Non-thermal plasma technology for the effective regeneration of macroscopic adsorbent materials used in the removal of patent blue V dye from aqueous solutions

In this work, two different commercial macroscopic adsorbent materials (Na-ZSM5 zeolite in spherical pellets and TiO2 cylindrical pellets) has been tested in the removal of model organic food dyes (Patent blue V, E131) and they were regenerated using an innovative techniques based on non-thermal plasma process. The adsorption experiments were carried out using a pyrex cylindrical reactor and liquid samples were analyzed in continuous mode by spectrophotometric measurement at λ = 636 nm. The results demonstrated that these materials were able to remove Patent blue V dye, with removal efficiency equal to 80% for the zeolite and 95% for TiO2 pellets after 400 min of treatment time. The adsorbent materials have been used for several cycles until their saturation. In particular, after seven adsorption cycles, the adsorbing capacity was reduced of about 60 and 20% for zeolite and TiO2 pellets, respectively. Subsequently, the materials were regenerated by nonthermal plasma and reused in the adsorption system. The results evidenced that the regeneration by nonthermal plasma was able to induce the complete degradation of the absorbed organic substance and consequently restoring the initial adsorption capacity of both macroscopic adsorbent materials.