Chlorine Dioxide for Bleaching, Industrial Applications and Water Treatment

Abstract

As an oxidant, chlorine dioxide is highly effective at alkaline pH. Chlorine dioxide exists as a free-radical monomer. It attacks the electron-rich centres of organic molecules and typically reacts with organics as an oxidant with little or no chlorination. It is selective owing to its unique ability to extract one electron during oxidation to be reduced to chlorite. When the oxidative strength of chlorine and ozone is compared, chlorine dioxide is efficient and effective at low concentrations and less chlorine dioxide is required to obtain an active residual disinfectant. The scope and applications of chlorine dioxide are wide ranging, including wastewater treatment, drinking water treatment, food and beverage processing, algae control, oil well treatment, rendering plant odour control, phenol destruction, sludge disinfection, process water treatment, cooling towers, water clarification improvement, zebra mussel control, hydrogen sulphide destruction, leather processing, paper biocide, colour removal and cotton bleaching to mention a few.

Keywords:

• Chlorine dioxide
• Disinfection
• Water treatment
• Oxidative degradation
• Bleaching

Acknowledgments

The authors sincerely thank Professor Mithileshjha and the Organising committee of CHEMCON-2012 for the invitation, the National Research Foundation, Pretoria, South Africa and the University of KwaZulu-Natal for financial support, and the research students who contributed to this work over the years.