Synthesis of value-added materials from the sewage sludge of cosmetics industry effluent treatment plant

In this work, biochar and bio-oil were produced from the sewage sludge of cosmetics industry effluent treatment plant via pyrolysis under N2 atmosphere, at 500 and 600 °C and 30 and 60 min. The biochar presented micrometric particles with a porous structure, with a surface area between 203 and 231 m2 g–1 and amorphous aspect containing crystalline quartz structures. The superior calorific power (SCP) for different biochar was 5.9–7.6 MJ kg−1. Bio-oils presented fatty acids, alcohols and esters with long aliphatic chains as main constituents. The SCP of these materials showed a high value (41 MJ kg−1), with the possibility to be used as a precursor for the biofuels production. The biochar, was applied as an adsorbent for the methylene blue (MB) dye from aqueous system. The adsorption parameters such as contact time (0–120 min), adsorbent dosage (0.25–1.0 g L−1) and initial pH (5–9.5) were studied. Kinetics and adsorption isotherm studies were also carried out. Pseudo-second order and Langmuir isotherm models fit the data better, showing adsorption maximum amount of 51 mg g−1 at 45 °C. The MB removal by biochar is an endothermic process and the material can be reactivated and reused. From the results, it can be concluded that the sludge from the cosmetic industry can be used as raw material to obtain new products with added value, such as biochar and bio-oil. [Display omitted] •Sustainable management of sludge from effluent treatment of the cosmetics industry.•Value-added materials such as bio-oil and biochar were obtained.•Biochar obtention with specific surface area greater than 203 mg g−1.•Biochar used as biosorbent in methylene blue removal from water (qmax = 51 mg g−1).•Bio-oil obtention with Superior Calorific Power of 41 MJ kg−1 with fuel potential.