Application of soluble bio-organic substances (SBO) as photocatalysts for wastewater treatment: Sensitizing effect and photo-Fenton-like process

Soluble bio-organic substances (SBO) isolated from urban biorefuses have been investigated in photocatalytic processes for wastewater treatment using a cationic dye, namely crystal violet (CV) as target compound. The SBO have been found to enhance the photobleaching of CV solutions with an optimal SBO concentration of ca. 20 mg L-1. Mechanistic investigation based on chemical probes and changes in the absorption spectrum of CV in the presence of SBO seems to indicate that a complex formed between sensitizer and substrate plays a major role in the process. SBO have also been tested for the implementation of photo-Fenton processes at circumneutral media: the observed pseudo first order rate constants for CV decoloration was higher for UV/SBO/Fe(II)/H2O2 (5.5 x 10(-3) min(-1)) than for UV/Fe(II)/H2O2 (1.5 x 10(-3) min(-1)). A modified mechanism, in which HO center dot are less relevant that at the acidic medium, is in agreement with results of experiments carried out with chemical probes. (C) 2012 Elsevier B.V. All rights reserved.Gomis Vicens, J.; Vercher Pérez, RF.; Amat Payá, AM.; Martire, DO.; Gonzalez, MC.; Prevot, AB.; Montoneri, E.... (2013). Application of soluble bio-organic substances (SBO) as photocatalysts for wastewater treatment: Sensitizing effect and photo-Fenton-like process. Catalysis Today. 209:176-180. doi:10.1016/j.cattod.2012.08.036S17618020

Changes in global groundwater organic carbon driven by climate change and urbanization

YesClimate change and urbanization can increase pressures on groundwater resources, but little is known about how groundwater quality will change. Here, we rely on a global synthesis (n = 9,404) to reveal the drivers of dissolved organic carbon (DOC), which is an important component of water chemistry and substrate for microorganisms which control many biogeochemical reactions. Groundwater ions, local climate and land use explained ~ 31% of observed variability in groundwater DOC, whilst aquifer age explained an additional 16%. We identify a 19% increase in DOC associated with urban land cover. We predict major groundwater DOC increases following changes in precipitation and temperature in key areas relying on groundwater. Climate change and conversion of natural or agricultural areas to urban areas will decrease groundwater quality and increase water treatment costs, compounding existing threats to groundwater resources