In brief, the filtrate is a liquid that can pass through a filter. Therefore, it is what we get after filtering off a suspension. Residue, on the other hand, is the solid mass we get on the filter paper after filtering off a suspension. We usually use these terms when we talk about the analytical technique, filtration. Filtration is a separation technique. It can be biological, physical or mechanical separation.
What is Filtrate?
The filtrate is the fluid portion we can obtain after a filtration process. It is the fluid that passes through the filter paper we use for filtration. Filtration is an analytical technique we can use to separate fluid portion from the solid portion of a suspension.
However, depending on the size of the pores of the filter paper and the size of the particles present in the suspension, some fine particles may pass through the filter paper; therefore, we can observe some fine particles in the filtrate. In such cases, we say the filtrate is contaminated. Here, the separation is not complete. Although the filtrate is often a liquid, there are some occasions where the filtrate can be a gas or even supercritical fluid.
What is Residue?
The residue is the solid portion we can obtain after a filtration process. Initially, the solid is suspended in the solution that we are going to filter. The solid residue is trapped on the filter paper during the filtration. After pouring the solution completely through the filter paper, we can obtain the total solid portion, which was present in the solution.
We can use different methods to separate different components in mixtures. For instance, in physical filtration methods, large-sized solid mass remains on the filter; in biological filtration methods, we can obtain solids such as metabolites and different cell particulates.
What is the Difference Between Filtrate and Residue?
Filtrate and residue are the components we obtain after a filtration process. The key difference between filtrate and residue is that the filtrate is a fluid, whereas the residue is a solid present in a suspension. Filtration separates the two portions from each other and via further purification, we can obtain pure substances. Besides, a further difference between filtrate and residue is that the filtrate can be either a gas or a liquid, but the residue is always in the solid-state.
When considering the end products of a filtration technique, we can obtain the filtrate as a fluid contaminated with the fine solid particles, and we can obtain the residue as a solid which has some remaining fluid on the surface. For example, drinking water obtained from water filters, the serum of blood, etc. are some examples for filtrates, whereas crystals produced during chemical reactions that take place via physical filtration, metabolites obtained from biological filtration, etc. are examples for residue.
Summary – Filtrate vs Residue
In summary, the filtrate and residue are the components that we obtain after a filtration process. Wherein, the key difference between filtrate and residue is that the filtrate is a fluid, whereas the residue is a solid present in a suspension. A suspension contains these two portions together. Filtration separates the two portions from each other and via further purification, we can obtain pure substances.
1. “Filtration.” Wikipedia, Wikimedia Foundation, 18 Sept. 2019, Available here.