Journal Article
Arsenic, chromium and mercury removal using mussel shell ash or a sludge/ashes waste mixture
Seco-Reigosa, N; Peña-Rodríguez, S; Nóvoa-Muñoz, JC; Arias-Estévez, M; Fernández-Sanjurjo, MJ; Álvarez-Rodríguez, E; Núñez-Delgado, A
Environmental Science and Pollution Research
ISSN: 0944-1344
EISSN: 1614-7499
Different batches of valued mussel shell and waste mussel shell ash are characterised. Shell ash has pH > 12 and high electrical conductivities (between 16.01 and 27.27 dS m(-1)), while calcined shell shows pH values up to 10.7 and electrical conductivities between 1.19 and 3.55 dS m(-1). X-ray fluorescence, nitric acid digestion and water extractions show higher concentrations in shell ash for most parameters. Calcite is the dominant crystalline compound in this ash (95.6 %), followed by aragonite. Adsorption/desorption trials were performed for mussel shell ash and for a waste mixture including shell ash, sewage sludge and wood ash, showing the following percentage adsorptions: Hg(II) >94 %, As(V) >96 % and Cr(VI) between 11 and 30 % for shell ash; Hg(II) >98 %, As(V) >88 % and Cr(VI) between 30 and 88 % for the waste mixture. Hg and As desorption was <5 % for both shell ash and the waste mixture, while Cr desorption was between 92 and 45 % for shell ash, and between 19 and 0 % for the mixture. In view of that, mussel shell ash and the mixture including shell ash, sewage sludge and wood ash could be useful for Hg(II) and As(V) removal.
Ash from shell calcination; Calcined mussel shell; Heavy metals adsorption; Sewage sludge; Waste recycling; Waste mixture; Wood ash
