Efficient removal of ammonium and phosphorus from wastewater via potassium permanganate-modified Chinese medicine residues.

The disposal of Chinese medicine residues has become a pressing environmental issue in China due to the rapid expansion of the Chinese medicine industry. This study investigated the removal of ammonium and phosphate from wastewater by the use of potassium permanganate (KMnO4)-modified Chinese medicine residues. The results showed that the adsorption capacity of the KMnO4-modified residues (MR) for nitrogen and phosphorus was significantly enhanced, which was 1.23 and 1.27 times higher than that of unmodified residue (UR). Bohm titration showed a twofold increase in carboxyl groups, while FT-IR and BET analyses indicated the formation of Mn-O compounds on the MR surface, which increased the specific surface area and pore volume by approximately 6 and 16 times, respectively, compared to UR. Furthermore, the adsorption behavior of MR follows a pseudo-second-order kinetic model and fits the Langmuir isotherm model. These findings open a new window for resource utilization of Chinese medicine residues and the protection of the environment.