Destruction of PAHs from soil by using pressurized hot water extraction coupled with supercritical water oxidation

Remediation of PAH-contaminated sediments by chemical oxidation

“…These radicals are highly reactive and seem to be able to degrade even most recalcitrant compounds or contaminants in the sorbed form [19,29,33,24,25]. Therefore, vigorous oxidation condition can allow to increase the remediation efficiency, by attacking even the most refractory compounds.…”

“…Several Authors have in fact reported that the oxidation can enhance the biodegradability of PAHs, the application of chemical pre-oxidation having found to overcome the PAH recalcitrance to biodegradation [8,[20][21][22][23]. In certain conditions, the mineralization effect can be achieved by using a pressurized hot water flux (about 250-300 • C) as extracting or oxidant agent [24,25]. This technique, named supercritical water oxidation, has proved to be very effective in PAH remediation.…”

Polycyclic aromatic hydrocarbons sorbed on soils: A short review of chemical oxidation based treatments

“…Although the option of using other solvents different from water can be considered, WAO and SWAO do not necessitate of nonenvironmentally friendly substances (only water and oxygen are used). Accordingly, these processes can be included in the so called "green chemistry" [69].…”

“…Fig. 6 illustrates the experimental equipment used by Kronholm et al [69][70][71]. These authors reported the optimum conditions for extraction + supercritical oxidation of a mixture of PAHs deposited onto sea sand and previously dissolved in toluene [69].…”

Promoted wet air oxidation of polynuclear aromatic hydrocarbons

“…The process is normally performed in the presence of water and an oxygen containing gas as the oxidising agent, although other possibilities include the use of inorganic peroxides (promoted wet air oxidation). Several works have detailed the results of applying the WAO technology to polluted soils [4][5][6][7][8], however, the efficiency of WAO in the remediation of contaminated soils depends not only on the extraction capability but also on its potential to oxidise the target contaminants. In this sense, most of the literature has reported the PAHs removal level attained in the specific soils treated with none or little attention paid to the oxidation degree and kinetics occurring in the water phase.…”