Study On Phenolic Wastewater Treatment Using Photo-Fenton Reagent

The thesis expatiated on the quality and harm of phenolic wastewater. It was necessary and important to decontaminate the phenolic wastewater. It summarized the productions that many pursuers studied in the field of phenolic wastewater treatment and the traits of diversified technologies. It summed roundly up the theories about Fenton and Photo-Fenton, and the situation and progress in the treatment of refractory-degraded organic pollutant using Fenton and Photo-Fenton reagent.According to literatures, Fenton process is a kind of promising technology in wastewater treatment, and it gets an advantage over common oxidation process. So, for the sake of studying on "phenolic wastewater treatment by Photo-Fenton process", this paper studied on many experiments as following: (1) phenolic wastewater treatment by Fenton process: it was in order to understand the effect rule which were begotten by time, initiative pH value , H₂O₂ and Fe²⁺ concentration;(2)the optimal operating conditions using Photo-Fenton reagent: this part involved contratest effect using three types of degradative method—UV-Fenton, solar-Fenton and Fenton, analyzed the effect of diversified factor, and determined the optimal operating conditions by orthogonal experiments using solar-Fenton reagent;(3) disposal of dissimilar phenolic wastewater which concentration were different by Fenton and Photo-Fenton process: its primary aim was known the effect of initiative concentration;(4) disposal of dissimilar wastewater which phenolic compounds were different by Photo-Fenton process: there were hydroquinone, resorcinol and phlorglucinol;(5)the effect of metallic ion in Fenton reagent: in this part, the Cu²⁺,Co²⁺,Cr²⁺, Ni²⁺ and Sn²⁺ were studied;(6) reaction theories: there were two experiments—reactive kinetics and the intermediates.The experimental results indicated that UV-Fenton and solar-Fenton both could enhance effectively the removal efficiency of COD and phenol. When the average photic intensity was 35000Lux, the phenol and COD removal were 99% and over 60% respectively at [H₂O₂]= 12mmol/L, [Fe²⁺]=2.7mmol/L, pH=3, t=30min. Contrast to Fenton process, Photo-Fenton process had four merits as following: (1) The degradative efficiency was better. (2) The dosage was little. The dosage using Photo-Fenton was about 60% as much as that using Fenton process. (3) The condition of reaction was facile. The essential acidity was so low that the demand for equipment and the chroma of wastewater were reduced. (4) The high concentrated phenolic wastewater was degraded very well by Photo-Fenton process. Therefore, Photo-Fenton process, which is a kind of promising technology inwastewater treatment, can degrade diversified phoenolic wastewater economically and effectively. Considering adopting clean technology and economizing energy sources, we should attach importance to utilize sun's rays and we can take into account that solar-Fenton will be introduced into practical engineering.The experimental results also showed that the polyhydric phenol could be degraded by Photo-Fenton process. Under the same condition of photic intensity, the dihydric phenol and COD removals were 98.4% and 68.7% respectively at [H2O2]=7mmol/L, [ Fe2*]=1.5mmol/L, t=30min. While the tribasic phenol and COD removals were 99.6% and 74.8%. The degradative efficiency of phenolic compound was involved in hydroxy number, while not involved in hydroxy position.This paper pointed out that the degradative efficiency could be enhanced if Gu2+ or Co2+ replaced Fe2+ as catalyzer. The phenol removal can be enhanced 10 to 20 percents. The problem of chroma can be solved likewise. Furthermore, Cu2+ is a facile ion. So phenolic wastewater can be degraded better by solar- H2C>2-Ou2+ process.The research into reactive kinetics and the intermediates demonstrated that phenol became hydroquinone or catechol firstly in the reactive course. Secondly, they were oxidated organic acid by *OH. Finally, phenol was degraded drastically to CO2 and H2O2.