Separation and Purification Technology 57 (2007) 11–16 Removal behavior of sericite for Cu(II) and Pb(II) from aqueous solutions: Batch and column studies Diwakar Tiwari a , Hyoung-Uk Kim b , Seung-Mok Lee b,∗ a Department of Chemistry, School of Physical Sciences, Mizoram University, Aizawl 796 009, India b Department of Environmental Engineering, Kwandong University, Gangnung, Gangwon-do 210-701, Republic of Korea Received 11 October 2006; received in revised form 5 March 2007; accepted 7 March 2007 Abstract Applicability of naturally and abundantly available sericite was assessed for the removal of two important heavy metal toxic ions viz., Cu(II) and Pb(II) from aqueous solutions. The present investigation is an attempt for cleaner/greener cost effective technologies in waste/effluent water treatment. The batch type experiments showed, sericite was found to be useful sorbent for the removal of these two cations from aqueous solutions. It is to be observed that with the increase in sorptive concentration, the amount of metal uptake increased and the concentration dependence data were fitted well for the Langmuir adsorption isotherm than Freundlich adsorption model. Langmuir monolayer adsorption capacity was found to be 1.674 mg g -1 for Cu(II) and 4.697 mg g -1 for Pb(II). Kinetic studies enabled, a rapid equilibria was established between the soild/solution interface as within ca. 10 min for Cu(II) and ca. 90 min for Pb(II). Moreover, the removal behavior of sericite for these two metal ions was greatly influenced by the solution pH. Further, the column data were explained with the Thomas model hence to optimize the Thomas constants for these two ions, i.e., Cu(II) and Pb(II) for sericite. © 2007 Elsevier B.V. All rights reserved. Keywords: Sericite; Cu(II); Pb(II); Adsorption; Langmuir isotherm; Wastewater treatment 1. Introduction The removal of heavy metal toxic ions from wastewaters has received an increased attention in recent decade for global awareness of the underlying detriment of heavy metals in the environment. Applications of traditional treatment techniques need enormous cost and continuous input of chemicals, which become impracticable and unconventional and also caused for further environmental concern. Moreover, beyond the certain limit the conventional methods viz., chemical precipitation, electrode-deposition, membrane separations, evaporation, sol- vent extraction, etc., are technologically inapplicable. Hence, the interest lies for more effective, economic and eco-friendly tech- niques to be developed for fine-tuning of effluent/wastewater treatment [1–2]. In this regard ion-exchangers play a promi- nent role for the removal/speciation of several cationic/anionic species in waste waters and if the adsorbent is chosen so care- fully and the solution chemistry adjusted accordingly, it can ∗ Corresponding author. Tel.: +82 33 649 7535; fax: +82 33 642 7635. E-mail address: leesm@kwandong.ac.kr (S.-M. Lee). provide an effective waste treatment even at wide range of solu- tion pH [3–6]. Interestingly, the adsorption process may also offer to remove effectively/efficiently inorganic- and organic- complexed metals that would not be removed by conventional treatment methods [7–9]. Applications of clay and minerals in waste water treatment, particularly the speciation/removal of heavy metals, has long been assessed because of their high specific surface area, chem- ical and mechanical stability, variety of structural and surface properties, higher values of cation exchange capacities, etc. [10–20]. Presence of both Bronsted and Lewis acidity on clay surface further enhances its adsorption capacity [21]. Moreover, since the clays are able to exchange their alkali metal cations with protons, hence they can behave as a buffering medium in controlling the pH of lakes undergoing acid rain [22]. Sericite is a layered silicates mineral, generally recognized as white fine powders of muscovite in form, with nano-sized layer structure, interlayer spacing of (0 0 2) plane is 10 ˚ A. It has been reported that it is widely used in the alkali flux [23] and cosmetics [24] however; the application in wastewater treatment is yet to be explored. Hence, in a quest for eco-friendly and cost effective cleaner technologies we attempted to exploit the abundantly 1383-5866/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.seppur.2007.03.005