Activated Carbon Fiber Coupled With8-hydroxy Quinoline Ferric For Degradation Of Dyes

Fenton technology has been widely applied to environmental catalysis due to its simpleoperation, high efficiency and environmental-friendly oxidant. However, the usefulness of thecurrent technology is limited by the narrow pH range (2-3.5) and the separation of superfluousiron ions from the reaction media at the end of the reaction. Therefore, to overcome thedisadvantages associated with Fenton technology and develop Fenton-like catalysts with widerapplied pH range is a challenging project in the field of environmental catalysis. In this work,8-hydroxyquinoline was used to complex with ferric (QuFe). The obtained8-hydroxyquinolineferric was supported onto ACFs, which have excellent structural characteristics such as largesurface area, facilitating in machine-shaping and physical and chemical modification, to getnovel Fenton-like catalytic fibers (QuFe@ACFs), by an impregnation method. In thisdissertation, QuFe@ACFs not only have a simple preparation method, breaking the bottleneckthat limits the widespread application of Fenton-like catalyst to some extent, broadening itsapplication range, but also have important academic and practical value to solve more and moreserious water contamination. The main contents are as follows:1. Under neutral conditions, using H2O2as oxidant, the catalytic performance of QuFe@ACFsfor the degradation of reactive red M-3BE was studied. The experimental results showed thatQuFe@ACFs can efficiently activate H2O2to catalytically degrade reactive red M-3BE andremained almost unchanged catalytic activity at pH3，7and9after four repeated utilizationindicating that QuFe@ACFs had good sustaining catalytic ability. In addition,2. QuFe@ACFs can also catalyze oxidation of other dyes, such as Reactive Blue M-BRE,Reactive Brilliant Red M-3BE, Reactive Red X-3B, Basic Brilliant Green, Basic Green, AcidOrange II, Acid Red5B, etc. Compared with (Fe@ACFs) and QuFe, QuFe@ACFs showed moreexcellent pH-tolerant performance and reuse ability, suggesting that neither using ligands tocomplex iron ion (QuFe), nor using support to load iron ion (Fe@ACFs) can overcome the poorpH-tolerant performance of QuFe@ACFs, only the incorporation of the two strategies(Fe@ACFs and QuFe) can successfully solving this problem and get Fenton-like catalysts withexcellent pH-tolerance.3. The repeated utilization performance and structural stability of QuFe@ACFs at acidic (pH3), neutral (pH7) and alkaline (pH9) conditions were examined to investigate its pH-tolerant capability. Electron paramagnetic resonance (EPR) spectroscopy was employed to test thevariation of hydroxyl radicals in the QuFe@ACFs/H2O2system during the repeated utilization toinvestigate the catalytic stability of QuFe@ACFs. Meanwhile, a hydroxyl radical scavenger,O-phenylenediamine (OPDA), was used to further quantitatively investigate the variation ofhydroxyl radicals. Experimental results showed that the intensity of characteristic peaks ofhydroxyl radicals in each catalytic cycle remained almost unchanged, and generated high andstable amount of hydroxyl radicals. We also used UV-Vis spectra to examine the change ofQuFe@ACFs before and after repeated use, the results showed that the UV-Vis spectra ofQuFe@ACFs remained almost unchanged after4repeated utilizations, indicating thatQuFe@ACFs remained stable structure during the catalytic degradation of dyes and QuFe didnot self-decompose.4. Reactive dye (Reactive Red M-3BE) was selected as a basis, and was mixed with basic dye(alkaline Brilliant Green), acid dye (Acid Red5B), direct dye (direct blending yellow D-3RNL),reactive dye (reactive Yellow M-3RE), respectively to formulate simulated printing and dyeingwastewater. And H2O2was used as the oxidant to investigate the catalytic removal performanceof QuFe@ACFs, the results showed that the QuFe@ACFs/H2O2system effectively treated thetwo-component mixing dyes. Meanwhile, we also chose three typical reactive dyes (ReactiveBrilliant Red M-3BE, reactive blue M-BRE and Reactive Yellow M-3RE) to formulatethree-component mixed reactive dyes. The catalytic removal performance of QuFe@ACFs/H2O2system for the mixed reactive dyes was investigated and the result showed thatQuFe@ACFs/H2O2system can effectively catalytic degradation of three-component mixed dyes.In addition, we examined the effect of the degradation products of RR M-3BE (such as succinicacid and oxalic acid) and dyeing auxiliaries (such as sodium chloride and urea) on the catalyticdegradation of mixed dyes and the results showed that degradation products and additives hadalmost no influence on the catalytic degradation.