Quintáns Fondo, AnaCoelho, Gustavo FerreiraArias Estévez, ManuelNóvoa Muñoz, Juan CarlosFernández Calviño, DavidÁlvarez Rodríguez, EsperanzaFernández Sanjurjo, María J.Núñez Delgado, Avelino2020-04-012020-04-012019Quintáns-Fondo, A.; Ferreira-Coelho, G.; Arias-Estévez, M.; Nóvoa-Muñoz, J.C.; Fernández-Calviño, D.; Álvarez-Rodríguez, E.; Fernández-Sanjurjo, M.J.; Núñez-Delgado, A. Chromium VI and Fluoride Competitive Adsorption on Different Soils and By-Products. Processes 2019, 7, 748http://hdl.handle.net/10347/21042Chromium (as Cr(VI)) and fluoride (F−) are frequently found in effluents from different industrial activities. In cases where these effluents reach soil, it can play an important role in retaining those pollutants. Similarly, different byproducts could act as bio-adsorbents to directly treat polluted waters or to enhance the purging potential of soil. In this work, we used batch-type experiments to study competitive Cr(VI) and F− adsorption in two different soils and several kinds of byproducts. Both soils, as well as mussel shell, oak ash, and hemp waste showed higher adsorption for F−, while pyritic material, pine bark, and sawdust had a higher affinity for Cr(VI). Considering the binary competitive system, a clear competition between both elements in anionic form is shown, with decreases in adsorption of up to 90% for Cr(VI), and of up to 30% for F−. Adsorption results showed better fitting to Freundlich’s than to Langmuir’s model. None of the individual soils or byproducts were able to adsorbing high percentages of both pollutants simultaneously, but it could be highly improved by adding pine bark to increase Cr(VI) adsorption in soils, thus drastically reducing the risks of pollution and deleterious effects on the environment and on public healtheng© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)https://creativecommons.org/licenses/by/4.0/AdsorptionChromiumCompetitionFluorideSoil and water pollutionjournal article10.3390/pr71007482227-9717open access