Low-cost biosorbent: Anadara inaequivalvis shells for removal of Pb(II) and Cu(II) from aqueous solution

Experimental and theoretical consideration of the factors influencing cationic pollutants retention by seashell waste

“…Unfortunately, the equilibrium pH values were not reported for oyster shell structures and arca shells, to enable comparison. In contrast, using Anadara inaequivalvis shells, no clear changes in pH were recorded during and after Cu 2+ and Pb 2+ biosorption …”

“…The mineralogical composition of SW remained virtually unchanged after exposure to Cu 2+ solution, confirming that the observed fast sorption of Cu 2+ occurred at the external surface of aragonite by complexation with surface sites and exchange with Ca 2+ . In previous studies, Cu 2+ sorption by aragonite in A. inaequivalvis shells was explained by the formation of CaCu compounds based on XRD analysis, whereas calcite structure in oyster shells was retained after Cu 2+ sorption . Similarly, in the experimental and theoretical consideration of metal cation reaction with calcite surface, the sorption data for Cu 2+ were interpreted in terms of a surface‐solid solution of Cu x Ca 1‐x CO 3 .…”

“…Thus acidic pretreatment of bivalve mollusc shells has increased Cu 2+ sorption capacity, while Mytilus galloprovincialis shells calcined at 550 °C exhibited higher sorption capacity for Hg(II) ions with respect to untreated samples . In addition to the properties of shells, other parameters of the process were found to affect metal removal, namely, initial metal concentration, initial pH, contact time, presence of competitive species and temperature . Overall results are promising not only regarding capacities of seashells to host a variety of heavy metals, but the reactions are also considerably faster using biogenic than geological carbonates .…”

“…Previous research in relation to applications of seashells have also been directed towards immobilization of heavy metals, such as Pb, Cd, Cu, Zn, Ni, Co, from aqueous phase . Shell species commonly explored in sorption studies were oyster and mussel shells, due to their vast amounts from the fishery industry.…”

“…15 Previous research in relation to applications of seashells have also been directed towards immobilization of heavy metals, such as Pb, Cd, Cu, Zn, Ni, Co, from aqueous phase. [16][17][18][19][20][21][22][23] Shell species commonly explored in sorption studies were oyster and mussel shells, due to their vast amounts from the fishery industry. Furthermore, species typical for a certain region and/or with wide geographic distribution were studied, 16,19,22 as well as invasive species, 18 and also unspecified shell waste.…”