Resins that reversibly bind algae for harvesting and concentration

Algae have great potential to address a number of important needs such as water remediation and as a feedstock for biofuel and biochemicals. At present, harvesting or removing algae is expensive, especially in terms of the cost of making biofuel. The expense of harvesting algae arises from the cost of pumping and processing large amounts of water. In an effort to explore less expensive methods for harvesting, a series of weak anion exchange resins incorporating various weak bases with different pK_a values were developed to bind and release algae as a function of pH. The best of these resins bind about 10% of their weight in algae, show 100% reversibility and reusability, and the ability to concentrate algae from dilute suspension to 30 g L^-1. Furthermore, they have the potential for desalting algae grown in high salt media. These resins provide a low cost method for harvesting algae without pumping water or introducing large amounts of chemicals into the feedwater, harvested algae, or the environment. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1143-1149, 2013