| 摘要: | 太陽能電池廠製程氨氮廢水為單一產出源，源自CVD製程使用的氨氣，製程廢氣經CVD機台附屬設備洗滌處理後形成氨氮廢水，廢水中氨氮濃度相對偏低且變化劇烈，濃度介於236 ~ 910mg/ L，同時CVD製程因使用SiH4導致廢水中含大量粒狀SiO2汙染物。
本研究運用MD膜組選擇性功能來分餾萃取製程廢水中的氨氮，並以硫酸吸附成為硫酸銨，研究結果顯示，氨氮廢水pH調升至11.4後，氨氮(NH4+ )與游離氨(NH3(g))轉態率達99%，提高氨氮廢水溫度可增加轉態率，但溫度提升會增加操作成本，加溫僅適用於季節低溫時維持廢水溫度已保持系統處理效能。
硫酸最適合操作區間為pH = 2 ~ pH =3區間， 氨氮濃度界於323 ~ 448 mg/L低濃度區間時，低於循環硫酸流量與氨氮廢水流量最適操作比為2：1，氨氮濃度界於672 ~ 1,210 mg/L高濃度區間時則須操作於1：1，以降低水分滲透MD速率，以使硫酸銨產出比重可提升到22~24%；低濃度區間流量比越高系統處理效率越高，高濃度區間則呈相反結果，流量比提升後會因水分競爭因素導致游離氨穿透MD膜空間不足，系統處理效率相對降低。
串聯兩組MD後系統高處理效率可高達99%，與pH =11.4的氨氮(NH4+ )與游離氨(NH3(g))轉態率99%完全一致，顯示滯留時間充足且各項操作條件控制得宜，MD處理系統的效能極高，非常適用於處理太陽能製程氨氮廢水。
;The NH3-N wastewater in the process of solar cell plant is generated from single source, N2 used in CVD process. The waste gas generated in the process forms NH3-N wastewater after washed by the auxiliary equipment of CVD machine. With drastic change, the ammonia nitrogen concentration in the wastewater is relatively low in the range of 236 ~ 910mg/ L. Moreover, the wastewater contains large amount of SiO2 pollutant because SiH4 is used in CVD process.
The study applies the selective function of MD film module for fractional extraction of NH3-N contained in the wastewater, which is then adsorbed by H2SO4to form (NH4)2SO4. As shown in the results, after the addition of ammonia nitrogen wastewater pH value raises to 11.4, the transition rate of NH 4+ and and and NH 3(g)3(g) 3(g) may reach may reach may reach may reach may reach may reach may reach 99% , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature , which may be increased with the temperature of of ammonia nitrogen wastewater. However, the temperature increase will add operation cost. Heating is only applicable to maintain the temperature of wastewater during seasons with low temperature, so as to retain the system processing performance.
The optimal operation range for H2SO4 is pH = 2 ~ pH =3. When the NH3-N concentration is within the low range of 323 ~ 448 mg/L, the optimal operation ratio lower than the cyclic H2SO4 flow and NH3-N waste water flow is 2:1. When the ammonia nitrogen concentration is within the high range of 672 ~ 1,210 mg/L, the operation ratio is 1:1. This can decelerate the water permeating MD, and increase the output proportion of (NH4)2SO4 to 22~24%. Higher the flow ratio within the low concentration range will result in higher system processing efficiency, and vice versa. When the flow ratio is increased, it will result in insufficient space for NH 3(g)3(g) 3(g) to permeate MD film due to the water
competition factor, and the system processing efficiency will be lowered accordingly.
After serial connection of two MDs, the system processing efficiency can reach as high as 99%, which is completely consistent with the transition rate of NH 4+ and NH 3(g)3(g) 3(g) under pH =11.4. It may provide sufficient retention time and control various operation conditions properly. Moreover, it may get extremely high efficiency of MD processing system. So it is quite suitable to the treatment of ammonia nitrogen wastewater in the solar process. |
