21. The B�chner funnel holds the sample isolated from the suction by a layer of filter paper . 22. Every 30 seconds, filter paper or a paper towel is used to draw off the blood. 23. Copy paper or KOH-impregnated filter paper are some low cost examples of sorbents which can be used. 24. The filter paper is used only once. 25. Second, the filter paper was strong enough to hold all the coffee grounds within the sealed paper. 26. In 1936, the widely recognised cone-shaped filter paper that fit inside the tapered filter top was introduced. 27. This image shows highly absorbent filter paper coated with a super-hydrophobic paint developed at University College London. 28. Other products include artist papers for traditional painting and printing techniques and filter paper for industry and research. 29. Here a circular filter paper is taken and the sample is deposited at the center of the paper. 30. They easily pass through filter paper .
