Sonochemical synthesis, crystal structure, and magnetic properties of a novel organic-inorganic complex based on Mn (II), designed to produce a highly efficient and recyclable sorbent

Abstract

A new weak ferrimagnet inorganic complex formulated as [Mn(Phen)2(Cl)) (H2O)]. Cl. Tu (complex 1), where phen = 1,10-phenanthroline and Tu= thiourea has been synthesized under sonochemical irradiation and fully characterized by elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), vibration sample magnetometer (VSM), and single-single crystal X-ray diffraction (SCXRD). Complex 1 crystallizes in a triclinic system, space group Pī with unit cell parameters a = 9.8691(7) Å, b = 11.3619(7) Å, c = 12.8563(7) Å, β =86.007(5), and γ= 77.919(5) at 100 K. The coordination geometry around Mn (II) can be described as a slightly distorted octahedral. In the crystal packing of complex 1 many hydrogen bonds can be found between the non-coordinated chloride atoms and hydrogen atoms of coordinated water molecules. In the following, the sorbent of α-MnO2/TiO2 was prepared by thermal decomposition of new inorganic precursor [Mn(Phen)2(Cl)) (H2O)]. Cl. Tu/TiO2. The synthesized sorbent was characterized by FT-IR spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and N2 adsorption-desorption analysis. Batch experiments were carried out at room temperature to study the main parameters such as pH, contact time, and sorbent dosage on the adsorption of Cd2+by α-MnO2/TiO2. It was found that the adsorption of Cd2+ tends to increase with the increase of pH and reached a maximum value at 6 with 97% of adsorption capacity. A regeneration study revealed that α-MnO2/TiO2 can be rapidly separated and repeatedly used for more than five cycles with removal efficiency >90%.