Chemosphere 2012-01-01

Peroxymonosulfate-Co(II) oxidation system for the removal of the non-ionic surfactant Brij 35 from aqueous solution.

Michele Pagano, Angela Volpe, Giuseppe Mascolo, Antonio Lopez, Vito Locaputo, Ruggiero Ciannarella

Index: Chemosphere 86(4) , 329-34, (2012)

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Abstract

The non-ionic surfactant Brij 35 was effectively removed from concentrated aqueous solution by the peroxymonosulfate/Co(II) system, using oxone (2KHSO(5)·KHSO(4)·K(2)SO(4)) as a source of peroxymonosulfate. At pH=2.3 and initial Brij 35 concentration in the range 680-2410 mg L(-1), 86-94% removal was achieved after 24 h, using Co(II)=15 μM and oxone=5.9 mM. The effectiveness of removal did not change when initial pH was in the range 2.3-8.2. After five subsequent additions of Co(II) and oxone to the solution, COD and TOC removals increased up to 64% and 33%, respectively. Radical quenching tests confirmed that sulfate radical was the dominant radical species in the system. The main identified by-products from surfactant degradation were: (a) low molecular weight organic acids; (b) aldehydes and formates with shorter ethoxy chain than Brij 35; (c) alcohol ethoxylates carrying hydroxyl groups bonded to ethoxy chain. By-products identification allowed to hypothesize the pathways of Brij 35 degradation.Copyright © 2011 Elsevier Ltd. All rights reserved.