Study On The Purification Performance Of Formaldehyde By Chitosan Purification Unit

Indoor air quality is closely related to people's health and China's indoor air quality is generally in poor condition.Formaldehyde pollution is particularly prominent and widely known,and it is not easy to remove.In this study,chitosan was selected as the formaldehyde purification material,and the chitosan filter cloth was made into chitosan filters with different pleat numbers,pleat heights and thickness.The impact of above parameters and filtration rate on purification performace were studied.Temperature of the duct system was?20±3??,and the relative humidity was 50%⁷5%.Experimental results showed that resistance increased linearly with the increase of pleat number,but single-pass efficiency and quality factor both decreased as pleat number increased.At the filtration rate of 0.05 m/s,when the total weight of chitosan was 28.5 g,the single-pass efficiency of a four-pleat-filter was 13.1%,the resistance was 6 Pa,and the quality factor was 0.023 Pa^-1.When the amount of chitosan was constant,the filter resistance decreased with the increase of pleat height.The single-pass purification efficiency and quality factor increased with the increase of pleat height,that is,the resistance increased with the increase of the pleat angle.Purification efficiency and quality factor increased as the pleat angle decreased.When pleat number,heights,widths and filtration rate were constant,the resistance increased linearly with the increase of the thickness of filter layers,and purification efficiency increased too,but the growth trend gradually slowed down.There was not much difference in the quality factor of filters with different thicknesses.When filter parameters were constant,as filtration rate increased,the resistance increased with a power function,and the purification efficiency decreased linearly.The quality factor decreased rapidly with increasing filtration rate.In this study,at the filtration rate of 0.05 m/s,the4-pleat-filter with a thickness of 5 mm had a better performance,wherein the single-pass purification efficiency was 54.73%,the resistance was 34 Pa,and the quality factor was 0.022 Pa^-1,and the amount of formaldehyde purified by every unit of chitosan was 0.029?g/s.In this paper,chitosan filter was combined with air purifiers too.The temperature and relative humidity was controlled at?23±2??and?50±10?%.Circulating air volume was 150 m³/h and the initial concentration of formaldehyde was 1 mg/m³.The purification efficiency achieved 23.12%at 1 h,and the total amount of formaldehyde purified is 6.9 mg,that is,the purification amount of formaldehyde per unit weight of chitosan is 0.0175 mg/g.The CADR of chitosan purifier achieved 7.38 m³/h.The above researching conclusions indicate that Chitosan purifiers have greater advantages than ordinary activated carbon purifiers.