Sargassum-based potential biosorbent to tackle pollution in aqueous ecosystems – An overview Sara Saldarriaga-Hernandez a, ** , Erik Francisco N ajera-Martínez b , María Adriana Martínez-Prado b , Elda M. Melchor-Martínez a, * a Tecnologico de Monterrey, School of Engineering and Sciences, Ave. Eugenio Garza Sada 2501, CP 64849, Monterrey, N.L, Mexico b Tecnologico Nacional de M exico-Instituto Tecnol ogico de Durango, Department of Chemical and Biochemical Engineering, Boulevard Felipe Pescador 1830, CP 34080, Durango, Dgo, Mexico ARTICLE INFO Keywords: Biosorption Bioremediation Environmental pollution Aqueous ecosystems Sargassum spp. biomass Biosorption mechanisms ABSTRACT The uncontrolled release of toxic pollutants related to anthropogenic processes has threatened biodiversity and the ecological integrity of aqueous ecosystems during years. The bioaccumulation and biomagnification of toxic pollutants at different trophic levels have raised concern. Several bioremediation approaches have been tested for efficient mitigation and removal of toxic compounds such as metal ions from aquatic environments. Biosorption by biodegradable and renewable sources such as micro and macroalgae biomass has an increasing scope. How- ever, the biosorption mechanisms of Sargassum spp. have not been completely elucidated, and there are still some drawbacks to overcome. Sargassum spp. biomass has been recognized to be a natural, renewable, and cost- effective material to arrest pollutants from aqueous systems. This mini-review is a compendium that spotlights the potentialities of Sargassum-based biosorbents as an alternative for the removal of toxic contaminants from aquatic environments. Main biosorption mechanisms, key factors influencing biosorption, and the challenges regarding its implementation are highlighted with suitable examples. 1. Introduction The accelerated industrial progress has resulted in massive pollution of all ecosystems, threatening environment integrity, biodiversity, and human health. Industrial development depends on the exploitation of compounds such as pesticides, polychlorinated biphenyls, heavy metals, halogenated aliphatics, phenols, polycyclic aromatics, among others. Due to their high toxicity, low degradation rate, and bioaccumulation through the trophic chains, these compounds trigger significant adverse effects on the environment and living organisms [1,2]. Pollutants usually end up in aqueous systems through leaching, atmospheric deposition, filtration, direct dumping, etc. (Fig. 1)[3]. There is an increasing interest in the recovery, removal and/or degradation of pollutants from the aquatic environment. Different physiochemical techniques, such as ion exchange, photocatalysis, mem- brane separation, filtration processing, coagulation/flocculation, and electrochemical methods, have been employed [1]. Nevertheless, phys- icochemical processes have presented limitations as chemical precipitation leading to the formation of toxic sludge, low efficiency in the total removal of contaminants, and high costs [3]. In this context, alternative methods are demanded a cheap and effective removal option and/or recovery of pollutants. Algae biomass has been described to remove potentially toxic com- pounds from aqueous systems through biosorption, which is rapid, reversible, has minimal environmental impact, is a safe, economical, and efficient method [1,3]. Brown seaweed biomass, has gained recognition as a biosorbent (over other organisms biomass such as bacteria and fungi) for water bioremediation [4]. For brown seaweeds, the main mechanisms reported to remove pollutants in aqueous systems are based on (1) sur- face adsorption, which does not require living-biomass; and (2) bio- accumulation, which is metabolism dependent and requires living-biomass [5]. The surface adsorption has become the most used method to capture pollutants because of its cost–benefit relationship which is determined by the low-cost of non-living biomass maintenance and the high adsorption yields obtained by the algae biomass related to their complex cell wall properties (rich in alginate, fucoidan, and high * Corresponding author. ** Corresponding author. E-mail addresses: sarasaldarriaga.h@gmail.com (S. Saldarriaga-Hernandez), elda.melchor@tec.mx (E.M. Melchor-Martínez). Contents lists available at ScienceDirect Case Studies in Chemical and Environmental Engineering journal homepage: www.editorialmanager.com/cscee/default.aspx https://doi.org/10.1016/j.cscee.2020.100032 Received 23 June 2020; Received in revised form 28 July 2020; Accepted 9 August 2020 2666-0164/© 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by- nc-nd/4.0/). Case Studies in Chemical and Environmental Engineering 2 (2020) 100032