It has been shown that the chemical nature of functional groups
present in the hydrogel primarily influences the operational pH
range (Tang et al., 2010). Ideally, hydrogels should be such designed
to be capable of removing the pollutants over a wide pH range.
Ajmal et al. (2015) investigated the effect of different solution pH
values on the adsorptive removal of metal ions (Cd(II) and Cr(III))
using an anionic amidoximated poly(MAa-co-AN) hydrogel. It was
found that the adsorption was lower at low pH values (