Effective extraction of lithium from high Mg2+/Li+ratio brine lakes is of great challenge.In this work,organic–inorganic hybrid silica nanofiltration(NF)membranes were prepared by dip-coating a 1,2-bis(triethoxysilyl...Effective extraction of lithium from high Mg2+/Li+ratio brine lakes is of great challenge.In this work,organic–inorganic hybrid silica nanofiltration(NF)membranes were prepared by dip-coating a 1,2-bis(triethoxysilyl)ethane(BTESE)-derived separation layer on tubular TiO2 support,for efficient separation of LiC l and MgCl2 salt solutions.We found that the membrane calcinated at 400°C(M1–400)could exhibit a narrow pore size distribution(0.63–1.66 nm)owing to the dehydroxylation and the thermal degradation of the organic bridge groups.All as-prepared membranes exhibited higher rejections to LiCl than to MgCl2,which was attributed to the negative charge of the membrane surfaces.The rejection for LiCl and MgCl2 followed the order:LiCl N MgCl2,revealing that Donnan exclusion effect dominated the salt rejection mechanism.In addition,the triplecoated membrane calcined at 400°C(M3–400)exhibited a permeability of about 9.5 L·m-2·h-1·bar-1 for LiCl or MgCl2 solutions,with rejections of 74.7%and 20.3%to LiCl and MgCl2,respectively,under the transmembrane pressure at 6 bar.Compared with the previously reported performance of NF membranes for Mg2+/Li+separation,the overall performance of M3–400 is highly competitive.Therefore,this work may provide new insight into designing robust silica-based ceramic NF membranes with negative charge for efficient lithium extraction from salt lakes.展开更多
基金supported by the National Natural Science Foundation of China(21490581)the China Petroleum and Chemical Corporation Limited Project(317008-6)+1 种基金the Innovation Driven Development Special Fund Project of Guangxi Province(AA17204092)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Effective extraction of lithium from high Mg2+/Li+ratio brine lakes is of great challenge.In this work,organic–inorganic hybrid silica nanofiltration(NF)membranes were prepared by dip-coating a 1,2-bis(triethoxysilyl)ethane(BTESE)-derived separation layer on tubular TiO2 support,for efficient separation of LiC l and MgCl2 salt solutions.We found that the membrane calcinated at 400°C(M1–400)could exhibit a narrow pore size distribution(0.63–1.66 nm)owing to the dehydroxylation and the thermal degradation of the organic bridge groups.All as-prepared membranes exhibited higher rejections to LiCl than to MgCl2,which was attributed to the negative charge of the membrane surfaces.The rejection for LiCl and MgCl2 followed the order:LiCl N MgCl2,revealing that Donnan exclusion effect dominated the salt rejection mechanism.In addition,the triplecoated membrane calcined at 400°C(M3–400)exhibited a permeability of about 9.5 L·m-2·h-1·bar-1 for LiCl or MgCl2 solutions,with rejections of 74.7%and 20.3%to LiCl and MgCl2,respectively,under the transmembrane pressure at 6 bar.Compared with the previously reported performance of NF membranes for Mg2+/Li+separation,the overall performance of M3–400 is highly competitive.Therefore,this work may provide new insight into designing robust silica-based ceramic NF membranes with negative charge for efficient lithium extraction from salt lakes.
