Hollow fiber membranes, membrane contactors, and related production and use methods. The asymmetric hollow fiber membranes include a porous substrate having a multiplicity of pores and including at least one semi-crystalline thermoplastic polyolefin (co)polymer. A skin layer including at least one polydiorganosiloxane polyoxamide copolymer overlays the porous substrate. The skin layer is less porous than the porous substrate and forms an outer surface of the asymmetric hollow fiber membrane, while the porous substrate forms an inner surface of the hollow fiber membrane. The skin layer is preferably nonporous.

The present disclosure provides a method of making a chemical mechanical planarization slurry. The method includes contacting a chemical mechanical planarization slurry precursor including a carrier and a plurality of abrasive particles with a semi-permeable fiber membrane. Upon contact, the method further includes separating the chemical mechanical planarization slurry precursor into a concentrate and an effluent. The concentrate includes the chemical mechanical planarization slurry and the effluent includes the carrier and a plurality of particles. The particles of the effluent have a median size that is less than a median size of the abrasive particles of the concentrate. In the method a pressure difference measured between an inlet to which the chemical mechanical planarization slurry precursor is supplied and a first outlet to which the effluent is supplied is in a range of from about 1 psi to about 15 psi.

The present disclosure provides a method of making a chemical mechanical planarization slurry. The method includes contacting a chemical mechanical planarization slurry precursor including a carrier and a plurality of abrasive particles with a semi-permeable fiber membrane. Upon contact, the method further includes separating the chemical mechanical planarization slurry precursor into a concentrate and an effluent. The concentrate includes the chemical mechanical planarization slurry and the effluent includes the carrier and a plurality of particles. The particles of the effluent have a median size that is less than a median size of the abrasive particles of the concentrate. In the method a pressure difference measured between an inlet to which the chemical mechanical planarization slurry precursor is supplied and a first outlet to which the effluent is supplied is in a range of from about 1 psi to about 15 psi.

A fluid separation apparatus comprising a fluid separation membrane is provided. The fluid separation apparatus comprises a fluid separation membrane extending in one direction and having a cross-section with a closed curve shape, wherein the fluid separation membrane has a thickness of 0.1 mm to 2 mm, and an outer diameter of 60 mm to 360 mm when the cross-section is adjusted to be circular.

A filtration method that includes a cleaning step using a chemical agent, wherein provided is the filtration method with excellent chemical resistance performance. The filtration method pertaining to the present invention comprises a filtration step in which a liquid to be filtered is filtered by being passed through a porous membrane formed of a resin, and a cleaning step in which the membrane interior of the porous membrane is cleaned after the filtration step, wherein a porous membrane for which the area ratio of a resin part having an area of 1 μm.sup.2 or less included in a cross section of the membrane interior is at least 70% of the total area of the entire resin part included in the cross section, and said cleaning step includes a step in which an aqueous solution of at least 1% sodium hydroxide is passed through the porous membrane.

A filtration method that includes a cleaning step using a chemical agent, wherein provided is the filtration method with excellent chemical resistance performance. The filtration method pertaining to the present invention comprises a filtration step in which a liquid to be filtered is filtered by being passed through a porous membrane formed of a resin, and a cleaning step in which the membrane interior of the porous membrane is cleaned after the filtration step, wherein a porous membrane for which the area ratio of a resin part having an area of 1 μm.sup.2 or less included in a cross section of the membrane interior is at least 70% of the total area of the entire resin part included in the cross section, and said cleaning step includes a step in which an aqueous solution of at least 1% sodium hydroxide is passed through the porous membrane.

The present invention relates to a method for preparing a membrane comprising sorbent particles that bind urea. The invention also relates to the sorbent-comprising membranes per se, and to methods of using the membranes. The membranes are useful for undergoing subsequent reactions with small molecules such as urea, for instance to remove urea from a solution.

The present invention relates to a method for preparing a membrane comprising sorbent particles that bind urea. The invention also relates to the sorbent-comprising membranes per se, and to methods of using the membranes. The membranes are useful for undergoing subsequent reactions with small molecules such as urea, for instance to remove urea from a solution.

Water or wastewater filtration processes and systems have a plurality of membrane modules, each having filter media therein, the plurality of membrane modules arranged in parallel fluid flow, a main bottom feed conduit, a main top feed conduit, and separate feed conduits fluidly connecting the main bottom feed conduits and the main top feed conduits to respective membrane modules. A main filtrate conduit, and separate filtrate conduits fluidly connect respective membrane modules to the main filtrate conduit. A backwash conduit fluidly connects the main filtrate conduit to respective membrane modules through the main top and bottom feed conduits. A pump having a pump feed conduit and a pump discharge conduit, the pump discharge conduit fluidly connected to the main top and bottom feed conduits, and a plurality of automatically controllable valves positioned in the main top and bottom feed conduits, the main filtrate conduit, the pump discharge conduit, and the backwash conduit, with a controller configured to actuate the plurality of automatically controllable valves to control feed and backwash flows through the membrane modules using pressure developed only by the pump. The pump is preferably operated by a variable-speed prime mover.

Water or wastewater filtration processes and systems have a plurality of membrane modules, each having filter media therein, the plurality of membrane modules arranged in parallel fluid flow, a main bottom feed conduit, a main top feed conduit, and separate feed conduits fluidly connecting the main bottom feed conduits and the main top feed conduits to respective membrane modules. A main filtrate conduit, and separate filtrate conduits fluidly connect respective membrane modules to the main filtrate conduit. A backwash conduit fluidly connects the main filtrate conduit to respective membrane modules through the main top and bottom feed conduits. A pump having a pump feed conduit and a pump discharge conduit, the pump discharge conduit fluidly connected to the main top and bottom feed conduits, and a plurality of automatically controllable valves positioned in the main top and bottom feed conduits, the main filtrate conduit, the pump discharge conduit, and the backwash conduit, with a controller configured to actuate the plurality of automatically controllable valves to control feed and backwash flows through the membrane modules using pressure developed only by the pump. The pump is preferably operated by a variable-speed prime mover.