Study of sorption properties of nickel on chitosan

Sorption of nickel on the selected sorbent was studied by a batch method. The effect of contact time and pH to reach sorption equilibrium was studied. During sorption of Ni2+ ions there proceed predominantly ion-exchange reactions on its surface. Time to reach sorption equilibrium of nickel on chitosan was 14 hours. Sorption percentage after 14 hours reached a value of 84 %. Solutions with starting pH value between 3.9 and 8.1 were used for sorption of nickel. A sorption of nickel on chitosan was > 97% in monitored interval of pH after 24 hours of contact . At an initial pH from 3.9 to 6.4 was the final pH 6.6 due to protonisation of amino groups. A pH value was 6.4 after sorption of 7.1. Sorption of nickel is reduced by increasing of concentrations of Ni2+ ions in the solution. Langmuir isotherm was used for interpretation of nickel sorption on chitosan. A maximum sorption capacity for chitosan was 2,67 · 10-3 mol/g-1. (authors)