Proceedings: Indoor Air 25 EXPERIMENT OF NANOMETER PHOTOCATALYTIC TO ELIMINATE DILUTE FORMALDEHYDE IN AIR S Geng 1*, R Wang 1, X Han 2, L Wang 1 1 Engineering Institute of Engineer Corps PLA University of Science and Technology Nanjing 217 2 Tsinghua University Beijing China 184 ABSTRACT To search the eliminate performance of to the indoor dilute contamination; makes measurement with through changing the original and the outside parameter (the temperature, relative humidity, the airflow velocity and TiO 2 ). Compared with the adsorption result of activated carbon fiber, the results show that the eliminate performance of the nanometer materials was more effective than the activated carbon fiber; at the condition of single influencing factors the effect of the temperature was more obvious than the others; to the interaction of all the influencing factors the average discrimination of the original was bigger than the others so the effect to the performance was the most obvious; the effect of the relative humidity was unobvious. INDEX TERMS Nanometer materials, Photocatalysis, Activated carbon fiber, Formaldehyde, Indoor air quality INTRODUCTION Along with the crisis of the energy resource and the development of architecture in 197 s, to decrease the running energy consume, the tight of the building is improvement which made the fresh air reduced; another in the modern building many new decorate materials have been used, this made the people suffer the injury of the sick building symptom. Especially some volatility organic compounds have became the most severity threaten to people s health. The methods of to eliminate the VOCs is one of the research points in the field of indoor air quality. In recent years with the nanometer materials to eliminate the VOCs in air is a new technique, and it has received more attentions. Fujishima and Honda found the phenomena of photocatalyse the water with TiO 2 in surface which indicated the beginning of the photocatalyse research (Peral and Ollis 1992) in 1972; Jose Peral has made the research with P25 to eliminate the gas-phase organic compound (Alberici and Jardim 1997). Rosana M. Alberici has made the experiment research to 17 kinds of VOCs with the nanometer TiO 2 (Yang 22) Now our country has also made research to this area: Lin Jindong has made the research to the eliminate with the material of Fe-TiO 2 photocatalysis(lin and Liang 24); Shang Jing has made research to the effect of gas-solid phase nanometer TiO 2 to eliminate VOCs in JinLin University(Shang et al. 2); Zhou Yusong has made experiment research to the elimination at the different parameter(zhou 23). But these researches mainly lay particular stress on the structure characteristic of the sorbets or the effect to high contaminations, and there have no researches to low contaminations. So this paper introduces the eliminate performance of nanometer TiO 2 materials to low contamination and the effect of temperature, relative humidity, original and air velocity EEPERIMENT SET-UP Experiment equipment The experiment equipments consist of IAQ laboratory, fan, inspecting apparatus and the adsorption box. The instruction of the IAQ laboratory is as the followed: the shape is 2.5 2.5 2.5m, alnico frame, crystal glass and the floor is aluminum board. The inspecting apparatus is PPM Formaldymeter TM 4 which was made in England. * Corresponding author email: ruihaiwang@126.com 331
Proceedings: Indoor Air 25 Experiment materials The activated carbon fibers which were made in SuTong Corporation of NanTong, main quality index is as followed: 2 2 Type: STC-13; Specific surface area: 12± 1m / g ; STD weight: 5 ~ 3g / m ; Thickness:.3mm ; Adsorption capacity for Iodine: 46 ~ 52wt %. The was made in LianShi Reagent Corporation of Shanghai. Experiment method and process 1. First the was released to the IAQ laboratory; control the temperature and relative humidity through the air-conditioning and humidifier and make the uniformity. 2. When the in IAQ laboratory reaches to an enactment level stop to release to it and install the activated carbon fiber to the adsorption box; inspect the and note the data once 5 minutes. 3.When the was not change at 4 times it could be recognized reach to the stabilization and the adsorption reached to the balance; closed the fan and take out the activated carbon fiber. 4. Change the original condition and prepare the next experiment. Tight inspect of the IAQ laboratory The tight inspect of the IAQ laboratory could be refer to the reference 12. THE EXPERIMENT COMPARISON BETWEEN THE PHOTOCATALYTIC AND ADSORPTION In this experiment the TiO 2 was loaded in the activated carbon fiber which was easily adsorb the so when analyzing the result of the effect of the adsorption should be considered and the comparison method was used in the experiment; keep the same condition to make the experiment of nanometer material and the adsorption and contrast the result,the result is as the followed figure 1: fo rm ald eh yd e c on ce nt rat io n ( pp m).5.4.3.2.1 5 1 15 2 25 3 adsorb Figure 1. the comparison result of the and adsorb.5.4.3.2.1 T=22 T=26 T=3 6 12 18 24 3 36 Figure 2. the effect of temperature to the nanometer The results show that the eliminate efficiency of the adsorption was 43.5% and the was 67.4%; the has great evident to the elimination. THE EFFECT OF SINGLE FACTOR TO NANOMETER PHOTOCATALYTIC The effect of temperature to the Nanometer Photocatalytic Φ = 6%, C =. 48ppm make the experiment through changing the temperature T, the result is as the followed figure 2: The results show that: when the temperature is 22, 26 and 3, the eliminate efficiency of the nanometer to the is 69.6%,65.2% and 58.7% and the difference is 1.9%; As the increase of temperature the eliminate efficiency would decreased. It s because that in the experiment the based was activated carbon fiber which adsorption efficiency would decreased as the increase of temperature according to the 332
Proceedings: Indoor Air 25 adsorption balance equation, and the grads would decrease, so the eliminate efficiency would decreased. The effect of relative humidity to the Nanometer Photocatalytic T = 24 C =. 46ppm make the experiment through changing the temperature T, the result is as the followed figure 3: The results show that: when the relative humidity is 5%, 6% and 7%, the eliminate efficiency of the nanometer to the is 68.5%,67.2% 和 65.6% and the difference is too little. It could be recognized has no evident effect to the eliminate efficiency. The effect of original to the Nanometer Photocatalytic T = 24 Φ = 6% make the experiment through changing the original C, the result is as the followed figure 4:.5.4.3.2.1 Φ=7% Φ=6% Φ=5% 3 6 9 12 15 18 21 24 Co=.45 Co=.65 Co=.35.7.6.5.4.3.2.1 6 12 18 24 3 36 Figure 3. the effect of relative humidity to the Figure 4. the effect of original to the The results show that: when the original is.35ppm,.45ppm and.65ppm,the eliminate efficiency of the to the is 62.8%,69.6% and 73.2% and the difference is 9.5%; As the increase of the eliminate efficiency would increased. The author thinks that the result could be explained by the quality balance: the is a chemistry reaction and the as a reactant could be strengthened the reaction as the increasing. The effect of airflow velocity to the Nanometer Photocatalytic T = 24 C =.48ppm, Φ = 6% make the experiment through changing the airflow velocity V, the result is as the figure 5:.5.4.3.2.1 V=1.23 1.55.8 6 12 18 24 3 36 Figure 5. the effect of airflow velocity to the nanometer.5.4.3.2.1 4% 2%.5%.25% 1 2 3 4 Figure 6. the effect of TiO 2 to the The results show that: when the airflow velocity is.8m/s, 1.23m/s and 1.55m/s,the eliminate efficiency of the to the is 67.4%,71.7% and 69.6%; As the increasing of airflow velocity 333
Proceedings: Indoor Air 25 the eliminate efficiency would increased but when increased to a level it would depress as the increasing of airflow velocity. The reason is that the reaction of needs some time, when the airflow velocity is larger there was no time to react between the nanometer material and the so the effect was inconspicuous and as the decrease of the airflow velocity the efficiency of would enhanced; but when the airflow velocity was too small to overcome the diffuse resistance which was produced by the surface of activated carbon fiber, the efficiency of also was small; so it has maximal quantity at the middle airflow velocity. The effect of TiO 2 to the Nanometer Photocatalytic T = 24 C.48, 6% = ppm Φ = TiO 2 C, the result is as the followed figure 6: make the experiment through changing the The results show that: the eliminates efficiency all were about 65% and the difference was too small. But as a reactant, according to the balance theory of the chemic reaction the should be decreased as the increasing of the TiO 2 and the eliminate efficiency should be increased. There were two possible reasons: one was that the was too small so that the.25% TiO 2 was enough; another was that when the TiO 2 was 4% the was too big and made the scale surface reduced and decreased the grads, so the reaction degree has no raise. THE EFFECT OF INTEGRATIVE FACTORS TO NANOMETER PHOTOCATALYTIC To seeing about the influence of the integrative factors to the effect of the author make the experiment at the condition of interrelated effective factors, the experiment design schedule and the results were as the followed table 1: Table 1. experiment design schedule and the results Original Temperature T Relative humidity % C Airflow velocity V Eliminate efficiency % 1 2 5.65 1.2.721 2 24 5.35.8.637 3 28 5.48 1.5.65 4 2 6.48.8.673 5 24 6.65 1.5.717 6 28 6.35 1.2.652 7 2 7.35 1.5.695 8 24 7.48 1.2.627 9 28 7.65.8.685 K1 2.89 1.963 2.123 1.995 K3 1.942 2.7 1.984 2.17 difference.147.44.139.24 The results show that in this experiment the difference of the temperature and original was the maximal and the others were smaller; this show that the temperature and original were the mainly influence factors. CONCLUSION From the experiment result we could found that: 1. The eliminate efficiency of the activated carbon fiber based nanometer material was larger than the adsorption. 2. single influencing factors the effect of the original was more obvious than the others. 3. To the interaction of all the influencing factors the average discrimination of the original and temperature was bigger than the others so it s effect to the performance were the most obvious 4. The effect of the relative humidity was unobvious. 334
Proceedings: Indoor Air 25 5. So at the process of designing some air filter the activated carbon fiber based could be used to adsorb the contamination and enhance the grads to increase the eliminate efficiency. REFERENCE Alberici RM., Jardim WF. Photocatalytic destruction of VOCs in the gas-phase using titanium dioxide. Applied Catalysis B: Environmental. 1997, 14, 55-68. Chen LX., Wu YX. The explore and application of the air purify technique China Environment and Health 2.3 Fujishima Al., Honda K. First-principles molecular dynamics simulation Nature 1972, 37, 238. Lin JD., Liang LY., Preparation of Fe-TiO 2 coating material and characterization of it s performance of degradation under visible irradiation Fine Chemicals 24.2 Peral J.and Ollis DF. Heterogeneous Photocatalytic Oxidation of Gas-Phase Organics for Air Purification: Acetone, 1-Butanol, Butyraldehyde, Formaldehyde, and m-xylene Oxidation. Journal of Catalysis 136, 554-565 (1992) Shang J., Du YG., Xu ZL. Progress in gas-solid heterogeneous oxidation of VOCs on TiO 2 nanoparticle Techniques and Equipments for Environment Pollution Control 2.3 Tian SY., Xiao YR. Experiment design and data processing China Architecture & Building Press Wang RH., Han X., Geng SB. Experiment of the adsorption performance of activated carbon fiberd to lower contaminates. Yang R., Zhang YP., Wang XK., et al. Experiment of air filter to eliminate dilute toluene in air Tsinghua University Beijing Heating Ventilation and air-conditioning 23.5 Yang R., Zhang YP. Performance parameters for reactors and a convenient method for measuring them Journal of engineering thermophysics 23.2 Yang JB. Research on CO 2 and VOCs based demand control ventilation Nanjing master degree paper of PLA university 22 Zhou YS., Chen LD., Wang QL. Et al. The experiment research of the to decompose the at the different technical parameter Environment Science and Technical 23.7 335