Chlorine Dioxide Pilot Study

From 9-26-14.

Performed chlorine dioxide gas pilot study at the USDA ARS BRL building. This was performed as a collaboration with the Animal Metabolism Unit a the USDA. We will be generating chlorine dioxide gas in anaerobic chambers. Gas is generated more efficiently at higher humidity, however water serves as a sink for generated gas. So, we wanted to determine the effect of having a water source in the anaerobic container while generating chlorine dioxide gas. For this pilot, we used modified anaerobic chambers equipped with a nozzle attached and sealed to the cover of each container. Experiment was performed in a laminar flow hood in a room with closed windows and no lights on.

Gas concentrations were measured using chlorine gas detection tubes (seen below) in conjugation with a GasTec (Link) pump. At each time point the glass detection tube was broken on each end and attached to the nozzle on the cover and a volume of 100 mL was pulled into the tube twice, for a total of 200 mL.

Six modified anaerobic chambers were utilized, with three containing a 100 mL beaker containing 50 mL of ddH2O. 86 mg of each component A and B to generate chlorine dioxide gas were combined together in a PCR tube, This amount was calculated to generate 125 ppmV of chlorine gas after six hours. closed and mixed briefly for 10 seconds, and the cap was opened and the tube was placed in cryofreeze tube that was in a small beaker to prevent tipping. The lid of the anaerobic chamber was closed. Gas concentrations were measured every hour for six hours in each of the containers.

Raw Data (ppm)
125 ppmV	Hour
	1	2	3	4	5	6
Box 1	90	95	90	95	80	75
Box 2	95	100	95	90	80	80
Box 3	80	80	80	75	70	60
Box 4	85	90	85	80	70	60
Box 5	90	90	90	80	70	65
Box 6	75	80	75	75	75	70

Boxes 3, 4, and 6 contained 50 mL of water.

Chlorine dioxide gas will be fully generated after six hours. The biggest issue with the results that were collected is that we are essentially diluting the concentration each time we take a 200 mL volume from the container. The generation rate of gas also needs to be taken into account. Further calculations of the raw data need to be performed in order to fully gauge the generation rate of gas between the two treatment groups.

In the future, only one 200 mL gas sample will be taken from a container, and not multiple times. This will require the use of multiple containers, one for each time point. Additionally, a small fan will be added to the container during the generation of gas to aid in mixing and generation of chlorine dioxide gas.

//EWW