ASSESSMENT OF POLYACRYLAMIDE DEGRADATION USING ADVANCED OXIDATION PROCESSES AND FERRATE(VI) OXIDATION

Abstract

The aim of this work was to investigate the degradation of six polyacrylamide (PAM) polymers when submitted to advanced oxidation processes (AOP) and ferrate(VI) oxidation. PAM is a highly versatile polymer made of acrylamide monomers, and it is widely used for water and wastewater treatment purposes. The degradation of these polymers using Fenton reagent, H₂O₂/UV, Fe²⁺/H₂O₂/UV, and Fe³⁺/H₂O₂/UV, as well as ferrate(VI), showed that PAM may present different behaviors under oxidation processes, especially regarding their ionic charge. Among the oxidative processes, the photochemical processes present the best overall results towards PAM degradation. COD and TOC were successfully used to assess PAM degradation, while ammonia determination has shown that ^•OH radicals produced by AOP tends to rapidly attack the amide group, releasing NH₃ as a reaction product. Finally, the influence of each oxidation process, its reagent concentration, and photo-induced conditions on PAM degradation are discussed.

Keywords:

• Advanced oxidation processes
• Fenton processes
• Oxidation
• Photodegradation
• Polymers
• Wastewater treatment

Acknowledgments

Financial support and a fellowship from CNPq/CT-Hidro are gratefully acknowledged. Special acknowledgments are due for the generous support of all coworkers of LEMA/UFSC and Prof. Raul Rosenhaim (LACOM/UFPB).

Notes

Initial pH 7.0.

^a Estimation of –NH₂ concentration calculated in accordance with the acrylamide percent (50–70%, as stated by the manufacturer) in aPAM Flonex 9073.

^b Sum of NO₂, NO₃, and NH₃ content present in the PAM solutions after AOP.