Regularities of the effects of the nature of polysaccharide materials on distribution of heavy metal ions in a heterophase biosorbent–water solution system

Resumo

The possibility of using cellulose-containing biosorbents obtained on the basis of agro-industrial wastes and byproducts to recover heavy metal ions from aqueous solutions was considered. The influence of the nature of sorbents (composition of biopolymers, content of carboxyl groups, specific surface, pore diameter and pore volume, swelling) on the kinetics and thermodynamics of distribution of heavy metal ions in a heterophase system consisting of water and biopolymer sorbent was determined. It was established that cellulose-based sorbents act as cationites at pH of 1–7, being inferior in their kinetic characteristics and sorption properties to commercial sorbents. Relying on literature data and the experimental results, it was found that the Langmuir, Freundlich, and TVFM models and other theories describe reasonably well the process (the correlation coefficients were 0.99); however, the Langmuir model provided the most exact determination of maximum sorption capacity of sorbents. It was concluded that, despite the comparatively low equilibriumkinetic characteristics, the cellulosic sorbents have received greater attention from researchers around the world due to their clear advantages with respect to ecological cleanliness, availability, and renewability of raw materials.