CORN FIBER CITRATE - PREPARATION AND ION-EXCHANGE PROPERTIES

Corn fiber (CF) was allowed to react thermochemically with citric acid (CA) to yield potentially biodegradable products possessing high ion- exchange capacity. The reaction variables studied were: citric acid le vel (0-100 g), reaction time (0-24 h), pH (1.5-8.3) and temperature (1 10-140 degrees C). Moisture content and pH were found to be controllin g factors. Reaction efficiencies approaching 100% were achieved, while minimizing cross-linking and maximizing carboxyl content. Carboxyl co ntent (0.5-3.6 mmol/g) was determined and copper-binding capacity (0.1 -2.0 mmol/g) at pH 4.5 was evaluated for the various CF-CA products.