scholarly journals Surface-water purification using cellulose paper impregnated with silver nanoparticles

2021 ◽  
Vol 14 (1) ◽  
pp. 95-102
Author(s):  
Shahad A. Raheem ◽  
Alaa H. Alfatlawi
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Water Purification ◽  
Environmental Protection Agency ◽  
Chemical Reduction ◽  
The United States ◽  
Silver Concentration ◽  
Effluent Water ◽  
Cellulose Paper ◽  
Point Of Use

Abstract. The objective of this study is to prepare a cellulose paper that was impregnated with silver nanoparticles (AgNPs) for the purpose of water purification (disinfection and filtration). AgNP papers were prepared by chemical reduction of silver nitrate (AgNO3) with various concentrations (0.005 M, 0.015 M, 0.03 M, and 0.05 M) using sodium borohydride (NaBH4) as a reducing agent. Two ratios for NaBH4/AgNO3 of 2:1 and 10:1 were used to show the effect of reduction on the formation and removal efficiencies of AgNPs. AgNP papers were characterized using scanning electron microscopy and transmission electron microscopy. An acid digestion using HCl acid followed by analyzing the samples in an atomic absorption spectrometer (ASS) was conducted to measure the silver concentration in AgNP papers. TEM images showed that the silver nanoparticle size in the papers varied from 1.3 to 75 nm. Water samples, after filtration through AgNP papers, were analyzed using ASS to measure the silver concentration in the effluent water. AgNP paper antibacterial efficiency ranged from 99 % to 100 % for both reduction ratios. The average silver content in the effluent water for the three replicates ranged from 0 to 0.082 mg L−1, which meets the United States Environmental Protection Agency (US-EPA) guideline for drinking water of less than 0.1 mg L−1. Turbidity tests showed that these papers can be usefully used as point-of-use filters as the turbidity reduced to less than 1 NTU (Nephelometric Turbidity Units).

scholarly journals Surface Water Purification using cellulose Paper Impregnated with Silver Nanoparticles

2020 ◽  
Author(s):  
Shahad A. Raheem ◽  
Alaa H. Alfatlawi
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Water Purification ◽  
Environmental Protection Agency ◽  
Chemical Reduction ◽  
Enterobacter Aerogenes ◽  
The United States ◽  
Silver Concentration ◽  
Effluent Water ◽  
Cellulose Paper

Abstract. The objective of this study is to prepare a cellulose paper was impregnated with silver nanoparticles (AgNPs) for the purpose of water purification (Disinfection (removal of Escherichia Coli, Staphylococcus Aureus, Enterococcus Faecalis, Enterobacter Aerogenes, Klebsiella Pneumoniae, and Proteus mirabilis) and filtration). AgNPs papers were prepared by chemical reduction of silver nitrate (AgNO3) with various concentrations (0.005 M, 0.015 M, 0.03 M, and 0.05 M) using sodium borohydride (NaBH4) as a reducing agent. Two ratios of NaBH4 / AgNO3 of 2 : 1 and 10 : 1 were used to show the effect of reduction on the formation and removal efficiencies of AgNPs. AgNPs papers were characterized using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). An acid digestion using HCL acid followed by analyzing the samples in Atomic Absorption Spectrometer (ASS) was conducted to measure the silver concentration in AgNPs papers. TEM images showed that the silver nanoparticles size in the papers varies from 1.3 to 75 nm. Water samples, after filtration through AgNPs papers, were analyzed using (ASS) to measure the silver concentration in the effluent water. AgNPs paper antibacterial efficiency ranged (99 % to 100 %) for both reduction ratios. The average silver content in the effluent water for the three replicates ranged from 0 to 0.082 mg/L which meets the United States- Environmental Protection Agency (US-EPA) guideline for drinking water of less than 0.1 mg/L Turbidity tests showed that these papers can be usefully used as a point of use filters as the turbidity reduced to less than 1 NTU.

Scanning electron microscopy of asbestos-containing material where the asbestos fibers are considered locked in a binder

1993 ◽  
Vol 51 ◽  
pp. 472-473
Author(s):  
J. R. Millette ◽  
R. S. Brown
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Protection Agency ◽  
Building Materials ◽  
The United States ◽  
Protection Agency ◽  
Asbestos Fibers ◽  
Different Types ◽  
Binder Material ◽  
Scanning Electron

The United States Environmental Protection Agency (EPA) has labeled as “friable” those building materials that are likely to readily release fibers. Friable materials when dry, can easily be crumbled, pulverized, or reduced to powder using hand pressure. Other asbestos containing building materials (ACBM) where the asbestos fibers are in a matrix of cement or bituminous or resinous binders are considered non-friable. However, when subjected to sanding, grinding, cutting or other forms of abrasion, these non-friable materials are to be treated as friable asbestos material. There has been a hypothesis that all raw asbestos fibers are encapsulated in solvents and binders and are not released as individual fibers if the material is cut or abraded. Examination of a number of different types of non-friable materials under the SEM show that after cutting or abrasion, tuffs or bundles of fibers are evident on the surfaces of the materials. When these tuffs or bundles are examined, they are shown to contain asbestos fibers which are free from binder material. These free fibers may be released into the air upon further cutting or abrasion.

scholarly journals Fabrication, Characterization, and Antibacterial Properties of Electrospun Membrane Composed of Gum Karaya, Polyvinyl Alcohol, and Silver Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Vinod Vellora Thekkae Padil ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Miroslav Černík
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Food Packaging ◽  
Chemical Reduction ◽  
Antibacterial Properties ◽  
Hydroxyl Groups ◽  
Ag Nps ◽  
Gum Karaya ◽  
Nanofiber Membranes

Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3(at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negativeEscherichia coliandPseudomonas aeruginosaand Gram-positiveStaphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.

scholarly journals Microwave-assisted incorporation of silver nanoparticles in paper for point-of-use water purification

2014 ◽  
Vol 1 (4) ◽  
pp. 367-378 ◽  
Author(s):  
Theresa A. Dankovich
Keyword(s):  
Silver Nanoparticles ◽  
Microwave Irradiation ◽  
Water Purification ◽  
Microwave Assisted ◽  
Point Of Use

The microwave irradiation-formed AgNPs on paper filters very effectively inactivated model bacteria in water purification experiments.

scholarly journals Green Synthesis of Silver Nanoparticles Using Diospyros malabarica Fruit Extract and Assessments of Their Antimicrobial, Anticancer and Catalytic Reduction of 4-Nitrophenol (4-NP)

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1999
Author(s):  
Kaushik Kumar Bharadwaj ◽  
Bijuli Rabha ◽  
Siddhartha Pati ◽  
Bhabesh Kumar Choudhury ◽  
Tanmay Sarkar ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Environmental Protection Agency ◽  
Catalytic Reduction ◽  
The United States ◽  
Single Step ◽  
Diffusion Method ◽  
Fruit Extract ◽  
Primary Glioblastoma ◽  
Pharmaceutical Industries

The green synthesis of silver nanoparticles (AgNPs) has currently been gaining wide applications in the medical field of nanomedicine. Green synthesis is one of the most effective procedures for the production of AgNPs. The Diospyros malabarica tree grown throughout India has been reported to have antioxidant and various therapeutic applications. In the context of this, we have investigated the fruit of Diospyros malabarica for the potential of forming AgNPs and analyzed its antibacterial and anticancer activity. We have developed a rapid, single-step, cost-effective and eco-friendly method for the synthesis of AgNPs using Diospyros malabarica aqueous fruit extract at room temperature. The AgNPs began to form just after the reaction was initiated. The formation and characterization of AgNPs were confirmed by UV-Vis spectrophotometry, XRD, FTIR, DLS, Zeta potential, FESEM, EDX, TEM and photoluminescence (PL) methods. The average size of AgNPs, in accordance with TEM results, was found to be 17.4 nm. The antibacterial activity of the silver nanoparticles against pathogenic microorganism strains of Staphylococcus aureus and Escherichia coli was confirmed by the well diffusion method and was found to inhibit the growth of the bacteria with an average zone of inhibition size of (8.4 ± 0.3 mm and 12.1 ± 0.5 mm) and (6.1 ± 0.7 mm and 13.1 ± 0.5 mm) at 500 and 1000 µg/mL concentrations of AgNPs, respectively. The anticancer effect of the AgNPs was confirmed by MTT assay using the U87-MG (human primary glioblastoma) cell line. The IC50 value was found to be 58.63 ± 5.74 μg/mL. The results showed that green synthesized AgNPs exhibited significant antimicrobial and anticancer potency. In addition, nitrophenols, which are regarded as priority pollutants by the United States Environmental Protection Agency (USEPA), can also be catalytically reduced to less toxic aminophenols by utilizing synthesized AgNPs. As a model reaction, AgNPs are employed as a catalyst in the reduction of 4-nitrophenol to 4-aminophenol, which is an intermediate for numerous analgesics and antipyretic drugs. Thus, the study is expected to help immensely in the pharmaceutical industries in developing antimicrobial drugs and/or as an anticancer drug, as well as in the cosmetic and food industries.

scholarly journals Silver Nanoparticles Obtained by Aqueous or Ethanolic Aloe vera Extracts: An Assessment of the Antibacterial Activity and Mercury Removal Capability

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ederley Vélez ◽  
Gloria Campillo ◽  
Gladis Morales ◽  
César Hincapié ◽  
Jaime Osorio ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Environmental Protection Agency ◽  
Chemical Reduction ◽  
Aloe Vera ◽  
Agar Plate ◽  
Size Control ◽  
Ethanolic Extract ◽  
World Health ◽  
Mercury Removal

Silver nanoparticles (AgNPs) were synthesized by chemical reduction of Ag+ ions (from silver nitrate AgNO3), using aqueous or ethanolic Aloe vera extracts as reducing, stabilizing, and size control agent. The nanoparticles’ sizes were between 2 and 7 nm for ethanolic extract and between 3 and 14 nm for aqueous extract, as measured by High-Resolution Transmission Electron Microscope (HRTEM). The antibacterial activity against a mesophilic microorganism, Kocuria varians, a Gram-positive coccus, was measured by counting bacterial colonies in agar plate for both extracts. We found that 4% effective concentration is the lowest concentration that completely inhibited visible growth. Mercury removal was investigated by Atomic Absorption Spectroscopy (AAS) measurements, where it was shown that it is not necessary to use high concentrations of nanoparticles for effective removal of mercury inasmuch as with a 20% V/V concentration of both extracts; the Hg(II) removal percentage was above 95%. These results show that the mercury remaining unremoved from the different essays is below the level allowed by World Health Organization (WHO) and the Environmental Protection Agency (EPA).

Antimicrobial Activity of Silver Nanoparticles Prepared Under an Ultrasonic Field

2011 ◽  
Vol 4 (3) ◽  
pp. 1491-1496
Author(s):  
Umadevi M ◽  
Rani T ◽  
Balakrishnan T ◽  
Ramanibai R
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Reduction Method ◽  
Therapeutic Potential ◽  
Chemical Reduction ◽  
Ultrasonic Field ◽  
Great Promise ◽  
Chemical Reduction Method ◽  
E Coli

Nanotechnology has great promise for improving the therapeutic potential of medicinal molecules and related agents. In this study, silver nanoparticles of different sizes were synthesized in an ultrasonic field using the chemical reduction method with sodium borohydride as a reducing agent. The size effect of silver nanoparticles on antimicrobial activity were tested against the microorganisms Staphylococcus aureus (MTCC No. 96), Bacillus subtilis (MTCC No. 441), Streptococcus mutans (MTCC No. 497), Escherichia coli (MTCC No. 739) and Pseudomonas aeruginosa (MTCC No. 1934). The results shows that B. subtilis, and E. coli were more sensitive to silver nanoparticles and its size, indicating the superior antimicrobial efficacy of silver nanoparticles. 

Municipal Wastewater Treatment Technology Transfer Activities of the United States Environmental Protection Agency

1989 ◽  
Vol 21 (6-7) ◽  
pp. 685-698
Author(s):  
J. J. Convery ◽  
J. F. Kreissl ◽  
A. D. Venosa ◽  
J. H. Bender ◽  
D. J. Lussier
Keyword(s):  
Technology Transfer ◽  
Environmental Protection ◽  
Case Studies ◽  
Environmental Protection Agency ◽  
The United States ◽  
Environmental Research ◽  
Outreach Program ◽  
Small Community ◽  
Protection Agency ◽  
Transfer Programs

Technology transfer is an important activity within the ll.S. Environmental Protection Agency. Specific technology transfer programs such as the activities of the Center for Environmental Research Information, the Innovative and Alternative Technology Program, as well as the Small Community Outreach Program are used to encourage the utilization of cost-effective municipal pollution control technology. Case studies of three technologies including a plant operations diagnostic/remediation methodology, alternative sewer technologies and ultraviolet disinfection are presented. These case studies are presented retrospectively in the context of a generalized concept of how technology flows from science to utilization which was developed in a study by Allen (1977). Additional insights from this study are presented on the information gathering characteristics of engineers and scientists which may be useful in designing technology transfer programs. The recognition of the need for a technology or a deficiency in current practice are important stimuli other than technology transfer for accelerating the utilization of new technology.

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