Removal of bacteria and viruses from waters using layered double hydroxide nanocomposites

Abstract

We have identified synthetic layered double hydroxides (LDH) nanocomposites as an effective group of material for removing bacteria and viruses from water. In this study, LDH nanocomposites were synthesized and tested for removing biological contaminants. LDH was used to remove MS2 and fX174 (indicator viruses), and Escherichia coli (an indicator bacterium) from synthetic groundwater and to remove mixed communities of heterotrophic bacteria from raw river water. Our results indicate that LDH composed of magnesium-aluminium or zinc-aluminium has a viral and bacterial adsorption efficiency X99% at viral concentrations between 5.9 Â 10 6 and 9.1 Â 10 6 plaque forming units (pfu)/L and bacterial concentrations between 1.6 Â 10 10 and 2.6 Â 10 10 colony forming units (cfu)/L when exposed to LDH in a slurry suspension system. Adsorption densities of viruses and bacteria to LDH in suspension ranged from 1.4 Â 10 10 to 2.1 Â 10 10 pfu/kg LDH and 3.2 Â 10 13 -5.2 Â 10 13 cfu/kg LDH, respectively. We also tested the efficiency of LDH in removing heterotrophic bacteria from raw river water. While removal efficiencies were still high (87-99%), the adsorption capacities of the two kinds of LDH were 4-5 orders of magnitude lower than when exposed to synthetic groundwater, depending on if the LDH was in suspension or a packed column, respectively. r

Enhancing atrazine biodegradation by Pseudomonas sp. strain ADP adsorption to Layered Double Hydroxide bionanocomposites

“…strain ADP was dramatically enhanced in the presence of Mg 2 Al(OH) 6 NO 3 ·nH 2 O hydrotalcite like compound (Layered Double Hydroxides or LDH) although AT was not sorbed on this inorganic matrix. A few other papers have reported that microorganisms can strongly interact with LDH [7,25], the purpose of all these experiments being to set up efficient anti-microbial processes or wastewaters treatments. LDH is a class of ionic lamellar minerals with positively charged hydroxylated layers of divalent and trivalent metallic cations ([M II 1−x M III x (OH) 2 ] x+ ) and exchangeable hydrated gallery anions ([X q− x/q ·nH 2 O]) [26].…”

Nanosized silver–anionic clay matrix as nanostructured ensembles with antimicrobial activity

“…550 °C) to yield low crystalline mixed oxides and then reconstructed by treatment with aqueous solutions containing anionic species [16,17]. In view of all this information, our work has focused on obtaining nanostructured ensembles able to combine the properties of the biocompatible matrix of the anionic clay and the specific induced characteristics of the nanosized metals into one single material.…”

A review on carbon nanotubes in an environmental protection and green engineering perspective

“…In addition to serving as sorbent for organic and inorganic contaminants, current technology has used CNTs as nanofilters to reduce particle concentrations in waste water (Srivastava et al, 2004;Jin et al, 2007;Tahaikt et al, 2007). Similar to sorbents, specific selectivity on CNTs filters can be manipulated through the attachment of different functionalities at the pore entrances (Fornasiero et al, 2008).…”