Oxidative Removal of Bisphenol A by Manganese Dioxide: Efficacy, Products, and Pathways

Abstract

Bisphenol A (BPA) is a ubiquitous environmental contaminant with endocrine disruption potential. In this study, exploiting the outstanding oxidative capacity of manganese dioxide (delta-MnO2), we explored forthe firsttime the efficacy and mechanisms of BPA removal by MnO2. In aqueous solutions, MnO2 demonstrated an extremely efficient capacity to remove BPA. Nearly all BPA (>99%) was eliminated in 6 min in a pH 4.5 solution initially containing 800 microM MnO2 and 4.4 microM BPA. While humic acid showed negligible inhibition on BPA removal, coexisting metal ions such as Mn2+, Ca2+, Mg2+, and Fe3+ displayed suppressive effects and the inhibitive capacityfollowed the order Mn2+ > Ca2+ > Mg2+ approximately Fe3+. A total of 11 products or intermediates were indentified and a detailed reaction scheme was suggested. The products could be ascribed to a suite of reactions of radical coupling, fragmentation, substitution, and elimination, triggered by the BPA radical formed through electron transfers to MnO2. The exceptional efficiency of MnO2 in removing BPA represents a potential use of MnO2 to treat waters containing phenolic compounds and also suggests a potentially important role of oxide-facilitated abiotic transformations in BPA attenuation in natural soil and sediment environments.

Pharmaceutical removal from water with iron- or manganese-based technologies: A review

“…For instance, MnO 2 oxidation is negatively influenced by cosolute compounds, such as metal ions and natural organic compounds which inhibit the chemical reaction by occupying the reactive surface site of MnO 2 (Zhang and Huang, 2003;Lin et al, 2009;Hendratna, 2011;He et al, 2012). In addition, reactant loading has influence on this oxidation process.…”

Synthetic conditions-regulated catalytic Oxone efficacy of MnO x /SBA-15 towards butyl paraben (BPB) removal under heterogeneous conditions

“…Among these applications, using MnO x as adsorbents, oxidizing agents or catalysts to remove various environmentally important pollutants is such a case. For example, MnO 2 has been shown to have oxidative and adsorption capacity towards endocrine disruption compounds and organic dyes [2,3]. Meanwhile, MnO x has also been demonstrated as a prominent catalyst to degrade organic pollutants in water and air [4][5][6][7][8].…”

“…Furthermore, at current stage some key questions still remain unknown: (1) how do the physicochemical features of MS composites evolve when their synthetic conditions were changed? (2) What is the response of MS composites with varied properties towards the catalytic Oxone efficacy? and (3) How is the catalytic Oxone performance of the optimized MS composite against the removal of PPCPs?…”

Characterization and reactivity of biogenic manganese oxides for ciprofloxacin oxidation

“…Manganese oxides (MnO 2 ), ubiquitously found in soils and sediments, have been broadly studied as the most important naturally occurring oxidants in promoting the transformation of a wide array of complex organic pollutants, including substituted phenols (Stone, 1987), atrazine (Shin andCheney, 2004), 17α-ethynylestradiol (de Rudder et al, 2004), bisphenol A (Lin et al, 2009), and various kinds of antibacterial agents (Zhang and Huang, 2005). Recently, biogenic manganese oxides (BioMnO x ) have exhibited higher catalytic reactivity than chemically produced MnO 2 due to their specific characteristics (Forrez et al, 2010).…”