The Design Of A Photocatalytic Air Purifier And Experimental Study Of Formaldehyde Degradation

Formaldehyde is widely present in the environment, as one of the main pollutants in the air will produced many adverse impact on human health if long-term exposure. Therefore, the removal of formaldehyde has been a serious problem to be solved at present. In recent years, photocatalytic oxidation technology with its advantages such as the fast reaction rate, the complete reaction, etc. has becomed a study focus in indoor air purification. For the current studies, it has important theoretical and practical significance to study how to apply photocatalytic oxidation technology to practice preferably and how to achieve the photocatalytic air purifier with small, practical and low-cost technology.Firstly, a simple structure wall-mounted photocatalytic air purifier was designed according to the principle of photocatalytic reactions and maded into a model machine with a manufacturer, which can improve the reaction rate of photocatalytic in theory; Secondly, a experimental platform was builded, program was designed and materials were prepared to study the degradation effect of formaldehyde and compretive analysis with traditional flat-type reactor; Then, a orthogonal experiment was designed through the setting of several controllable factors and the experimental results were analysis with intuitive and variance method by using mathematical statistics knowledge to determine the best matching conditions of the experimental device; Finally, made experiment under the best matching conditions to determine the best purification effect of the experimental device. Main research results are as follows:①Compaired with the traditional flat-type reactor under the same experimental conditions, the result says that this device was better than the flat-type reactor on degradation and the degradation efficiency increased by14%.②The results by the orthogonal experiment showed that, the best operating conditions of self-made photocatalytic air purifier were initial concentration of formaldehyde0.7mg/m3, environmental temperature25℃and P25TiO2capacity lmg/cm2in the range of experimental conditions.③By analysis of variance, the several controllable factors such as environmental temperature, initial concentration of pollutant and capacity of photocatalyst existed significant differences impact on air purifier, the influence of the level of significance as follows:environmental temperature> initial concentration of formaldehyde> P25TiO2 capacity.④Under the best matching conditions, the rate of degradation of formaldehyde can be achieved89%within120min in the total attenuation experiment and the coefficient of total attenuation reached0.02, the degradation is better and it follows that the purification efficiency of this device belongs to Class C range by converting the environmental test chamber volume to the purification standard volume.