Hydroxyl radical pretreatment for low-viscosity sodium alginate production from brown seaweed

Formalin pollution and water wastage are two of the main problems in the alginate industry. A novel pre-extraction treatment method based on the Fenton and electro-Fenton reactions is proposed to disrupt the cell wall of Macrocystis pyrifera and reduce the alginate filtrate viscosity, as an environmentally friendly process for alginate extraction. Under optimum Fenton (7.4 mM FeSO4 90 min) and electro-Fenton (EF-Fere 9 V, 90 min at pH 3, stirring) pre-extraction treatment conditions, the filtrate viscosity decreased by 83.99% and 97.79%, respectively. The filtrate viscosity decreased significantly as compared to the traditional approach under suitable operating conditions. Using of electro-Fenton for pre-extraction reduced water consumption by 60% in the filtration step and eliminated the use of formaldehyde during the process, reducing production costs and environmental pollution. Moreover, the yield and the quality of the alginate extracted after the pre-extraction improved.