arsenates; D002593:Cetrimonium Compounds; D058185:Magnetite Nanoparticles; D014874:Water Pollutants, Chemical; C025657:arsenic acid; D000077286:Cetrimonium