Characterization and use of agroindustrial by-products in the removal of metal ions in aqueous solution

Abstract

Contamination of surface waters with heavy metals causes concern due to their toxicity, resistance to degradation and adverse effects on human health and aquatic biota. On the other hand, the search for uses and applications of agroindustrial waste has become a priority in the environmental agenda, due to the large volumes generated. Thus, adsorption is presented as an alternative to using these wastes in the treatment of water contaminated with metal ions. The objective of this work was the study of the use and characterisation of adsorbents of an agroindustrial source (palm bagasse) and by-products of the process of obtaining starch (yam and plantain), for its use in the removal of Cr (VI) and Ni (II) ions in a batch system. The adsorption tests were carried out at an initial concentration of 100 ppm ions at 200 rpm using 1 g of material in 100 mL of solution. The adsorbents were characterised by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, micro-elemental analysis, physicochemical analysis and surface area measurement by Brunauer-Emmett-Teller analysis. From the results, it is established that the palm bagasse has a pore volume twice higher than the other biomaterials. It was determined by the adsorption results, for Cr (VI), were superior in all materials to those obtained for Ni (II). The three agroindustrial residues studied presented high percentages of adsorption efficiency, above 70%, with palm bagasse standing out with an adsorption efficiency of 92%; Therefore, the use of these three biomasses is recommended to treat water contaminated with Cr (VI).