Thesis Archive
EFFECT OF COBALT IN DDT DEGRADATION USING EMULSIFIED AND NON-EMULSIFIED ZERO VALENT IRON (ZVI) (2012)
Cangco, Lorraine Manalo
Chan, Belinda Monica Chua
Chua, Keith Timothy Ang
Abstract:
-This study investigated the effect of cobalt in the degradation of DDT in water matrix using zero valent iron (ZVI) in both non-emulsified and emulsified forms. The ZVI loading was varied at 0%, 50%, and 100% and the initial concentration of DDT varied at 10, 15, and 20 ppm. The effects of ZVI loading and initial DDT concentration on the extent of DDT degradation were determined using a full factorial design of experiment. All experimental runs were in batch mode at room temperature, initial pH was 2.0, total metal loading was the same for all runs and reaction was for four hours. The samples were analyzed using GC-ECD. Results show that the non-emulsified metals performed better than their emulsified counterparts. The highest amount of DDT degraded at 246.5 mg DDT per g metal per liter solution was achieved when the initial DDT concentration was 20 ppm using pure non-emulsified ZVI. Among the emulsified variants, extent of DDT degradation was highest at 155.02 mg DDT per g metal per liter solution. This occurred when the initial DDT concentration was 15 ppm and 100% ZVI loading was used. When the initial DDT concentration was 15 ppm, the extent of DDT degradation was almost the same for the non-emulsified and emulsified metals, in both cases, pure ZVI was used. Results also show that the addition of cobalt had minimal effect on the extent of DDT degradation. It was the initial concentration of DDT that exhibited significant effect. The kinetic study conducted showed that the non-emulsified variant of pure ZVI exhibited first order kinetics with a specific rate constant of 0.0192/min. All the other conditions resulted in second order kinetics. In the emulsified variant, highest rate was at 15ppm using pure ZVI with a rate constant of 0.0009 li/mg-min. A simulation of the time course of DDT concentration showed that the emulsified variant of ZVI+Co gave the best fit nonetheless, the performance of pure ZVI was still superior in terms of the extent of DDT The kinetic study conducted showed that the non-emulsified variant of pure ZVI exhibited first order kinetics with a specific rate constant of 0.0192/min. All the other conditions resulted in second order kinetics. In the emulsified variant, highest rate was at 15ppm using pure ZVI with a rate constant of 0.0009 li/mg-min. A simulation of the time course of DDT concentration showed that the emulsified variant of ZVI+Co gave the best fit nonetheless, the performance of pure ZVI was still superior in terms of the extent of DDTThe kinetic study conducted showed that the non-emulsified variant of pure ZVI exhibited first order kinetics with a specific rate constant of 0.0192/min. All the other conditions resulted in second order kinetics. In the emulsified variant, highest rate was at 15ppm using pure ZVI with a rate constant of 0.0009 li/mg-min. A simulation of the time course of DDT concentration showed that the emulsified variant of ZVI+Co gave the best fit nonetheless, the performance of pure ZVI was still superior in terms of the extent of DDT degradation.
Adviser:
“Josephine Borja
Joseph Auresenia