Biopolymer foam for remediation of aquatic environments contaminated with particulates and heavy metals

Abstract The negative impacts of heavy metals on the environment, public health, and the economy are a constant concern. Adsorption processes can be used for the treatment of water contaminated with the heavy metals. Biopolymers are attractive for industrial use due to their adsorptive characteristics, offering efficient metal removal, widespread availability, low cost, and biodegradability. In this work, a chitosan-based biopolymer was tested for the remediation of aquatic systems contaminated with particulate matter and high concentrations of heavy metals. The material, consisting of a two-layer foam, was characterized using scanning electron microscopy and energy dispersive spectroscopy, and was applied in the removal of particulate matter and heavy metals from water. Analysis of metals present in the biopolymer wash water and in the supernatant was performed by inductively coupled plasma optical emission spectrometry. The chitosan polymer in Layer B has circular pores, with diameters of 2–20 μm, while those of Layer A were irregular, with diameters of 100–350 μm. The biopolymer foam reduced water turbidity by 97% after a contact time of 48 h, and provided high retention of metals, especially iron and silver, with initial concentrations of 200 ppm decreasing to less than 0.6 ppm. The material developed could be used to help in emergencies, including natural and anthropogenic disasters involving collapse of barriers, mining activities, and water pollution with respect to the adsorption of heavy metals and particulate contaminants in these situations. The material is easy to deploy and remove in situations requiring the purification of aquatic environments.