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Currently, the interest in eco-friendly treatments for the removal of pollutants has increased and more sustainable treatment solutions are required. In this study, the homogeneous and heterogeneous activation of peroxymonosulfate (PMS) was carried out for the degradation of an industrial dye. Initially, the homogeneous PMS activation by different transition metals (Co, Cu, Ni, Fe) was ascertained. Cobalt resulted in the best performance attaining removal levels around 100% in only 30 min. Then, the influence of operational parameters such as pH and pollutant concentration were evaluated. The results displayed a high efficiency in the degradation and mineralisation operating close to neutral pH. The mechanism of the reaction was also studied and the obtained results demonstrated that sulfate radical is the primary reactive specie involved in the pollutant degradation. The optimisation of the degradation process was then carried out by a response surface methodology and several variables (PMS and Co concentration and temperature) were evaluated. The optimisation was performed in order to maximise the degradation and minimise the consumption of catalyst resulting in values of Co concentration 0.0125 mM, temperature 40 °C and PMS concentration 0.895 mM. Finally, heterogeneous activation by Co-catalyst immobilisation using alginate beads (Co-AB) and amberlite (Co-A) was performed. The results showed the superiority of Co-AB maintaining a high removal level after four treatment cycles with low Co leaching.

In this study, the application of hydrocolloid and fiber industry wastes and their transformation in biochar and biocomposite as biosorbents for emerging pollutants effective removal was carried out. Initially, the adsorption ability of six different wastes was ascertained in single and competitive removal of sulfamethoxazole (SMX) and methylparaben (MePa). Among them, fiber extraction process wastes presented the best result attaining maximum uptakes with removal levels up to 23 and 48% of MePa and SMX, respectively. The adsorption capacity was enhanced by fiber waste biochar preparation at 500 °C and 30 min under nitrogen atmosphere, and improved by the preparation of laccase-biocomposites, achieving maximum uptakes more than ten-fold the obtained using raw material. The simultaneous removal of the pollutants by the biocomposite followed a pseudo-second order kinetic and resulted in maximum uptakes of 24.06 and 23.15 mg/g for SMX and MePa, respectively. Finally, raw material and laccase-biocomposite behaviours were simulated by homogeneous surface diffusion model. Previously, the isotherms were studied fitting well to Freundlich model. The obtained results remarked the feasibility of laccase-biocomposite in which reactive groups incorporation on the biochar surface could be responsible for facilitating the pollutants removal from the aquatic environment.