Thermodynamic and kinetic parameters of ofloxacin adsorption from aqueous solution onto modified coal fly ash

Abstract

Batch adsorption experiments were carried out for the removal of ofloxacin from aqueous solution using modified coal fly ash as adsorbent. The effects of various parameters such as contact time, initial solu tion concentration and temperature on the adsorption system were investigated. The optimum contact time was found to be 150 min. The adsorption isotherm data fit well with the Langmuir model, and the kinetic data fit well with the pseudo second order and the intra particle diffusion model. Intra particle diffusion analysis demonstrates that ofloxacin diffuses quickly among the particles at the beginning of the adsorption process, and then the diffusion slows down and stabilizes. Thermodynamic parameters such as ΔG, ΔH, and ΔS were also calculated. The negative Gibbs free energy change and the positive enthalpy change indicated the spon taneous and endothermic nature of the adsorption, and the positive entropy change indicated that the adsorp tion process was aided by increased randomness.

A review of the antibiotic ofloxacin: Current status of ecotoxicology and scientific advances in its removal from aqueous systems by adsorption technology

“…The two biochar produced in the study by Akhtar et al [47] present SBET of only 0.144 and 1.99 m 2 g -1 , but the capacities of both materials were high, being 3702 and 669.5 mg g -1 , respectively. In the third situation, the coal fly ash material had an area of only 17.5 m 2 g -1 , where a low q= 2.643 mg g -1 was also observed [135]. The same situation was observed in the study by Jaswal et al [57], where capacity (37.31 mg g -1 ) and surface area (17.17 m 2 g -1 ) showed low values.…”

“…x pseudo-second order/not linear 0.99 [54] Thermal kaolin 250 pseudo-second order/not linear 0.97 [64] Bentonite clay 200 pseudo-second order/not linear 0.99 [56] Rice husk 480 pseudo-second order/not linear 0.99 [129] Boron nitride nanosheets 100 pseudo-second order/not linear 0.99 [130] Hydroxyapatite/activated carbon (HAP/AC) 60 pseudo-second order/not linear 0.97 [50] Rice husk ash 180 pseudo-second order/not linear 0.97 [38] Chitosan/Biochar Composite 30 pseudo-second order/not linear 0.95 [132] AC derived from luffa sponge 240 pseudo-second order/not linear 0.99 [11] Magnetic carboxylated cellulose nanocrystals (M-CCNs) 20 pseudo-second order/not linear 0.99 [133] rGO-MoS2 heterostructure 240 pseudo-second order/linear 0.91 [57] AC from Cassava Stem 120 pseudo-second order/linear 0.98 [55] Fe/Cu oxides composite 20 Double-constant rate equation/not linear 0.99 [46] Fe/Co bimetallic modified biochar 360 pseudo-second order/not linear 0.97 [58] Copper-Doped ZIF-8 180 pseudo-second order/not linear 0.99 [21] Fe3O4@MIL-100(Fe) 30 pseudo-second order/not linear 0.97 [51] Zeolitic Imidazolate Framework-8 (ZIF-8) 120 pseudo-second order/not linear 0.99 [52] Bagasse biochar 90 pseudo-second order/linear 0.99 [59] rGO@CuO/6A5N2TU colloidal heterostructures 50 pseudo-second order/not linear 0.99 [60] Coal fly ash 150 pseudo-second order/not linear 0.99 [135] Industrial sludge (AC) 240 pseudo-second order/not linear 0.94 [61]…”

“…Hydroxyapatite /activated carbon (HAP/AC) [50], AC from Cassava Stem [55], Fe/Cu oxides composite [46], Zeolitic Imidazolate Framework-8 (ZIF-8) [52] and coal fly ash [135]. Three studies observed an exothermic behavior (∆H°<0), where the augmentation in temperature in the system diminished the adsorption of OFL, being desirable adsorbents to be applied in real 369 conditions.…”

Oil shale powders and their interactions with ciprofloxacin, ofloxacin, and oxytetracycline antibiotics

“…Finally, it must be pointed out that the sorption efficiency determined in this work for CIP and OFL are in an intermediate range of reported values for other mineral sorbents, activated carbons and biomass extracts (El-Shafey 2012; Liu et al 2013;Wang et al 2014;Zhang et al 2012). For OTC, the OST100 sorption efficiency (ca.…”