Final answer:
To keep the solid wet during filtration, water is poured over a filter that allows water to pass while retaining the solid on the filter paper. The filtration media used can vary from sand filters to artificial membranes, depending on the particle size and required filtration speed.
Step-by-step explanation:
If you want to keep the solid and ensure it remains wet during the filtration process, a method that permits the liquid to pass through while retaining the solid on the filter is needed. The most common type of filtration in such a case would involve simply pouring the water over a filter, where the filter paper retains the wet solid, such as sand while allowing the water to pass through. This is encountered routinely in laboratories where a mixture of a solid and liquid needs to be separated and the solid is to be retained in a wet state for further analysis or use. The filtration media could range from coarse to fine depending on the size of the particles and the desired speed of filtration. Materials like sand filters, artificial membranes, charcoal, or even more advanced filtering systems may be employed depending on the cleanness requirements and the properties of the solid to be retained. Filtration could also be a part of a larger water treatment process that involves sedimentation, where floc particles settle, followed by filtration to remove remaining suspended particles, bacteria, and other organic matter. The choice of filtration method will be influenced by whether gravity or pressure is used to drive the flow through the filter medium.