| Summary: | The adsorption and desorption of Oxytetracycline hydrochloride (OTC HCl) onto
wood-based powdered activated carbon was studied in batch equilibrium experiments.
Various experimental parameters were studied including initial OTC HCl
concentration (5-25 ppm), pH of the solution (3-7) and temperature of the solution
(30-50�). The experimental data were analysed using Langmuir and Freundlich
isotherm model and the goodness of fits were checked by using linear regression
coefficients (R2). It was found that, Langmuir isotherm model best represented the
equilibrium data. Pseudo-first-order and pseudo-second-order kinetic model were
used to analyse the kinetic data. It was found that the best fitting corresponded to the
pseudo-second-order kinetic model. Various thermodynamics parameters, such as
Gibbs energy, enthalpy change and entropy change, were calculated, which indicated
that the present system was unspontaneous and endothermic process for OTC HCl.
Based on the value of activation energy, it is also found that the adsorption mechanism
was not only limited to physical adsorption but also chemisorption too for several
different temperatures. The adsorption of OTC HCl on this activated carbon can be
maintained above 80% across the 5 adsorption-desorption cycles and potassium
chloride had been used as a desorption medium. The activated carbon was
characterized by using FTIR, TGA, and surface area analyser. Other than that, the
pHpzc of the activated carbon also had been identified in this experiment.
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