TEMPERATURE-GRADIENT AIDED DIFFUSIOPHORETIC WATER FILTRATION DEVICE

Abstract

A water filtration device is provided including a diffusiophoretic water filter having an inlet and an outlet and for receiving a colloidal suspension at the inlet and flowing the colloidal suspension between the inlet and the outlet in a flow direction, a diffusiophoretic-inducing membrane, a cover, the membrane and the cover defining a plurality of channels extending between the inlet and the outlet, an outlet splitter for the plurality of channels being fixed with respect to the membrane or the cover, and a heater or cooler for controlling a temperature of at least one of the colloidal suspension, the membrane or the cover.

Claims

1. A water filtration device comprising a diffusiophoretic water filter having an inlet and an outlet and for receiving a colloidal suspension at the inlet and flowing the colloidal suspension between the inlet and the outlet in a flow direction; a diffusiophoretic-inducing membrane; a cover, the membrane and the cover defining a plurality of channels extending between the inlet and the outlet; an outlet splitter for the plurality of channels being fixed with respect to the membrane or the cover, and a heater or cooler for controlling a temperature of at least one of the colloidal suspension, the membrane or the cover.

2. A method for operating a diffusiophoretic water filter comprising heating or cooling a colloidal suspension, upstream of the filter, or at a cover or diffusiophoretic-inducing membrane.

3. A method for aiding diffusiophoretic motion of a particle by inducing a temperature gradient on the particle to move it in a same direction as the diffusiophoretic motion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One schematic embodiment of the water filtration system of the present invention is shown by reference to FIG. 1, in which:

[0017] FIG. 1 shows a schematic view of an embodiment of a water filtration device system according to the present invention; and

[0018] FIG. 2 shows the device in more detail.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0019] FIG. 1 shows a water filtration system 100 for cleaning river water, which may contain various particles such as colloidal plastic or metallic particles, and other bioparticles such as bacteria and viruses. Many of these particles are charged negatively or positively. Any type of water with charged colloidal particles may be filtered using the present invention. Colloidal particle as defined herein is any particle that can form a colloid or colloidal suspension in water. Such colloidal particles typically range in sizes of a micrometer or less, but larger sizes are possible. The present invention is not limited to filtering colloidal particles, but can also be used to filter larger particles that are impacted by diffusiophoresis, for example even up to 100 nanometers in size or larger, from water. Preferably the particles to be filtered are less than 250 nanometers in size, even if not colloidal. These non-colloidal particles can have very low sedimentation rates, and thus the present invention can aid in sedimentation or forcing these larger particles downwardly.

[0020] Water can be taken by taking water from a river or pond or other source, for example by a hose 100 working via gravity, such as a siphon. The hose 100 delivers water to a first filter 110 to remove larger particles and impurities. First filter 110 can be for example a membrane filter with an absolute pore size of 1 micrometer or 1000 nanometers, for example as commercially available from Brita. Filter 110 also could simply be a settling tank or a sand filter. The water with suspended colloidal particles, i.e. a colloidal suspension, together with possible other particles that are larger than typical colloidal sizes, then passes to the water filtration device 200 of the present invention.

[0021] Water filtration device 200 is designed to remove negatively charged colloidal particles and other particles, the removal of which can significantly increase the water quality, and clean water can exit from the bottom of the device at a clean water stream 250, and waste water can be discarded at stream 260.

[0022] A heater or cooler 12 can be provided upstream of the water filter 280, for example in inlet manifold 210. A cover heater or cooler 10 can be laid on or integral within a cover of water filter 220.

[0023] A gas driven diffusiophoretic water filter, shown in FIG. 2 schematically in cross section, has a gas permeable membrane 222 over a gas chamber 220 and a gas permeable cover 310. Tapes 317, 318, 319 define with the membrane 222 and cover 310 channels with a width W and a thickness t.

[0024] A gas permeable heater or cooler 404, for example an electrically-heated metal honeycomb structure, can sit over membrane 310 and also aid in preventing bulging.

[0025] A gas permable heater or cooler 500 can sit in chamber 220, for example against membrane 222.