Synthesis and characterization of precipitated calcium carbonate from marble waste for its application in papermaking

CaCl2 solution and Ca(OH)2 slurry, both prepared from marble waste (MARWAS), were carbonated with CO2 gas in the presence of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), Teepol-610s, Triton X-100, and Tween-80 as the surface modifiers in a semi-batch foam-bed reactor (FBR) to synthesize ultrafine or submicron precipitated calcium carbonate (PCC) particles with enhanced hydrophobicity. Nano/ultrafine PCC particles with and without surfactant were also synthesized in a semi-batch stirrer reactor (SR) using CaCl2 solutions made from MARWAS and NH4HCO3 as the carbonating agent by single or simultaneous application of ultrasonication (US) and surfactant, respectively. The products were characterized by SEM, TEM, XRD, FTIR, and drop-shape analyzer. In the presence of SDS in the FBR, distinct and smaller hydrophobic (water contact angle of 103.3 degrees) vaterite particles (426 nm) could be produced using CaCl2 solution than those with the Ca(OH)2 slurry. However, in the SR, methanol was more effective than the aqueous solvent in synthesizing needle-like aragonite nanoparticles (215.6 nm with L/D = 8.55) from CaCl2 solution without any use of US or surfactant. Handmade papers were manufactured using ground MARWAS powder, modified- and unmodified-PCC. The physical, mechanical, and optical properties of these filler-loaded papers were determined. The use of surface-modified and unmodified PCC was superior to the commercial PCC in increasing filler retention, burst strength, tear strength, brightness, and opacity of the paper handsheets. Even the direct use of MARWAS powder was more effective than ground calcium carbonate in enhancing the optical properties with a slight decrease in the mechanical strength.Graphical abstract Utilization of marble waste into papermaking