Adsorption Of Cephalosporins On Modified Activated Carbon

In recent decades, the antibiotic pollution problem has attractted more and more attention. Especially in drinking water some antibiotic has been detected. The presence of antibiotic has caused great threaten to mankind and ecological environment. Thus, the research of how to remove the type of water pollutants is imperative.In this paper, different modification methods were selected. The adsorption capacity of different modified activated carbon were compared. Three kind of modified activated carbon AC-Cu, AC-Al and AC-Fe were used in the subsequent experiments.The structures and properties of three kind of modified activated carbon have been analyzed first. The results showed that after modification, the surface of the activated carbons were more rough. The specific surface area of AC-Cu was reduced less. In addition, the content of C=C and benzene functional groups were increased. The specific surface area of AC-Fe was similar as AC-Cu. And the content of benzene and carboxylic oxygen containing functional groups were reduced. The specific surface area of AC-Al reduced a lot. The oxygen-containing functional groups such as carboxyl and hydroxyl groups were increased in AC-Al. In addition, there were corresponding metal element in three kinds of activated carbon.The effect of different conditions on the adsorption of ceftazidime by three kinds of activated carbon were studied. The results showed that as the increasing of ionic strength, the adsorption capacity of ceftazidime increased a little. But with the increasing of pH value, the adsorption capacity of ceftazidime decreased sharply. Low temperature was more conducive for the adsorption. The presence of natural organic matter(humic acid) had little influence on the adsorption of ceftazidime.The adsorption of ceftazidime on three kinds of activated carbon obey the pseudo-second order kinetic model. The maximum adsorption quantity of ceftazidime calculated by pseudo-second order kinetic model were 200.0 mg·g-1 (298 K),196.1 mg·g-1 (303 K) and 185.2 mg·g1 (308 K). It was much higher than that of AC-Fe and AC-Al. The uptake of ceftazidime was mainly controlled by liquid film mass transfer and intra-particular mass transfer. According to the adsorption isotherm and thermodynamics analysis, the adsorption process was spontaneous and exothermic process, and can better meet the Freundlich and Tempkin isothermal equation.