A method for preparing a functional membrane for recovering precious metal ions from oily wastewater is provided. The method includes: obtaining carbon nanotubes functionalized by polyacrylic acid (CNTs-PAA) by grafting acrylic acid onto a surface of carbon nanotubes (CNTs) via graft polymerization; obtaining carbon nanotubes modified by acyl hydrazine functional groups (CNTs-PAH) by reacting adipic dihydrazide (ADH) with carboxyl functional groups of the CNTs-PAA; preparing single-layer MXene nanosheets using Ti.sub.3AlC.sub.2 powder; and preparing a CNTs-PAH/MXene composite membrane by vacuum filtration based on the CNTs-PAH and the single-layer Mxene nanosheets.

Provide are an ionic liquid composition for a carbon dioxide separation membrane, a carbon dioxide separation membrane retaining the composition in voids, and a carbon dioxide concentration apparatus provided with the carbon dioxide separation membrane that can be used to separate carbon dioxide from high partial pressure to low partial pressure. The permeability of CO.sub.2 and CO.sub.2 selectivity ratio of the carbon dioxide separation membrane can be improved, and carbon dioxide from high partial pressure to a low partial pressure of 1 kPa or lower can be selectively separated and recycled by using an ionic liquid composition prepared by combining: an ionic liquid (I) that is an aminium having one or more primary or secondary amino groups and an ethylenediamine or propylenediamine backbone in the cation; and an ionic liquid (II) in which the cation has no primary or secondary amino group and the anion is an oxoacid anion.

A ceramic membrane filtration assembly comprising a membrane assembly extending from a first membrane assembly end to a second membrane assembly end, where the membrane assembly is defined by a membrane assembly length, the membrane assembly including at least one membrane. At least one of the membranes have channels therein, and at least one channel has channel ends. The filtration assembly further includes at least one sealing device coupled with the membrane assembly adjacent to at least one of the first and second membrane assembly ends, where the sealing device has an inner and outer perimeter. The sealing device has a sealing feature disposed along the outer perimeter, and the inner perimeter of the sealing device is sealed with a portion of the membrane assembly.