Recycled cyanobacteria ashes for sono-enhanced photo-Fenton wastewater decontamination

Abstract

Currently, there is massive generation of persistent organic pollutants, which are hazardous sub-stances, owing to the exponential industrial growth and the associated waste production. Conse-quently, green and reliable strategies for decontaminating wastewater and generating value-added products are needed to realize the global demand of sustainability. In this study, an efficient sustain-able circular process for water remediation with nearly zero residue production is developed using iron-rich cyanobacteria ashes. These cyanobacteria ashes are obtained from the combustion of Ar-throspira platensis var lonar and are used as Fenton-like photocatalysts in different assisted photo-Fenton reactions (processes enhanced by light). The use of these iron-rich cyanobacteria ashes is par-ticularly effective for the sono-enhanced photo-Fenton processes for water remediation (mineraliza-tion > 94.9%), with an outstanding reusability. At the end of the effective lifetime of the photocata-lyst, the remaining ashes can be subsequently reused as a supplement during the growth of new cy-anobacteria, thus closing the circular process. The proposed approach is a green and sustainable pro-cess integrating both carbon dioxide fixation and clean-water production aimed at attaining sustain-able development.