Environmentally Friendly Synthesis of Hydrophobic CaCO۳ Nanoparticles from Paper Waste: A Facile Approach

At present, the escalating magnitude of waste represents a formidable global concern, wherein paper waste alone constitutes approximately ۲۶% of the overall waste deposited in landfills. Thus, the transformation of paper waste into viable products assumes paramount significance. In this study, paper waste was converted to CaCO۳ using a thermal process and surface-modified with stearic acid. The effect of environmental pH and process temperature on the crystalline structure and morphology of the product was evaluated. The prepared CaCO۳ was used to deactivate gram-negative agrobacterium tumefaciens and hydrophobicity's effect on the CaCO۳ antibacterial activity was studied. XRD, SEM, FT-IR, BET/BJH, contact angle, and TEM characterization techniques were utilized to characterize the structure and physicochemical properties of prepared CaCO۳. According to the XRD analysis, the optimal temperature for the conversion process was ۵۰۰°C in an air environment without any changes in pH. SEM analysis confirmed that as the calcination temperature increased, the number of cracks and holes on the surface also increased. BET analysis confirmed this by showing a decrease in the specific surface area in the Ca-۷۵۰ sample. TEM analysis revealed nanoparticles with spherical and irregular spherical geometries, ranging in size from ۳۰ to ۹۰ nm. According to the contact angle analysis, increasing the concentration of stearic acid led to an increase in the contact angle to ۱۲۱.۴°. This increase in contact angle indicates an enhancement in the hydrophobicity of the prepared nanoparticles, which had a synergistic effect on their antibacterial activity. The antibacterial activity test of both prepared hydrophilic and hydrophobic CaCO۳ depicted the high antibacterial activity of both CaCO۳ while the hydrophobic CaCO۳ revealed higher antibacterial activity compared to hydrophilic CaCO۳.

Keywords:

Paper Waste , Conversion Process , CaCO۳ , Surface modification , Hydrophobic. Nanoparticles , Antibacterial activity