Which filtration method is least likely to remove dissolved solids?

Microfiltration is recognized as the filtration method that is least likely to remove dissolved solids. This technique primarily targets larger particles, such as bacteria and some suspended solids, with pore sizes typically in the range of 0.1 to 10 micrometers. Due to these larger pore sizes, microfiltration does not effectively filter out smaller dissolved substances, like salts or other tiny molecules, which remain in the permeate.

In contrast, reverse osmosis, nanofiltration, and ultrafiltration are all designed to remove smaller particles and dissolved solids. Reverse osmosis has very fine pores and can effectively remove a wide range of dissolved solids, including salts. Nanofiltration also targets smaller particles and can handle divalent ions effectively, while ultrafiltration can remove larger macromolecules but is still more effective than microfiltration in terms of dissolved solids reduction. Therefore, among these options, microfiltration is the least capable of removing dissolved solids from water.