Assessment of carbon nanotubes and silver nanoparticles loaded clays as adsorbents for removal of bacterial contaminants from water sources

Abstract

This work evaluated the antimicrobial efficacy of kaolin clay and its loaded forms with carbon nanotubes (CNTs) and silver nanoparticles (AgNPs) against bacterial isolates from different water supplies (tap, underground and surface water) in addition to wastewater. A total of 160 water samples were collected from different water sources in the investigated districts. Samples were cultured for isolation and serological identification of pathogenic bacteria. AgNPs were synthesized by a typical one-step synthesis protocol, where CNTs were carried out in a reactor employing the double bias-assisted hot filament chemical vapor deposition method. Both were characterized using transmission electron microscopy, infrared and X-ray fluorescence (XRF) spectroscopy. The antimicrobial efficacy of each of natural kaolin clay, AgNPs- and CNTs-loaded clays were evaluated by their application in four concentrations (0.01, 0.03, 0.05 and 0.1 ppm) at different contact times (5 min, 15 min, 30 min and 2 h). AgNPs-loaded clays at concentrations of 0.05 and 0.1 mg/l for 2 h contact time exhibited a higher bactericidal efficacy on Escherichia coli and Salmonella spp. (70, 70, 80 and 90%, respectively) compared to CNTs-loaded clay. Concluding, the application of AgNPs-loaded clay for removal of water bacterial contaminants at a concentration of 0.1 ppm for 2 h contact times resulted in highly effective removals.

Current Trends in the Application of Nanomaterials for the Removal of Emerging Micropollutants and Pathogens from Water

“…The antibacterial activity of CNTs-loaded clay at the same concentration was 70% for each of Salmonella spp. and Klebsiella pneumonia, while it was 60% for E. coli strains [144,145]. In another study, hybrid polyaniline/graphene/carbon nanotube materials were fabricated and achieved 99.5% and 99.2% removal for S. aureus and E. coli, respectively [146].…”

“…The presence of a disinfection residue has a pivotal role for the control of the microbial growth during water storage and distribution. The main disadvantage of most nanomaterial-based disinfection processes is the lack of such residue [145,162]. Under normal conditions, some nanomaterials are inherently unstable and tend to agglomerate.…”

A comparative study of stability, antioxidant, DNA cleavage and antibacterial activities of green and chemically synthesized silver nanoparticles

“…Metallic nanoparticles are classified into most useful products applying as adsorbents, catalysts, reinforcers, drug carriers and nano-fertilizers in the various area of science and technologies including healthcare, electronics, new medicine, cosmetics and agriculture [1][2][3][4][5]. Among this nanoscale category, silver nanoparticles (AgNPs) have proven their potential to apply in research and development centres resulting from some unique physical, chemical and biomedical properties [6].…”

Layer-by-Layer Assembly of Clay–Carbon Nanotube Hybrid Superstructures

“…27 Moreover, due to the synergistic effect of clay nanoplatelets and carbon nanotubes, these hybrid structures have been proposed as flame retardants in unsaturated polyester resins and poly(methyl methacrylate) 28,29 as well as adsorbents for the removal of bacterial contaminants from different water supplies. 30…”

“…36 Carbon nanotubes attached to smectite layers are also particularly attractive for polymer reinforcement 37,38 and the high surface area of these hybrid nanomaterials can be exploited for the removal of bacterial contaminants from different water supplies. 39…”