Suri Rominder P S, Liu Junbiao, Crittenden John C, Hand David W
a Department of Civil and Environmental Engineering , Villanova University , Villanova , Pennsylvania , USA.
b Department of Civil and Environmental Engineering , Michigan Technological University , Houghton , Michigan , USA.
J Air Waste Manag Assoc. 1999 Aug;49(8):951-958. doi: 10.1080/10473289.1999.10463861.
The overall objective of this pilot-scale study is to investigate the technical feasibility of the removal and destruction of organic contaminants in water using adsorption and photocatalytic oxidation. The process consists of two consecutive operational steps: (1) removal of organic contaminants using fixed-bed adsorption; and (2) regeneration of spent adsorbent using photocatalysis or steam, followed by decontamination of steam condensate using photocatalysis. The pilot-scale study was conducted to evaluate these options at a water treatment plant in Wausau (Wisconsin) for treatment of groundwater contaminated with tetrachloroethene (PCE), trichloroethene (TCE), cis-dichloroethene (cis-DCE), toluene, ethylbenzene (EB), and xylenes. The adsorbents used were F-400 GAC and Ambersorb 563. In the first treatment strategy, the adsorbents were impregnated with photocatalyst and used for the removal of aqueous organics. The spent adsorbents were then exposed to ultraviolet light to achieve photocatalytic regeneration. Regeneration of adsorbents using photocatalysis was observed to be not effective, probably because the impregnated photocatalyst was fouled by background organic matter present in the groundwater matrix. In the second treatment strategy, the spent adsorbents were regenerated using steam, followed by cleanup of steam condensate using photocatalysis. Four cycles of adsorption and three cycles of steam regeneration were performed. Ambersorb 563 adsorbent was successfully regenerated using saturated steam at 160 °C within 20 hours. The steam condensate was treated using fixed-bed photo-catalysis using 1% Pt-TiO photocatalyst supported on silica gel. After 35 minutes of empty bed contact time, more than 95% removal of TCE, cis-DCE, toluene, EB, and xylenes was achieved, and more than 75% removal of PCE was observed. In the case of activated carbon adsorbent, steam regeneration was not effective, and a significant loss in adsorbent capacity was observed.
这项中试规模研究的总体目标是调查使用吸附和光催化氧化去除和销毁水中有机污染物的技术可行性。该过程包括两个连续的操作步骤：（1）使用固定床吸附去除有机污染物；（2）使用光催化或蒸汽对废吸附剂进行再生，随后使用光催化对蒸汽冷凝液进行净化。在威斯康星州沃索的一家水处理厂进行了中试规模研究，以评估这些方案对受四氯乙烯（PCE）、三氯乙烯（TCE）、顺式二氯乙烯（cis-DCE）、甲苯、乙苯（EB）和二甲苯污染的地下水的处理效果。使用的吸附剂是F-400颗粒活性炭（GAC）和Amber sorb 563。在第一种处理策略中，吸附剂浸渍有光催化剂并用于去除水中有机物。然后将废吸附剂暴露于紫外光下以实现光催化再生。观察到使用光催化对吸附剂进行再生无效，可能是因为浸渍的光催化剂被地下水基质中存在的背景有机物污染。在第二种处理策略中，使用蒸汽对废吸附剂进行再生，随后使用光催化对蒸汽冷凝液进行净化。进行了四个吸附循环和三个蒸汽再生循环。Amber sorb 563吸附剂在160℃下使用饱和蒸汽在20小时内成功再生。使用负载在硅胶上的1%Pt-TiO₂光催化剂通过固定床光催化处理蒸汽冷凝液。在空床接触时间为35分钟后，TCE、cis-DCE、甲苯、EB和二甲苯的去除率超过95%，PCE的去除率超过75%。对于活性炭吸附剂，蒸汽再生无效，并且观察到吸附剂容量有显著损失。
