Cu(II) adsorption on modified bentonitic clays: different isotherm behaviors in static and dynamic systems

Abstract

Cu (II) removal equilibrium from aqueous solutions using calcined clays "Bofe" and "Verde-lodo" has been studied by batch and fixed-bed in static and dynamic systems, respectively. Analyses were performed for physicochemical characterization of clays using the techniques: X-ray fluorescence (XRF), thermogravimetry (TG), N 2 adsorption (BET) and Cationic Exchange Capacity (CEC). Batch experiments were performed at a constant temperature, adjusting the pH of the solution in contact with clays. Adsorption assays in fixed bed were conducted at the flow rate determined through mass transfer zone (MTZ). Langmuir and Freundlich models were adjusted to equilibrium data. The results of characterization indicated that the temperature of 500 °C is best suited for the calcination of the clays. The maximum adsorption capacity was higher for dynamic system than fixed bed compared to static system, enhancing from 0.0748 to 0.1371 and from 0.0599 to 0.22 mmol.g -1 of clay for "Bofe" and "Verde-lodo", respectively.

Removal of Cadmium(II) and Lead(II) ions from aqueous phase on sodic bentonite

“…The negative charges on the surface of the crystals attract cations and this process is known as ion exchange and confers important properties to clays in industrial applications 15 . Several studies have been developed using bentonite clay as adsorbent of heavy metals: Almeida et al 16 evaluated the removal of copper using bentonite clay, achieving around 81% of efficiency using raw clays and 42% by calcined bentonite clays. Bertagnolli et al 17 used Brazilian bentonite clay for adsorption of copper in porous beds, obtaining 50% of the removal percentage.…”

Inorganic-organic hybrids originating from organosilane anchored onto leached vermiculite

“…The resulting operation from leaching can yield favorable components that introduce pores in the final products. In case of porous silica this has proven useful as pollutants adsorbents [12][13][14][15] , catalyst supports [16][17][18] and cracking catalysts 19 . One of the most explored native clay material is vermiculite that can be naturally found as a 2:1 composition and its importance is reflected in many commercial applications 20,21 .…”

Analysis of Silver´s Adsorption on Calcined Verde-Lodo Clay

“…In this context, adsorption is also used for this goal, being considered an efficient method with low costs when compared to other treatments (Almeida Neto et al, 2012). Thus, adsorption can be applied both to treat contaminated effluents and also to recover valuable materials, reducing the costs involved in the process.…”