Photocurable compositions that have a color change during curing and methods of preparation and use of such compositions. More particularly, the present invention relates to photocurable compositions that that have a color change during curing and are useful for forming topographical features, e.g., spacer features, and/or fold protection coatings on a portion of a membrane surfaces, and particularly on membranes used in osmosis and reverse-osmosis applications, such as membrane filters.

In embodiments of the present invention, flow dividing strips are used in the construction of the spiral wound element to segregate and direct feed to reject flow of a reverse osmosis element Flow dividing strips isolate the flow of fluid through distinct regions of the spiral-wound element. The flow dividing features can also be used to direct flow within the element in order to create a longer flow path for the fluid through the element, enabling even higher recovery in some applications.

The present invention relates to a crossflow membrane module configured to separate a feed fluid into a permeate fluid and a residue fluid across one or more membrane sheet(s). The crossflow module comprises a second end offset from a first end along the first direction where an inlet is provided at the first end and an outlet is provided at the second end. The one or more membrane sheet(s) each have a first portion and a second portion. A conduit is adjacent to the first side of each membrane sheet and is configured to receive and output the permeate fluid separated from the feed fluid. The second portion of the membrane sheet has a greater permeance for a major component than the first portion such that the second part of the permeate fluid, which is generated by separation across the second portion of the membrane sheet, has a higher concentration of the major component than the first part of the permeate fluid, which is generated by separation across the first portion. The second portion is spaced apart from the first side of the membrane sheet along the second direction thereby causing the second part of the permeate gas to flow towards the first side of the membrane sheet such that the second part of the permeate gas mixes with the first part of the permeate gas thereby reducing the concentration of the minor component in the first part of the permeate gas.

Provided are a composite semipermeable membrane capable of enhancing adhesion between a separation functional layer provided with a coating layer and a protective tape while maintaining an effect of the coating layer to some extent, and a spiral membrane element using the composite semipermeable membrane.

A composite semipermeable membrane includes: a porous support; a separation functional layer formed on the porous support; and a coating layer provided on a surface of the separation functional layer, the coating layer having different surface roughnesses due to different adhesion amounts of a coating material depending on locations. The composite semipermeable membrane has a coating layer-side surface on which a glossy portion having a surface roughness Ra of 30 nm or less and a non-glossy portion having a surface roughness Ra of 50 nm or more are provided.

Embodiments of the invention provide replacements for a continuous layer of feed spacer mesh in spiral-wound reverse osmosis elements and replacing such mesh with discrete regions of feed spacer supporting the inlet and outlet ends of the element and a stiffening bridge feature to bridge between these regions at the tail end of each membrane leaf comprising the element during the element rolling process. The stiffening bridge feature prevents inward deflection of the inner layer of the membrane leaf during rolling, facilitating proper sealing of the adhesive through the permeate carrier to the adjacent membrane film using known membrane rolling techniques.

In embodiments of the present invention, flow dividing strips are used in the construction of the spiral wound element to segregate and direct feed to reject flow of a reverse osmosis element Flow dividing strips isolate the flow of fluid through distinct regions of the spiral-wound element. The flow dividing features can also be used to direct flow within the element in order to create a longer flow path for the fluid through the element, enabling even higher recovery in some applications.

Spiral wound reverse osmosis devices with reduced lateral leakage and thereby increased salt rejection are made by compacting a microporous layer within a composite reverse osmosis membrane longitudinally along its lengthwise periphery. Means and method for causing longitudinal indentations in composite membranes during manufacturing operations are disclosed and described.

The present invention relates to a spiral wound membrane element designs that utilize entrance and exit points in the feed space channel and utilize barriers on the perimeter of the feed space as well as barriers in the feed space area to direct fluid flow in the membrane element.

The present invention relates to a counterflow membrane module configured to separate a feed fluid into a permeate fluid and a residue fluid across one or more membrane sheet(s). The counterflow module comprises a second end offset from a first end along the first direction where an inlet is provided at the first end and an outlet is provided at the second end. The one or more membrane sheet(s) each have a first portion, a second portion and a permeate section. A conduit is adjacent to the permeate section of the membrane and is configured to receive and output the permeate fluid separated from the feed fluid.

Spiral wound reverse osmosis devices with reduced lateral leakage and thereby increased salt rejection are made by compacting a microporous layer within a composite reverse osmosis membrane longitudinally along its lengthwise periphery. Means and method for causing longitudinal indentations in composite membranes during manufacturing operations are disclosed and described.