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Biochar from carrot residues chemically modified with magnesium for removing phosphorus from aqueous solution

de Carvalho Eufrásio Pinto, Marina, David da Silva, Demetrius, Amorim Gomes, Ana Luiza, Menezes dos Santos, Rodrigo Morais, Alves de Couto, Ricardo Alexandre, Ferreira de Novais, Roberto, Leopoldo Constantino, Vera Regina, Tronto, Jairo, Pinto, Frederico Garcia
Journal of cleaner production 2019 v.222 pp. 36-46
adsorbents, adsorption, agricultural wastes, aqueous solutions, biochar, carrots, fertilizers, magnesium, magnesium chloride, phosphorus, pyrolysis, recycling, soil, temperature
The continuous increase in the world population requires more agricultural production; therefore, phosphorus compounds (P) are essentials. Considering that P reserves are finite, studying its recycling and reusing is essential. Biochar made from agricultural residues is an interesting material to be studied for P recovery and reuse in agriculture. This study shows the preparation and characterization of a biochar obtained from the pyrolysis of carrot residue for P adsorption studies in aqueous solution. Carrot was pyrolyzed at different temperatures values, with and without pretreatment with MgCl2. Biochar impregnated with Mg and pyrolyzed at 400 °C showed higher efficiency in P removal in aqueous solution (138 mg g−1). The characterization techniques indicated that after P adsorption by biochar, a chemical reaction occurred between Mg and P species with formation of Mg(H2PO4)2. The biochar from carrot residue obtained in this work is a promising adsorbent for P recycling and has potential to be used as soil fertilizer.