EDGE Outreach Chlorine Generator Lonna Edwards (ECE), Zachary Russo (ECE), Ryan Shamel (ECE) Mark Hogg, Executive Director; Bob Browning, Field Operations; 1500 Arlington Avenue; Louisville, KY 40206

Water Purification Humble beginnings in Africa John Snow links cholera to water contamination in 1800’s Louis Pasteur discovers the ‘germ’ in the late 1800’s Water purification for the masses in London, Chicago, and New Jersey Membrane cells become common use for chlorine generation and sodium hydroxide production

Frightening Statistics

“More children die from bad water than war”

Chlorine Generator Cell Operation Theory Uses electrolysis to decompose a brine solution (NaCl) into chlorine gas, sodium hydroxide, and hydrogen gas (modified)

Electrochemical Reactions Anode Chamber: 2Cl - -> Cl 2 (gas) + 2e - Chloride ions are oxidized to chlorine gas and free Na + Cathode Chamber: 2H 2 O + 2e - -> H 2 (gas) + 2 OH - Hydrogen ions from the water are reduced to hydrogen gas, leaving behind a solution of sodium and hydroxide ions, i.e. a solution of sodium hydroxide The membrane cell’s successful operation depends on the membrane between the anode and cathode chambers It is a modified “Teflon-like” material called Naflion (a du Pont polymer) A cation-exchange membrane The membrane will pass cations (Na + ions), but not anions (OH - ) between the compartments of the cell

EDGE Chlorine Generator Chlorine gas released from anode chamber through this tubing Hydrogen gas released

Test Configurations

System Diagram Continuous Sampled

Standard Solutions A known 250 PPM Standard Solution was used to develop the Calibration Curve Calibration Curve correlates Absorbance (wavelength) to Chlorine Concentration (PPM) Known solution was verified with HACH Colorimeter

Standard Solutions

Calibration Curve Best Fit

Initial Testing Condition Variations

NaCl vs Varied NaOH Concentrations Referenced percentages represent weight percentage Initially each cell was filled with 20 oz. of water (equivalent to 573 g of water) Thus 573 g became the reference point for weight percentages Sodium Chloride (NaCl) concentrations were held constant: 16 weight % (equivalent to 92 g of NaCl)

NaOH Concentration vs Varied Voltages NaOH concentrations were held constant while 3 different chlorine generator operation voltages were tested: 8 V 12 V (standard currently in use by EDGE) 24 V

NaCl: 16% vs NaOH: 0% Known as a ‘cold start’ by EDGE Occurs frequently in the field No NaOH molecules present in cathode during testing initialization. We began with 18 Mega Ohm water in cathode

NaCl: 16% vs NaOH: 0% (cont.)

NaCl: 16% vs NaOH: 5% NaOH concentration in the cathode is 5% of total chamber water volume during testing initialization

NaCl: 16% vs NaOH: 10% NaOH concentration in the cathode is 10% of total chamber water volume during testing initialization

NaCl: 16% vs NaOH: 15% NaOH concentration in the cathode is 15% of total chamber water volume during testing initialization

NaCl vs NaOH (in %): 0, 5, 10, 15 Rate of chlorine concentration increases proportionately with increase in NaOH

Observations: NaCl vs NaOH We began with 18 Mega Ohm water in the cathode chamber (0% NaOH). The solution was therefore, highly resistive With each NaOH concentration increase, the amount of Sodium ions migrating through cell membrane proportionately increased This increase created enough NaOH to reduce resistance of the cathode chamber triggering adequate conduction current and, thus, increased chlorine gas production

Observations: NaCl vs NaOH (cont.) Conduction current provides the necessary energy for electrolytic chemical reactions within the chlorine generator Ohm’s Law: V = IR Since voltage was constant (12V), resistance across the electrodes had to decrease in order to increase current

Varying Voltages

Varying Chlorine Generators

Conclusions

Testing should be done on each generator to verify performance Generation performance is reproducible Standard test condition: 10% NaOH, 16% NaCl, 12 V Additional work is required to characterize NaOH concentration at the end of the experimental run

Inventory PC Monitor for PC Keyboard Mouse LabVIEW Executable Installed on PC Microsoft EXCEL Installed on PC 2 Vernier SensorDAQs 2 USB cables

Inventory (cont) Reverse Osmosis Water System: Reservoir Elix Filters (2) 3 Graduated Cylinders (measuring 250 mL) 1 Pipette (5 mL) 250 PPM Standard Chlorine Solution Cuvettes for Vernier Colorimeter Chlorine Reagent Total Chlorine Reagent Dispenser by HACH Stirring Rod Scale Sodium Hydroxide Iodized Salt

Inventory (cont) 5-Gallon Reservoir Fume Hood Current Sensor Voltage Probe pH Sensor Salinity Sensor Temperature Probe Vernier Colorimeter Turbidity Sensor 12 V Power Supply

Turn Over Team will meet with EDGE staff for hands-on training workshop Topics covered: Software Usage Equipment Usage Test procedures Inventory Ordering Procedures

Questions?

Instrumentation

Instrumentation-Turbidity Sensor Water sample which was purified by using the chlorine generator that is being tested will be placed into the turbidity sensor We will be using Vernier Turbidity Sensor which can measure from 0 to 200 NTU. 1 NTU is standard for unfiltered drinking water, 0.5 NTU for filtered

Instrumentation - Voltage Probe Voltage probe will be connected to the chlorine generator to measure approximately 12V across electrodes We will be using Vernier 30 Volts Voltage Probe which is able to measure voltages in the range of -30 to 30 Volts

Instrumentation - Current Sensor Current sensor will be connected to the 12VDC Power Supply We will use Vernier High Current Sensor The High Current Sensor has a range of ±10 A

Instrumentation - pH Sensor The PH sensor will be placed into a beaker with water which was purified by using the chlorine generator that is being tested We will be using Vernier PH sensor

Instrumentation - Salinity Sensor Salinity sensor will be placed in the beaker with water The Salinity Sensor easily and precisely measures the total dissolved salt content in an aqueous solution We will be using Vernier Salinity sensor This sensor has range of 0 to 50,000 ppm Drinking water salinity should be < 3,000 ppm

Instrumentation-Temperature Sensor Temperature probe will be placed in the beaker with water We will be using Vernier Stainless Steel Temperature Probe, which has a range of -40 to 273 F

Instrumentation - Colorimeter The colorimeter will be used to test the amount of chlorine generated We sill be using a Vernier colorimeter 4 wavelength 5VDC, 25 mV Supply Voltage 40 mV Supply Current

Instrumentation - Potentiostat We will use a potentiostat to create graphs of voltage vs. current We are using an Arduino potentiostat

Data Acquisition Module All sensors will be plugged into a data acquisition (DAQ) module We will be using 2 SensorDAQ modules, which are made by Vernier. Turbidity Sensor PH Sensor Salinity Sensor Voltage Probe Current Sensor Temp Probe USB to DDMS