Crumpled graphene oxide decorated SnO2 nanocolumns for the electrochemical detection of free chlorine

Thiagarajan Soundappan,Kelsey Haddad,Ramesh Raliya,Pratim Biswas,Shalinee Kavadiya

doi:10.1007/s13204-017-0603-x

Thiagarajan Soundappan, Kelsey Haddad + Show 3 more

Open Access

https://doi.org/10.1007/s13204-017-0603-x

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Abstract

A crumpled graphene oxide–SnO2 nanocolumn (CGO–SnO2) composite electrode was fabricated using aerosol-based techniques. First, SnO2 nanocolumn thin films were fabricated using an aerosol chemical vapor deposition (ACVD) technique. The surface of the nanocolumn was then decorated with CGO by electrospray deposition. The CGO–SnO2 electrode was utilized for the electrochemical detection and determination of the free chlorine concentration in aqueous solutions using linear sweep voltammetry (LSV) and amperometric i–t curve techniques. The CGO–SnO2 electrodes worked through the direct electrochemical reduction of hypochlorite ions (ClO−) on the surface of the electrode, which was used to determine the free chlorine concentration. The electrodes operate over a wide linear range of 0.1–10.08 ppm, with a sensitivity of 2.69 µA µM−1 cm−2. Further, selectivity studies showed that these electrodes easily conquer the electrochemical signals of other common ions in drinking water distribution systems, and only shows the electrochemical reduction signals of free chlorine. Finally, the CGO–SnO2 electrodes were successfully employed for the detection of free chlorine in tap water solutions (St. Louis, MO 63130, USA) with a sensitivity of 5.86 µA µM−1 cm−2. Overall, the sensor fabricated using simple and scalable aerosol-based techniques showed a comparable performance to previous studies on amperometric chlorine sensing using carbon-based electrodes.

Highlights

The quality of drinking water has to be monitored continuously to avoid waterborne diseases including cholera, diarrhea, and typhoid fever in many developing nations
The crumpled graphene oxide (CGO)–SnO2 electrodes were successfully employed for the detection of free chlorine in tap water solutions
We have demonstrated the electrode performance for the detection of free chlorine using linear sweep voltammetry (LSV) and amperometric techniques in neutral pH conditions and in real water resources

Summary

Introduction

The quality of drinking water has to be monitored continuously to avoid waterborne diseases including cholera, diarrhea, and typhoid fever in many developing nations. Chlorine is the most commonly used disinfectant for the treatment of various water resources including drinking water, waste water, and swimming pools. The environmental protection agency (EPA) requires water supply utilities to maintain a residual disinfectant concentration throughout the distribution system to inhibit microbial re-contamination of treated drinking water. Excess chlorine residuals can interact with organic matter to form disinfection by-products (DBPs). These DBPs are toxic and pose a threat to the health of consumers. The EPA has established maximum contaminant levels (MCLs) for DBPs, which apply to both large community water systems and non-transient, noncommunity water systems that add disinfectant. Small communities are vulnerable to compliance failures with regulatory standards for DBPs, which can be largely attributed to the limited resources available for monitoring (Sinha et al 2006; Hall et al 2007)

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