School of Mechanical Engineering, Faculty of Engineering and Water Research Center, Tel Aviv University, Tel Aviv 69978, Israel.
Unit of Energy Engineering, Faculty of Engineering Sciences, Ben-Gurion University of the Negev, PO Box 653, Beer-Sheva 84105, Israel.
Chemosphere. 2017 Oct;184:1020-1027. doi: 10.1016/j.chemosphere.2017.06.076. Epub 2017 Jun 19.
Rhodamine B (RhB) is a water-soluble fluorescent dye that is often used to determine flux and flow direction in biotechnological and environmental applications. In the current research, RhB in soluble (termed free) and virus-bound (termed nano-bound) forms was used as an efficiency indicator for three environmental processes. The degradation of free and nano-bound RhB by (i) direct UV photolysis and (ii) UV/HO advanced oxidation process (AOP) was studied in a collimated beam apparatus equipped with medium-pressure mercury vapor lamp. The degradation by (iii) solar light-induced photocatalysis was studied in a solar simulator with titanium dioxide and bismuth photocatalysts. Results showed negligible RhB degradation by direct UV and solar light, and its nearly linear degradation by UV/HO and photocatalysis/photosensitization in the presence of a solid catalyst. Considerable adsorption of free RhB on bismuth-based catalyst vs. no adsorption of nano-bound RhB on this catalyst or of any form of the dye on titanium dioxide produced two important conclusions. First, the better degradation of free RhB by the bismuth catalyst suggests that close proximity of a catalyst hole and the decomposing molecule significantly influences degradation. Second, the soluble form of the dye might not be the best option for its use as an indicator. Nano-bound RhB showed high potential as an AOP indicator, featuring possible separation from water after the analysis.
罗丹明 B（RhB）是一种水溶性荧光染料，常用于生物技术和环境应用中测定通量和流动方向。在当前的研究中，将可溶性（称为游离态）和病毒结合的罗丹明 B（称为纳米结合态）用作三种环境过程的效率指标。在配备中压汞蒸气灯的准直光束装置中，研究了游离态和纳米结合态 RhB 通过（i）直接紫外光解和（ii）紫外/HO 高级氧化工艺（AOP）的降解情况。通过（iii）太阳能光诱导光催化在配备有二氧化钛和铋光催化剂的太阳能模拟器中进行了降解研究。结果表明，直接紫外光和太阳光对 RhB 的降解可忽略不计，而在固体催化剂存在下，紫外/HO 和光催化/光敏化作用下 RhB 几乎呈线性降解。游离态 RhB 大量吸附在基于铋的催化剂上，而纳米结合态 RhB 则不吸附在该催化剂上，或任何形式的染料均不吸附在二氧化钛上，这产生了两个重要结论。首先，铋催化剂对游离态 RhB 的更好降解表明，催化剂孔和分解分子的紧密接近显著影响降解。其次，染料的可溶性形式可能不是作为指示剂的最佳选择。纳米结合态 RhB 作为 AOP 指示剂具有很大的潜力，在分析后可能与水分离。
