Technological Prospecting, Assessment and Scale-Up of Macauba (Acrocomia aculeata)-Based Biosorption of Metal Ions from Water

Superficial water contamination by anthropomorphic activities and environmental disasters has reached dangerous levels for the water security of humanity, turning this situation in a global concern, which is why the United Nations (UN), in the sixth Objective of Sustainable Development, proposes sanitation and access to clean water for all. Thus, alternative strategies using innovation for metal ions for removal from water is an urgent necessity, where environmental disasters such as those that occurred in Brazil (MG), Mariana (2015) and Brumadinho (2019), have polluted the water to levels that make their consumption unviable. These emerging technologies must ensure synergy with conventional technologies and guarantee economic and environmental viability.<br/>Among the alternatives one could find the bio-based materials, as agricultural waste, for biosorption is a green strategy which helps to the solution of two problems and same time, recovery of polluted water and reuse of biomass materials. The main objective of the present work is the assessment and scale-up of bio-based residual materials for biosorption of metal ions in polluted superficial waters using the residual biomass Macauba (Acrocomia Aculeata) from the vegetable oil extraction process and its use in the design of adsorption systems with a high fluid dynamic regime.<br/>Chemical treatments of the macauba endocarp with NaOH, H₂SO₄, H₂O₂ and NaClO were evaluated, as well as physical treatment with ultrasound waves, to improve the biosorption capacity. The materials obtained were characterized by TGA, MEV-EDS, X-Ray Fluorescence, metal quantification and Zeta potential. Adsorption tests were carried out, on a laboratory scale, with the metals Al³⁺, Mn²⁺, Pb²⁺ and Fe³⁺ at different conditions of pH, temperature and contact time, and a comparison was made with the use of natural material. Metals quantification was made by atomic absorption. The best results were obtained with the material treated with NaOH, achieving removals above 34% for Fe³⁺, 28% for Mn²⁺, 51% for Pb²⁺ and 46% for Al³⁺, using 100 grams of macauba biomass and 234L/h of flow in a high-rate system.<br/>Considering these results, the potential of this material for scale-up into a continuous separation operation is concluded, for which different strategies, as combination with minerals materials, are being tested to obtain a prototype of a high fluid dynamic regime adsorption system as an innovative strategy. In addition, technology prospection and bibliometric studies were carried out using public and private database, such as Scopus and Questel-Orbit.<br/>Acknowledgments: The authors would like to thank to the Network for the study, development and application of technologies based on sustainable nanomaterials for the recovery of water from the Doce River basin (N°06/2016), sponsored by the entities: FAPEMIG, CNPQ, CAPES, ANA, FAPES and development in Chemistry Department of UFMG.