ADSORPTION OF CEFIXIME TRIHYDRATE ONTO CHITOSAN 10B FROM AQUEOUS SOLUTION: KINETIC, EQUILIBRIUM AND THERMODYNAMIC STUDIES

An efficient and biodegradable adsorbent chitosan 10B was used to eliminate cefixime trihydrate from aqueous solution. The kinetic behavior of cefixime trihydrate adsorption onto chitosan 10B was studied in aqueous medium, from various operational aspects, such as contact time, solution pH, antibiotic concentrations, and temperatures. Cefixime adsorption onto chitosan 10B was confirmed by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDX). The antibiotic adsorption kinetics obeyed a pseudo-second-order model rather than pseudo-first-order and Elovich kinetic models. The best illustration of antibiotic adsorption equilibrium was made by the Langmuir model, with the highest adsorption ability qm: 37.04 μmol/g at 298 K. The activation energy (Ea) of the present adsorption system was computed to be 44.18 kJ/mol. The values of activation (ΔG‡, ΔH‡ and ΔS‡) and thermodynamic (ΔG, ΔH and ΔS) parameters confirmed that the cefixime trihydrate adsorption onto chitosan 10B in aqueous medium is an exothermic physisorption process. Cefixime desorption from antibiotic-loaded chitosan 10B was performed in 0.1 M NaOH solution and the recycled adsorbent was utilized for a second time without significant loss of its adsorption capacity.

Synthesis and Characterization of TiO2 Nanoparticles Doping on Cellulose as Adsorbent for Removal of Rhodamine B in Aqueous Solution

Cellulose from banana fruit bunch was used as a precursor for doping titanium oxide (TiO2) in producing of TiO2/cellulose adsorbent. Cellulose was obtained by chemical impregnation using potassium hydroxide (KOH) and followed by the hydrothermal process at 250oC for 5 h. The mixture of TiO2 nanoparticles and cellulose was carried out into hydrothermal reactor under de-ionized water and ethanol and heated up to 200oC for 4 h in graphite furnace. Surface morphology analysis showed that the TiO2 clearly immobilized on the surface of cellulose with an increasing roughness of surface and irregular size of porosity. The development of the amorphous to the crystalline phase of TiO2/cellulose was clearly observed by the XRD. The effectiveness of TiO2/cellulose for removal of rhodamine B was investigated from different parameters of adsorption in aqueous solution. Kinetic models were well described by the pseudo-first and second-order with the best correlation coefficient (R2) attributing to the occurrence of chemisorption and physisorption mechanism.