Characterization of anion diffusion in polymer hydrogels used for wastewater remediation

Ion exchange systems for the removal of nutrient pollutants, even at extremely low concentrations, from wastewater effluents are a major environmental need. This work reports on the features of batch sorption processes for the ultimate removal and recovery of reactive phosphorus, nitrogen, and sulfur anions from aquaculture production wastewater effluents. The sorbent used was a crosslinked polyamine (PAA·HCl) polymeric hydrogel. The PAA·HCl hydrogels were prepared by chemically crosslinking aqueous solutions of linear PAA·HCl chains with epichlorohydrin (EPI). The nutrient anion binding capacity of the gels was studied as a function of various processing parameters. Lab scale batch and experiments showed maximum anion removal, from aquaculture wastewater, with regard to PO43− by 99%, NO3− by 70%, and SO42− by 95%. PO43− diffusivities of 16, 10, and 8×10−6 cm2/s were measured at pH levels of 5.5, 7.0, and 8.5.