Synthesis And Properties Of Porous Composites Through Colloidal Crystal Template Method

Nowadays,organic dyes are widely used in industrial production of paper,plastics,textiles and rubber.Even the low solubility of organic dyes is highly visible,and those colored wastewater enters the river or surface water system,which seriously disturbs the ecological environment.On the one hand,photocatalytic technology has low energy consumption.On the other hand,the reaction conditions are easy to control and there is no secondary pollution.At present,it is considered to be the most valuable method for wastewater treatment.Therefore,it is of practical significance to study the degradation of organic dyes by composite photocatalysts.In general,synthesis of ordered porous materials through template method,which have the advantages of simple process,fast method,high repeatability,and other advantages.Titanium dioxide is widely used in the field of photocatalytic.Nitrogen-doped titania is supported on calcined ordered porous magnesium aluminum composite metal oxide?MgAl-LDO?to prepare nitrogen-doped titania-porous Mg-Al hydrotalcite composite oxides?N-TiO₂-porous MgAl-LDO composites materials?with both photocatalytic and adsorption properties.The photocatalytic degradation of methyl orange and rhodamine B in the simulated light was studied under different conditions.This paper is mainly divided into three parts:?1?Melamine and formaldehyde solution were used as raw materials to prepare monodisperse MF microspheres with their particle sizes about 1?m.The colloidal crystal template of MF microspheres was obtained by gravity deposition method.Mg-Al-double hydroxides solution with Mg/Al molar ratio of 2 have been synthesized by coprecipitation method,which was filled into the MF microsphere template as a precursor solution for 48hours.The porous MgAl-LDO materials was obtained through calcining for 2 hours after drying at 500°C.The effects of the amount of precursor solution and the calcination temperature on the morphology and structure of the porous MgAl-LDO material were investigated.The results show that the porous MgAl-LDO material obtained at the current dosage of 10 wt.%and the calcining temperature of 500°C has good pore order,uniform pore size,and neat alignment.The surface area of MgAl-LDO material is 57.13 m²/g.?2?N-TiO₂ is prepared using urea as a nitrogen source,N-TiO₂ was implanted into the catalyst carrier with porous MgAl-LDO as catalyst support,and calcined to obtain N-TiO₂with anatasecrystal.The influence of the amount of N-TiO₂ on the morphology of the composite was investigated.The results show that the morphology and structure of N-TiO₂-porous MgAl-LDO composites materials are better when the amount of nitrogen doped titanium dioxide is 15 wt.%.The surface is smooth and the pore structure is better.The morphology and structure are better.The surface area of N-TiO₂-porous MgAl-LDO composites materials is 38.42 m²/g.?3?N-TiO₂-porous MgAl-LDO composite materials were used as a photocatalyst to degrade the organic dye methyl orange and rhodamine B standered solution.The degradation rates of methyl orange and rhodamine B solutions were investigated by investigating the calcination temperature,the amount of N-TiO₂,the calcination time,and the amount of composite photocatalyst used.The results showed that when the calcination temperature was 500°C,the amount of N-TiO₂ was 15 wt.%,the calcination time was 2 h,and the amount of composite photocatalyst was 200 mg,the photocatalytic degradation of methyl orange was achieved at 180 min.The highest degradation rates were 90.67%,96.07%,94.33%,and 94.12%respectively.When the calcination temperature was 500°C,the amount of N-TiO₂ was 10 wt.%,the calcination time was 2 h,and the amount of composite photocatalyst was 150 mg,the photocatalytic degradation of rhodamine B reached the maximum degradation at 180 min.The degradation rates were 94.01%,96.07%,96.98%,and 94.21%,respectively.