Copper ion removal by almond shell carbons and commercial carbons: Batch and column studies

Phosphoric acid-activated/oxidized, and steam-activated and steam-activated/oxidized almond shell granular activated carbons (GACs) were investigated for their utility in removing copper ion (Cu2+) from solution in both batch and column applications compared to commercially available GACs. Adsorption isotherms were developed and found to best fit the Freundlich model. Experimental and commercial carbons were packed into columns and exposed to two different empty bed contact times using a solution of 3 mM CuCl2 buffered at pH 4.8. The most effective GACs for removal of copper ions in batch mode were the phosphoric acid-activated/oxidized and steam-activated/oxidized experimental carbons. The most effective carbon in column mode appeared to be the phosphoric acid-activated/oxidized sample. A column packed with this carbon showed higher breakthrough volumes and greater estimated hours of operation than other experimental carbons and commercial carbons evaluated. This carbon could function as an effective metal ion adsorbent in water and wastewater treatment.