Removal of diclofenac from aqueous solutions by adsorption on thermo-plasma expanded graphite.The adsorption of diclofenac on thermo-plasma expanded graphite (a commercial product) from water solutions was investigated.  The effect of pH on the adsorption capacity was evaluated in the range 1-7 and the adsorption mechanism was described by kinetic and isothermal studies.  Pseudo-second order and Dubinin-Radushkevich models agreed with theoretical values of adsorption capacity (i.e. 400 and 433 mg g-1, respectively) and resulted to be the best fit for kinetics and isothermal experimental data.  The thermodynamics of the process was evaluated by plotting the adsorption capacity/concentration ratio at the equilibrium as a function of different values of the multiplicative inverse of temperature.  Solvent washing performed with NaOH 0.2 M and thermo-treatment carried out by heating in an oven at 105 °C for 2 h and then at 200 °C for 4 h.  The thermo-treatment was the best technique to regenerate the adsorbent, ensuring same performance after 4 cycles of use and regeneration.
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