Pretreatment membranes can be utilized to prolong the lifetime of reverse osmosis membranes and to remove biological and inorganic foulants from water feedstocks. A promising strategy to produce pretreatment membranes is through electrospinning, which creates nanoscale, nonwoven fibrous mats of polymeric materials with a very high surface area to volume ratio. The characteristics of the polymer mat can be tailored by polymer selection as well as post-processing functionalization strategies. This work will highlight a recent strategy to i) tune pretreatment membrane mechanical strength using post-electrospinning crosslinking reactions, and ii) introduce functional groups that enable the selective removal of heavy metal atoms. Specifically, poly(vinyl alcohol) is electrospun into nonwoven mats, crosslinked using a poly(ethylene glycol) diacid, and then functionalized with carboxylic acids by ring opening succinic anhydride. The mechanical properties, membrane morphology water flux, and metal-removal efficiency will be highlighted.