Binding Al3+, Cu2+ jons and polyelectrolytes with macromolecules in sugar beet juice

Abstract

The affinity of binding Al3+ and Cu2+ ions to non-sucrose compounds in sugar beet juice has been studied. The efficacy of ion binding was determined according to electrophoretic method by measuring Zeta potential. Model solutions of pectin and protein preparations (0.1% w.) were treated with solutions of CuSO4 and Al2(SO4)3 at seven different concentrations. The efficacy of Al3+ and Cu2+ ion binding was expressed as a minimal concentration of CuSO4 and Al2(SO4)3 needed for charge neutralization i.e. reaching zero Zeta potential. For pectin preparation, concentrations of these salts were 82 mg/dm3 CuSO4 and 105 mg/dm3 Al2(SO4)3. For protein preparation the concentrations were 115 mg/dm3 CuSO4 and 122 mg/dm3 Al2(SO4)3. Identical experiments were performed with the addition of cationic polyelectrolyte at 3 mg/dm3. Concentrations of CuSO4 and Al2(SO4)3 needed to change Zeta potential to zero decreased within interval from 7 to 20 mg/dm3. When the doses of tested ions were recalculated to industrial conditions, they were much lower in relation to consumption of Ca2+ ions in form of CaO (1 - 3% w.) which is commonly used in rafination of sugar juice.

Keywords

• macromolecules
• sugar beet
• al3+ and cu2+ ions
• polyelectrolytes