Effects of anions on the biosorption of microelement cations by macroalga Enteromorpha prolifera in single- and multi-metal systems

Abstract

The results of research on the effects of anions on the biosorption of microelement cations by the edible marine macroalga Enteromorpha prolifera in single-and multi-metal systems are discussed in this paper. It was shown that the maximum biosorption capacity (q max ) in a single-metal system of Co (II) The biosorption of metal ions by algae has been widely reported in the literature. However, the majority of the published work describes single-metal biosorption systems. Very little information is available on multi-metal biosorption systems such as binary [1][2][3][4][5], ternary [1,[4][5][6], and quaternary systems [7]. There is a necessity to perform experiments on such systems because they better reflect real effluents from industrial operations. Another issue, which is often neglected in the literature, is the investigation of the effects of anions on biosorption processes. This aspect should also be taken into consideration because the presence of anions in aqueous solutions could affect metal cation biosorption [8].In the literature, two aspects of the effects of anions on biosorption processes are considered: the effects of anions on the maximum biosorption capacity in single-metal systems [9], and the effects of anion concentration on the biosorption of several metal ions in multi-metal systems [8,10,11]. It is important to emphasize that the influence of the anion on the biosorption capacity could differ depending on the biomass used and the biosorbed metal ions. The anions NO 3 -and SO 4 2-did not significantly influence the removal efficiency of the fungus Aspergillus niger for Cr(VI), Co(II), Ni(II), and Zn(II) ions, whereas the presence of Cl -anions significantly decreased the efficiency of metal ion biosorption in multi-metal systems [10]. In the case of another fungus, namely Rhizopus arrhizus, the degree of inhibition of the biosorption of La(III), Cd(II), Pb(II), and Ag(I) cations generally followed the order EDTA > SO 4 2-> Cl -> PO 4 3-> glutamate > CO 3 2- [12]. During biosorption of Co(II) cations by the brown macroalga Ascophylum nodosum, the presence of SO 4 2-and PO 4 3-anions did not result in any change in biosorption, in contrast to NO 3 -anions, which were the strongest inhibitor [13]. The opposite situation was observed in the case of biosorption of Zn(II) cations by the cyanobacterium Oscillatoria anguistissim, for which the inhibitory order of the anions was as follows: SO 4 2-> Cl -> NO 3 -(i.e., SO 4 2-anions were the strongest inhibitor) [11].

A comprehensive analysis of biosorption of metal ions by macroalgae using ICP-OES, SEM-EDX and FTIR techniques

“…Slightly higher content of magnesium in the enriched biomass was noted for the sulphate. Similar results were obtained for a green marine macroalga– Enteromorpha prolifera , where biosorption capacity of Cu(II) ions used as chloride was 46.0 mg/g, whereas for copper sulphate it was 42.8 mg/g [ 33 ].…”

“…Additionally we checked if there is an effect of the magnesium inorganic salt (sulphate and chloride) used for the preparation of a stock solution for the biosoption process on its sorption by algae. In the literature it is noted that metal anions (e.g., sulphate, nitrate, chloride) can influence the biosorption capacity of green algae [ 33 ].…”