Carbonization synthesis of hydrophobic CaCO3 at room temperature

Hydrophobic CaCO3 was prepared by stearic acid (SA) at room temperature via a carbonization route in the presence of polyethylene glycol phosphate (PGP). When [Ca2+] = 21 mmol/L, mSA:mCaCO3=2%mSA:mCaCO3=2%, MNaOH: MSA = 0.5, and mPGP:mCaCO3=0.5%mPGP:mCaCO3=0.5%, the reactive ratio of CaCO3 is 90%, the contact angle of CaCO3 is 116.34°, and the density of SA is estimated at ∼1.1 × 104. The effects of the additives, such as SA, NaOH and PGP, on the surface hydrophobicity of CaCO3 were examined. Based on the change of hydrophobicity, a general formation mechanism was deduced. The cooperative interactions of SA and PGP play a key role in the formation of the hydrophobic CaCO3. This method opens a new way to prepare hydrophobic CaCO3 in mild conditions.