Aragonite precipitated calcium carbonate from magnesium rich carbonate rock for polyethersulfone hollow fibre membrane application

A reaction-assisted synthesis using a naturally occurring dolomite and aloe vera (Aloe barbadensis Miller) extract as a morphological modifier was employed for aragonite-precipitated calcium carbonate (A-PCC) synthesis. The as-synthesized precipitated calcium carbonate was utilized to produce a polyethersulfone (PES) hollow fiber membrane for application of oil-in-water separation. The D-glucose extraction of Ca before precipitation reaction with CO2 dominated the influence of tainted Mg on the as-synthesized PCC purity. The reaction was carried out via the carbonation route and 1 L/min CO2 flowrate at ambient conditions. The aloe vera extract (5 v/v%) and unleached in situ Mg influenced the phase transformation from calcite and vaterite polymorphs to flower-like structure with radiating ends. The A-PCC synthesized using aloe vera did not require external heating, thereby representing an attractive energy-conserving process for this type of precipitated calcium carbonate. The prepared membranes were characterized using porosity, field-emission scanning electron microscope, hydrophilicity, mechanical properties, and pore size. Their performances for oil-in-water filtration were evaluated. At an optimal amount of 3 wt% aragonite PCC in the hollow fiber membrane, the permeate flux and oil rejection reached 102 kg/m2h and >99%, respectively. Furthermore, the introduction of A-PCCs in the PES matrix improved the antifouling properties of the composite membranes. Therefore, PES/A-PCC composite membranes are desirable in treating wastewater and wastewater containing oil.