Wastewater treatment with desorbing of an adsorbate from an adsorbent with a solvent in the near critical state

Claim 1

A process for removing organic impurities from wastewater, comprising the steps of a. contacting an adsorbent with wastewater containing organic impurities thereby to adsorb said impurities as adsorbates on said adsorbent; b. contacting said adsorbent containing residual water remaining on said adsorbent subsequent to step (a) and having said adsorbate adsorbed thereon with a solvent for said residual water and said adsorbate, said solvent being inert to said adsorbent and being a liquid in the near critical state wherein the temperature of said solvent ranges between about 0.95 and 0.995 times its critical temperature in degrees K and the pressure of said solvent is at least equivalent to its vapor pressure at the temperature at which it is used, thereby to remove said residual water and to desorb said adsorbate and dissolve it in said near critical liquid; c. separating said near critical liquid with said residual water and said adsorbate dissolved therein from said adsorbent; d. vaporizing at least a portion of said near critical liquid containing said residual water and said adsorbate dissolved therein to form a multi-phase system comprising solvent-rich vapor and a water/adsorbate-rich phase; e. condensing said solvent-rich vapor to form a liquid; and f. adjusting the temperature and pressure of said liquid from step (e) thereby to convert it to said near critical liquid from recycling in the process.