title: Nano-silica fabricated with silver nanoparticles: antifouling adsorbent for efficient dye removal, effective water disinfection and biofouling control.
abstract: A nano-silica-AgNPs composite material is proposed as a novel antifouling adsorbent for cost-effective and ecofriendly water purification. Fabrication of well-dispersed AgNPs on the nano-silica surface, designated as NSAgNP, has been achieved through protein mediated reduction of silver ions at ambient temperature for development of sustainable nanotechnology. The coated proteins on AgNPs led to the formation of stable NSAgNP and protected the AgNPs from oxidation and other ions commonly present in water. The NSAgNP exhibited excellent dye adsorption capacity both in single and multicomponent systems, and demonstrated satisfactory tolerance against variations in pH and dye concentration. The adsorption mainly occurred through electrostatic interaction, though π-π interaction and pore diffusion also contributed to the process. Moreover, the NSAgNP showed long-term antibacterial activity against both planktonic cells and biofilms of Gram-negative Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of AgNPs retarded the initial attachment of bacteria on NSAgNP and thus significantly improved the antifouling properties of the nanomaterial, which further inhibited biofilm formation. Scanning electron and fluorescence microscopic studies revealed that cell death occurred due to irreversible damage of the cell membrane upon electrostatic interaction of positively charged NSAgNP with the negatively charged bacterial cell membrane. The high adsorption capacity, reusability, good tolerance, removal of multicomponent dyes and E. coli from the simulated contaminated water and antifouling properties of NSAgNP will provide new opportunities to develop cost-effective and ecofriendly water purification processes.
authors.affiliation: Environmental Technology Division, Council of Scientific and Industrial Research (CSIR)-Central Leather Research Institute (CLRI), Chennai, India. sujoy@clri.res.in
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Das
authors.forename: Md Motiar R
authors.initials: MM
authors.lastname: Khan
authors.forename: T
authors.initials: T
authors.lastname: Parandhaman
authors.forename: Fathima
authors.initials: F
authors.lastname: Laffir
authors.forename: Arun K
authors.initials: AK
authors.lastname: Guha
authors.forename: G
authors.initials: G
authors.lastname: Sekaran
authors.forename: Asit Baran
authors.initials: AB
authors.lastname: Mandal
mesh_terms: D000327:Adsorption; D018441:Biofilms / Q000187:drug effects; D057219:Biofouling; D004396:Coloring Agents / Q000737:chemistry*; D004203:Disinfection; D004926:Escherichia coli / Q000502:physiology; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D011550:Pseudomonas aeruginosa / Q000502:physiology; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D014871:Water Microbiology; D018508:Water Purification
chemical_list: D004396:Coloring Agents; D012834:Silver; D012822:Silicon Dioxide