The interaction of silver ions and hydrogen peroxide in the inactivation of E. coli: a preliminary evaluation of a new long acting residual drinking water disinfectant

The inactivation efficiencies of silver ions, hydrogen peroxide and their combination was studied as part of a performance evaluation of the combined disinfectant for drinking water applications. The major advantages of such combined disinfectant include, low toxicity of its components, long lasting residual effect and low disinfection by product formation. Specific strains of E. coli (E. coli-B (SR-9) and E. coli K-12) were used in this study as target microorganisms and the separate and combined inactivation efficiencies of silver and hydrogen peroxide were evaluated at different concentrations and exposure durations. Both, silver and hydrogen peroxide exhibited a significant inactivation performance even at concentrations that do not pose any health risk according to the EEC, WHO and the USEPA (the USEPA Maximum Contaminant Level (MCL) of silver is 90 ppb, and currently, there is no MCL for hydrogen peroxide but it is approved as a food additive in the USA). Combinations of 1:1000 silver:hydrogen peroxide (w) exhibited higher inactivation performance as compared with each of the disinfectants alone and in some cases a synergistic effect was observed, i.e., the combined disinfectant exhibited higher inactivation performance than the sum of the inactivation levels of the separate disinfectants. Thus, for example, one hour exposure to 30 ppb silver, 30 ppm hydrogen peroxide and their combination yielded 2.87, 0.65 and 5 logs of inactivation respectively. While the rate of inactivation shown by this combined disinfectant, now available commercially in a stabilized formulation is relatively slow, it may well hold promise as a secondary disinfectant providing long lasting residuals and biofilm control required for distribution systems. Its disinfection action may be similar to chloramines, the use of which has been recently outlawed in France and in Germany and which are now under careful scrutiny in other countries due to the formation of undesirable by-products.

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Effect of Chloride Ions on the Point-of-Use Drinking Water Disinfection Performance of Porous Ceramic Media Embedded with Metallic Silver and Copper

Water ◽

10.3390/w12061625 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1625

Author(s):

Rekha Singh ◽

Woohang Kim ◽

James A. Smith

Keyword(s):

Drinking Water ◽

Porous Ceramic ◽

Chloride Ion ◽

Silver Ions ◽

Chloride Ions ◽

Ion Concentration ◽

Metallic Silver ◽

E Coli ◽

Ion Concentrations ◽

Copper Release

This study quantifies the effects of chloride ions on silver and copper release from porous ceramic cubes embedded with silver and copper and its effect on E. coli disinfection in drinking water. Log-reduction of E. coli by silver ions decreased after 4 h of contact time as the chloride ion concentration increased from 0 to 250 mg/L but, it was not changed by copper ions under the same conditions. For silver addition by silver-ceramic cubes, log reductions of E. coli decreased sharply from 7.2 to 1.6 after 12 h as the chloride concentration increased from 0 to 250 mg/L. For the silver-ceramic cube experiments, chloride ion also reduced the total silver concentration in solution. After 24 h, total silver concentrations in solution decreased from 61 µg/L to 20 µg/L for corresponding chloride ion concentrations. According to the MINTEQ equilibrium model analysis, the decrease in disinfection ability with silver embedded ceramic cubes could be the result of precipitation of silver ions as silver chloride. This suggests that AgCl was precipitating within the pore space of the ceramic. These results indicate that, although ionic silver is a highly effective disinfectant for E. coli, the presence of chloride ions can significantly reduce disinfection efficacy. For copper-ceramic cubes, log reductions of E. coli by copper embedded cubes increased from 1.2 to 1.5 when chloride ion concentration increased from 0 to 250 mg/L. Total copper concentrations in solution increased from 4 µg/L to 14 µg/L for corresponding chloride ion concentrations. These results point towards the synergistic effect of chloride ions on copper oxidation as an increased concentration of chloride enhances copper release.

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Development of nanosilver-coated geopolymer beads (AgGP) from fly ash and baluko shells for antimicrobial applications

MATEC Web of Conferences ◽

10.1051/matecconf/201926805003 ◽

2019 ◽

Vol 268 ◽

pp. 05003 ◽

Cited By ~ 1

Author(s):

Kimmie Dela Cerna ◽

Jose Isagani Janairo ◽

Michael Angelo Promentilla

Keyword(s):

Hydrogen Peroxide ◽

Fly Ash ◽

Controlled Release ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Antimicrobial Agents ◽

Setting Time ◽

Silver Ions ◽

Foaming Agents ◽

E Coli

Geopolymers are a class of materials formed from treating alumina (Al2O3) and silica (SiO2) containing materials with an alkali activator. They are most notable for being environmentally-friendly substitutes to Ordinary Portland Cement; however, recent findings have shown that they may have potential as support matrices for antimicrobial agents such as nanosilver, particularly with the addition of foaming agents and setting time accelerators. In this study, nanosilver-coated geopolymer beads (AgGP) were made from fly ash (FA), calcined Baluko shells or pen shells (BS), and hydrogen peroxide (H). Addition of BS and H reduces the setting time and increases the porosity of the geopolymer beads. The beads were then dipped in AgNO3 and NaBH4 respectively to provide the nanosilver coating. When immersed in water, a controlled release of silver ions leaches out from the beads, neutralizing any bacteria in the water. It was found that the AgGP removed as much as 99.96% of the E. coli in a suspension originally at 105 CFU/mL.

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Inexpensive test detects E. coli in drinking water

AccessScience ◽

10.1036/1097-8542.br0820141 ◽

2015 ◽

Keyword(s):

Drinking Water ◽

E Coli

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Children Need Clean Water to Grow: E. Coli Contamination of Drinking Water and Childhood Nutrition in Bangladesh

10.1596/1813-9450-9054 ◽

2019 ◽

Author(s):

George Joseph ◽

Sabrina S. Haque ◽

Nazia Moqueet ◽

Yi Rong Hoo

Keyword(s):

Drinking Water ◽

Clean Water ◽

Childhood Nutrition ◽

E Coli

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Effect of Turmeric and Ginger on Lipid Profile in Male Rats Exposed to Oxidative Stress

International Journal of Pharmaceutical Quality Assurance ◽

10.25258/ijpqa.10.1.23 ◽

2019 ◽

Vol 10 (01) ◽

Author(s):

Eman A. Al-Rekabi ◽

Dheyaa K. Alomer ◽

Rana Talib Al-Muswie ◽

Khalid G. Al-Fartosi

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Drinking Water ◽

Lipid Profile ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Male Rats ◽

Control Group ◽

Very Low Density Lipoprotein ◽

Low Density

The present study aimed to investigate the effect of turmeric and ginger on lipid profile of male rats exposed to oxidative stress induced by hydrogen peroxide H2O2 at a concentration of 1% given with consumed drinking water to male rats. Methods: 200 mg/kg from turmeric and ginger were used, and the animals were treatment for 30 days. Results: the results showed a significant increase in cholesterol, triglycerides, low density lipoprotein (LDL), very low density lipoprotein (VLDL), whereas it explained a significant decrease in high density lipoprotein (HDL) of male rats exposed to oxidative stress when compared with control group. the results showed a significant decrease in cholesterol, triglycerides, (LDL), (VLDL), whereas it explained a significant increase in (HDL) of rats treated with turmeric and ginger at dose 200 mg/kg when compared with male rats exposed to oxidative stress.

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Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

International Journal of Pharmaceutical Sciences and Nanotechnology ◽

10.37285/ijpsn.2012.5.1.7 ◽

2012 ◽

Vol 5 (1) ◽

pp. 1638-1642 ◽

Cited By ~ 2

Author(s):

Vidyasagar G M ◽

Shankaravva B ◽

R Begum ◽

Imrose ◽

Sagar R ◽

...

Keyword(s):

Antimicrobial Activity ◽

Silver Nanoparticles ◽

Silver Ions ◽

Human Beings ◽

Streptomyces Species ◽

Force Microscopy ◽

E Coli ◽

Extracellular Synthesis ◽

Atomic Force ◽

Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

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Decomposition of hydrogen peroxide on nickel-silver two-component catalyst

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19842222 ◽

1984 ◽

Vol 49 (10) ◽

pp. 2222-2230 ◽

Cited By ~ 3

Author(s):

Viliam Múčka ◽

Rostislav Silber

Keyword(s):

Hydrogen Peroxide ◽

Chemical Properties ◽

Silver Ions ◽

Surface Concentration ◽

Chloride Ions ◽

Nickel Silver ◽

Silver Catalysts ◽

Physico Chemical ◽

Low Degree ◽

Defective Crystal

The catalytic and physico-chemical properties of low-temperature nickel-silver catalysts with nickel oxide concentrations up to 43.8% (m/m) are examined via decomposition of hydrogen peroxide in aqueous solution. The mixed catalysts prepared at 250°C are composed of partly decomposed silver carbonate or oxide and nickel carbonate or hydroxide decomposed to a low degree only and exhibiting a very defective crystal structure. The activity of these catalysts is determined by the surface concentration of silver ions, which is affected by the nickel component present. The latter also contributes to the thermal stability of the catalytic centres of the silver component, viz. the Ag+ ions. The concentration of these ions varies with the temperature of the catalyst treatment, the activity varies qualitatively in the same manner, and the system approaches the Ag-NiO composition. The catalytic centres are very susceptible to poisoning by chloride ions. A previous exposition of the catalyst to a gamma dose of 10 kGy from a 60Co source has no measurable effect on the physico-chemical properties of the system.

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