Removal of Mn from aqueous solution by manganese oxide coated zeolite

The preparation, characterization, and adsorption properties of Mn by manganese oxide coated zeolite (MOCZ) and its ability in removing Mn by adsorption were investigated. Characterization analyses were used to monitor the surface properties (and their changes) of the coated layer and metal adsorption sites on the surface of MOCZ. The adsorption experiments were carried out as a function of solution pH, adsorbent concentration and contact time. Binding of Mn ions onto MOCZ was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Mn adsorption by MOCZ, the medium pH decreased and enhanced with increasing adsorbent concentration. The pseudosecond-order model fitted better among all the kinetic models suggesting that the adsorption mechanism might be a chemisorption process. The equilibrium data showed excellent correlation for both Langmuir and Freundlich isotherm model and this implies both monolayer adsorption and a heterogeneous surface existence in MOCZ. At pH = 6, the Mn uptake by MOCZ attained as high as 1.1 meq Mn g 1 at equilibrium. The results suggested that MOCZ presents a fairly good potential as an adsorbent for an efficient removal of Mn ions from aqueous solution. 2010 Elsevier Ltd. All rights reserved.