Techno Press


Advances in Environmental Research   Volume 4, Number 1, March 2015, pages 49-68
DOI: http://dx.doi.org/10.12989/aer.2015.4.1.049
 
Aqueous phase removal of ofloxacin using adsorbents from Moringa oleifera pod husks
Raymond A. Wuana, Rufus Sha'Ato and Shiana Iorhen

 
Abstract     [Full Text]
    Chemically activated and carbonized adsorbents were prepared from Moringa oleifera pod husks (MOP), characterized and evaluated for their ability to remove a common antibiotic - ofloxacin (OFX) from aqueous solution. The pulverized precursor was steeped in a saturated ammonium chloride solution for a day to give the chemically activated adsorbent (AMOP). A portion of AMOP was pyrolyzed in a muffle furnace at 623 K for 30 min to furnish its carbonized analogue (CMOP). The adsorbents showed favorable physicochemical attributes. The effects of operational parameters such as initial OFX solution pH and concentration, adsorbent dosage, temperature and contact time on OFX removal were investigated. At equilibrium, optimal removal efficiencies of 90.98% and 99.84% were achieved at solution pH 5 for AMOP and CMOP, respectively. The equilibrium adsorption data fitted into both the Langmuir and Freundlich isotherms. Gibbs free energy change (ΔGo), enthalpy change (ΔHo) and entropy change (ΔSo) indicated that the adsorption of OFX was feasible, spontaneous, exothermic and occurred via the physisorption mode. Adsorption kinetics obeyed the Blanchard pseudo-second-order model. The results may find applications in the adsorptive removal of micro-contaminants of pharmaceutical origin from wastewater.
 
Key Words
    ofloxacin; Moringa oleifera pod husks; adsorption isotherms; adsorption kinetics; wastewater
 
Address
Department of Chemistry and Centre for Agrochemical Technology,Federal University of Agriculture, Makurdi 970001, Nigeria.
 

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