TITLE:
Activated Carbon and Clay Minerals for the Sorptive Removal of Denatonium Ions from Denatonium Benzoate Solutions
AUTHORS:
Garry S. Crosson, Kenya M. Crosson, Stephanie Thorpe, Lindsie MacPherson, Madeline Murdock, Bartina Smith
KEYWORDS:
Denatonium Benzoate, Activated Carbon, Clay Minerals, Sorption, Water Treatment, Wastewater Treatment
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.8,
June
25,
2014
ABSTRACT: This
study assessed the feasibility of utilizing activated carbon and clay minerals
for treating water impacted with the bittering agent denatonium benzoate (DB).
Our specific study objectives were to 1) evaluate denatonium ion sorption to
smectite clay minerals (bentonite and hectorite) and activated carbon (powdered
and granular) at constant pH and ionic strength and 2) examine the impact of pH
on denatonium ion sorption to each solid material. The experimental results
indicated that high doses (33,000 mg/L) of as-received granular activated
carbon and as-received clay minerals completely removed denatonium from aqueous
solutions containing 100 - 1000 mg/L denatonium benzoate. Powdered activated
carbon at doses of 5 - 100 mg/L exhibited favorable monolayer sorption of
denatonium ions from a pH 6.95, 70 mg/L aqueous denatonium benzoate solution
with a Langmuir separation factor (r)
of 0.481, a maximum sorption capacity (Sm)
of 74 mg/g, and a Langmuir constant of 15.3 L/g. A maximum removal of 23% of
denatonium was achieved at the highest powdered activated carbon dosage
employed. Denatonium ion removal with peroxide treated bentonite and peroxide
treated hectorite did not result in complete removal of the ion and exhibited
favorable sorption as evidenced by Freundlich 1/n values ranging from 0.803 to 1.194; Freundlich constants (Kf) ranged from 8 ng/L to 575
ng/L. Denatonium ion sorption to peroxide treated bentonite appeared to depend
on pH while hectorite sorption of denatonium ions was independent of hydrogen
ion concentrations. For powdered activated carbon adsorption, as pH increased
denatonium ion sorption decreased. Overall, the work demonstrates that
denatonium can be effectively removed from water via activated carbon or clay
mineral sorption.