The Characteristic Study Of Different Type Of Soils Absorption/Desorption For Sulfamethoxazole

Sulfa antibiotics are widely used in animal husbandry because of their role in the prevention and treatment of bacterial infections and other diseases.However,in the process of use,more than 50% of sulfa antibiotics are not absorbed and excreted with animal feces,and then into the soil environment,resulting in the latent pollution of the soil environment.In view of the indiscriminate use of antibiotics and its serious harm to environment,3 kinds of typical soils which were meadow black soil,Albic soil and dark brown loam soil in Jilin province were selected in this study,Sulfamethoxazole(SMZ for short),as the tested drug,the effects of SMZ on the adsorption/desorption characteristics of 3 Soils under different experimental conditions were studied.The main research results were summarized as follows:(1)The adsorption/desorption processes of SMZ in 3 soils can be divided into two stages: rapid adsorption/desorption and slow equilibrium adsorption/desorption.The adsorption/ desorption processes are in accordance with the particle diffusion equation,the Elovich equation and the double constant equation.(2)The isothermal adsorption process of three kinds of soils to SMZ was in accordance with Freundlich equation,Langmuir equation and linear equation and it reached a significant correlation level.The HI values of SMZ in 3 kinds of soils were all less than 0.7,which indicated that the SMZ of all the 3 kinds of soils had obvious hysteresis.The ?G values of 3 kinds of soils to SMZ were less than 0,which indicated that the adsorption process was spontaneous;and its absolute value is less than 40 k J·mol-1,indicating that the reaction of absorption is main affected by physical adsorption;?H is less than 0,indicating that reaction is exothermic,and system energy continued decreasing.(3)With the increasing of temperature,the quantity of adsorption and desorption for SMZ in the 3 soils showed downward,which indicated that the increase of temperature could suppressed adsorption/desorption of SMZ.When the temperature is increase by 10?,SMZ in 3 kinds of soil in desorption were decrease 12%~57%,12%~44% and 3%~24%.(4)The increase of p H could inhibit adsorption/ desorption of SMZ in 3 kinds of soils.it had little effect on the adsorption capacity of SMZ in soil in the Ca2+,or K+ solution,However Al3+ as a kind of amphoteric element has different forms in soil,which leads to different adsorption quantity.The initial concentration background electrolyte solution increases promoted adsorption/desorption of SMZ in different type of cation solution.The content of organic matter increase promoted desorption/adsorption of SMZ in soils,but the difference of increase is obvious.