scholarly journals Effect of water compounds on photo-disinfection efficacy of TiO2 NP-embedded cellulose acetate film in natural water

2020 ◽  
Author(s):  
Jing Xie ◽  
Yen-Con Hung
Keyword(s):  
Humic Acid ◽  
Cellulose Acetate ◽  
Natural Water ◽  
Water Hardness ◽  
Prediction Equation ◽  
Water Disinfection ◽  
Kaolin Clay ◽  
E Coli ◽  
Cellulose Acetate Film ◽  
Effect Of Water

Abstract Photocatalysis disinfection has great potential for irrigation water disinfection to improve fresh produce safety. Titanium dioxide (TiO2) nanoparticle (NP)-embedded cellulose acetate (CA) film has shown effectiveness against Escherichia coli (E. coli) O157:H7 in water. The current study evaluated the effect of natural water compounds on the photo-disinfection efficacy of TiO2 NP-embedded CA film. Humic acid, calcium carbonate (CaCO3), and kaolin clay solutions were prepared at four concentrations, respectively. When concentration increased from 0 to 20 ml/L, inactivation of E. coli O157:H7 in humic acid, CaCO3, and kaolin clay solutions decreased from 6 log to 5, 4, and 2 log CFU/ml, respectively after 3 h treatment. Turbidity, UVT-254, water hardness, total suspended solids (TSS), and total organic carbon (TOC) of the solutions were measured. UVT-254 and turbidity had the highest correlation with the inhibition effect of water compounds on photo-disinfection efficacy. A prediction equation was developed with UVT-254 and water hardness as independent variables to predict photo-disinfection efficacy in natural water. E. coli O157:H7 decreased by 1 and 2.5 log CFU/ml in unfiltered and filtered natural creek water samples after treatment. The results from this study showed promise in the use of TiO2 NP-embedded CA film to inactivate pathogens in natural water.

Effect of Water Hardness on Efficacy of Sodium Hypochlorite Inactivation of Escherichia coli O157:H7 in Water

2017 ◽  
Vol 80 (3) ◽  
pp. 497-501 ◽  
Author(s):  
Sara Swanson ◽  
Tong-Jen Fu
Keyword(s):  
Escherichia Coli ◽  
Sodium Hypochlorite ◽  
Water Hardness ◽  
Hard Water ◽  
Free Chlorine ◽  
Total Hardness ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Effect Of Water ◽  
The Impact

ABSTRACT This study examined how the hardness of water affected the efficacy of sodium hypochlorite in inactivating Escherichia coli O157:H7 in water. Water was prepared at different degrees of total hardness (0, 50, 100, 200, 500, 1,000, 2,000, and 5,000 mg/liter CaCO3). Inactivation was assessed at different levels of free chlorine (0, 0.2, 0.5, and 1.0 ppm) at 2 to 4°C and pH 6.5. Thirty milliliters of chlorinated water was inoculated with 6 log CFU/ml of E. coli O157:H7 and allowed to mix for 3, 10, 20, or 30 s. In the absence of sodium hypochlorite, no reduction in counts of E. coli O157:H7 was observed regardless of the degree of water hardness. However, in the presence of hard water, under certain chlorine concentrations and exposure times, the reduction of E. coli O157:H7 in chlorinated hard water was significantly less than the reduction observed in chlorinated deionized water. For example, after exposure to 0.5 ppm of free chlorine for 10 s, E. coli O157:H7 counts were reduced by 4.8 ± 1.4, 2.0 ± 1.3, 1.6 ± 0.7, 0.5 ± 0.7, and 0.0 ± 0.1 log CFU/ml in water containing 0, 100, 1,000, 2,000, and 5,000 mg/liter CaCO3, respectively. With the exception of 5,000 mg/liter CaCO3, the effect of water hardness was no longer visible after 20 s of exposure to 0.5 ppm of free chlorine. Also, hard water significantly lowered the efficacy of sodium hypochlorite at 3 s of exposure to 1.0 ppm of free chlorine. But after 20 s of exposure to 1.0 ppm of free chlorine, the impact of water hardness was no longer observed. This study demonstrated that water hardness can affect the germicidal efficacy of sodium hypochlorite, and such an impact may or may not be apparent depending on the condition of the solution and the treatment time at which the observation is made. Under the conditions typically seen in commercial produce washing operations, the impact of water hardness on chlorine efficacy is likely to be insignificant compared with that of organic load.

scholarly journals Comparison of the ColiPlate™ Kit with Two Common E. coli Enumeration Methods for Water

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1804
Author(s):  
Cassi J. Gibson ◽  
Abraham K. Maritim ◽  
Jason W. Marion
Keyword(s):  
High Risk ◽  
Natural Water ◽  
Membrane Filtration ◽  
Fecal Contamination ◽  
Reference Method ◽  
World Health ◽  
Risk Levels ◽  
E Coli ◽  
Field Samples ◽  
Very High

Quantitatively assessing fecal indicator bacteria in drinking water from limited resource settings (e.g., disasters, remote areas) can inform public health strategies for reducing waterborne illnesses. This study aimed to compare two common approaches for quantifying Escherichia coli (E. coli) density in natural water versus the ColiPlate™ kit approach. For comparing methods, 41 field samples from natural water sources in Kentucky (USA) were collected. E. coli densities were then determined by (1) membrane filtration in conjunction with modified membrane-thermotolerant E. coli (mTEC) agar, (2) Idexx Quanti-Tray® 2000 with the Colilert® substrate, and (3) the Bluewater Biosciences ColiPlate kit. Significant correlations were observed between E. coli density data for all three methods (p < 0.001). Paired t-test results showed no difference in E. coli densities determined by all the methods (p > 0.05). Upon assigning modified mTEC as the reference method for determining the World Health Organization-assigned “very high-risk” levels of fecal contamination (> 100 E. coli CFU/100 mL), both ColiPlate and Colilert exhibited excellent discrimination for screening very high-risk levels according to the area under the receiver operating characteristic curve (~89%). These data suggest ColiPlate continues to be an effective monitoring tool for quantifying E. coli density and characterizing fecal contamination risks from water.

scholarly journals Green Synthesis and Incorporation of Sericin Silver Nanoclusters into Electrospun Ultrafine Cellulose Acetate Fibers for Anti-Bacterial Applications

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1411
Author(s):  
Mujahid Mehdi ◽  
Huihui Qiu ◽  
Bing Dai ◽  
Raja Fahad Qureshi ◽  
Sadam Hussain ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Green Synthesis ◽  
Cellulose Acetate ◽  
Antibacterial Properties ◽  
Vital Role ◽  
Silver Nanoclusters ◽  
Composite Fibers ◽  
E Coli ◽  
Antibacterial Performance ◽  
Field Emission Electron Microscopy

Fiber based antibacterial materials have gained an enormous attraction for the researchers in these days. In this study, a novel Sericin Encapsulated Silver Nanoclusters (sericin-AgNCs) were synthesized through single pot and green synthesis route. Subsequently these sericin-AgNCs were incorporated into ultrafine electrospun cellulose acetate (CA) fibers for assessing the antibacterial performance. The physicochemical properties of sericin-AgNCs/CA composite fibers were investigated by transmission electron microscopy (TEM), field emission electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and wide X-ray diffraction (XRD). The antibacterial properties of sericin-AgNCs/CA composite fibers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were systematically evaluated. The results showed that sericin-AgNCs incorporated in ultrafine CA fibers have played a vital role for antibacterial activity. An amount of 0.17 mg/mL sericin-AgNCs to CA fibers showed more than 90% results and elevated upto >99.9% with 1.7 mg/mL of sericin-AgNCs against E. coli. The study indicated that sericin-AgNCs/CA composite confirms an enhanced antibacterial efficiency, which could be used as a promising antibacterial product.

scholarly journals Temperature Dependence of Limiting Fluorescence Anisotropy of POPOP in Cellulose Acetate Film

1985 ◽  
Vol 40 (6) ◽  
pp. 559-561
Author(s):  
A. Kawski ◽  
A. Kubicki ◽  
I. Weyna ◽  
I. Janić
Keyword(s):  
Temperature Dependence ◽  
Cellulose Acetate ◽  
Fluorescence Anisotropy ◽  
Thermal Relaxation ◽  
Effect Of Temperature ◽  
Torsional Vibrations ◽  
Slow Increase ◽  
Cellulose Acetate Film ◽  
Luminescent Centre

The effect of temperature (103 K < T < 303 K) upon the limiting fluorescence anisotropy r0 of POPOP was investigated in a cellulose acetate film. A slow increase in r0 was observed when reducing the temperature. Based on the Jabłoński theory, the frequency of the torsional vibrations of POPOP was determined to be w = 1.3 x 1012s−1. The depolarization due to these torsional vibrations was found to occur immediately following excitation during the thermal relaxation of the luminescent centre, thus somewhat lowering the value of the fundamental fluorescence anisotropy rf to the limiting r0 value.

scholarly journals Performance of silver-coated red soil nanocomposites in water disinfection

2018 ◽  
Vol 54 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Ebrahim Mahmoudi ◽  
Farid Moeinpour
Keyword(s):  
Contact Time ◽  
Elimination Rate ◽  
Red Soil ◽  
Water Disinfection ◽  
Box Behnken Design ◽  
E Coli ◽  
Surface Response Method ◽  
Research Findings ◽  
Response Method ◽  
Bacterial Effect

Abstract The present research studied the anti-bacterial effect of silver-coated red soil nanoparticles on Gram-negative bacteria Escherichia coli (E. coli) from water. The effects of disinfectant concentration (0.02, 0.05 and 0.1 g/mL), contact time (10, 20 and 30 minutes) and bacteria number (102, 104 and 106 CFU/mL) have been also investigated. To obtain important factors, the interactions between factors and optimal experimental design in surface response method were used based on Box-Behnken design. According to the research findings, the system is efficient in eliminating E. coli. The results showed that E. coli elimination efficiency intensified through increasing the amount of disinfectant from 0.02 to 0.1 g/mL. Expanding contact time from 10 minutes to 30 minutes also heightened the E. coli elimination rate. R2 for E. coli elimination is 0.9956 indicating a good agreement between model experimental data and forecasting data.

Effect of water hardness on surface tension and dilational visco-elasticity of sodium dodecyl sulphate solutions

2012 ◽  
Vol 377 (1) ◽  
pp. 1-6 ◽  
Author(s):  
V.B. Fainerman ◽  
S.V. Lylyk ◽  
E.V. Aksenenko ◽  
N.M. Kovalchuk ◽  
V.I. Kovalchuk ◽  
...  
Keyword(s):  
Surface Tension ◽  
Sodium Dodecyl Sulphate ◽  
Sodium Dodecyl ◽  
Water Hardness ◽  
Effect Of Water

scholarly journals Assessing efficiency of pre-ammonization aimed at reducing carcinogenic risks caused by trihalomethanes in drinking water

2020 ◽  
pp. 70-77
Author(s):  
L.A. Deryabkina ◽  
◽  
B.I. Marchenko ◽  
N.K. Plugotarenko ◽  
A.I. Yukhno ◽  
...  
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Natural Water ◽  
Water Source ◽  
Water Disinfection ◽  
Residual Chlorine ◽  
Gas Liquid Chromatography ◽  
Initial Water ◽  
Organic Chlorine ◽  
Deep Purification

In most Russian regions there is still a pressing issue related to providing population with high quality and safe drinking water. Up to now, chlorination has been the primary technique applied to disinfect drinking water as it is highly efficient, reliable, and relatively cheap. However, when chlorine is used to disinfect natural water that contains organic pollutants, it results in risks of by-products occurrence. These products are trihalomethanes, epigenetic carcinogenesis promoters that cause elevated carcinogenic risks under oral, inhalation, and subcutaneous exposure. Our research goal was to hygienically assess efficiency of pre-ammonization applied in water treatment procedures in order to prevent occurrence of carcinogenic organic chlorine compounds during chlorination and to minimize carcinogenic risks. We determined trihalomethanes and residual chlorine contents in model samples of natural water taken from a surface water source after chlorination with different doses of chlorine. We examined 52 pair parallel samples that had undergone pre-ammonization with ammonia sulfate and control ones. Trihalomethanes concentrations were determined in model water samples with gas-liquid chromatography. Basing on the results obtained via experiments on laboratory chlorination of river water, we determined quantitative characteristics and built regression models showing dependence between concentrations of organic chlorine compounds occurring due to chlorination (chloroform, dichlorobrommethane, dibromchloromethane) and chlorine doses and preammonization parameters. It was established that pre-ammonization was the most efficient in terms of preventing trihalomethanes occurrence under such disinfection modes when contents of residual active chlorine didn’t exceed recommended levels (0.8–1.2 mg/L). Basic ways to minimize carcinogenic risks caused by trihalomethanes are systemic control over their contents in drinking water during social and hygienic monitoring procedures; preliminary ammonization of water taken from surface water sources; prevention of unjustified hyper-chlorination; preliminary deep purification of initial water; disinfection with ultrasound radiation instead of preliminary chlorination; etc.

Biodegradation behavior of acid-containing cellulose acetate film in soil

2005 ◽  
Vol 98 (1) ◽  
pp. 466-473 ◽  
Author(s):  
Yoichiro Yamashita ◽  
Takeshi Endo
Keyword(s):  
Cellulose Acetate ◽  
Cellulose Acetate Film
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