Theoretical and Experimental Study of Pb2+ and Hg2+ Adsorption on Biopolymers, 1. Theoretical Study

Theoretical and Experimental Study of Pb2+ and Hg2+ Adsorption on Biopolymers, 2. Experimental Part

“…Chitosan-metal ion complexes retain the twofold helix conformation. Hg 2+ adsorption is stronger than the adsorption of hydrolyzed species, therefore the equilibrium is displaced to the left -this fact is supported by our EHMO calculation results (see part 1 [1] ) -the "free" Hg 2+ concentration is drastically diminished. The involvement of non-dissociated C(3)OH groups remains unclear.…”

“…The two reactions would be slow for Hg 2+ adsorption, but the adsorption energy of Hg 2+ on NH 2 would be higher than for Pb 2+ adsorption (-5.72 eV vs. -1.49 eV) at the same distance (2.5 ) (see Table 2). The adsorption energy of this species is high (near -2.17 eV, see part 1 [1] ). The first reaction would occur with [Hg(H 2 O) 5 OH] + also.…”

“…[4,8,25] The available data seem to prove chitosan is better for Hg 2+ adsorption, whereas pectin is better for the adsorption of Pb 2+ . [1] pH Variation and adsorption kinetics of Hg 2+ on pellets. The same order of selectivity was found for the two pectins, decreasing in the order Cu 2+ l Pb 2+ S Zn 2+ A Cd 2+ l Ni 2+ A Ca 2+ .…”

“…In part 1 [1] we studied theoretically (by means of the Extended Huckel Method (EHMO), the Parameterized Model version 3 (PM3) and MM2) Hg 2+ and Pb 2+ adsorption, and intra-and intermolecular chelation of models for pectin and chitosan (as di-or oligosaccharides). The aim of this work was to study these two adsorbent systems (pectin, and chitosan) with regard to their feasibility for removing low concentrations of Hg 2+ and Pb 2+ from contaminated water.…”

Solid Phase Extraction of Inorganic Mercury Using 5‐Phenylazo‐8‐hydroxyquinoline and Determination by Cold Vapor Atomic Fluorescence Spectroscopy in Natural Water Samples

“…The chemistry of mercury in aqueous solutions is more complicated than any other metal. Mercuric ions can be easily hydrolyzed according to the equation [46]. The coordination of water influences mercury adsorption dynamics and can relatively allow for slow diffusion, $\begin{array}{c}{\text{Hg}{\left({\text{H}}_2\text{O}\right)}_6}^{2+}\to {\left[\text{Hg}{\left({\text{H}}_{\mathrm{2}}\text{O}\right)}_{\mathrm{5}}\text{OH}\right]}^{+}+{\text{H}}^{+}.\end{array}$ …”