Citric Acid Synthesis Of Mesoporous Materials And Their Application Of Cu <sup> 2 </ Sup> To Remove

Mesoporous silica and magnetic mesoporous silica nanoparticles are becoming research focus due to their important potential applications in chemical industry, biomedicine, environment, energy sectors and so on. So far, mesoporous silica is a type of porous material whose synthesis procedure follows supramolecular self-assembly way generally by means of surfactant as the template. However, the mesoporous silica formation method is too complex and also the removal process of surfactant by high-temperature calcination, solvent extraction, microwave removal and else will be energy and time-consuming. The template will be hardly recycled and the harmful substances from template decomposition will result in serious environmental pollution.Cu2+is a common heavy metal in wastewater and generally from metallurgy, electroplating, printing, textile, fertilizer, paper industries and many other areas. High Cu2+concentration is not only hazardous to the aquatic plants and animals, impeding water purification, but also harmful to human health. Adsorption method for heavy metal ions removal is an effective way but the key is to find suitable absorption materials for the sake of wide applications.In order to open up a simple path for mesoporous materials'formation by means of non-surfactants, from which can remove Cu2+from wastewater well, this paper just explores the aspects as follows.1. This paper tells a simple and low-cost route for synthesizing mesoporous silica materials with high silanol groups by means of sol-gel technique under aqueous solution system. This method takes citric acid as the template, tetraethylorthosilicate (TEOS) as the silica source. In this synthesis, the citric acid can directly work as an acid catalyst for the hydrolysis of TEOS besides the function as a pore-forming agent. By using a water extraction method the citric acid template in as-prepared mesoporous silica composite can be easily removed and rich silanol groups were retained in the mesopores, then the citric acid in the filtrate can be recycled after being dried. The structural properties of the obtained mesoporous silica materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and nitrogen adsorption-desorption analysis. Due to rich silanol groups are propitious to the graft of organic functional groups, we used amino groups to modify the mesoporous silica and then take it to the use of Cu2+removal from aqueous solution, which showed excellent adsorption properties.2. Magnetic mesoporous nano-composite materials become research hot spot currently. Based on the above non-surfactant citric acid way for mesoporous silica synthesis, this paper extended its application to the synthesis of ordered mesoporous Fe3O4@SiO2 nanocomposite microspheres. N2 adsorption/desorption experiment results showed the high surface area, large pore volume and single aperture of the magnetic mesoporous Fe3O4@SiO2 nanoparticles. TEM and SEM images showed that the composite material is of spherical shape with core-shell structure and meanwhile silica shell has a certain mesoporous ordering. FTIR also showed Fe3O4@SiO2 nanocomposite microspheres have rich silanol groups. After functioned with amino group, the nanocomposite microspheres presented large Cu2+removal capacity and good magnetic recoverable capacity.