Biogenic manganese oxides generated by green algae Desmodesmus sp WR1 to improve bisphenol A removal

Biogenic manganese oxides (BioMnOx) have attracted considerable attention as active oxidants, adsorbents, and catalysts. This study investigated the characteristics of algae-generated BioMnOx and determined its oxidative activity towards bisphenol A (BPA), an endocrine disrupter. Amorphous nanoparticles with a primary Mn valency of +3 were found in BioMnOx produced by Desmodesmus sp. WRI. The mechanism might be that algal growth created conditions favorable to Mn oxidation through increasing DO and pH. Initial Mn2+ concentrations of 6, 30, and 50 mg L-1 produced a maximum of 5, 13, and 11 mg L-1 of BioMnOx, respectively. Mn2+-enriched cultures exhibited the highest BPA removal efficiency (similar to 78%), while controls only reached about 27%. BioMnOx may significantly promote BPA oxidation in algae culture, enhancing the accumulation of substrates for glycosylation. Moreover, continuous BioM-nOx increase and Mn2+ decrease during BPA oxidation confirmed Mn oxide regeneration. In conclusion, Mn oxide formation by microalgae has the potential to be used for environmental remediation. (C) 2017 Elsevier B.V. All rights reserved.