scholarly journals A New Method for the Deposition of Metallic Silver on Porous Ceramic Water Filters

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Kathryn N. Jackson ◽  
James A. Smith
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Removal Rate ◽  
Aqueous Suspension ◽  
Porous Ceramic ◽  
New Method ◽  
Metallic Silver ◽  
E Coli ◽  
Filter Performance ◽  
Continuous Feed

A new method of silver application to a porous ceramic water filter used for point-of-use water treatment is developed. We evaluated filter performance for filters manufactured by the conventional method of painting an aqueous suspension of silver nanoparticles onto the filter and filters manufactured with a new method that applies silver nitrate to the clay-water-sawdust mixture prior to pressing and firing the filter. Filters were evaluated using miscible displacement flow-through experiments with pulse and continuous-feed injections of E. coli. Flow characteristics were quantified by tracer experiments using [3H]H2O. Experiments using pulse injections of E. coli showed similar performance in breakthrough curves between the two application methods. Long-term challenge tests performed with a continuous feed of E. coli and growth medium resulted in similar log removal rates, but the removal rate by nanosilver filters decreased over time. Silver nitrate filters provided consistent removal with lower silver levels in the effluent and effective bacterial disinfection. Results from continued use with synthetic groundwater over 4 weeks, with a pulse injection of E. coli at 2 and 4 weeks, support similar conclusions—nanosilver filters perform better initially, but after 4 weeks of use, nanosilver filters suffer larger decreases in performance. Results show that including silver nitrate in the mixing step may effectively reduce costs, improve silver retention in the filter, increase effective lifespan, and maintain effective pathogen removal while also eliminating the risk of exposure to inhalation of silver nanoparticles by workers in developing-world filter production facilities.

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

Water ◽  
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.

Comparative Analysis of Antibiotic Effect of AgNO3 and Silver Nanoparticles Synthesized from Penicillium fellutanum

2013 ◽  
Vol 760 ◽  
pp. 9-14 ◽  
Author(s):  
Anima Nanda ◽  
Shahnaz Majeed
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Culture Filtrate ◽  
Pathogenic Bacteria ◽  
Room Temperature ◽  
High Dose ◽  
Fungal Culture ◽  
Proteus Vulgaris ◽  
E Coli ◽  
Antibiotic Effect

The proposed study was to synthesize silver nanoparticles by using filamentous fungus Penicillium fellutanum. From the ancient period, silver has been used against microorganisms due to its own antibacterial properties. The fungal culture of Penicillium fellutanum was isolated from the soil samples of Sathyabama University, Chennai, Tamil Nadu, India. The fungal isolates were inoculated in culture medium and incubated at room temperature for three days and the culture filtrate was separated and divided into two parts. One part of the culture filtrate was mixed with equal volume of 1mM silver nitrate [AgNO3,(1 mM)] and agitated at room temperature in dark condition. And the second half was kept as such. In the other hand only 1mM silver nitrate was added into the equal volume of Milli Q water and one half was plain Milli Q water. All the four samples were tested against pathogens like Bacillus cereus, E. coli, Proteus vulgaris, Staphylococcus aureus, Staphylococcus epidermidis and the results were compared. Proteus vulgaris showed the highest zone where E coli showed the least zone of inhibition, in the culture filtrate added with silver nitrate. The cell filtrate on treatment with silver nitrate and prior incubation were observed for change in color and characterized by UV-Vis spectrophotometer which detected AgNPs in the solution. The maximum absorbance 410nm confirmed the formation of silver nanoparticles. Size and morphology of silver nanoparticle were investigated using Atomic Force microscopy (AFM). The silver Nanoparticles after confirmation were checked for its antibacterial activity against selected pathogenic bacteria. The biologically synthesized Nanoparticles from Penicillium fellutanum showed the good inhibitory effect against the selected pathogens, which would be the novel remedy substituent in the place of high dose antibiotics.

scholarly journals Field Investigation and Economic Benefit of a Novel Method of Silver Application to Ceramic Water Filters for Point-Of-Use Water Treatment in Low-Income Settings

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 285
Author(s):  
Nkosinobubelo Ndebele ◽  
Joshua N. Edokpayi ◽  
John O. Odiyo ◽  
James A. Smith
Keyword(s):  
Silver Nanoparticles ◽  
Water Treatment ◽  
Silver Nitrate ◽  
Silver Nanoparticle ◽  
Total Coliform ◽  
Raw Material ◽  
E Coli ◽  
Ceramic Water Filters ◽  
Point Of Use ◽  
Water Filters

In this study, we report on field testing of ceramic water filters (CWFs) fabricated using a new method of silver application (using silver nitrate as a raw material) compared to conventionally manufactured CWFs (fabricated with silver nanoparticles). Both types of filters were manufactured at the PureMadi ceramic filter production facility in Dertig, South Africa. Thirty households received filters fabricated with silver nitrate (AgNO3), and ten of those households were given an extra filter fabricated with silver nanoparticles. Filter performance was quantified by measurement of total coliform and Escherichia coli (E. coli) removal and silver residual concentration in the effluent. Silver-nitrate CWFs had removal efficiencies for total coliforms and E. coli of 95% and 99%, respectively. A comparison of the performance of silver-nitrate and silver-nanoparticle filters showed that the different filters had similar levels of total coliform and E. coli removal, although the silver nitrate filters produced the highest average removal of 97% while silver nanoparticles filters recorded an average removal of 85%. Average effluent silver levels were below 10 ppb for the silver-nitrate and silver-nanoparticle filters, which was significantly below the Environmental Protection Agencies of the United States (EPA) and World Health Organization (WHO) secondary guidelines of 100 ppb. Silver-nitrate filters resulted in the lowest effluent silver concentrations, which could potentially increase the effective life span of the filter. A cost analysis shows that it is more economical to produce CWFs using silver nitrate due to a reduction in raw-material costs and reduced labor costs for production. Furthermore, the production of silver-nitrate filters reduces inhalation exposure of silver by workers. The results obtained from this study will be applied to improve the ceramic filtration technology as a point-of-use (POU) water treatment device and hence reduce health problems associated with microbial contamination of water stored at the household level.

Green Synthesis and Characterization of Silver Nanoparticles by Using Aloe Vera Leaf Extract to Study the Effects of Synthesis Parameters

2016 ◽  
Vol 860 ◽  
pp. 179-184
Author(s):  
Asif Rahman ◽  
A.K.M. Bazlur Rashid ◽  
Md Abdul Aziz Antor ◽  
Md Ashif Anwar ◽  
Roisul Hasan Galib
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Leaf Extract ◽  
Nitrate Solution ◽  
Aloe Vera ◽  
Bath Temperature ◽  
Heating Time ◽  
Water Bath ◽  
Metallic Silver ◽  
Nanoparticle Suspension

In this research silver nanoparticles were synthesized by reducing silver nitrate solution using aloe vera leaf extract as reducing agent. The synthesized nanoparticles had been characterized and the effects of different parameters of synthesis had been evaluated. Silver nanoparticles began to form just after reaction and the whole reduction reaction was completed within 3 hours. The color changed from transparent to dark brown of the aqueous salt solution. Later the nanoparticles were separated out from the mixture by ultra-centrifugation. Here the effects of water bath temperature, the effects of heating time at that certain temperature and the effects of changing concentration of silver nitrate on the size of the synthesized nanoparticles was studied. The particle size and morphology of the synthesized silver nanoparticles were identified by SEM analysis. It was found to be 12-200 nm in different parameters (12-25 nm at the best condition) and spherical in shape. It was also found that the size of silver nanoparticles increased with increasing water bath temperature, increasing heating time and increasing silver nitrate concentration. Energy dispersive X-ray spectroscopy was used to confirm that the nanoparticle suspension contains nothing but metallic silver. It was found that 70% of elemental silver nanoparticles were present.

Silver Nanoparticles/Montmorillonite Composites Prepared Using Nitrating Reagent at Water and Glycerol

2008 ◽  
Vol 8 (6) ◽  
pp. 3050-3058 ◽  
Author(s):  
Marta Valášková ◽  
Gražyna Simha Martynková ◽  
Jana Lešková ◽  
Pavla Čapková ◽  
Volker Klemm ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Interlayer Space ◽  
Exchangeable Cations ◽  
Metallic Silver ◽  
Transmission Electron ◽  
Modeled Structure ◽  
Silicate Layers ◽  
20 Nm ◽  
Nanoparticles Of Silver

Three procedures (P) were applied to prepare silver nanoparticles on natural Ca-montmorillonite (MT). The intercalation of the montmorillonite with silver nitrate in aqueous solution (P1), the intercalation of the montmorillonite with silver nitrate in glycerol (P2) and the successive combination of both P1 and P2methods resulted to P3 method. X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier Transform Infrared (FTIR) spectroscopy and the molecular modeling were employed to characterize silver nanoparticles and montmorillonite nanocomposite. The P1 produced MT-1 composite with 2.3 wt% Ag and the partially collapsed layered structure. Nanoparticles of silver larger than 20 nm with a lot of planar defects were randomly distributed on the MT-1 surface; nanoparticles smaller than 20 nm were oriented to the montmorillonite substrate. The MT-2 composite from P2 contained only 1 wt% of Ag. The molecular simulation model of MT-2 showed the interlayer space with the exchangeable cations and metallic silver atoms arrangement within the glycerol bilayer. The P3 produced composite MT-3 that contained 2.4 wt% Ag. The nanoparticles > 20 nm size had a well-defined geometry, very small nanoparticles were amorphous. The modeled structure showed the exchangeable cations, Ag+ and Ag0 located close to the silicate layers and monolayer of glycerol molecules in the interlayer space.

scholarly journals An Organic–Inorganic Hybrid Nanocomposite as a Potential New Biological Agent

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2551
Author(s):  
Mateusz Dulski ◽  
Katarzyna Malarz ◽  
Michał Kuczak ◽  
Karolina Dudek ◽  
Krzysztof Matus ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antimicrobial Effect ◽  
Metallic Silver ◽  
Silica Network ◽  
E Coli ◽  
Silica Nanocomposites ◽  
Independent Mechanism ◽  
Silver Oxide Nanoparticles ◽  
Genetic And Environmental Factors ◽  
Average Size

To solve the problem of human diseases caused by a combination of genetic and environmental factors or by microorganisms, intense research to find completely new materials is required. One of the promising systems in this area is the silver-silica nanocomposites and their derivatives. Hence, silver and silver oxide nanoparticles that were homogeneously distributed within a silica carrier were fabricated. Their average size was d = (7.8 ± 0.3) nm. The organic polymers (carboxymethylcellulose (CMC) and sodium alginate (AS)) were added to improve the biological features of the nanocomposite. The first system was prepared as a silver chlorine salt combination that was immersed on a silica carrier with coagulated particles whose size was d = (44.1 ± 2.3) nm, which coexisted with metallic silver. The second system obtained was synergistically interacted metallic and oxidized silver nanoparticles that were distributed on a structurally defective silica network. Their average size was d = (6.6 ± 0.7) nm. Physicochemical and biological experiments showed that the tiny silver nanoparticles in Ag/SiO2 and Ag/SiO2@AS inhibited E. coli, P. aeruginosa, S. aureus, and L. plantarum’s cell growth as well as caused a high anticancer effect. On the other hand, the massive silver nanoparticles of Ag/SiO2@CMC had a weaker antimicrobial effect, although they highly interacted against PANC-1. They also generated reactive oxygen species (ROS) as well as the induction of apoptosis via the p53-independent mechanism.

Green Synthesis of Silver Nanoparticles Using Prunus Amygdalus Extract and their Anti-Microbial Activity

2015 ◽  
Vol 1119 ◽  
pp. 165-169
Author(s):  
S.K. Srikar ◽  
D.D. Giri ◽  
C. Upadhyay ◽  
P.K. Mishra ◽  
S.N. Upadhyay
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Single Step ◽  
Prunus Amygdalus ◽  
E Coli ◽  
Bacteriostatic Property ◽  
Silver Nitrate Concentration ◽  
Average Size ◽  
20 Nm ◽  
Sun Light

Highly stable silver nanoparticles synthesized in single-step green method by mixing silver nitrate and aqueous extract of Almond (Prunus amygdalus). Experiments were conducted to influence the change in the silver nitrate concentration and time on the synthesis of silver nanoparticles at room temperature under dispersed sun light. The almond extract acted both as the reducing and stabilizing agent for the synthesis of silver nanoparticles. The change in the color of the reaction mixture was monitored using UV-Visible spectrometry whereas particles synthesized were characterized using Scanning Electron Microscopy, Dynamic Light Scattering and Fourier Transform Infrared Spectroscopy. The synthesized nanoparticles were almost spherical in shape with an average size about 20 nm and they exhibited bacteriostatic property against E. coli.

scholarly journals DETERMINATION OF OPTIMAL PARAMETERS FOR SYNTHESIS OF SILVER NANOPARTICLES STABILIZED WITH POLYETHYLENE GLYCOL

2021 ◽  
pp. 32-43
Author(s):  
Андрей Владимирович Блинов ◽  
Алексей Алексеевич Гвозденко ◽  
Анастасия Александровна Блинова ◽  
Анна Витальевна Кобина ◽  
Алексей Борисович Голик ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Polyethylene Glycol ◽  
Silver Nitrate ◽  
Chemical Reduction ◽  
Reaction System ◽  
Correlation Spectroscopy ◽  
Metallic Silver ◽  
Chemical Hardness ◽  
Optimal Parameters ◽  
Characteristic Absorption Band

В рамках данной работы представлены результаты исследования влияния концентраций стабилизатора и прекурсора на процесс синтеза наночастиц серебра. В качестве прекурсора использован нитрат серебра, а в качестве стабилизатора -полиэтиленгликоль с молекулярной массой от 200 до 600 Да. Синтез осуществляли методом химического восстановления в водной среде. Полученные образцы исследовали фотонно-корреляционной спектроскопией и спектрофотометрией. Установлено наличие характеристической полосы поглощения на 400 нм в спектрах поглощения всех образцов наноразмерного серебра, стабилизированного полиэтиленгликолем, что обусловлено возникновением поверхностного плазмонного резонанса у металлических наночастиц серебра. Также установлено, что при наибольшей и наименьшей концентрации стабилизатора, равных, соответственно, 0. 005 и 0,1 мас. %, в реакционной системе наблюдается формирование крупных частиц серебра со средним гидродинамическим радиусом от 132 до 1900 нм. В результате определены оптимальные параметры синтеза агрегативно устойчивых наночастиц серебра: концентрация нитрата серебра С (AgNO) = 0,05 M и концентрация полиэтиленгликоля, равная 0,01 - 0,05 %. Проведено компьютерное квантовохимическое моделирование. Установлено, что энергетически выгодным является взаимодействие атома серебра с концевой гидроксогруппой в молекуле полиэтиленгликоля в элементарном акте взаимодействия при стабилизации наночастиц серебра данным полимером. Данный тип взаимодействия характеризуется абсолютной химической жесткостью, равной ƞ = 0,146 эВ, и внутренней энергией E = -2048,34 ккал / моль. Within the framework of this work, the results are presented of a study of the effect of the concentrations of the stabilizer and precursor on the synthesis of silver nanoparticles. Silver nitrate was used as a precursor, and polyethylene glycol with a molecular weight from 200 to 600 Da was used as a stabilizer. The synthesis was carried out by the method of chemical reduction in an aqueous medium. The obtained samples were investigated by photon correlation spectroscopy and spectrophotometry. The presence of a characteristic absorption band at 400 nm in the absorption spectra of all samples of nanosized silver stabilized with polyethylene glycol was established, which is due to the appearance of surface plasmon resonance in metallic silver nanoparticles. It was also found that at the highest and lowest concentration of the stabilizer, equal, respectively, 0,005 and 0,1 mass. %, the formation of large silver particles with an average hydrodynamic radius from 132 to 1900 nm is observed in the reaction system. As a result, the optimal parameters for the synthesis of aggregatively stable silver nanoparticles were determined: the concentration of silver nitrate C(AgNO) = 0,05 M and the concentration of polyethylene glycol equal to 0,01 - 0,05 %. Computer quantum-chemical modeling is carried out. It is found that the interaction of the silver atom with the terminal hydroxogroup in the polyethylene glycol molecule in the elementary act of interaction during the stabilization of silver nanoparticles by this polymer is energetically advantageous. This type of interaction is characterized by an absolute chemical hardness equal to ƞ = 0,146, and an internal energy of E = -2048,34 kcal / mol.

scholarly journals Synergistic Efficacy of Antibiotics and Silver Nanoparticles Synthesized from Eichhornia crassipes

2016 ◽  
Vol 6 ◽  
Author(s):  
S Basker
Keyword(s):  
Silver Nanoparticles ◽  
Eichhornia Crassipes ◽  
Bacterial Resistance ◽  
Synergistic Effects ◽  
Public Health Issue ◽  
Metallic Silver ◽  
Gram Positive ◽  
Zone Formation ◽  
Gram Negative ◽  
E Coli

<p><strong>The increasing prevalence of bacterial resistance has made an important public health issue in the present scenario.  Thus it is urging to develop alternate and more effective therapeutic strategies to treat both Gram-negative and Gram-positive microbes.</strong>  <strong>Now a days silver nanoparticles (AgNPs) synthesized biologically gaining much importance with different applications as they are nontoxic and eco-friendliness.</strong> <strong>The antimicrobial activity of biosynthesized silver nanoparticles synthesized from aqueous extracts of</strong><strong><em> Eichhornia crassipes</em></strong><strong> was evaluated with the panel of antibiotics </strong><strong>like vancomycin, penicillin, streptomycin and tetracycline</strong><strong> and microorganisms </strong><strong>in the category of either gram positive or gram negative type.</strong><strong> <em>E. coli</em> and <em>S. aureus </em>proved to be effective with highest zone formation. In addition, possible synergistic effects of antibiotics were loaded with standard concentration of 20</strong> <strong>μl</strong><strong> of AgNPs and the effect of inhibition was highest in the antibiotic Tetracycline followed by Streptomycin, Vancomycin and Penicillin with different tested microbes. </strong><strong>The synergistic association of antibiotics with biosynthesized metallic silver nanoparticles proved to be effective against the tested microbes than control. The antibiotics showed higher zone of inhibition when added to AgNPs.</strong></p>

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