Dissertation > Environmental science, safety science > Environmental pollution and its prevention > Water pollution and its control

Photocatalytic Nitrogen Removal from Water Using CdS/TiO2

Author ChenXiaoHui
Tutor LiuLiFen
School Dalian University of Technology
Course Environmental Engineering
Keywords Sol - gel method . Inorganic nitrogen Titanium dioxide CdS Light corrosion
Type Master's thesis
Year 2006
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Inorganic nitrogen is the main pollutants in water, the sol - gel method in combination with other process and subsequent heat treatment were prepared CdS doped TiO 2 Photocatalyst characterized through a variety of analytical tools and investigated catalytic denitrification activity of the catalyst under different conditions of light, the main content and conclusions are as follows: 1. The prepared CdS doped TiO 2 composite nanoparticles catalyst, and X-ray diffraction, transmission electron microscopy (TEM), UV - visible wavelength scanning analysis. The amount of catalyst, CdS composite amount, plus light source, inorganic nitrogen components photocatalytic activity. Experiments show that when n (CdS): n (TiO 2 ) = 0.17 when nitrogen removal. Ammonia initial mass concentration of 50mg / L of simulated wastewater through the air stirred 2h photocatalytic UV irradiation of ammonia nitrogen removal rate of 41.5%. Stir and add nitrite nitrogen and nitrate nitrogen nitrogen removal of inorganic nitrogen coupling oxidation state and reduced state. The amount of load of the catalyst CdS affect the photocatalytic activity of the important factors. UV light source for the fixed ammonia mass concentration of 25mg / L and pass air agitation, when the proportion of the mass concentration of ammonia and nitrite / nitrate nitrogen were 1:1 and 1:2 coupling removal best, this when the total nitrogen removal rates were 22.2% and 40.1%, product mainly gaseous products such as nitrogen. 2. Preparation of CdS doped TiO 2 glass load film catalyst and UV - visible full wavelength scan analysis. CdS Composite coating layers, the heat treatment temperature, plus light and inorganic nitrogen initial concentration of photocatalytic activity. The experimental results show that: the most suitable of CdS composite volume of n (CdS): n (TiO 2 ) = 0.2, the film most suitable heat treatment temperature to 500 ℃, the optimum coating layers for layer 2 , have a higher activity in the UV - visible wavelength and the initial concentration of certain inorganic nitrogen within simulated wastewater For initial inorganic nitrogen concentration of about 50mg / L (wherein the concentration of ammonia nitrogen and nitrite nitrogen are 25mg / L) under UV irradiation 2h stirring in a stream of nitrogen, ammonia removal efficiency reached 34.0%, 27.4% nitrite nitrogen removal rate, the main product to gaseous products such as nitrogen. Also studied the CdS doped proportion, light corrosion degree of impact of the different valence states of inorganic nitrogen in the reaction solution in CdS composite catalyst.

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