Bali Ulusoy, Catalkaya Ebru, Sengül Füsun
Environmental Engineering Department, Cumhuriyet University, 58140 Sivas, Turkey.
J Hazard Mater. 2004 Oct 18;114(1-3):159-66. doi: 10.1016/j.jhazmat.2004.08.013.
The photodegradation of three commercially available dyestuffs (C.I. Reactive Black 5, C.I. RB5, C.I. Direct Yellow 12, C.I. DY12, and C.I. Direct Red 28, C.I. DR28) by UV, UV/H(2)O(2) and UV/H(2)O(2)/Fe(II) processes was investigated in a laboratory-scale batch photoreactor equipped with an 16W immersed-type low-pressure mercury vapour lamp. The experimental results were assessed in terms of absorbance and total organic carbon (TOC) reduction. The initial concentration was kept constant at 100 mg l(-1) for all dyes. Initial results showed that, color removal efficiencies by UV or H(2)O(2) alone were negligible for all dyes. Almost complete disappearance of C.I. RB5 (99%) and DY12 (98%) in UV/H(2)O(2) process was possible to achieve after 60 min of irradiation. The maximum color removal efficiency of C.I. DR28 after 60 min of irradiation, however, was only 40% and reached a maximum value of 70% after 120 min of irradiation. Corresponding mineralization efficiencies were 50, 55 and 7-12%, respectively. The addition of Fe(II) to the system, so-called the photo-Fenton process, greatly enhanced the color removal, the efficiencies being 98, 88 and 85% for C.I. RB5, C.I. DY12 and C.I. DR28 only after 5 min of irradiation. Corresponding mineralization efficiencies were 98% for 45 min irradiation, 100% for 60 min irradiation and 98% for 90 min irradiation, respectively. However, marginal benefit was less significant in the higher range of both H(2)O(2) and Fe(II). Furthermore, decreases in both decolorization and mineralization were observed at higher concentrations of oxidant and catalyst due to the scavenging effect of excess H(2)O(2) and OH radicals. The degradation of all dyes was found to follow first-order reaction kinetics.
在配备16W浸入式低压汞灯的实验室规模间歇式光反应器中，研究了三种市售染料（C.I.活性黑5、C.I. RB5、C.I.直接黄12、C.I. DY12和C.I.直接红28、C.I. DR28）在紫外线、紫外线/H₂O₂和紫外线/H₂O₂/Fe(II)工艺下的光降解情况。通过吸光度和总有机碳（TOC）的降低来评估实验结果。所有染料的初始浓度均保持在100 mg l⁻¹不变。初始结果表明，单独使用紫外线或H₂O₂时，所有染料的脱色效率都可忽略不计。在紫外线/H₂O₂工艺中，照射60分钟后，C.I. RB5（99%）和DY12（98%）几乎完全消失。然而，C.I. DR28照射60分钟后的最大脱色效率仅为40%，照射120分钟后达到最大值70%。相应的矿化效率分别为50%、55%和7 - 12%。向系统中添加Fe(II)，即所谓的光芬顿工艺，大大提高了脱色效果，对于C.I. RB5、C.I. DY12和C.I. DR28，仅照射5分钟后的效率分别为98%、88%和85%。相应的矿化效率分别为照射45分钟时98%、照射60分钟时100%和照射90分钟时98%。然而，在较高的H₂O₂和Fe(II)范围内，边际效益不太显著。此外，由于过量H₂O₂和OH自由基的清除作用，在较高浓度的氧化剂和催化剂下，脱色和矿化都有所下降。发现所有染料的降解均符合一级反应动力学。
