A process for removing at least Ca.sup.2+ and Mg.sup.2+ from a lithium-containing brine. The process comprises (i) providing an aqueous lithium-containing brine feed comprising dissolved Ca.sup.2+ and Mg.sup.2+ impurities in a weight ratio of Li.sup.+:Ca.sup.2+ of about 4:1 to 50:1 wt/wt and in a weight ratio of Li.sup.+:Mg.sup.2+ of about 4:1 to 50:1; (ii) subjecting said brine feed to nanofiltration to produce a lithium-containing permeate from which Ca.sup.2+ and Mg.sup.2+ components are being removed concurrently; and (iii) conducting the nanofiltration so that a separation occurs and a retentate solution is formed with a total amount of Ca.sup.2+ and Mg.sup.2+ of at least 75% of the total amount of Ca.sup.2+ and Mg.sup.2+ in the original aqueous lithium-containing brine feed and forming an aqueous lithium-containing permeate solution in which the total content of dissolved Ca.sup.2+ and Mg.sup.2+ is decreased to 25% or less as compared to the original aqueous lithium-containing brine feed.

A process for removing at least Ca.sup.2+ and Mg.sup.2+ from a lithium-containing brine. The process comprises (i) providing an aqueous lithium-containing brine feed comprising dissolved Ca.sup.2+ and Mg.sup.2+ impurities in a weight ratio of Li.sup.+:Ca.sup.2+ of about 4:1 to 50:1 wt/wt and in a weight ratio of Li.sup.+:Mg.sup.2+ of about 4:1 to 50:1; (ii) subjecting said brine feed to nanofiltration to produce a lithium-containing permeate from which Ca.sup.2+ and Mg.sup.2+ components are being removed concurrently; and (iii) conducting the nanofiltration so that a separation occurs and a retentate solution is formed with a total amount of Ca.sup.2+ and Mg.sup.2+ of at least 75% of the total amount of Ca.sup.2+ and Mg.sup.2+ in the original aqueous lithium-containing brine feed and forming an aqueous lithium-containing permeate solution in which the total content of dissolved Ca.sup.2+ and Mg.sup.2+ is decreased to 25% or less as compared to the original aqueous lithium-containing brine feed.

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

An apparatus is disclosed for separating and preserving biomolecules of a biological fluid sample. The apparatus includes an assembly having sides forming a hollow shape having a first opening at one end and second opening at the opposite end, a sample mixing chamber positioned adjacent the first opening within the assembly, the sample mixing chamber from which a flow of the biological fluid sample is actuated in a direction from the sample mixing chamber to the first matrix layer, the sample mixing chamber being in a direction downstream of the first opening, a first valve positioned between the sample mixing chamber and the first matrix layer, the first valve configured to control the flow to the first matrix layer, a first input in fluid communication with the sample mixing chamber and positioned upstream of the first valve, a second input positioned between the first matrix layer and the second matrix layer, and a second valve positioned between the second matrix layer and the second opening, the second valve configured to control the flow to the second matrix layer.

An apparatus is disclosed for separating and preserving biomolecules of a biological fluid sample. The apparatus includes an assembly having sides forming a hollow shape having a first opening at one end and second opening at the opposite end, a sample mixing chamber positioned adjacent the first opening within the assembly, the sample mixing chamber from which a flow of the biological fluid sample is actuated in a direction from the sample mixing chamber to the first matrix layer, the sample mixing chamber being in a direction downstream of the first opening, a first valve positioned between the sample mixing chamber and the first matrix layer, the first valve configured to control the flow to the first matrix layer, a first input in fluid communication with the sample mixing chamber and positioned upstream of the first valve, a second input positioned between the first matrix layer and the second matrix layer, and a second valve positioned between the second matrix layer and the second opening, the second valve configured to control the flow to the second matrix layer.

The present invention relates to a porous membrane including a polymer including a polyvinylidene fluoride-based resin as a main component, and a branched polyvinylidene fluoride-based resin as the polyvinylidene fluoride-based resin, in which the polymer has a value of a of 0.32 to 0.41 and a value of b of 0.18 to 0.42, each of which is determined by approximation according to the formula 1 below from a radius of gyration <S.sup.2>.sup.1/2 and an absolute molecular weight M.sub.w of the polymer which are measured by GPC-MALS (gel permeation chromatograph equipped with a multi-angle light scattering detector). <S.sup.2>.sup.1/2=bM.sub.w.sup.a (Formula 1).

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

Described in the present application are methods of producing silane-crosslinked polymer membranes at moderate temperatures using acid catalysts that, in certain embodiments, result in membranes with unexpectedly high permeabilities and selectivities. In certain embodiments, grafting and crosslinking of the silanes occur by immersing a preformed membrane in a solution comprising a silane and an acid catalyst. Alternatively, in certain embodiments, grafting of silanes to a polymer occurs in the presence of acid catalyst in solution and subsequent casting and drying produces crosslinked membranes. In certain embodiments, an acid catalyst is a weak acid catalyst. Also described in the present application are asymmetric crosslinked polymer membranes with porous layers. In certain embodiments, crosslinked cellulose acetate membranes have permeability up to an order of magnitude greater than the permeability of unmodified cellulose acetate membranes. The membranes have porous layers with a high porosity due to their processing in moderate conditions.

A gas sensor including a substrate, an output layer, a sensing layer, and a nanoporous polymer film is provided. The output layer is disposed on the substrate. The sensing layer is disposed on the output layer. The nanoporous polymer film is disposed on the sensing layer.