Water Recovery from Wastewater by Hydrogels

Abstract

Hydrogels possess a strong water absorption capability and can release absorbed water in response to physical or chemical stimuli, making them promising materials for water recycling. To explore the concept of using hydrogels to recover water from wastewater, we synthesized and utilized poly­(acrylic acid-co-acrylamide) (PAAM) hydrogels to extract water from solutions containing various organic pollutants and salt concentrations. The swelling ratio of PAAM hydrogels reached up to 510 g/g with a water recovery of around 44% and a water production rate of approximately 3200 L/kg/day. The removal rates of organic pollutants reached up to 89%, depending on the pollutant’s properties such as molecular weight, functional group, solubility, and charge. This confirms the potential of using hydrogels to recover water from various wastewaters, especially for those containing large molecular pollutants.