Comparative antibacterial activities of Garcinia cowa and Piper sarmentosum extracts against Staphylococcus aureus and Escherichia coli with studying on disc diffusion assay, material characterizations, and batch experiments

Using extracted plants is an attractive option because they consist of good chemical properties against different types of bacteria, and the idea of a form modification in beads may conveniently apply to the disinfection of wastewater systems. Garcinia cowa and Piper sarmentosum leaves were extracted for the synthesis of bead materials and studied material characterizations. A disc diffusion assay, batch experiments, adsorption isotherms, adsorption kinetics, and desorption experiments were studied for investigating the bacteria removal efficiencies of materials. G. cowa and P. sarmentosum leaves were prepared in powder (GCP and PSP), ethanol extracted (EGC and EPS), and synthesized bead materials (GCB and PSB). GCB had a higher surface area than PSB whereas the particle size and pore size were smaller than PSB. GCP and PSP had heterogeneous cracking surfaces whereas GCB and PSB had sphere-shaped and rough surfaces. Carbon (C), oxygen (O), calcium (Ca), and functional groups of O–H, C–H, N–H, C–O, and C–Cl were found in GCP, PSP, GCB, and PSB. Both extracted and beaded materials demonstrated high antibacterial activities on Staphylococcus aureus and Escherichia coli by a disc diffusion assay, and GCB demonstrated high bacteria removals on both bacteria types by almost 100% by batch experiments. Freundlich isotherm and a pseudo-second-order kinetic model are good fit models for explaining the adsorption pattern and mechanism of GCB related to a physiochemical adsorption and chemisorption mechanism. Moreover, GCB could reuse more than 3 cycles, so it is possible to use GCB for disinfection in a wastewater treatment system.