Low-cost activated carbon for adsorption and heterogeneous ozonation of phenolic wastewater

Abstract

This work is aimed at elaborating an innovative material from palm tree waste that can be used in industrial applications for adsorption and catalytic oxidation. This low-cost activated carbon, elaborated from Borassus palm tree waste (bpAC) showed textural and chemical properties comparable with common activated carbon. Moreover, it demonstrated interesting behaviour when it was coupled with ozone to remove a phenolic compound, 2,4-dimethylphenol (2,4-DMP). This refractory model molecule was removed two times faster in the presence of bpAC and was achieved in only 7 min. The total organic carbon (TOC) removal by only adsorption on bpAC was satisfactory with a value of 93.8% after 8 h. Nevertheless, the most interesting result concerned the TOC removal during catalytic ozonation which increased from 26% (single ozonation, i.e., without bpAC) to 91% in the presence of bpAC. The addition of a radical scavenger (tert-butanol) showed that hydroxyl radicals were involved during ozonation with bpAC. Moreover, a kinetics study highlighted that both radical and molecular mechanisms were acting in heterogeneous reaction. All the results were finally validated by treating real wastewater spiked with 2,4-DMP, confirming the ability of this bpAC to enhance the treatment of phenolic wastewaters.