Phosphorus removal from eutrophic water using modified biochar

Sarah Vieira Novais; Mariana Delgado Olivieira Zenero; Matheus Sampaio Carneiro Barreto; Célia Regina Montes; Carlos Eduardo Pelegrino Cerri

doi:10.1016/j.scitotenv.2018.03.246

Phosphorus removal from eutrophic water using modified biochar

Sci Total Environ. 2018 Aug 15:633:825-835. doi: 10.1016/j.scitotenv.2018.03.246. Epub 2018 Mar 28.

Authors

Sarah Vieira Novais¹, Mariana Delgado Olivieira Zenero², Matheus Sampaio Carneiro Barreto³, Célia Regina Montes⁴, Carlos Eduardo Pelegrino Cerri³

Affiliations

¹ Department of Soil Science, Escola Superior de Agricultura Luiz de Queiroz, São Paulo University, Piracicaba, São Paulo, Brazil. Electronic address: sarahnovais@usp.br.
² Department of Soil Science, São Carlos Federal University, Araras, São Paulo, Brazil.
³ Department of Soil Science, Escola Superior de Agricultura Luiz de Queiroz, São Paulo University, Piracicaba, São Paulo, Brazil.
⁴ Center for Nuclear Energy in Agriculture, CENA-USP, São Paulo University, NUPEGEL, Piracicaba, São Paulo, Brazil.

PMID: 29602120
DOI: 10.1016/j.scitotenv.2018.03.246

Abstract

Increasing problems related to water eutrophication, commonly caused by the high concentration of phosphorus (P), are stimulating studies aimed at an environmentally safe solution. Moreover, some research has focused on the reuse of P due to concerns about the end of its natural reserves. Biochar appears to be a solution to both problems and may act as a recovery of eutrophic/residual water with the subsequent reuse of P in agriculture, the purpose of which is to test such an assertion. Samples of biochar from poultry manure (BPM) and sugarcane straw (BCS) had their maximum adsorption capacities of Al obtained by Langmuir isotherm. These values were used to conduct the so-called post-doping process, conferring P adsorption capacity to the pyrolysed materials. Langmuir and Freundlich isotherms were adjusted for the same biochar types (Al-doped) at increasing P concentrations, in order to obtain their maximum P adsorption capacities (MPAC) and their parameters. The desorption of the adsorbed P in its MPAC was tested by three extractors: H₂SO₄, NaHCO₃, and H₂O. Finally, these biochars were used in competitive adsorption assays of phosphate, sulfate, chloride and nitrate anions and applied in a synthetic eutrophic water. The high values of MPAC of the powder materials (701.65 and 758.96mgg^-1 of P for BPM and BCS, respectively) are reduced by almost half for the fragment materials (356.04 and 468.84mgg^-1 of P for BPM and BCS, respectively), these values being almost entirely extracted the extractors. Its application in eutrophic/residual water, in addition to presenting a good MPAC, these materials adsorbed, in equal proportions, phosphates and sulfates, as well as to a lesser extent, nitrates and chlorides. Thus, biochar from poultry manure and sugarcane straw, after post-doping with Al, have high MPAC, being excellent materials for the recovery of waters and subsequent reuse in agriculture.

Keywords: Al doping; P desorption; Potential reuse; Poultry manure; Sugar cane straw.