scholarly journals Bacterial Disinfection by CuFe2O4 Nanoparticles Enhanced by NH2OH: A Mechanistic Study

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
Yu Gu ◽  
Furen Xiao ◽  
Liumin Luo ◽  
Xiaoyu Zhou ◽  
Xiaodong Zhou ◽  
...  
Keyword(s):  
Water Treatment ◽  
Noble Metals ◽  
Low Cost ◽  
Water Disinfection ◽  
Mechanistic Study ◽  
Copper Ferrite ◽  
Bacterial Inactivation ◽  
E Coli ◽  
Reactive Oxygen Species Content ◽  
Current Water

Many disinfection technologies have emerged recently in water treatment industry, which are designed to inactivate water pathogens with extraordinary efficiency and minimum side effects and costs. Current disinfection processes, including chlorination, ozonation, UV irradiation, and so on, have their inherent drawbacks, and have been proven ineffective under certain scenarios. Bacterial inactivation by noble metals has been traditionally used, and copper is an ideal candidate as a bactericidal agent owing to its high abundance and low cost. Building on previous findings, we explored the bactericidal efficiency of Cu(I) and attempted to develop it into a novel water disinfection platform. Nanosized copper ferrite was synthesized, and it was reduced by hydroxylamine to form surface bound Cu(I) species. Our results showed that the generated Cu(I) on copper ferrite surface could inactivate E. coli at a much higher efficiency than Cu(II) species. Elevated reactive oxygen species’ content inside the cell primarily accounted for the strong bactericidal role of Cu(I), which may eventually lead to enhanced oxidative stress towards cell membrane, DNA, and functional proteins. The developed platform in this study is promising to be integrated into current water treatment industry.

scholarly journals Design of a cost-effective electrochlorination system for point-of-use water treatment

2020 ◽  
Vol 26 (5) ◽  
pp. 200437-0
Author(s):  
Mainak Bhattacharya ◽  
Koyel Bandyopadhyay ◽  
Anirban Gupta
Keyword(s):  
Water Treatment ◽  
Continuous Flow ◽  
Low Cost ◽  
Developed Countries ◽  
Water Disinfection ◽  
Residual Chlorine ◽  
Waterborne Diseases ◽  
Bacterial Inactivation ◽  
Treatment Unit ◽  
Continuous Flow Reactors

Bacteriological contamination in drinking water is known to be responsible for the spread of various waterborne diseases. Although chlorine is frequently used as disinfectant in water treatment, low-cost disinfecting technologies in the villages of developing and under-developed countries are not yet successfully implemented. This study contributed in designing a simple and inexpensive water disinfection unit to produce chlorine from the naturally available dissolved chloride of groundwater by electrochlorination, using inert and cheap graphite electrodes. Laboratory-based experiments were performed in both batch and continuous flow reactors to study the effect of time, current, electro charge loading (ECL), and surface area of electrodes in chlorine generation and bacterial inactivation. Controlled experiments in continuous mode in the absence of chlorine further indicated the possibility of partial inactivation of bacteria under the influence of the electric field. Finally, a treatment unit with drilled anodes, and undrilled cathode electrodes, in continuous flow set-up was installed in four schools of four different villages in West Bengal, India. An average residual chlorine concentration and removal efficiency of total coliform in the designed systems were determined as 0.3 ± 0.07 mg/L, and 98.4% ± 1.6%, respectively.

scholarly journals The Pathway towards Photoelectrocatalytic Water Disinfection: Review and Prospects of a Powerful Sustainable Tool

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 921
Author(s):  
Sergi Garcia-Segura ◽  
Omotayo A. Arotiba ◽  
Enric Brillas
Keyword(s):  
Synergistic Effects ◽  
Low Cost ◽  
Water Disinfection ◽  
Bacterial Inactivation ◽  
Sustainable Development Goal ◽  
E Coli ◽  
Light Delivery ◽  
System Requirements ◽  
Photo Electrode ◽  
Nanostructure Control

Photoelectrocatalysis is a hybrid photon/electron-driven process that benefits from the synergistic effects of both processes to enhance and stabilize the generation of disinfecting oxidants. Photoelectrocatalysis is an easy to operate technology that can be scaled-up or scaled-down for various water treatment applications as low-cost decentralized systems. This review article describes the fundamentals of photoelectrocatalysis, applied to water disinfection to ensure access to clean water for all as a sustainable development goal. Advances in reactor engineering design that integrate light-delivery and electrochemical system requirements are presented, with a description of photo-electrode material advances, including doping, nano-decoration, and nanostructure control. Disinfection and cell inactivation are described using different model microorganisms such as E. coli, Mycobacteria, Legionella, etc., as well the fungus Candida parapsilosis, with relevant figures of merit. The key advances in the elucidation of bacterial inactivation mechanisms by photoelectrocatalytic treatments are presented and knowledge gaps identified. Finally, prospects and further research needs are outlined, to define the pathway towards the future of photoelectrocatalytic disinfection technologies.

A novel low-cost multi-barrier system for drinking water treatment in rural and suburban areas

2019 ◽  
Vol 15 (1) ◽  
pp. 48-65 ◽  
Author(s):  
Stephen Siwila ◽  
Isobel C. Brink
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Granular Media ◽  
Low Cost ◽  
Water System ◽  
Drinking Water Treatment ◽  
Fecal Coliforms ◽  
E Coli ◽  
Suburban Areas ◽  
Novel Concept

Abstract A low-cost multi-barrier drinking water system incorporating geotextile fabric for pre-filtration, silver-coated ceramic granular media (SCCGM) for filtration and disinfection, granular activated carbon (GAC) as an adsorption media and a safe storage compartment for treated water has been developed and tested. The developed system offers a novel concept of point-of-use drinking water treatment in rural and suburban areas of developing countries. The system is primarily aimed at bacterial and aesthetic improvement and has been optimised to produce >99.99% E. coli and fecal coliforms removal. Although particular emphasis was placed on the elimination of bacteria, improvement of the acceptability aspects of water was also given high priority so that users are not motivated to use more appealing but potentially unsafe sources. This paper discusses key system features and contaminant removal performance. A system using SCCGM only was also tested alongside the multi-barrier system. Strengths and weaknesses of the system are also presented. Both the developed and SCCGM-only systems consistently provided >99.99% E. coli and fecal coliforms removal at an optimum flow of 2 L/h. The developed system significantly recorded improvements of aesthetic aspects (turbidity, color, taste and odor). Average turbidity removals were 99.2% and 90.2% by the multi-barrier and SCCGM-only systems respectively.

Synthesis, Characterization and Bactericide Properties of Al2O3 Nanoparticles and Al2O3-PAN Membranes for Alternative Water Disinfection Methods

MRS Advances ◽  
2017 ◽  
Vol 2 (30) ◽  
pp. 1605-1610 ◽  
Author(s):  
Abdiel Oquendo-Cruz ◽  
Ana Vega-Avila ◽  
Oscar Perales-Pérez
Keyword(s):  
Water Treatment ◽  
Water Disinfection ◽  
Diffusion Method ◽  
Al2o3 Nanoparticles ◽  
E Coli ◽  
Disinfection Methods ◽  
Removal Capacity ◽  
Bacterial Removal ◽  
Electrospun Membranes ◽  
Ft Ir

ABSTRACTAs the global populations grow, water demand and pollution of water resources will increase. As a consequence, water borne disease outbreaks are on the rise and current disinfection methods have been shown to be ineffective in inactivating all pathogens during water treatment. Aluminum oxide nanoparticles (Al2O3 NPs) have been shown to poses antimicrobial properties. Also, Al2O3 has high thermal and chemical stability, which makes these NPs an excellent candidate for water treatment applications. Thus, the objective of this work is to assess the bactericidal properties of Al2O3 NPs synthesized using a polyol-based process in presence of polyvinylpyrrolidone (PVP). For practical applications nanoparticles must be immobilized in a medium to ensure that particles are not dispersed into the treated water. For this reason, synthesized nanoparticles were dispersed in electrospun polyacrylonitrile (PAN) membranes to also evaluate the bacterial removal capacity. X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) analysis suggests that synthesized nanoparticles are γ-Al2O3 after annealing at 800°C for 6 hours. Scanning Electron Microscopy (SEM) characterization was used to determine the morphology and size of synthesized nanoparticles. Composite electrospun membranes were also characterized by XRD, FT-IR, and SEM. The bactericide activity of the synthesized γ-Al2O3 NPs and commercially available Al2O3 particles was evaluated by the disc diffusion method against E. coli bacteria. Also, Al2O3-PAN composite electrospun membranes bacterial filtration capacity was tested. Both synthesized and industrially produced particles exhibited antibacterial activity against E. coli, but polyol-based synthesized nanoparticles demonstrated better bactericide properties. The bacterial removal capacity of PAN and PAN/Al2O3 fibers was comparable to that of paper filters.

Antibacterial properties of Ag and Ag/AgCl nanoparticles from radish and tea extracts for water treatment applications

2015 ◽  
Vol 16 (1) ◽  
pp. 171-179
Author(s):  
Yuphada Boonto ◽  
Jirapat Ananpattarachai ◽  
Puangrat Kajitvichyanukul
Keyword(s):  
Antibacterial Activity ◽  
Water Treatment ◽  
Microwave Irradiation ◽  
Green Synthesis ◽  
Plant Extracts ◽  
Antibacterial Properties ◽  
Water Disinfection ◽  
E Coli ◽  
High Antibacterial Activity ◽  
Complete Inactivation

Silver nanoparticles (AgNPs) have antibacterial properties and are widely used for water disinfection. This technology is commercially applied in point-of-use water treatment as a post-treatment for filtrate water. However, the current process of synthesizing AgNPs has several disadvantages including the use of hazardous chemicals, consumption of a large amount of energy and the formation of hazardous byproducts. Here, we report an alternative and green synthesis using plant extracts. In this work, the plant extracts came from radish (R) and tea (T), and the AgNPs were derived from a microwave irradiation method. The AgNPs synthesized by chemical-based microwave irradiation (Ag-C) were also used as a control material. The novel method produced a smaller size of nanostructures with good dispersion ability and less agglomeration than those from chemical synthesis. The antibacterial properties of AgNPs on Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus) were investigated. The results revealed that AgNPs from both green synthesis and chemical-based methods inactivated both types of bacteria. The green-synthesized AgNPs from radish juice provided a higher percentage of inhibition of E. coli than that of S. aureus. The inactivation rates of the AgNPs increased with increasing concentration of AgNPs. As the concentration of the Ag/AgCl-R and Ag-R increased from 150 μg/mL to 300 μg/mL, complete inactivation required a reduced time for the reaction from 300 minutes to only 30 minutes. Finally, the Ag/AgCl-R and Ag-R offered high antibacterial activity while the Ag-T provided the lowest antibacterial activity. This work provides an alternative method for the eco-synthesis of antibacterial nanomaterials for water treatment.

scholarly journals Factors involved in sustained use of point-of-use water disinfection methods: a field study from Flores Island, Indonesia

2014 ◽  
Vol 12 (3) ◽  
pp. 573-583 ◽  
Author(s):  
E. Roma ◽  
T. Bond ◽  
P. Jeffrey
Keyword(s):  
Water Treatment ◽  
Low Cost ◽  
Qualitative Evaluation ◽  
Ease Of Use ◽  
Water Disinfection ◽  
Cross Sectional ◽  
Household Water Treatment ◽  
Implementation Phase ◽  
Point Of Use ◽  
Sustained Use

Many scientific studies have suggested that point-of-use water treatment can improve water quality and reduce the risk of infectious diseases. Despite the ease of use and relatively low cost of such methods, experience shows the potential benefits derived from provision of such systems depend on recipients' acceptance of the technology and its sustained use. To date, few contributions have addressed the problem of user experience in the post-implementation phase. This can diagnose challenges, which undermine system longevity and its sustained use. A qualitative evaluation of two household water treatment systems, solar disinfection (SODIS) and chlorine tablets (Aquatabs), in three villages was conducted by using a diagnostic tool focusing on technology performance and experience. Cross-sectional surveys and in-depth interviews were used to investigate perceptions of involved stakeholders (users, implementers and local government). Results prove that economic and functional factors were significant in using SODIS, whilst perceptions of economic, taste and odour components were important in Aquatabs use. Conclusions relate to closing the gap between factors that technology implementers and users perceive as key to the sustained deployment of point-of-use disinfection technologies.

scholarly journals Photocatalytic water disinfection by simple and low-cost monolithic and heterojunction ceramic wafers

2015 ◽  
Vol 14 (6) ◽  
pp. 1190-1196 ◽  
Author(s):  
Neel M. Makwana ◽  
Rachael Hazael ◽  
Paul F. McMillan ◽  
Jawwad A. Darr
Keyword(s):  
Low Cost ◽  
Water Disinfection ◽  
Bacterial Inactivation ◽  
Charged Species

Ceramic wafers prepared by a simple, low-cost method, are investigated for photocatalytic water disinfection. Heterojunction wafers were able to sustain the formation of charged species responsible for bacterial inactivation.

Bacterial inactivation by a carbon nanotube–iron oxide nanocomposite: a mechanistic study usingE. colimutants

2018 ◽  
Vol 5 (2) ◽  
pp. 372-380 ◽  
Author(s):  
Maya Engel ◽  
Yitzhak Hadar ◽  
Shimshon Belkin ◽  
Xinglin Lu ◽  
Menachem Elimelech ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Iron Oxide ◽  
Mechanistic Study ◽  
Bacterial Inactivation ◽  
E Coli

Inactivation ofE. coliby the carbon nanotube–iron oxide nanocomposite.

scholarly journals Evaluation of an alternative household water treatment system based on slow filtration and solar disinfection

2021 ◽  
Author(s):  
Guilherme Otávio Rosa e Silva ◽  
Helen Oliveira Loureiro ◽  
Laura Guimarães Soares ◽  
Laura Hamdan de Andrade ◽  
Rana Gabriela Lacerda Santos
Keyword(s):  
Water Treatment ◽  
Water Disinfection ◽  
Treatment System ◽  
Household Water Treatment ◽  
Water Treatment System ◽  
Total Coliforms ◽  
Solar Disinfection ◽  
E Coli ◽  
Solar Water Disinfection ◽  
Slow Filtration

Abstract Drinking water consumption is essential to maintain a good quality of life, but it is not available for all communities. Therefore, this work aimed to develop an alternative and accessible process for water treatment, based on filtration and solar disinfection, and evaluate it in both bench and pilot scales. The construction cost of the system was estimated and compared with other available options so that its economic viability could be discussed. For this purpose, water from a stream was collected and analyzed. A filter made of PVC tubes, sand, and gravel was built, acting, respectively, as a column, filtering medium, and support layer. As for the disinfection process, the SODIS (Solar Water Disinfection) methodology was adopted. The water was exposed to the sun, and the best exposure time was determined based on the analysis of total coliforms and E. coli. Finally, a prototype was built for a flow rate of 37.5 L d−1, consisting of two filters operating at a filtration rate of 2.38 m3 m−2 d−1. About 97% turbidity removal was obtained, as well as 99.9% for total coliforms and 99.1% for E. coli. It is estimated that the cost of building a water treatment system for one person is approximately USD 29.00.

A Comparison of Solar Photocatalytic Inactivation of Waterborne E. coli Using Tris (2,2′-bipyridine)ruthenium(II), Rose Bengal, and TiO2

2005 ◽  
Vol 129 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Julián A. Rengifo-Herrera ◽  
Janeth Sanabria ◽  
Fiderman Machuca ◽  
Carlos F. Dierolf ◽  
Cesar Pulgarin ◽  
...  
Keyword(s):  
Water Treatment ◽  
Rose Bengal ◽  
Water Soluble ◽  
Water Disinfection ◽  
Ros Generation ◽  
Mutagenic Potential ◽  
Illumination Time ◽  
E Coli ◽  
Chemical Structures ◽  
Bacteria Inactivation

Background. The development of alternative processes to eliminate pathogenic agents in water is a matter of growing interest. Current drinking water disinfection procedures, such as chlorination and ozonation, can generate disinfection by-products with carcinogenic and mutagenic potential and are not readily applicable in isolated rural communities of less-favored countries. Solar disinfection processes are of particular interest to water treatment in sunny regions of the Earth. Solar light may be used to activate a photocatalyst or photosensitizer that generates, in the presence of molecular oxygen dissolved in water, reactive oxygen species (ROS), such as the HO• radical, singlet oxygen (O21), or superoxide (O2•), which are toxic to waterborne microorganisms. Method of Approach. Wild and collection-type Escherichia coli have been selected as model bacteria. Inactivation of such bacteria by either TiO2 nanoparticles, water-soluble tris(2,2′-bipyridine)ruthenium(II) dichloride or Rose bengal (RB) subject to simulated sunlight have been compared. Although TiO2 is the prototypical material for heterogeneous photocatalysis, the other two dyes are known to generate significant amounts of O21 by photosensitization but have different chemical structures. The concentration of dye, illumination time, photostability, presence of scavengers, and post-treatment regrowth of bacteria have been investigated. Results. After 1hr of solar illumination the Ru(II) complex produced a strong loss of E. coli culturability monitored with solid selective agars. Both the collection- and wild-type bacteria are sensitive to the treatment with 2-10mgL−1 of dye. This photosensitizer showed a better inactivation effect than TiO2 and the anionic organic dye RB due to a combination of visible light absorption, photostability, and production of O21 and other ROS when bound to the bacterial membrane. A complete loss of culturability was observed when the initial concentration was 103CFUmL−1, with no bacteria regrowth detected after 24hr of the water treatment. At higher initial microorganism levels, culturability still remains and regrowth is observed. Scavengers show that the HO• radical is not involved in bacteria inactivation by photosensitization. Conclusions. A higher quantum yield of ROS generation by the sensitizing dyes compared to the semiconductor photocatalyst determines the faster sunlight-activated water disinfection of photodynamic processes. The homogeneous nature of the latter determines a more efficient interaction of the toxic intermediates with the target microorganisms. Solid supporting of the Ru(II) dye is expected to eliminate the potentials problems associated to the water-soluble dye.

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