A filter including a plurality of pillar-shaped honeycomb structure segments made of porous ceramics, side faces of the segments being bonded together via a bonding material, wherein each of the pillar-shaped honeycomb structure segments includes an outer peripheral side wall, and partition walls partitioning a plurality of cells extending from a first end face to a second end face, and in each of the pillar-shaped honeycomb structure segments, an average porosity of the outer peripheral side wall is lower than that of the partition walls.

A honeycomb structure body is constituted of a circumferential region including the outermost circumference in a cross section of the honeycomb structure body which is perpendicular to an extending direction of cells, and a central region excluding the circumferential region. The circumferential region includes a specific circumferential region in which pressure loss with soot when an amount of the deposited soot is 4 g/L is higher than the pressure loss with soot of the central region as much as 15% or more and in which an open frontal area of the circumferential region is the same as or larger than an open frontal area of the central region. In the cross section of the honeycomb structure body, a ratio of an area of the specific circumferential region is 5% or more to a total area of the circumferential region and the central region.

A honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, wherein the partition walls have projecting portions, in the cells of 10% or more of the plurality of cells, the projecting portions project into the cells, a tip curvature radius R of an apex of each of the projecting portions is from 0.01 to 0.1 mm, side surfaces of the projecting portions are inclined to the surfaces of the partition walls at an inclination angle of 40 to 70, and a relation of 0.04H/A0.4 is satisfied.

A honeycomb structure has grooves dented inwardly from the surfaces of the partition walls along a cell direction An open width of an open end of the groove is 0.015-0.505 mm and smaller than the open width a length of one side of each of the cells with the grooves, a bottom width of a bottom of the groove is 0.01-0.5 mm and smaller than the open width, a height from the bottom of the groove to the open end is 0.01-0.05 mm, a thickness of the partition wall in a groove portion is 50 m or more, a ratio of the number of the cells with the grooves to the number of the total cells is 80% or more, and a value obtained by subtracting the open frontal area when the grooves excluded from the open frontal area when the grooves included is 0.1-8.0%.

A filter comprising a columnar honeycomb structure part, the columnar honeycomb structure part including: a plurality of first cells each extending from a first bottom surface to a second bottom surface of the columnar honeycomb structure part, the first bottom surface being opened and the second bottom surface being plugged for the plurality of first cells; a plurality of second cells each extending from the first bottom surface to the second bottom surface of the columnar honeycomb structure part, the first bottom surface being plugged and the second bottom surface being opened for the plurality of second cells; and porous cordierite partition walls that define the first cells and the second cells, the partition walls having an average pore depth of 1.5 m or more and 3.5 m or less as measured by a laser microscope, and a porosity of from 50 to 60% as measured by a mercury porosimeter.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall surrounding cells each of which has one end plugged by a plugging portion. An open frontal area O (%) of the cells in the honeycomb structure body is 75 to 80%, a porosity P (%) of the partition wall measured by a mercury press-in method is 52 to 58%, an average pore diameter D (m) of the partition wall measured by the mercury press-in method is 6 to 12 m, and a pore volume rate A (%) of pores whose pore diameters are not less than 20 m with respect to an overall pore volume of the partition wall is not more than 13.5%.

A separator element comprising a porous rigid single-piece substrate (2) made of a single porous material, and including internally at least one channel (3) for passing a flow of the fluid medium, which channel opens out in one end of the porous substrate for inlet of the fluid medium for treatment and in another end of the porous substrate for outlet of the retentate. At least one empty space (10) is arranged in the porous substrate so as to be surrounded by a portion of the material constituting the single-piece substrate (2) either completely so as to form a closed cavity or partially so as to form a cavity (10.sub.1) that opens out locally through the peripheral envelope (2.sub.2) of the substrate via a passage (10.sub.2) of section smaller than the section of the cavity (10.sub.1).

The invention relates to a particulate filter for collecting particulate matter from the exhaust gases of an internal combustion engine, having a canal geometry that evolves along the entire length of the canal, such that: the perimeter of the cross section of the canal decreases continuously from an open end (310) of the canal (370) as far as a reference cross section (350) of the canal, then increases continuously from the reference cross section as far as a closed end (360) of the canal, and the surface area of the cross section of the canal decreases monotonously from the open end of the canal as far as the closed end. The closed ends are situated in the body of the filter near the outlet and inlet faces respectively for the inlet and outlet canals of the filter.

Disclosed is a filtration structure, comprising: a substrate, wherein the substrate is a three-dimensional lattice formed from repeating geometric shapes; a layer of porous material bonded over the substrate; and a liquid amine retained within the pores of the porous material. Also disclosed is a carbon dioxide scrubber comprising the filtration structure.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face side or the outflow end face side of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region, is higher than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portion ranges from 76% to 85%, and that of the circumferential plugging portion from 60% to 75%.