Thesis (M.Sc.)--Chulalongkorn University, 2012

A new MCM-48 based magnetic adsorbent containing thiol groups (MP-Fe2O3@MCM) was prepared and used for Hg(II) ion removal. Surface area of MCM-48, γ-Fe2O3@MCM-48 and MP-Fe2O3@MCM-48 were determined to be 941.67, 850.16,677.58 m2/g, respectively. The obtained products were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. Then the adsorption of Hg(II) by MP-Fe2O3@MCM-48was investigated in batch method using solid concentration of 0.2 g/L. The effects of solution pH and contact time were also evaluated. The suitable pH for adsorption of Hg(II) was found to 6 and 60 minutes, respectively. The adsorption behavior followed Langmuir isotherm with calculated maximum adsorption capacity of 208.3 mg Hg/g adsorbent. MP-Fe2O3@MCM-48 could effectively adsorb Hg(II) ions up to 4 cycles of adsorption/regeneration using 1.0 M thiourea in 2 %w/v HNO3 as eluent. The composite successfully removed Hg(II) from refinery wastewater. In addition, MP-Fe2O3@MCM-48 provides a magnetic property that is beneficial in the separation of solid from the treated water.