Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

scholarly journals Electrochemical Detection of Free-Chlorine in Water Samples Facilitated by In-Situ pH Control Using Interdigitated Microelectrodes

2020 ◽  
Author(s):  
Alan O'Riordan ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Ian Seymour ◽  
James Rohan
Keyword(s):  
Water Samples ◽  
Hypochlorous Acid ◽  
Control Method ◽  
Tap Water ◽  
Distribution Networks ◽  
Ph Control ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
Solution Ph

Residual free-chlorine concentration in water supplies is a key metric studied to ensure disinfection. High residual chlorine concentrations lead to unpleasant odours and tastes, while low concentrations may lead to inadequate disinfection. The concentration is most commonly monitored using colorimetric techniques which require additional reagents. Electrochemical analysis offers the possibility for in-line analysis without the need for additional reagents. Electrochemical-based detection of chlorine is influenced by the solution pH, which defines the particular chlorine ionic species present in solution. As such, controlling the pH is essential to enable electrochemical based detection of residual chlorine in water. To this end, we explore the application of solid state interdigitated electrodes to tailor the in-situ pH of a solution while simultaneously detecting free-chlorine. Finite element simulations and subsequent electrochemical characterization, using gold interdigitated microelectrode arrays, were employed to explore the feasibility of an in-situ pH control approach. In practice, the approach converted residual chlorine from an initial mixture of two species (hypochlorous acid and hypochlorite ion), to one species (hypochlorous acid). Chlorine detection was shown in water samples using this exploratory method, resulting in a two-fold increase in signal response, compared to measurements without pH control. Finally, tap water samples were measured using the in-situ pH control method and the results showed excellent correlation (within experimental error) with a commercial instrument, demonstrating the efficacy of the developed technique. This work establishes the possibility of deploying an electrochemical based reagent-free, in-line chlorine sensor required for water distribution networks.

scholarly journals Electrochemical detection of free-chlorine in Water samples facilitated by in-situ pH control using interdigitated microelectrodes

2020 ◽  
Vol 325 ◽  
pp. 128774 ◽  
Author(s):  
Ian Seymour ◽  
Benjamin O’Sullivan ◽  
Pierre Lovera ◽  
James F. Rohan ◽  
Alan O’Riordan
Keyword(s):  
Electrochemical Detection ◽  
Water Samples ◽  
Ph Control ◽  
Free Chlorine ◽  
Interdigitated Microelectrodes

Sensory aspects of drinking water in contact with epoxy lined copper pipe

2007 ◽  
Vol 55 (5) ◽  
pp. 161-168 ◽  
Author(s):  
T.H. Heim ◽  
A.M. Dietrich
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Compounds ◽  
Sensory Analysis ◽  
Water Samples ◽  
Distribution System ◽  
Distribution Systems ◽  
Free Chlorine ◽  
Copper Pipe

Pipe relining via in situ epoxy lining is used to remediate corroded plumbing or distribution systems. This investigation examined the effects on odour, TOC, THM formation and disinfectant demand in water exposed to epoxy-lined copper pipes used for home plumbing. The study was conducted in accordance with the Utility Quick Test, a migration/leaching method for utilities to conduct sensory analysis of materials in contact with drinking water. The test was performed using water with no disinfectant and levels of chlorine and monochloramines representative of those found in the distribution system. Panelists repeatedly and consistently described a “plastic/adhesive/putty” odour in the water from the pipes. The odour intensity remained relatively constant for each of two subsequent flushes. Water samples stored in the epoxy-lined pipes showed a significant increase in the leaching of organic compounds (as TOC), and this TOC was demonstrated to react with free chlorine to form trichloromethane. Water stored in the pipes also showed a marked increase in disinfectant demand relative to the water stored in glass control flasks. A study conducted at a full scale installation at an apartment demonstrated that after installation and regular use, the epoxy lining did not yield detectable differences in water quality.

scholarly journals A Theoretical and Experimental Study of Electrochemical pH Control at Gold Interdigitated Microband Arrays

2021 ◽  
Author(s):  
Bernardo Patella ◽  
Robert Daly ◽  
Ian Seymour ◽  
Pierre Lovera ◽  
James Rohan ◽  
...  
Keyword(s):  
Electrode Array ◽  
Ph Control ◽  
Reduction Peak ◽  
Solution Ph ◽  
Ph Indicator ◽  
Ph Change ◽  
Initial Ph ◽  
The Impact ◽  
Strong Acids

In electroanalysis, solution pH is a critical parameter that often needs to be adjusted and controlled for the detection of particular analytes. This is most commonly performed by the addition of chemicals, such as strong acids or bases. Electrochemical in-situ pH control offers the possibility for the local adjustment of pH at the point of detection, without additional reagents. FEA simulations have been performed to guide experimental design for both electroanalysis and in-situ control of solution pH. No previous model exists that describes the generation of protons at an interdigitated electrode array in buffered solution with one comb acting as a protonator, and the other as the sensor. In this work, FEA models are developed to provide insight into the optimum conditions necessary for electrochemical pH control. The magnitude of applied galvanostatic current has a direct relation to the flux of protons generated and subsequent change in pH. Increasing the separation between the electrodes increases the time taken for protons to diffuse across the gap. The final pH achieved at both, protonators and sensor electrodes, after 1 second, was shown to be largely uninfluenced by the initial pH of the solution. The impact of buffer concentration was modelled and investigated. In practice, the pH at the electrode surface was probed by means of cyclic voltammetry, i.e., by cycling a gold electrode in solution and identifying the potential of the gold oxide reduction peak. A pH indicator, methyl red, was used to visualise the solution pH change at the electrodes, comparing well with the model’s prediction

scholarly journals Behavioural Toxicology of Midge Larvae Chironomous sp. after Acute In Situ Exposure of Different Industrial Effluents and Drinking Water

2014 ◽  
Vol 19 ◽  
pp. 11-20
Author(s):  
Debika Bhunia ◽  
Subhodeep Sarkar ◽  
Kushal Banerjee ◽  
Abantika Nandy ◽  
Soumendra Nath Talapatra
Keyword(s):  
Drinking Water ◽  
Water Sample ◽  
Water Samples ◽  
Tap Water ◽  
Industrial Effluent ◽  
Lead Acid Battery ◽  
Behavioral Activities ◽  
Behavioural Toxicology ◽  
Lead Acid

Behavioural activities in relation to toxicological aspects involve behavioural changes of aquatic organisms under the exposure of a contaminant. The present study aims to know behavioural activities of midge larvae Chironomus sp. at the in-situ acute exposure of different chemicals containing wastewater viz. lead-acid battery industrial effluent, mixed industrial effluent and fresh tap water (chlorinated) as drinking water in comparison to control (dechlorinated) water sample (aged tap water). The Chironomus larvae were kept in three different experimental chambers (perforated wall test vessels) with the exposure of different water samples. These samples were made with no dilution, 50 % dilution, 2.5 % dilution and control water sample. The behavioral activities for larvae of Chironomus sp. were measured at 0h, 2h, 24h and 48 h in in-situ condition. The behavioral activities viz. crawling, looping, ventilation, paralyses and subsequently death of the larvae were recorded in the field condition. A significant differences (P < 0.05, P < 0.01 and P< 0.001) were observed with increasing time of exposure while in few cases the data were increased without significance level. It was recorded that after exhibiting behavioural activities viz. crawling, looping, ventilation and paralyses finally all species were died 100 % of the population in lead acid battery effluent following both 24h and 48hr exposure. In addition, death of larvae were 70 % in mixed industrial effluent and 50 % in fresh tap water (chlorinated) after 48h exposure as compared to control sample water. In conclusion, the present results indicate that the larvae of Chironomous sp. are suitable indicators in the evaluation of the effluent quality in the studied stream, potential to know by behavioural toxicological study for heavy metals and organic pollution. Although it is a preliminary observation by assessing behavioural toxicology but future study in relation to biochemical and genetic damage of Chironomous larvae with the exposure of toxic water samples will provide bigger view.

scholarly journals Reagent Free Electrochemical-Based Detection of Silver Ions at Interdigitated Micro Electrodes Using in Situ pH Control

2020 ◽  
Author(s):  
Luiza Adela Wasiewska ◽  
Ian Seymour ◽  
Bernardo Patella ◽  
Catherine Burgess ◽  
Geraldine Duffy ◽  
...  
Keyword(s):  
Drinking Water ◽  
Tap Water ◽  
Linear Sweep Voltammetry ◽  
Silver Ions ◽  
Ph Control ◽  
Consumer Products ◽  
Electrode Arrays ◽  
Linear Calibration ◽  
Control Approach

<p>Silver ions, the most toxic form of silver, can be present in drinking water due to their release from silver nanoparticles which are widely used in consumer products. Due to their adverse health effects, a quick portable approach for detection in drinking water is needed. Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using linear sweep voltammetry with in situ pH control; enabled by closely space interdigitated electrode arrays. The in situ pH control approach, allows the pH of a test solution to be tailored to pH 3 thereby eliminating the current need for acid addition. A calibration curve between 0.2 - 10 µM was established for silver detection in sodium acetate when 1.25 V and 1.65 V was applied at the protonator electrode during deposition and stripping, respectively, as a proof of concept study. For the final application in tap water, 1.65 V was applied at the protonator electrode during deposition and stripping. The chlorine ions, present in tap water as a consequence of the disinfection process, facilitated the silver detection and no additional electrolyte had to be added. Combination of complexation of silver ions with chlorine coupled with in situ pH control resulted in linear calibration range between 0.25 and 2 µM in tap water without the need for acidification.</p>

scholarly journals Reagent Free Electrochemical-Based Detection of Silver Ions at Interdigitated Micro Electrodes Using in Situ pH Control

2020 ◽  
Author(s):  
Luiza Adela Wasiewska ◽  
Ian Seymour ◽  
Bernardo Patella ◽  
Catherine Burgess ◽  
Geraldine Duffy ◽  
...  
Keyword(s):  
Drinking Water ◽  
Tap Water ◽  
Linear Sweep Voltammetry ◽  
Silver Ions ◽  
Ph Control ◽  
Consumer Products ◽  
Electrode Arrays ◽  
Linear Calibration ◽  
Control Approach

<p>Silver ions, the most toxic form of silver, can be present in drinking water due to their release from silver nanoparticles which are widely used in consumer products. Due to their adverse health effects, a quick portable approach for detection in drinking water is needed. Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using linear sweep voltammetry with in situ pH control; enabled by closely space interdigitated electrode arrays. The in situ pH control approach, allows the pH of a test solution to be tailored to pH 3 thereby eliminating the current need for acid addition. A calibration curve between 0.2 - 10 µM was established for silver detection in sodium acetate when 1.25 V and 1.65 V was applied at the protonator electrode during deposition and stripping, respectively, as a proof of concept study. For the final application in tap water, 1.65 V was applied at the protonator electrode during deposition and stripping. The chlorine ions, present in tap water as a consequence of the disinfection process, facilitated the silver detection and no additional electrolyte had to be added. Combination of complexation of silver ions with chlorine coupled with in situ pH control resulted in linear calibration range between 0.25 and 2 µM in tap water without the need for acidification.</p>

scholarly journals The efficacy of chlorine-based disinfectants against planktonic and biofilm bacteria for decentralised point-of-use drinking water

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Gillian E. Clayton ◽  
Robin M. S. Thorn ◽  
Darren M. Reynolds
Keyword(s):  
Antimicrobial Activity ◽  
Drinking Water ◽  
Hypochlorous Acid ◽  
Drinking Water Treatment ◽  
Distribution Networks ◽  
Free Chlorine ◽  
Biofilm Reactor ◽  
E Coli ◽  
Point Of Use ◽  
Biofilm Bacteria

AbstractChlorine solutions are used extensively for the production of biologically safe drinking water. The capability of point-of-use [POU] drinking water treatment systems has gained interest in locations where centralised treatment systems and distribution networks are not practical. This study investigated the antimicrobial and anti-biofilm activity of three chlorine-based disinfectants (hypochlorite ions [OCl-], hypochlorous acid [HOCl] and electrochemically activated solutions [ECAS]) for use in POU drinking water applications. The relative antimicrobial activity was compared within bactericidal suspension assays (BS EN 1040 and BS EN 1276) using Escherichia coli. The anti-biofilm activity was compared utilising established sessile Pseudomonas aeruginosa within a Centre for Disease Control [CDC] biofilm reactor. HOCl exhibited the greatest antimicrobial activity against planktonic E. coli at >50 mg L−1 free chlorine, in the presence of organic loading (bovine serum albumen). However, ECAS exhibited significantly greater anti-biofilm activity compared to OCl- and HOCl against P. aeruginosa biofilms at ≥50 mg L−1 free chlorine. Based on this evidence disinfectants where HOCl is the dominant chlorine species (HOCl and ECAS) would be appropriate alternative chlorine-based disinfectants for POU drinking water applications.

scholarly journals Reduction of trihalomethane formation and detoxification of microcystins in tap water by ozonation

2008 ◽  
Vol 6 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Orapin Thapsingkaew ◽  
Vilailuck Kijjanapanich ◽  
Werawan Ruangyuttikarn
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Tap Water ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Residual Chlorine ◽  
Treated Water ◽  
Guideline Value ◽  
Phosphatase 2A ◽  
The Mean

The efficiency of ozonation in comparison to chlorination for removal of microcystins and production of trihalomethanes (THMs) in water was investigated. One hundred and ninety water samples of ozone and chlorine treated water were collected at a water treatment plant between August 2004 and March 2005. The level of THMs, total organic carbon and residual chlorine were determined. Protein phosphatase 2A inhibition assay was used to detect microcystins and the presence of microcystins was confirmed by HPLC. The results show that 91.5% of the THM species in treated water was chloroform and 8.5% was bromodichloromethane. The mean THM level± standard error of mean in chlorinated water (CW) (45.1±3.0 μg/L) was higher than the mean of THM level in ozonated water (OW) (18.6±2.2 μg/L). In addition, no OW sample exceeded the first stage U.S. EPA maximum THM contaminant level for drinking water (80 μg/L) and only 8% of these samples exceeded the second stage level (40 μg/L). On the other hand, 3% of CW samples exceeded 80 μg/L and 68% exceeded the 40 μg/L level. The microcystin level in all water samples was below the WHO guideline value (1 μg/L) for drinking water.

scholarly journals Elimination of Oxygen Interference in the Electrochemical Detection of Monochloramine, Using In-Situ pH Control at Interdigitated Electrodes

2020 ◽  
Author(s):  
Ian Seymour ◽  
Benjamin O'sullivan ◽  
Pierre Lovera ◽  
Alan O'Riordan ◽  
James Rohan
Keyword(s):  
Control Method ◽  
Primary Source ◽  
Ph Control ◽  
Water Systems ◽  
Potential Sweep ◽  
Sensor Development ◽  
Concentration Potential ◽  
Copper Phosphate ◽  
High Alkalinity

Disinfection by chloramination of water systems is an alternative to chlorination that is frequently used in North America. In such a case, monochloramine is used as the primary source of chlorine for disinfection. Regular monitoring of the residual concentrations of this species is crucial to ensure adequate disinfection. An amperometric sensor for monochloramine would provide fast, reagent free analysis, however the presence of dissolved oxygen in water complicates sensor development. In this work, we have explored the use of in-situ pH control as a method of eliminating oxygen as an interferent by conversion of monochloramine to dichloramine. The electrochemical reduction of dichloramine occurs outside the oxygen reduction window and is therefore not affected by oxygen concentration. Potential sweep methods were used to investigate the conversion of monochloramine to dichloramine at pH 3. The pH control method was used to calibrate monochloramine concentrations between 1 and 10 ppm, with a detection limit of 0.03 ppm. Tests were carried out in high alkalinity samples, wherein it was found that the sensitivity of this method effectively remained unchanged. Monochloramine was also quantified in the presence of common interferents (copper, phosphate and iron) which had no significant impact on the analysis

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