What type of filter is used when expelling solutions from a syringe?

The correct choice is membrane filters when discussing the type of filter used while expelling solutions from a syringe. Membrane filters are specifically designed to separate particles from a liquid, ensuring that the solution being expelled is free from any particulate contaminants. These filters have a defined pore size which can trap particles larger than the specified size, thus ensuring the integrity of the solution, which is especially important in medical applications where sterility and purity are critical.

Membrane filters effectively maintain the sterility of the drug solution and prevent larger particulate matter from being introduced into the body, which could potentially lead to complications. This is particularly vital in environments like hospitals where patients may be vulnerable to infections or adverse reactions.

Other filter types, such as particle filters, focus more on removing specific substances from a flow, often functioning in air filtration rather than liquid contexts like syringes. Absorbent filters are generally used for the purpose of absorbing substances rather than retaining particulates. Disposable filters may simply refer to any filter that can be used once but do not specify the specific function needed in the context of expelling solution from a syringe. These aspects make membrane filters the appropriate choice in this situation.