Abstract: A diffusiophoretic water filtration device includes a pressurized gas chamber receiving a pressurized gas; an inlet manifold receiving a colloidal suspension including colloidal particles in water; a flow chamber having an inlet and an outlet, the flow chamber receiving the colloidal suspension at the inlet from the inlet manifold, the colloidal suspension flowing between the inlet and at least one outlet in a flow direction; and a horizontal sheet separating the gas chamber and the flow chamber, the sheet being made of a gas permeable membrane, the gas capable of permeating the membrane, the membrane being water impermeable, the gas being carbon dioxide and permeating the membrane upwardly from the gas chamber in a direction normal to the membrane so as to induce diffusiophoretic motion on at least some of the colloid particles opposite to or in the direction normal to the membrane, the sheet covering a top of the pressurized gas chamber.