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Low-cost, local production of a safe and effective disinfectant for resource-constrained communities

Cite this dataset

Naranjo-Soledad, Andrea et al. (2024). Low-cost, local production of a safe and effective disinfectant for resource-constrained communities [Dataset]. Dryad. https://doi.org/10.5061/dryad.2547d7wz5

Abstract

Improved hygiene depends on the accessibility and availability of effective disinfectant solutions. These disinfectant solutions are unavailable to many communities worldwide due to resource limitations, among other constraints. Safe and effective chlorine-based disinfectants can be produced via simple electrolysis of salt water, providing a low-cost and reliable option for on-site, local production of disinfectant solutions to improve sanitation and hygiene. This study reports on a system (herein called “Electro-Clean”) that can produce concentrated solutions of hypochlorous acid (HOCl) using readily available, low-cost materials. With just table salt, water, graphite welding rods, and a DC power supply, the Electro-Clean system can safely produce HOCl solutions (~1.5 liters) of up to 0.1% free chlorine (i.e.,1000 ppm) in less than two hours at low potential (5 V DC) and modest current (~5 A). Rigorous testing of free chlorine production and durability of the Electro-Clean system components, described here, has been verified to work in multiple locations around the world, including microbiological tests conducted in India and Mexico to confirm the biocidal efficacy of the Electro-Clean solution as a surface disinfectant. Cost estimates are provided for making HOCl locally with this method in the USA, India, and Mexico. Findings indicate that Electro-Clean is an affordable alternative to off-the-shelf commercial chlorinator systems in terms of first costs (or capital costs), and cost-competitive relative to the unit cost of the disinfectant produced. By minimizing dependence on supply chains and allowing for local production, the Electro-Clean system has the potential to improve public health by addressing the need for disinfectant solutions in resource-constrained communities.

README: Low-cost, local production of a safe and effective disinfectant for resource-constrained communities

https://doi.org/10.5061/dryad.2547d7wz5

The files below contain the raw data for each figure and table present in the manuscript titled "Low-cost, local production of a safe and effective disinfectant for resource-constrained communities" and supporting information. Experimental methods and instruments used for data collection are described in the main manuscript.

Description of the data and file structure

All files are in Excel. Below are the descriptions of each file: 

Chlorine production by carbon electrodes in batch process.

This file contains the raw data of batch experiments with a volume of 1.35 L. Three trials are reported here. The current, in amps, was recorded at various electrolysis times. Other measurements include the measured Free Chlorine concentration in parts per million (ppm), and pH after electrolysis. 

Figure 5 & S4 Appendix. Long-term Experiments.

This file contains the raw data of the long-term experiments presented on Fig5 in the main manuscript and S4 Appendix. Three trials were conducted and reported. The tab named "Bare carbon rods" contains the raw data of the long-term experiments of the welding carbon electrodes without any coating, and the tab named "Baby oil-soaked carbon rods" contains the raw data of the long-term experiments of the welding carbon electrodes that were soaked in baby oil. In the raw data, the following data was recorded: 

Sampling time: Time at which the sample was taken

Electroclean time (min): Electrolysis time that has elapsed from last sampling time until current sampling time

Cumulative Electroclean time (min): Cumulative electrolysis time

Flowrate (mL/min): Flowrate of the electrolyte 

Volume (L): Volume of the reactor

Residence time (min): Volume of the reactor divided by flowrate

[NaCl] ppm: Salt concentration in the electrolyte

Voltage (V): Set voltage of the power supply

Current (A): Measured current

Coulombs: Current times electroclean time (in seconds)

Cumulative Coulombs: Current times cumulative electroclean time (in seconds)

Expected Chlorine Concentration (mg/L): Theoretical Chlorine concentration based on Faraday's law

Measured Chlorine Concentration (mg/L): Measured chlorine concentration of diluted sample 

Dilution Factor: dilution factor used when measuring the sample

Measured Chlorine Concentration (mg/L): Previous measured concentration times the dilution factor

Faradaic Efficiency (%): Measured chlorine concentration divided by theoretical chlorine concentration, times 100

Figure 6 - electrode disintegration

This file contains the raw data of Fig6 present in the main manuscript. Eight batch experiments with 1.75 liters of electrolyte are included in this file. Values for the initial pH, final pH, Turbidity (NTU) after electrolysis before filtering and after filtering, and free chlorine measurements before and after filtering were documented in this file. Additionally, the current at the anode and cathode at various electrolysis times were measured and documented here as well. 

Figure 7 - free chlorine decay

This file contains the raw data of the free chlorine decay experiments presented in Fig7 in the main manuscript. Three trials were conducted and reported here. The initial pH, and free chlorine concentration (mg/L) overtime were documented in this file. 

Table 1 and Table 2 - Effect of electrolyte pH on free chlorine production

This file contains the raw data of the experiments conducted to examine the effect of pH adjustment before and after electrolyis on the production of free chlorine. This data was presented in Table 1 and Table 2 in the main manuscript. Three replicates were performed and reported here. Current, in amps, was recorded and reported here at various electrolysis times. pH values before and after electrolysis, and before and after pH adjustment (when applicable) were also recorded. Other values included in this file include the electrolyte volume and the measured free clorine concentration. 

Table 3 - Reproducibility in other communities worldwide

This file contains the raw data of the results presented in Table 3 in the main manuscript. The raw data of each community was documented in their respective tab. Reported values include current (A) at various electrolysis times, electrolyte volume, estimated free chlorine concentration (mg/L) based on Faraday's law, measured free chlorine concentrations (mg/L), pH after electrolysis, volume of vinegar used to lower pH (mL), and the pH after adding vinegar. 

Table 4, Table 5, and Table 6 - Cost estimates

This file contains the raw data of the results presented in Tables 4, 5, and 6 in the main manuscript. Inputs, capital cost and operating cost estimates, and price points of different materials are listed in this file. 

S2 Appendix. Fig A

This file contains the raw data of the results presented in Fig A in the S2 Appendix. Only one trial was performed. The free chlorine concentration (mg/L) was measured over 67 days in varying container conditions. The initial pH was also recorded

S2 Appendix. Table A

This file contains the raw data of the results presented in Table A in the S2 Apprendix. Only one trial was performed. The free chlorine concentration (mg/L) was measured over 34 days in varying container conditions. The initial pH and final pH at the 34-day mark were recorded and reported here. 

S3 Appendix. Fig A

This file contains the raw data of the results presented in FigA in the S3 Appendix. Only two replicates were performed and reported here. The electrolyte volume (L), electrolysis time (min), average current (A), expected free chlorine (mg/L) based on Faraday's law, measured free chlorine (mg/L), Faradaic efficiency (%), and the number of Coulombs ( Coulombs = amps*electrolysis time in seconds) are reported here. 

S3 Appendix. Fig D

This file contains the raw data of the results presented in Fig D in the S3 Appendix. The number of electrolysis cycles (the batch number), the electrolyte volume (L), the electrolysis time (min), the average current (A), the expected free chlorine concentration (mg/L) based on Faraday's law, the measured free chlorine concentration (mg/L) and Faradaic Efficiency (%) are reported here. 

S3 Appendix. Fig F

This file contains the raw data of the results presented in Fig F in the S3 Appendix. The experiment configuration is explained for each set at the top of the data. The electrolyte volume (L), the electrolysis time (min), the average current (A), the expected free chlorine concentration (mg/L) based on Faraday's law, the measured free chlorine concentration (mg/L) and Faradaic Efficiency (%) are reported here for each experiment. 

S3 Appendix. Fig G

This file contains the raw data of the results presented in Fig G in the S3 Appendix. The tab named "Carbon-carbon" has the raw data for the experiments with both carbon electrodes. The tab named "Carbon-Copper" has the raw data for the experiments with the carbon anode, and copper-coated cathode. Measurements included here are initial and final pH, initial and final conductivity (mS/cm), turbidity (NTU) after electrolysis, measured free chlorine concentration (ppm), and average current throughout electrolysis. 

S3 Appendix. Fig H

This file contains the raw data of the results presented in Fig H in the S3 Appendix. Three trials were performed and reported here. Each trial was documented in its respective tab.  The electrolysis time (min), current (A), expected free chlorine (mg/L) based on Faraday's law, measured free chlorine (mg/L), Faradaic efficiency (%), the number of Coulombs ( Coulombs = amps*electrolysis time in seconds), and pH at the end of the electrolysis are reported here. 

S5 Appendix. Tables A, B and C

This file contains the raw data of the results presented in Tables A, B, and C in the S5 Appendix. The trial numbers are specified for each experiment. Values reported in this file include the counts of colony forming units (CFU) per mL. 

Sharing/Access information

Links to other publicly accessible locations of the data:

Methods

We conducted chemical experiments in a laboratory setting, performing each experiment in triplicate unless otherwise specified. The dataset presented here includes the raw data from these experiments. We used Excel to record the data and calculate the average and standard deviation. The file names correspond to the figures or tables in the manuscript or the Supporting Information Appendices. Detailed descriptions of the experimental methods can be found in the main manuscript.