Incorporation of copper nanoparticles into paper for point-of-use water purification

Abstract

As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 minutes and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1 ppm).

Comparative environmental fate and toxicity of copper nanomaterials

“…Based on the antifungal and antimicrobial properties of Cu + 2 , Cu NPs are actively being developed for applications in agriculture and food preservation (Park et al, 2015;Montes et al, 2015;Dugal and Mascarenhas, 2015;Ray et al, 2015;Kalatehjari et al, 2015;Ponmurugan et al, 2016;Maniprasad et al, 2015;Majumder and Neogi, 2016;Villanueva et al, 2016), textiles (Majumder and Neogi, 2016;Sedighi and Montazer, 2016), paints, coatings (e.g. lumber treatment) and water treatment (Ben-Sasson et al, 2016;Ma et al, 2016;Dankovich and Smith, 2014). The number of applications for regulatory approval of Cu-based nanopesticides has increased substantially in the past few years, highlighting the need for information about the likely exposure routes, doses and adverse effects on non-target organisms.…”

Inactivation of bacteria from contaminated streams in Limpopo, South Africa by silver- or copper-nanoparticle paper filters

“…2-5 A novel and affordable technology for eliminating bacteria from contaminated water is a thick filter paper embedded with silver or copper nanoparticles. 2,6,7 …”

Development of a low-cost water treatment technology using <italic>Moringa oleifera</italic> seeds

“…As an example, silverimpregnated ceramic filters effectively remove bacteria in the water but low water throughput and the release of silver ions into the treated water have been noted [4]. In another study, paper filters coated with copper nanoparticles have been shown to remove pathogens well but traces of copper were evident in the treated water [5]. Even though both of these point-of-use technologies are effective at microbial disinfection, they also require further water treatment to remove the residual chemicals in the water.…”