Activated Alumina for Removing Dissolved Organic Compounds

Abstract

Adsorption of natural organic matter on activated alumina (AA) improved when the organic matter was preoxidized with either ozone or hydrogen peroxide. The alumina was effectively regenerated in the laboratory with 0.1 percent (or greater) NaOH solutions, i.e., more than 8 × 10 −4 mol NaOH/g AA. The spent regenerant could be reused several times to reduce the quantity of process waste. The use of AA before granular activated carbon (GAC), combined with in situ regeneration of the AA, resulted in an 80 percent higher capacity of GAC for an organic micropollutant—2,4,‐dichlorophenol. Presumably there was reduced competition for adsorption sites on the GAC because the dichlorophenol was not adsorbed by the AA Pilot tests of AA adsorbers in parallel with GAC adsorbers showed that GAC had a higher capacity and could adsorb a larger percentage of natural organics than AA, that AA did not adsorb the semivolatile organics (analyzable by gas chromatography‐mass spectroscopy) in a surface water, and that preozonation improved removal by AA and GAC.