Oxidation of winery wastewater by sulphate radicals: catalytic and solar photocatalytic activations

Abstract

The treatment of winery effluents through sulphate radical-based advanced oxidation processes (SR-AOPs) driven by solar radiation is reported in this study. Photolytic and catalytic activations of peroxymonosulphate (PMS) and persulphate (KPS and SPS) at different pH values (4.5 and 7) were studied in the degradation of organic matter. Portugal is one of the largest wine producers in Europe. The wine making activities generate huge volume of effluents characterized by a variable volume and organic load, being their seasonal nature one of the most important drawbacks. Recently, SR-AOPs are gradually attracting attention as in situ chemical oxidation technologies, instead of hydroxyl radical AOPs (HR-AOPs). The studied concentrations are suitable to obtain notable values of organic matter degradation, with TOC removal around 50%. In general terms, no notable differences were observed between treatments at pH values 4.5 and 7. Photolytic activation of SPS with solar radiation treatments obtained the highest efficiency (28 and 40% of TOC removal with 1 and 50 mM, respectively, at pH 4.5) in comparison to KPS and PMS. The addition of a transition metal as catalyst, such as Fe(II) or Co(II), increased considerably the TOC removal efficiency higher than 50%, but not in all cases. For instance, the combination KPS or PMS with Co(II) at pH 4.5 did not allow to obtain better results than photolytic activation of these persulphate salts. In summary, the use of SR-AOPs could be a serious alternative as tertiary treatment for winery wastewaters.

Exploring the applicability of a combined electrodialysis/electro-oxidation cell for the degradation of 2,4-dichlorophenoxyacetic acid

“…This better performance of the process can be explained in terms of the ability of BDD anodes to form peroxodisulfate from sulphate ions, according to Equation 7 [46]. Peroxodisulfate is relatively stable but it behaves as a strong oxidant, capable to degrade a wide spectra of organic molecules [47], once it is activated by the addition of iron(II) salts [48,49], UV irradiation [50] or electrochemically by the hydroxyl radicals formed at the BDD anode from by water oxidation [46,51]. In this latter case, the use of BDD anodes may activate peroxodisulfate, increasing its capacity of degrading organic matter, as it is schematically represented by Equation ( 8).…”

Photocatalytic Mechanisms for Peroxymonosulfate Activation through the Removal of Methylene Blue: A Case Study

“…For instance, Pi et al [25] reported the successful removal of sulfamonomethoxine (97%, 90 min) with UV-A radiation (365 nm) and 10 mM of PMS. Even solar radiation is able to activate PMS, reducing the cost of treatments, just like Rodríguez-Chueca et al [26], Bandala et al [27], or Fernández et al [28] reported it for the elimination of organic matter, 2,4-dichlorophenol and Orange II, respectively.…”

Combination of Coagulation–Flocculation–Decantation and Ozonation Processes for Winery Wastewater Treatment

“…The application of ozonation processes in the treatment of WW is insufficient, with scarce examples of organic matter removal and energy consumption. Most of the authors studied the degradation of emerging contaminants and textile dye removal [91][92][93]; however, the degradation of the organic matter load of winery wastewater requires more demanding treatments, with higher energy consumption [20].…”