03966nas|a2200385 i 4500 20260818173856.0 020799s1999 th uzm rtt 00| a1eng d .b11753961 AIT Thesis no.EV-99-3 Zhu, Ling A preliminary study on heavy metal removal from contaminated soils using supercritical fluid extraction Bangkok : Asian Institute of Technology, 1999 68 leaves Thesis ; no. EV-99-3 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1999 The goal of the study was to investigate the feasibility of removing heavy metals from the tlu·ee types of tropical soil which is different in character, by chelation in supercritical carbon dioxide. The selected topsoil were Karat sandy soil, Pakchong kolinitic soil, and Rangsit acid sulfate soil. Copper was used as the model contaminant while Hexafluoracetylacetone (HF A) as a chelating agent. This study was consisted of two parts include ( 1) The investigation of the effect of density, temperature, methanol modifier, extraction time, HF A/Cu molar ratio, soil pH, moisture content and contaminant level on the extraction efficiency and (2) The comparison of the recovery yield, cost, and waste disposal problem between Supercritical fluid extraction and solvent extraction which is widely used in real site remediation. For the first part, The result indicated that, under optimum condition of SFE, 82%, 74%, 56% removal of copper can be achieved for Korat, Pakchong and Rangsit soils, respectively. Increased the density from 0.25 to 0.75 g/ml, it was found to have negligible effect on the copper recovery. At constant density (0.55 g/ml) increased the temperature from 40 °c to 80 °C were found to have negative effect on Rangsit soil and negligible effect on Korat and Pakchong soil. Adding methanol at 5% had the highest yield for all tlu·ee kinds of studied soils. The dynamic extraction time was conducted varying from 5 to 35 min. The pH appears to be an important factor determine the extraction efficiencies. The effective pH range has lied between 3 to 10. Addition of a small amount of water to the soil samples can significantly increase the extraction efficiency. Extraction of higher contaminated soil get higher recovery. The possible reasons were discussed. For the second pru1, by comparison between the two methods, it is discovered that both SFE and solvent extraction can yield quite similar removal efficiency. However, SFE is an environmental-friendly method for removing heavy metal in contaminated soil while conventional method created the waste disposal problem. It is important to conduct further study in order to reduce the treatment cost of the new SFE technique and enable it to be commercially accepted. Soil remediation Preeda Pakpian, Chairperson Ozaki, Hiroaki, Examination committee Apisit Eiumnoh, Examination Committee AIT employee Student, Scholarship donor Asian Institute of Technology. Thesis ; no. EV-99-3 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B12038 .b11753961 mnait y 240411 0 990702 m a y 2 mnait mnarc 22 40 Barcode : 30050120654867 CREATED : 2014-03-19 RECORD # : i12772835 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160077714 CREATED : 2016-05-23 RECORD # : i12988042 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 91107 91107 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.EV-99-3 30050120654867 2026-08-18 17:38:56 3 2026-08-18 22 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.EV-99-3 30050160077714 2026-08-18 17:38:56 2026-08-18 40