R. BOURI1, L. CHERIF¹*, R. DENOYEL²
* Corresponding author
1. Laboratoire de catalyse et synthèse en chimie organique BP 119 , Université de Tlemcen, Algérie
2. Laboratoire des Matériaux Divisés, Revêtements, Electrocéramiques, Thermodynamiques, Cinétiques, Electrochimie (MADIREL), Centre St-Jérôme 13397, Marseille cedex 20, France

Abstract

The aim of this study is to investigate the ability of CMK-3 to remove heavy metals (Pb (II), Cd (II) and Ni (II)) from aqueous solution when present singly. CMK-3 was synthesized using the mesoporous SBA-15 silica as structure template and was characterized by XRD, nitrogen adsorption-desoprtion and FT-IR , FT-IR spectrum shows that there are many functional groups at the surface of CMK-3. The adsorption process of ions on CMK-3 can be considered very fast, attaining 90% adsorption efficiency within 5 min for Pb (II) and Ni (II), and 10 min for Cd (II). The adsorption capacity of CMK-3 for the removal of Pb (II), Ni (II) and Cd (II) was 199,4, 198 and 180 mg/g of CMK-3, respectively. These capacities values are highest among those reported in the literature. The adsorption capacity was inversely proportional to the hydrated ionic radius of the metals. The effects of the adsorbent dose, pH and temperature on Pb (II) uptake from aqueous solution have been studied (not shown).The lead removal was pH dependent, and remained almost unchangeable with the increase in adsorbent dosage, indicating that sufficient adsorption sites are available at lower CMK-3 dose.The adsorption of Pb (II) when present in binary (Pb (II) + Cd (II), Pb (II) + Ni (II)) or in ternary system (Pb (II) + Cd (II) + Ni (II)) was also investigated. The results showed that the adsorption of Pb (II) decreased slightly in binary system. Interestingly, in the ternary system there was a substantial improvement in the removal of Pb (II).

INTRODUCTION
The release of industrial wastes containing toxic heavy metals poses a serious threat to the environment and the health of human populations. The heavy metal ions are stable and persistent environmental contaminants (1-5). Several studies have shown that nanomaterials are promising candidates for pollution treatment (6-29). Mesoporous SBA-15 silica has been widely studied owing to its 3-D structure with interconnected pores (30). An interconnected structure is required to use it as hard template to prepare ordered mesoporous materials as a stable replica of its structure. SBA-15 is used as hard template to synthesize mesoporous carbon CMK-3 (31). Mesoporous carbon has attracted much attention because of its unique structural features and many promising applications such as adsorbents, hydrogen storage, catalysts supports in addition to electrochemical double-layer capacitors (31-36).
The aim of this study is to investigate the ability of CMK-3 to remove heavy metals (Pb (II), Cd (II) and Ni (II)) from aqueous solution when present singly. The effects of the contact time, adsorbent dose, pH and temperature on Pb (II) uptake from aqueous ...