Biofouling and in situ electrochemical cleaning of a boron-doped diamond free chlorine sensor

Abstract

Biofouling presents a significant obstacle to the long-term use of electrochemical sensors in complex media. Drinking water biofilms reduce performance of sensors by insulating electrode surfaces by inter alia inhibiting mass transport. Boron-doped diamond (BDD) electrodes are relatively resistant to biofouling and inert at high potentials. These qualities can be exploited to create a drinking water quality sensor that resists biofouling to meet performance criteria for longer, and to enable electrochemical cleaning of the sensor surface in situ using high potentials without disconnecting or disassembling the sensor. A purpose-built BDD wall-jet sensor was compared with a glassy carbon (GC) sensor in ability to determine free chlorine, detect biofilm and remove biofilm in situ. It was found that the BDD produced accurate and reliable readings with a 4.86% standard error and a LOD of 0.18 ppm. The BDD could be electrochemically cleaned in situ whereas this was less successful with the GC electrode. The BDD electrode could also detect electroactive pyocyanin, secreted in the biofilm of the drinking water biofilm indicator organism Pseudomonas aeruginosa, potentially enabling biofouling and non-biological fouling such as scaling to be distinguished. Observed changes in flow sensitivity and current-voltage curves that correspond to fouling provide multiple fouling detection methods, resulting in an accurate, sensitive, water quality sensor that can be cleaned without disassembly or replacement of parts and can identify when cleaning is required

Environmental Applications of Boron‐Doped Diamond Electrodes: 2. Soil Remediation and Sensing Applications

“…Wilson et al . compared the performance of BDD wall‐jet sensor to detect free chlorine and biofilm; and to remove biofilm in‐situ with a glassy carbon sensor.…”

“…The 4-chlorophenol electrooxidation at BDD has also been shown to be advantageous by the use of power ultrasound during electrochemical degradation, offering further wastewater treatment applications of this dual technology. [102,103] Wilson et al [104] compared the performance of BDD wall-jet sensor to detect free chlorine and biofilm; and to remove biofilm in-situ with a glassy carbon sensor. Compared with glassy carbon electrode, BDD produced accurate and reliable results.…”

A Zero‐Power Optical, ppt‐ to ppm‐Level Toxic Gas and Vapor Sensor with Image, Text, and Analytical Capabilities

“…[10] Some gas sensors in the market are designed as badges and are potentially analytically accumulative but require the observer to distinguish color and color intensities. [11,12] To alleviate the potential drawbacks of current wearable sensors requiring battery power (based, for example, on metal oxide semiconductors, [13][14][15][16][17] electrochemical, [18][19][20][21][22][23][24] infrared, [25][26][27] photoionization detectors, [28,29] lasers, [30][31][32] among others) or recognizing a colorimetric read-out, a next generation sensor platform should not require either. One or some forms of color vision deficiency (color blindness) affects about one in twelve men (> 8%) and one in 200 women, [33,34] and men are the majority among emergency responders, military personnel, and firefighters.…”

Detection of Chlorine in a Non-aqueous Solution via Anodic Oxidation and a Photochemical Reaction

“…21 In water, the chlorine molecule transforms to oxo acid by hydrolysis. 22,23 In contrast, the non-polar chlorine molecule is polarized in a polar solvent, and forms a solvation cluster due to weak interactions with the solvent. 24,25 For example, it is possible to coordinate a polarized chlorine molecule to a solvent molecule using a polar aprotic solvent.…”