Calcium Carbonate Deposition on Cellulose.

Area of Science:

• Materials Science
• Crystallization Studies
• Surface Chemistry

Background:

• Understanding crystal nucleation and growth is crucial for materials science.
• Cellulose, a biopolymer, is a potential substrate for mineral formation.
• Investigating cellulose's role in calcite precipitation provides insights into biomineralization.

Purpose of the Study:

• To investigate cellulose powder as a substrate for calcite crystal deposition.
• To analyze the kinetics and mechanism of calcite precipitation on cellulose.
• To determine the influence of stereochemical factors on calcite polymorph formation.

Main Methods:

• Kinetic analysis of initial precipitation rates.
• Induction period measurements under varying supersaturation.
• Calculation of surface energy of calcite nuclei.
• Comparison of cellulose with other nucleating agents.

Main Results:

• Cellulose powder favors calcite deposition from stable supersaturated solutions.
• Precipitation rates are proportional to relative supersaturation, indicating a surface-controlled mechanism.
• The critical nucleus size was determined to be 5 ions, with a surface energy of 46 mJ m(-2).
• Cellulose exhibits selective nucleation, influenced by ionizable functional groups.

Conclusions:

• Cellulose acts as an effective nucleator for calcite, with kinetics dependent on supersaturation.
• Stereochemical factors play a significant role in determining calcite kinetics and polymorph formation.
• Cellulose's nucleating capability is comparable to sulfonated polystyrene but less effective than sulfonated polystyrene divinyl benzene copolymer.