Abstract: The erythromycin pharmaceutical waste residues discharged from one pharmaceutical company was used as a biosorbent to simulate the absorption tests of Pb²⁺. And the thermodynamic analysis on the adsorption process was carried out. The results showed that the modification of sodium hydroxide significantly improved the adsorption capacity of the erythromycin waste residues；The erythromycin waste residues modified by sodium hydroxide was used to treat the Pb²⁺ wastewater with the initial concentration of 11.8 mg/L, obtaining the appropriate conditions are solution pH=3.5, adsorption time 15 min and the dosage of residues 2 g/L at room temperature. Langmuir isotherm equation can well describe the adsorption behavior of erythromycin residues to Pb²⁺.

Key words: Erythromycin waste residues, Pb²⁺, Absorption, Langmuir isotherm equation