Filter paper is a semi-permeable Paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solid particles from liquids or gases.Filter paper: used for separating solid from liquid.The raw materials are different paper pulps. The pulp may be made from softwood, hardwood, fiber crops, or mineral fiber.

Properties

Filter paper has various properties. The important parameters are wet strenght, porosity, particle retention, volumetric flow rate, compatibility, efficiency and capacity.There are two mechanisms of filtration with paper; volume, and surface. By volume filtration, the particles are caught in the bulk of the filter paper. By surface filtration, the particles are caught on the paper surface. Filter paper is mostly used because of the ability of a small piece of filter paper to absorb a significant volume of liquid.