Hierarchically aligned nano silver/chitosan–PVA hydrogel for point-of-use water disinfection: contact-active mechanism revealed

2020 ◽  
Vol 7 (8) ◽  
pp. 2337-2350 ◽  
Author(s):  
Navneet Kaur Dhiman ◽  
Shekhar Agnihotri

Mechanically robust Ag/CS–PVA hydrogel displayed 100% disinfection efficacy against biomedical/natural contaminants through contact-active mechanism with ∼74 ppb Ag release.

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 4873-4882
Author(s):  
Gongyan Liu ◽  
Ruiquan Yu ◽  
Jing Jiang ◽  
Zhuang Ding ◽  
Jing Ma ◽  
...  

Point-of-use water disinfection by GA@AgNPs-LA-FP.


2021 ◽  
pp. 117825
Author(s):  
Shuang-Yu Pi ◽  
Yang Wang ◽  
Ying-Wen Lu ◽  
Guang-Li Liu ◽  
Hai-Ming Wu ◽  
...  

2021 ◽  
Author(s):  
Paloma Ozores Diez ◽  
M. Inmaculada Polo-López ◽  
Azahara Martínez-García ◽  
Monique Waso ◽  
Brandon Reyneke ◽  
...  

Abstract Solar water disinfection (SODIS) is a cost-effective point of use method for disinfecting water, usually in a 2 L polyethylene terephthalate (PET) plastic bottle. To increase the volume of water disinfected, three novel transparent reactors were developed using PET in 25 L transparent jerrycans, polymethyl methacrylate (PMMA) in tubular solar reactors capable of delivering >20 L of water and polypropylene (PP) in 20 L buckets. In vitro bioassays were used to investigate any toxic substances leached from the plastic reactors into disinfected water as a result of exposure to sunshine for up to 9 months. The Ames test was used to test for mutagenicity and the E-screen bioassay to test for estrogenicity. No mutagenicity was detected in any sample and no estrogenicity was found in the SODIS treated water produced by the PMMA reactors or the PP buckets. While water disinfected using the PET reactors showed no estrogenicity following exposure to the sun for 3 and 6 months, estrogenicity was detected following 9 months' exposure to sunlight; however levels detected were within the acceptable daily intake for 17β-estradiol (E2) of up to 50 ng/kg body weight/day.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Deepa Dixit ◽  
Virupakshi Soppina ◽  
Chinmay Ghoroi

AbstractAccess to safe drinking water is still a distant dream to millions of people around the world. Especially, people from the low-income group in the developing countries remain deprived of this fundamental right and causes millions of death. There is an urgent need to develop affordable and easy to handle water filter which can provide desired drinking water quality without any electricity. In the present work, a simple and low-cost surface engineered particle (SEP) based filter is developed via alkali treatment of soda-lime-silica particle. The SEP based filter can be used as a portable, non-electric, gravity-driven Point-of-Use (POU) water disinfection system. The developed SEP-based filter is capable to arrest the 99.48% (~2 to 2.5 log10 reduction) of gram-negative bacteria Escherichia coli (E. coli OP50) on its surface from the water containing 3 × 108 cells/ml. No bacterial regrowth is observed in the purified water for 12 h. The performance of SEP bed filter is implicated to the nano-scale surface roughness, its distribution along with the surface charge and surface hydrophobicity which are favorable to attract and adhere the bacteria in the flowing water. The observation is consistent over multiple filtration cycles indicating the suitability of SEP based bed filter for POU water disinfection. The SEP surface with 0.05 mM Ag+ loading (SEP+) completely inactivated (>99.99999%) bacteria and protects any bacteria recontamination in the purified water for its long term usage. The strong and effective silver binding property of SEP surface enables very minimal silver loading and eliminates any health hazard due to low silver leaching (~50 ppb) which is well below the drinking water equivalent level (DWEL ≤ 100 ppb). In rural and urban slum areas of developing countries where no water purification system exists prior to consumption, the easy-to-implement and affordable SEP-based gravity-driven non-electric point-of-use water purifier (materials cost ~ 0.25 USD) can be used to protect millions of lives from water borne diseases.


2020 ◽  
Vol 231 ◽  
pp. 115746 ◽  
Author(s):  
Zahid Hanif ◽  
Zeeshan Ahmad Khan ◽  
Mohd Farhan Siddiqui ◽  
Muhammad Zakria Tariq ◽  
Seungkyung Park ◽  
...  

2007 ◽  
Vol 6 (1) ◽  
pp. 53-65 ◽  
Author(s):  
Sarah A. Brownell ◽  
Alicia R. Chakrabarti ◽  
Forest M. Kaser ◽  
Lloyd G. Connelly ◽  
Rachel L. Peletz ◽  
...  

We describe a point-of-use (POU) ultraviolet (UV) disinfection technology, the UV Tube, which can be made with locally available resources around the world for under $50 US. Laboratory and field studies were conducted to characterize the UV Tube's performance when treating a flowrate of 5 L/min. Based on biological assays with MS2 coliphage, the UV Tube delivered an average fluence of 900±80 J/m2 (95% CI) in water with an absorption coefficient of 0.01 cm−1. The residence time distribution in the UV Tube was characterized as plug flow with dispersion (Peclet Number = 19.7) and a mean hydraulic residence time of 36 s. Undesirable compounds were leached or produced from UV Tubes constructed with unlined ABS, PVC, or a galvanized steel liner. Lining the PVC pipe with stainless steel, however, prevented production of regulated halogenated organics. A small field study in two rural communities in Baja California Sur demonstrated that the UV Tube reduced E. coli concentrations to less than 1/100 ml in 65 out of 70 samples. Based on these results, we conclude that the UV Tube is a promising technology for treating household drinking water at the point of use.


1999 ◽  
Vol 122 (1) ◽  
pp. 83-90 ◽  
Author(s):  
R. E. QUICK ◽  
L. V. VENCZEL ◽  
E. D. MINTZ ◽  
L. SOLETO ◽  
J. APARICIO ◽  
...  

A novel water quality intervention that consists of point-of-use water disinfection, safe storage and community education was field tested in Bolivia. A total of 127 households in two periurban communities were randomized into intervention and control groups, surveyed and the intervention was distributed. Monthly water quality testing and weekly diarrhoea surveillance were conducted. Over a 5-month period, intervention households had 44% fewer diarrhoea episodes than control households (P=0·002). Infants <1 year old (P=0·05) and children 5–14 years old (P=0·01) in intervention households had significantly less diarrhoea than control children. Campylobacter was less commonly isolated from intervention than control patients (P=0·02). Stored water in intervention households was less contaminated with Escherichia coli than stored water in control households (P<0·0001). Intervention households exhibited less E. coli contamination of stored water and less diarrhoea than control households. This promising new strategy may have broad applicability for waterborne disease prevention.


2020 ◽  
Vol 10 (4) ◽  
pp. 1012-1018
Author(s):  
T. M. Ngasala ◽  
S. J. Masten ◽  
C. Cohen ◽  
D. Ravitz ◽  
E. J. Mwita

Abstract This study was conducted in an agro-pastoral community in Northern Tanzania, where water sources are contaminated, and point-of-use water treatment is rarely used. The objectives of the study were to determine the quality of drinking water at the household level and to assess the perception and attitude towards the treatment methods that were introduced to community members. The three treatment methods evaluated were chlorine tablets, silver-infused ceramic tablets, and solar water disinfection (SODIS). These methods were selected due to their availability, ease of use, cost, and effectiveness in water with high levels of coliform bacteria. Each home within the study area was provided with one of three treatment methods. The use, performance, and acceptability of the new water treatment methods were assessed over a three-week period. Prior to the introduction of the methods, 40% of households reported that they treated water regularly. However, 80% of the household water samples tested positive for Escherichia coli. After introducing the new methods, 60% of households increased their water consumption, and all water samples tested negative for E. coli during the final week of testing. The work demonstrates the need to provide access to cost-effective household water treatment methods, especially in rural communities that lack access to potable water.


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