Photocatalytic degradation of eleven microcystin variants and nodularin by TiO2 coated glass microspheres

Abstract

Microcystins and nodularin are toxic cyanobacterial secondary metabolites produced by cyanobacteria that pose a threat to human health in drinking water. Conventional water treatment methods often fail to remove these toxins. Advanced oxidation processes such as TiO2 photocatalysis have been shown to effectively degrade these compounds. A particular issue that has limited the widespread application of TiO2 photocatalysis for water treatment has been the separation of the nanoparticulate power from the treated water. A novel catalyst format, TiO2 coated hollow glass spheres (Photospheres™), is far more easily separated from treated water due to its buoyancy. This paper reports the photocatalytic degradation of eleven microcystin variants and nodularin in water using Photospheres™. It was found that the Photospheres™ successfully decomposed all compounds in 5 minutes or less. This was found to be comparable to the rate of degradation observed using a Degussa P25 material, which has been previously reported to be the most efficient TiO2 for photocatalytic degradation of microcystins in water.Furthermore, it was observed that the degree of initial catalyst adsorption of the cyanotoxins depended on the amino acid in the variable positions of the microcystin molecule. The fastest degradation (2 minutes) was observed for the hydrophobic variants (microcystin-LY, -LW, -LF). Suitability of UV-LEDs as an alternative low energy light source was also evaluated.

Sustainable Methods for Decontamination of Microcystin in Water Using Cold Plasma and UV with Reusable TiO2 Nanoparticle Coating

“…However, most previous research focused on a single variant or artificial mixture of MCs, which could have different degradation dynamics and toxicity from natural MC mixture [20]. Therefore, there is a critical need for developing more environmentally-friendly and effective methods for controlling MC contamination to protect both public health and water/food safety, especially because harmful algal blooms are expected to be more frequent and intensive globally [21,22].…”

“…UV illumination induces hydroxyl radicals produced from the active electron and positive hole of TiO 2 , which reacts with pollutants in water [34,35]. It was reported that TiO 2 showed a great photocatalytic activity to enhance the degradation rate of MC-LR with UV [20,36]. The UV/TiO 2 wastewater treatment is effective and cost efficient, but increases by further separation of TiO 2 in the effluent [37].…”

Photocatalytic cementitious material for self-cleaning and anti-microbial application

“…However, the widespread application is limited as the use of suspension has additional separation problems to be recycled from treated water after use, making it time consuming and cost ineffective (Herrmann et al, 1997, Pestana et al, 2015, Rachel et al, 2002.…”

Prediction of Photocatalytic Degradation and Mineralization Efficiencies of Basic Blue 3 Using $${{\rm TiO}_{2}}$$ TiO 2 by Nonlinear Modeling Based on Box–Behnken Design

“…In this context, several kinds of physical [5][6][7][8][9], chemical [10][11][12], and biological [12][13][14][15][16] methods have been studied to treat the wastewaters by researchers for a long time. But results show that an effective method with a high efficiency has not been found from now on [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…But results show that an effective method with a high efficiency has not been found from now on [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Advanced oxidation processes (AOPs), such as Fenton, Fenton-like, ultrasound, ozonation and similar processes, have been gained an importance in wastewater treatment [17,18].…”