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Remediation of Polycyclic Aromatics Hydrocarbons- Containated Soils Using Plant-Derived Biousurfactants

Soltaninejad, Hajar | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45662 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical & Petroleum Engineering
  6. Advisor(s): Yaghmaei, Soheila; Bagheri Lotfabad, Tayebe
  7. Abstract:
  8. Polyaromatic hydrocarbons are toxic compounds generally produced by combustion of explosives and petroleum materials. They cause soil and ground water contamination. PAHs are carcinogenic and lead to serious health problems for human and other living things; hence they should be removed from the environment. Soil washing technique has been one of methods applied for soil treatment during the years and surface active compounds like emulsifiers and surfactants have been introduced into washing process to improve the removal efficiency. On the other hand, synthetic surfactants made of chemicals and petroleum materials are not degradable and remain in the environment. To void this secondary problem, present work introduced the plant-derived surfactants with environmental compatibility, low toxicity and high biodegradability in comparison with synthetic counterparts. In this regard, the saponin-plant was defatted and extracted by soxhlet method using methanol as solvent. Then, saponin solutions at different concentrations were used in each soil washing batch. Increasing the saponin concentrations improved the removal efficiency until the maximum level 84%. Results showed that remediation efficiency is affected by some factors such as pH of washing phase and contact time between contaminated soil and washing phase. Increasing the washing phase pH from 4 to 9 led the phenenthrene removal to decrease from 83.2% to 61.6%. Washing time studies in batch experiments showed that optimum time is needed to achieve the maximum removal efficiency so that by increasing washing time from 2h to 48h efficency improved from 29.3% to 86.6%. To simulate the in sito process of soil washing by ground water, column experiments were designed according to the results from batch experiments. The phenanthrene removal in column approach attained the yield of 58% after the fluid phase passed through the column reached the 8 pv
  9. Keywords:
  10. Polynuclear Aromatic Hydrocarbons (PAHs) ; Phenanthrene ; Biosurfactant ; Soil Washing ; Saponin

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