Waste Paper Pulp Derived Reduced Graphene Oxide for Antimicrobial Cement Composites

Reduced graphene oxide (RGO) multilayer sheets were synthesized using waste paper pulp as carbon source. Formation of RGO was confirmed by Raman spectroscopy. RGO was mixed with cement at different concentrations (0.001, 0.01, 0.05 and 0.1% w/w) to obtain graphene cement composites (GCC). RGO is supposed to impart hydrophobicity to cement; hence, the capillary test was conducted. Hydrophobic property of GCC was found to be dependent on time, concentration and temperature. Antimicrobial property of GCC was checked which included antibacterial and antifungal studies. GCC showed better antibacterial performance (90%) against gram positive bacteria (Bacillus subtilis) than the gram-negative bacteria (Escherichia coli, 85%). Gram negative bacteria possess structurally more complex cell membranes than gram positive bacteria; hence, it was more resistant to GCC. Our finding supports the concept of involvement of membrane bound macromolecules in antibacterial performance of RGO. GCC was also found to be effective (88% inhibition) against fungal strain (Aspergillus niger).