Adsorption/Desorption Characteristics Of Sulfa Antibiotics In River Sediment

In this paper, OECD Guideline batch equilibrium method were used to conducted adsorption/desorption experiments. It had researched the adsorption/desorption characteristics of sulfa antibiotics in river sediments. The results showed that:the Elovich equation was the optimal model to describe the adsorption of sulfa antibiotics in river sediments. The adsorption equilibrium time of dynamics was 24h. The adsorption experiments of mixed sulfa antibiotic can reduced the adsorption of sulfa antibiotics in sediments, but it has little influence on the adsorption equilibrium time. The desorption equilibrium time of dynamics was 36h. The adsorption isothermal characteristics of sulfa antibiotics in river sediments was in line with the Freundlich model, the same as desorption isothermal characteristics of sulfa antibiotics in river sediments. The desorption had hysteresis. The adsorption capacity of sulfamethoxazole in river sediments decrease with increasing temperature. The pH was in 2-12, the elevated pH restrained the occurrence of adsorption, it decreased the adsorption. In the condition of different cations, the change trend of the adsorption capacity ?K_f? was:M⁺?Na⁺?K⁺?NH₄⁺?>M²⁺(Ca²⁺?Mg²⁺? Zn²⁺). In the condition of the same cations, increasing the concentration of cationic solution would reduce the adsorption of sulfamethoxazole in river sediments. The adsorption experiment without organic matter showed that, the higher organic matter content, the more the adsorption of sulfamethoxazole in river sediments.