1 research outputs found
The Use of Alkaline Hydrolysis As a Novel Strategy for Chloroform Remediation: The Feasibility of Using Construction Wastes and Evaluation of Carbon Isotopic Fractionation
Laboratory
and field-scale pilot experiments were performed to
evaluate the feasibility of chloroform degradation by alkaline hydrolysis
and the potential of Ī“<sup>13</sup>C values to assess this induced
reaction process at contaminated sites. In batch experiments, alkaline
conditions were induced by adding crushed concrete (pH 12.33 Ā±
0.07), a filtered concrete solution (pH 12.27 Ā± 0.04), a filtered
cement solution (pH 12.66 Ā± 0.02) and a pH 12 buffer solution
(pH 11.92 Ā± 0.11). The resulting chloroform degradation after
28 days was 94, 96, 99, and 72%, respectively. The experimental data
were described using a pseudo-first-order kinetic model, resulting
in pseudo-first-order rate constant values of 0.10, 0.12, 0.20, and
0.05 d<sup>ā1</sup>, respectively. Furthermore, the significant
chloroform carbon isotopic fractionation associated with alkaline
hydrolysis of chloroform (ā53 Ā± 3ā°) and its independence
from pH in the admittedly limited tested pH range imply a great potential
for the use of Ī“<sup>13</sup>C values for in situ monitoring
of the efficacy of remediation approaches based on alkaline hydrolysis.
The carbon isotopic fractionation obtained at the lab scale allowed
the calculation of the percentage of chloroform degradation in field-scale
pilot experiments where alkaline conditions were induced in two recharge
water interception trenches filled with concrete-based construction
wastes. A maximum of approximately 30ā40% of chloroform degradation
was achieved during the two studied recharge periods. Although further
research is required, the treatment of chloroform in groundwater through
the use of concrete-based construction wastes is proposed. This strategy
would also imply the recycling of construction and demolition wastes
for use in value-added applications to increase economic and environmental
benefits