| Author | Waraporn Jiamjitrpanich |
| Note | A dissertation submitted in partial fulfillment of the requirements for the
degree of Doctor of Philosophy in
Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Trinitrotoluene (TNT) and its metabolites are environmental hazard substances because of their toxic, mutagenic, and carcinogenic potentials. This research aimed to investigate the applications of nanoscale zero valent iron particles (nZVI) to remediate or degrade TNT present in the contaminated water and soil samples. The effects of dosages of nZVI and reaction times and degradation rate were determined. Moreover, this study was designed to investigate the capabilities of two novelty combination of nanoparticles, it also included phytoremediation process (P. maximum and H. annuus) for degradation and removal of TNT and its metabolites-contaminated soil. From field observation in part I, the results showed that the concentration of TNT and its metabolites in soil, water, and sediment were mostly undetectable. However, at some points these were detectable, but lower than the guideline limits. Hazard quotient (HQ) was used to assessment of environmental risk, the HQ level of terrestrial and aquatic risks had no serious risks in these areas. However, monitoring programs should be launched for the sites to ensure that the TNT and its metabolites distribution and contamination are well controlled. Part II, the results of lab-scale experiments showed that the optimum dosage of nZVI for degradation of 10 mg/L TNT in water was 2000 mg/L at a reaction time of 20 min. The observed first-order degradation rate of TNT at 25 degree Celsius was 0.137 min-1 corresponding to the degradation rate of 0.156 L/m2·h. In the experiments of sandy clay loam soil containing 20 mg/kg TNT in slurry form (1:2 soil to solution ratio), the optimum dosage of nZVI was 5000 mg/kg soil. Results of this study indicated that it is feasible to use nZVI for the remediation of TNT-contaminated water and soil. The effects of nZVI on remediation of TNT-contaminated water and soil were investigated under the pilot-scale experiments using batch reactor as of part III. The water and soil washing treatment reactors were cylindrical shape with 30 cm diameter and 50 cm height. The TNT removal efficiency in water was only 68.31% at 20 min and around 100 % at 52 min at 25 degree Celsius. The first-order of degradation rate was found to be 0.069 min-1 at 25 degree Celsius corresponding to the degradation rate of 0.079 L/m2.h. These results demonstrated that the TNT removal efficiency was decreased at a large volume in batch reactor. The TNT removal efficiency in the slurry soil reactor was found to be 59.23 % at 20 min. Moreover, the reactor of soil leaching treatment was a rectangle shape with 50 cm length, 50 cm in width and 30 cm in height. The TNT removal efficiency was found in the column which it was combined with nZVI was higher than both the leaching column and non leaching column, respectively. Under the potting test of part IV nano-phytoremediation in pots having 15 cm width and 15 cm height with contained 1 kg of soil, P. maximum showed more tolerance than H. annuus in TNT and nZVI-contaminated soil. Therefore, P. maximum was selected as a hyperaccumulated plant for nano-phytoremediation potting test. The optimal tolerance dosage of P. maximum to TNT-contaminated soil was 500 mg/kg and nZVI-contaminated soil was 1000 mg/kg in a transplanting method. Nano-phytoremediation demonstrated higher potential than either nano-remediation or phytoremediation alone for degradation and removal of TNT-contaminated soil. Nano-phytoremediation method was the best method in the cost benefit analyses when compared with water treatment with nZVI, nano-washing, and nano-leaching due to nano-phytoremediation method is environmental friendly, low cost, and gives biomass yield. |
| Year | 2011 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy and Environment (EE) |
| Chairperson(s) | Preeda Parkpian ;Chongrak Polprasert; |
| Examination Committee(s) | Tripathi, Nitin Kumar ;Jutamaad Satayavivad ;Laurent, Francois ;Shimizu, Yoshihisa ; |
| Scholarship Donor(s) | Government of France ;RTG Fellowship ;Commission of Higher Education (CHE), Thailand; |