Assessment of possible solid-phase phosphate sorbents to mitigate eutrophication: Influence of pH and anoxia

Maíra Mucci; Valentini Maliaka; Natalia Pessoa Noyma; Marcelo Manzi Marinho; Miquel Lürling

doi:10.1016/j.scitotenv.2017.11.198

Assessment of possible solid-phase phosphate sorbents to mitigate eutrophication: Influence of pH and anoxia

Sci Total Environ. 2018 Apr 1:619-620:1431-1440. doi: 10.1016/j.scitotenv.2017.11.198. Epub 2017 Nov 25.

Authors

Maíra Mucci¹, Valentini Maliaka², Natalia Pessoa Noyma³, Marcelo Manzi Marinho³, Miquel Lürling⁴

Affiliations

¹ Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700, AA, Wageningen, The Netherlands. Electronic address: maira.mucci@wur.nl.
² Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700, AA, Wageningen, The Netherlands; Department of Aquatic Ecology and Environmental Biology, Radboud University Nijmegen, Toernooiveld1, 6525, ED, Nijmegen, The Netherlands; Society for the Protection of Prespa, Agios Germanos, Prespa 53077, Greece.
³ Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524-PHLC Sala 511a, 20550-900, Rio de Janeiro, Brazil.
⁴ Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700, AA, Wageningen, The Netherlands; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700, AB, Wageningen, The Netherlands.

PMID: 29734619
DOI: 10.1016/j.scitotenv.2017.11.198

Abstract

Managing eutrophication remains a challenge to water managers. Currently, the manipulation of biogeochemical processes (i.e., geo-engineering) by using phosphorus-adsorptive techniques has been recognized as an appropriate tool to manage the problem. The first step in finding potential mitigating materials is conducting a sequence of upscaling studies that commence with controlled laboratory experiments. Here, the abilities of 10 possible solid-phase-sorbents (SPS) to adsorb P were examined. Four materials adsorbed P, and two of these materials were modified, i.e., a lanthanum-modified-bentonite (LMB) and an aluminum-modified-zeolite (AMZ), and had the highest adsorption capacities of 11.4 and 8.9mgPg^-1, respectively. Two natural materials, a red soil (RS) and a bauxite (BAU), were less efficient with adsorption capacities of 2.9 and 3.4mgPg^-1, respectively. Elemental composition was not related to P adsorption. Since SPS might be affected by pH and redox status, we also tested these materials at pH values of 6, 7, 8 and 9 and under anoxic condition. All tested materials experienced decreased adsorption capacities under anoxic condition, with maximum adsorptions of 5.3mgPg^-1 for LMB, 5.9mgPg^-1 for AMZ, 0.2mgPg^-1 for RS and 0.2mgPg^-1 for BAU. All materials were able to adsorb P across the range of pH values that were tested. The maximum adsorption capacities of LMB and RS were highest at pH6, AMZ was higher at a pH of 9 and BAU at a pH of 8. Thus, pH influenced P adsorption differently. Given the effects of pH and anoxia, other abiotic variables should also be considered. Considering the criteria that classify a useful SPS (i.e., effective, easy to produce, cheap and safe), only the two modified materials that were tested seem to be suitable for upscaling to enclosure studies with anoxic sediments.

Keywords: Geo-engineering; Phosphate adsorption; Phosphorus control.