A decrease in solute permeance with

Due to the limited available data in the literature for (NH4)2SO4 containing solutions, the results of this study have been compared to those undertaken by others using different ammonium containing feed solutions. In the study conducted by Häyrynen et al. [21], which used reverse AZD8055 membranes to separate several contaminants including ammonium from mining wastewater using DOW SW30HR membranes, ammonium rejections were found to be between 0.828 and 0.909. Other investigated membranes gave rejections between 0.861 and 0.945 for the same samples. These rejections are much lower than those found in the current study; however, in the current study ammonium sulfate was the only salt in the feed solution. A separate study was conducted by Bodalo et al. [22], where cellulose acetate membranes were used to concentrate ammonium hydroxide from feeds of different concentrations. That study found rejections between 0.986 and 0.992, which is very close to the results reported here, but for a different solute. Another study was conducted by Kurama et al. [23] to remove high concentrations of ammonium as well as other contaminants from potable water using two stages of nanofiltration followed by two stages of reverse osmosis. In that study, a rejection of 0.969 was achieved, which is lower than the rejections found here, but again, their feed was composed of multiple contaminants. The membrane materials were not specified in that study, although the reverse osmosis membranes were low-pressure models of GE make.