Tóm tắt

The adsorption mechanism of two antibiotics, namely amoxicillin (AMX) and tetracycline (TCN), on durian shellrnactivated carbon (AC) was investigated in single and binary systems. Adsorption isotherms were determinedrnunder the same experimental conditions and they showed that the adsorption capacities of AMX were higherrnthan those of TCN at all tested temperatures suggesting that this adsorbent preferred to remove AMX from thernaqueous solution. It was also observed that all adsorption capacities decreased from single to binary systems,rnwhich was reasonably explained by an antagonistic adsorption between AMX and TCN on the active sites of ACrncreating an inhibition effect between these adsorbates. Monolayer and competitive monolayer models wererndeveloped via statistical physics theory and they were applied to explain and understand the adsorption mechanism of AMX and TCN via steric and energetic parameters. Results suggested that the parallel and nonparallel orientations of both antibiotics on the adsorbent surface of AC could be possible at tested experimentalrnconditions. Modeling results demonstrated that the numbers of accepted antibiotic molecules per active site ofrnAC varied with linear and inverse trends in single and binary systems, respectively, at all tested temperaturesrnthus corroborating the adsorption inhibition effect caused by both adsorbates. An estimation of adsorptionrnenergies was also performed to describe and characterize the interactions between both antibiotics and ACrnsurface. The assessment of the parameters of statistical physics models contributed to the explanation of thernsingle and binary adsorption mechanisms of these water pollutants.