Adsorptive performance of MCM-41 towards hg(II) in water. Adsorption and desorption studies

MCM-41 mesoporous material was prepared under a standard conditions by using cetyltrime-thylammonium bromide as a structure-directing agent and tetraethyl orthosilicate as silica source from the liquid phase at 80 °C. Powder X-ray diffraction and scanning electron microscopy used to characterize the product, showed that the MCM-41material had an average particle size of 110 nm. The synthesized material was used to investigate the effects of acidity, adsorption time, the concentration of Hg²⁺, adsorbent dosage and temperature on the adsorption of Hg²⁺. The results showed that the optimal adsorptive conditions were: pH 5.0, m(MCM-41):mHg²⁺ 6.67, temperature 20 °C and contact adsorption time 60 min, for the initial Hg²⁺concentration of 1.0 mg/cm³. The maximum adsorptive amount of Hg²⁺ was 56.48 mg Hg²⁺/g MCM-41. The results of the desorptive effect of three desorption agents such as HCl, HNO₃ and HAc showed that the best desorbent was HCl at the concentration of 0.10 mol/dm³. The highest desorption efficiency was 77.21% for the desorption time 2 h.