Replenishing Mg(II) to desalinated water by seawater nanofiltration followed by magnetic separation of Mg(OH)_2(s)Fe₃O₄ particles

TY - JOUR

T1 - Replenishing Mg(II) to desalinated water by seawater nanofiltration followed by magnetic separation of Mg(OH)2(s)Fe3O4 particles

AU - Lehmann, Orly

AU - Eckhaus, Or

AU - Lahav, Ori

AU - Birnhack, Liat

N1 - Publisher Copyright: © 2015 Balaban Desalination Publications. All rights reserved.

PY - 2016/9/7

Y1 - 2016/9/7

N2 - Magnesium (Mg2+) appears at high concentration in seawater and seawater-reverse-osmosis brines. In contrast, desalinated water is almost completely depleted of Mg2+, a mineral perceived essential for human health and agricultural irrigation. The paper introduces a cost-effective method to enrich desalinated water with an almost pure Mg(II) solution, originating from seawater. The method uses seawater nanofiltration (or nanofiltration of seawater-reverse-osmosis brine) to produce brine characterized by high Mg2+ concentration, accompanied by relatively low B, Cl−, and Na+ concentrations. Subsequently, Mg(II) is separated from the produced nanofiltration brine by precipitating Mg(OH)2(s) and adsorbing it onto the surface of micro-magnetite particles. Finally, the solid slurry (Fe3O4 + Mg(OH)2) is magnetically separated from the brine and the Mg(OH)2(s) is re-dissolved into the desalinated water in a separate reactor. Application of the method results in a relatively pure Mg(II) addition to the desalinated water product. For example, for Mg(II) addition of 10 mg/L (as recommended by the World Health Organization), the following negligible concentrations of unwanted species are added to the water (in mg/L units): Na+: 0.04, Cl−: 0.18, Ca2+: 0.05, and B: 0.0094. The cost of adding 10 mg Mg/L was estimated at 0.76 cent$/m3 of desalinated water, i.e. competitive with previously suggested processes.

AB - Magnesium (Mg2+) appears at high concentration in seawater and seawater-reverse-osmosis brines. In contrast, desalinated water is almost completely depleted of Mg2+, a mineral perceived essential for human health and agricultural irrigation. The paper introduces a cost-effective method to enrich desalinated water with an almost pure Mg(II) solution, originating from seawater. The method uses seawater nanofiltration (or nanofiltration of seawater-reverse-osmosis brine) to produce brine characterized by high Mg2+ concentration, accompanied by relatively low B, Cl−, and Na+ concentrations. Subsequently, Mg(II) is separated from the produced nanofiltration brine by precipitating Mg(OH)2(s) and adsorbing it onto the surface of micro-magnetite particles. Finally, the solid slurry (Fe3O4 + Mg(OH)2) is magnetically separated from the brine and the Mg(OH)2(s) is re-dissolved into the desalinated water in a separate reactor. Application of the method results in a relatively pure Mg(II) addition to the desalinated water product. For example, for Mg(II) addition of 10 mg/L (as recommended by the World Health Organization), the following negligible concentrations of unwanted species are added to the water (in mg/L units): Na+: 0.04, Cl−: 0.18, Ca2+: 0.05, and B: 0.0094. The cost of adding 10 mg Mg/L was estimated at 0.76 cent$/m3 of desalinated water, i.e. competitive with previously suggested processes.

KW - FeO, Mg(OH)

KW - Magnesium recovery

KW - Magnetic separation

KW - SWRO

UR - http://www.scopus.com/inward/record.url?scp=84946593446&partnerID=8YFLogxK

U2 - 10.1080/19443994.2015.1107858

DO - 10.1080/19443994.2015.1107858

M3 - 文章

AN - SCOPUS:84946593446

VL - 57

SP - 19903

EP - 19916

JO - Desalination and Water Treatment

JF - Desalination and Water Treatment

SN - 1944-3994

IS - 42

ER -