## 1 Introduction  
The worldwide energy crisis and global warming have both caused an increase in the research on the production of renewable energies [1]. The Kyoto Protocol committed the signatory countries to reduce the emission of greenhouse gases, so the production of third generation biofuels from photosynthetic microorganisms, such as microalgae and cyanobacteria, has stirred up considerable attention due to their CO\({}_{2}\) fixation capacity [2; 3]. Nowadays, only 5 kt/year of microalgal biomass are produced with production costs of 18.527 \(\upmu\)C/t [4], a reduction up to 296 \(\upmu\)C/t being needed to reach a competitive price in the biofuels market [5]. Furthermore, to substitute the consumption of biofuels in Europe by microalgal biodiesel, 9.25 millions of hectares (approximately the surface of Portugal) with a productivity of 40,000 L/ha/year [6] are needed. On the other hand, huge amounts of phosphorus and nitrogen are necessary for the culture of microalga, which reduces the sustainability of the process because of both their high price as a pure chemical product and their availability [7]. The above said has led to conducting research on the use of polluted effluents, such as municipal wastewater, as a source of nutrients for the production of microalgae and the reduction of associated costs. Furthermore, this utilization has the advantage of the enhanced depruration of these polluted waters [8; 9]. Using microalgae for wastewater remediation has been raised as a win-win paradigm within environmental biorefinery [10]. Among the several applications in wastewater treatment, biosorption has been defined as the passive uptake of pollutants by microalgal non-living biomass. In this sense, although most of the biosorption studies in the scientific literature deal with the removal of heavy metals [11], the adsorption capacity of organic pollutants by microalgae has also been proved [12]. Likewise, apart from their capacity of adsorption, low cost, and a huge availability, the utilization as biosorbent of the residual microalgal biomass after the extraction of the lipid content could mean a way to increase the economic viability of the biodiesel production from microalgae [13]. Currently, large concern exists about the presence of the so called emerging contaminants (ECs) in the environment. The presence of ECs in the environment is not regulated by legislation, but it is known that it may be a threat for ecosystems and human health [14]. These ECs include a large variety of compounds such as pharmaceuticals, personal care products, surfactants, flame retardants, antiseptics, etc. The way these pollutants enter the aquatic environment depends on their utilization pattern. In the case of the ECs from human consumption and/or excretion, such as pharmaceuticals, the main source are the municipal wastewater treatment plants (WWTP) [14] since they have been designed just for the reduction of the legislated parameters. The environmental concern of ECs, namely on pharmaceuticals, has led to the recent consideration by European regulations within the Water Framework Directive (2000/60/EC) (WFD). Three pharmaceuticals (diclofenac, 7-beta-estradiol (E2) and 17-alpha-ethinylestradiol (EE2)) were proposed to be included the list of priority substances by the Commission proposal of 31 January 2012. However, by the Directive 2013/39/EU, these pollutants were finally included in the watch list of substances to be monitored in all member states to support future reviews of the priority substances list [15]. Therefore, since legal limits about pharmaceuticals concentration in the effluents of the WWTPs are expected to be established in the near future, investigation of their removal from waters is essential. For this purpose, adsorption treatments are promissory, since they are efficient and besides, they do not imply the transformation of the ECs in different products, which may have more dangerous effects than the original compounds.