This article studies the effects of Co and Ni replacement in Fe_1-xCo_xFe₂O₄ and Fe_1-yNi_yFe₂O₄ (x, y = 0, 0.05, 0.1, 0.2, 0.5) nanoparticles, pH, weight of nanoparticles/mL of water, and time of stirring on the arsenic removal ability. The results showed that a small amount (0.25 g L^-1) of Fe₃ O₄ nanoparticles after stirring time of 3 min can reduce the arsenic concentration from 0.1 to 0.01 mg L^-1. The removal was also affected by the pH of the water. Absorption of arsenic by nanoparticles was effective when pH was smaller than seven and reduced with the increase of pH. At pH of 13, there was a strong release of arsenic ions from arsenic-absorbed nanoparticles back to water. The time of stirring was studied from 1 min to 2 h and the optimal time was about few minutes. Co and Ni's presence was reported to keep saturation magnetisation stable under working conditions. For Co replacement, absorption does not change significantly when x ≤ 0.1 and slightly reduces when x > 0.1. The presence of Ni improved the absorption in most cases.

Phu N.D., Phong P.C., Chau N., Luong N.H., Hoang L.H., Hai N.H.

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Từ khóa : Arsenic concentration; Arsenic ions; Arsenic removal; Magnetic nanoparticles; Magnetisation; Optimal time; Working conditions; Absorption; Arsenic; Dewatering; Ferrite; Gyrators; Nanoparticles; Nickel; Saturation magnetization; Water recycling; Chemicals removal (water treatment); arsenic; carbonic acid; ferrite; magnetite; nickel; superparamagnetic iron oxide nanoparticle; adsorption; article; concentration (parameters); controlled study; heavy metal removal; magnetism; molecular weight; nanoanalysis; nanochemistry; nanoimaging; nanotechnology; particle size; pH; priority journal; process development; transmission electron microscopy; water management; water treatment; X ray diffraction