Post-synthetic functionalization of the metal-organic framework: Clean synthesis, pollutant removal, and antibacterial activity

Herein, a metal-organic framework (ZIF-8) was synthesized and functionalized with 3-aminopropyl trimethoxy silane (APTMS). The synthesized materials (ZIF-8 and ZIF-8@APTMS) were characterized using various techniques, including SEM, TEM, FTIR, Raman, XRD, BET, and TGA. Pollutant (Direct Red 23(DR23)) removal ability of the materials from aqueous media was investigated. In addition, the antibacterial activity of the synthesized materials was investigated with Staphylococcus aureus, and Escherichia coli by three methods, including diffusion agar, minimum inhibitory concentration (MIC)/ minimum bactericidal concentration (MBC), and viable cell count. The effect of possible interactions with key parameters on pollutant removal was studied. The results showed that the DR23 adsorption obeyed the pseudo-second-order kinetic and the Freundlich isotherm with the experimental adsorption data. The maximum adsorption capacity and removal efficiency of DR23 with ZIF-8@APTMS adsorbent was 2159 mg/g and 93.59 %, respectively. The data from this study concluded that ZIF-8@APTMS was significantly capable of dye adsorbing from aqueous media. The antibacterial activity of the materials is almost similar and is slightly higher in the ZIF-8 sample. The MBC was obtained for both bacteria with the same MIC numbers, indicating the toxicity of similar materials as an inhibition zone. The growth inhibition halo was more visible on S. aureus than in E. coli. The percentage of bacterial decrease in the viable cell count method was 92 % on S. aureus and 20 % on E. coli.