The preparation and characterization of silver‐loading cellulose acetate hollow fiber membrane for water treatment

Abstract

Silver‐loading asymmetric cellulose acetate (CA) hollow fiber membrane was spun via the dry jet‐wet spinning technique. The spinning solution was prepared by dissolving AgNO3 and CA in N,N‐dimethylformamide (DMF). The silver ions were reduced in the spinning dope into silver nano‐particles. The morphology of the resulting hollow fibers was examined using a scanning electron microscope and the silver content in the fiber was measured using an inductively coupled plasma atomic emission spectrometer. The antibacterial activities were evaluated. These hollow fibers had a sponge‐like structure and dense inner and outer surfaces. At a 50 k magnification, the pore on the skin layer was not observable, while the nodule size was smaller than 10 nm. The residual silver content of as‐spun hollow fiber was about 60% of the original silver added in the polymer solution. After immersing in water bath for 180 days, the silver content in the bulk of the hollow fibers decreased to 60% and the silver content on the surface reduced to 10%, yet still showed antibacterial activity against Escherichia coli and Staphylococcus aureus. After permeating with water for 5 days, the silver content in the hollow fibers decreased, and did not show antibacterial activity against E. coli and S. aureus. Thus, silver content must be periodically replenished after permeation. The proper range of AgNO3 in the spinning solution for CA hollow fiber should be about 100–1000 ppm. Copyright © 2005 John Wiley & Sons, Ltd.

Ipomea carnea-based silver nanoparticle synthesis for antibacterial activity against selected human pathogens

“…Biofouling can be avoided using the bactericidal properties of silver nanoparticles, and indeed, silver is a typical example of a bactericide that is used for fouling mitigation in polymeric membranes. Escherichia coli and Staphylococcus aureus have typically been used as model organisms to evaluate the antimicrobial properties of AgNpimpregnated CA membranes [32]. However, in this study, we evaluated the antimicrobial activity of AgNps against M. smegmatis.…”

Evaluation of Antimicrobial Activity of Synthesized Silver Nanoparticles using Phyllanthus amarus and Tinospora cordifolia Medicinal Plants

“…Although, there are number of researchers which reported that P. amarus and T. cordifolia have shown antimicrobial activity against pathogenic microbial strains [16][17][18][19][20]. Whereas, the antimicrobial properties of silver compounds and silver ions had been historically recognized and applied in the wide range of applications [21]. Due to the growing need to develop environmentally benign technologies in material synthesis, biosynthesis of nanoparticles has received considerable attention [22].…”

Polysulfone ultrafiltration membranes impregnated with silver nanoparticles show improved biofouling resistance and virus removal

“…Rapid silver depletion could be addressed by future research focusing on better nAg fixation techniques that concentrate the silver near the surface of the membrane (where it is most effective) and encapsulate the silver to slow the release rate. Because eventual silver depletion may be unavoidable, the effectiveness of nAg regeneration by reductive deposition of silver salts should be further explored (Chou et al, 2005;Deng et al, 2008). While nAgimpregnated membranes would not guarantee protection against silver-resistant bacteria strains, they may ensure antimicrobial activity against a wide variety of bacteria and viruses and provide long-term protection against biofouling and viral penetration of water filtration membranes.…”

“…Nanosilver has been incorporated into cellulose acetate (Chou et al, 2005), polyimide (Deng et al, 2008), polyamide (Damm et al, 2007), and poly(2-ethyl-2-oxazoline (Kang et al, 2006) membranes on the lab scale. However, the long-term effectiveness of the incorporated nAg in preventing biofouling during continuous filtration has not been addressed.…”