Removal of hazardous oxide nanoparticles by the biopolymer flocculation in the presence of divalent salt

Unrestrained development of the industry constantly shows a new scale of emerging problems. One of them is a production and utilization of different nanoparticles (NPs). Contamination of the environment by NPs is a serious threat not only to nature but also to mankind. They are present in the environment as contaminants resulting from human activity, causing problems with drinking water purification. Moreover, NPs are both physically and biologically mobile so they can readily enter the ground waters and drinking wells and accumulate in a sediment phase with adverse effects on aqueous organisms. The aim of this paper was to investigate the possibility of using natural and biodegradable polysaccharide, fucoidan (FD), as a flocculating agent. Herein, we present the influence of calcium chloride and its ionic strength on the adsorption, electrokinetic properties and stability of three aqueous NPs suspensions: Al2O3, TiO2 and ZnO. By means of the turbidimetric method along with adsorption and zeta potential measurements a complete description of the flocculation mechanism has been proposed. The obtained results show a great potential of FD as a natural bioflocculant in the removal of hazardous NPs from the aqueous environment.