Portland State University. Department of Applied Science
Date of Award
Master of Science (M.S.) in Applied Science
1 online resource (110 pages). Digitized photocopy of typescript.
Sulfur dioxide, Douglas fir, Gases -- Absorption, Gases -- Adsorption
In recent years, people have raised their alertness to the hazard of air pollution. Sulfur dioxide is one of the most dangerous chemical compounds among those air pollutants. A study on removing sulfur dioxide from an air stream by adsorption using wood chips as the adsorbent is presented in this thesis. The reason for using wood as an adsorbent is that wood is a porous material and possesses a large surface of cell cavities which can hold a great amount of moisture. As sulfur dioxide gas is passed through the wood bed, it would be either condensed in the cell space of the wood by intermolecular attraction, adsorption or dissolved in the moisture held in the wood. This work was started with a review of literature. Then related references were collected and a proposal written. Douglas fir was chosen for the experiment because it is the most common kind of wood in the Pacific Northwest. After the process and proper equipment was set up, woodchips were screened and dried to prepare for further experiments. It was decided to use three different concentrations of sulfur dioxide. For each of the concentrations of sulfur dioxide, five levels of moisture (0%', 11%, 20%, 50% and saturated) were assigned to the selected woodchips. Fifteen combinations or experiments were done for the research. The results of the experiments show that dry wood (0% moisture content) had comparatively low characteristics in the adsorption of sulfur dioxide. For instance, at an influent so2 concentration of 1.12 ppm., about· 6 grams of dry woodchips adsorbed 29.37 µg. of sulfur dioxide in comparison to 2Q90.5 µg. of SO2 adsorbed in the same weight of woodchips but saturated with moisture. At an influent SO2 concentration of 1.83 ppm., the adsorption of sulfur dioxide increased from 7.73 µg. for the dry wood to 745.15µg. in the water saturated wood. For an influent SO2 concentration of 4.60ppm., dry wood adsorbed 15.26 µg. of SO2 while the moisture saturated wood adsorbed 1446.2 µg. The amount of dry woodchips used in above mentioned experiments were all about 6 grams. These data show that the moisture saturated wood adsorbed about 90 times the amount of sulfur dioxide that the dry wood adsorbed. It is clear that the wood adsorptivity increased with increasing moisture content. It was also found that wood adsorptivity and retention time were affected by the different flow rate of carrier gas. The figures show that most of the data fit a Freundlich equation. Other equations were developed to calculate the adsorptivity and retention time by obtaining the influent and effluent concentration of sulfur dioxide through the adsorbent bed.
Wang, Uen-Ping David, "Adsorption of Sulfur Dioxide on Douglas Fir Woodchips" (1971). Dissertations and Theses. Paper 1559.