(trichloroethylene [TCE], p-dichlorobenzene
borosilicate glass vial that was filled with the test
[PDCB], and tetrachloroethylene [PCE]); one ni-
solution so that there was no headspace. The vials
troaromatic compound (m-nitrotoluene [MNT]);
were capped with Teflon-lined plastic screw caps.
and 40 mg/L of mercuric chloride, which was
Vials with the test solution but no casing served
added to prevent any losses due to biological
as controls. The ratio of casing-surface area/solu-
tion volume was 0.8 cm2/mL.
activity. The test solutions were prepared by add-
ing the neat organic chemicals directly to deion-
The test pieces were left in the vials for a spec-
ized water in a volumetric flask. A small head-
ified time to sorb (Table 1). The two test pieces
space was left between the top of the liquid and
were then removed from the test solution and
the glass stopper to prevent any loss of the float-
given a decontamination treatment (Table 1). Fol-
ers. The top of the flask was tightly wrapped with
lowing decontamination, the two test pieces were
parafilm and the solution was stirred with a mag-
transferred to a fresh 40-mL borosilicate glass vial
netic stirrer for a minimum of three days.
containing deionized water, topped off with
Two pieces of casing were placed in a 40-mL
water, capped, and left to desorb for a specified
Table 1. Summary of experimental design of VOC decontamination experiments.
Exp.
Materials
Sorption/desorption
no.
Decontamination treatment
tested*
times*
1
None.
PTFE
10 min/10 min
PVC
24 hr/24 hr
SS
2
(a) No treatment.
PTFE
10 min/10 min
PVC
24 hr/10 min
SS
24 hr/24 hr
(b) 15-sec DI† water rinse with squirt bottle.
PTFE
10 min/10 min
PVC
24 hr/10 min
SS
24 hr/24 hr
3
(a) Brief DI water rinse with squirt bottle, soak in (100 mL) room-temp. solution
PTFE
10 min/10 min**
of 1% Liqui-Nox detergent with intermittent stirring, brief DI water rinse, soaked in
PVC
24 hr/10 min
SS †
(100 mL) DI water for 5 min, brief DI water rinse.
24 hr/24 hr
(b) Same as above except 5 min detergent wash and 5 min DI water rinse at ~100C.
PTFE
10 min/10 min
PVC
24 hr/10 min
24 hr/24 hr
4
(a) Hot water wash with detergent as described in 3(b).
PTFE
24 hr/24 hr
(b) Same as 4(a), followed by two 10-sec rinses with methanol (from a squirt bottle),
PTFE
24 hr/24 hr
and then blotted dry with paper towel.
(c) Hot water wash with detergent as described in 3(b) followed by two 10-sec rinses
PTFE
24 hr/24 hr
with hexane (from a squirt bottle), and then blotted dry with paper towel.
5
(a) Air dried (at room temperature) on paper towel.
PTFE
24 hr/24 hr
(b) Hot water wash with detergent as described in 3(b), followed by air drying
PTFE
24 hr/24 hr
at room temperature for 24 hr.
(c) Hot water wash with detergent as described in 3(b), followed by oven drying
PTFE
24 hr/24 hr
at 105C for 24 hr.
6
(a) Blotted dry with paper towel.
PTFE
24 hr/24 hr
7 days (168 hr)/24 hr
(b) Blotted dry with a paper towel and then oven dried at 105C for 1 hr.
PTFE
24 hr/24 hr
7 days (168 hr)/24 hr
(c) Blotted dry with paper towel and then oven dried at 105C for 4 hr.
PTFE
24 hr/24 hr
7 days (168 hr)/24 hr
* All the materials were tested for all sorption/desorption times listed, unless noted otherwise.
† DI = deionized.
** Stainless steel was not exposed to a 10 min/10 min sorption/desorption regime because rinsing had already been found
to be sufficient.
5
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