Degradation Of Methylene Blue In Pulsed High-voltage Discharge With Spent Tea Leaves

Methylene blue (MB) is a basic dye, it is a representative of the dyeing wastewater, if MB wastewater is not being treated, and it will induce to great toxicity. Dyeing industrial wastewater is considered to be of complex compositions, different types,poor biodegradability, and it is toxic and hazardous, especially wastewater from the end of dyeing and the dyeing stage process, so it is known as one of the world's industrial wastewater that difficult to treat. As to this type of waste, normal physical, chemical and biological methods are difficult to meet the technical and economic requirements of purifying technology. if we fail to control it or to effectively govern it, it will cause serious environmental pollution and destruction. The objective of this study was to investigate the effect of STL, the reaction kinetics, and the change in the surface and chemical properties of the STL when exposed to PDP process. The study provides a reference for studying of economic catalyst.The results are as follows:(1) With the increasing of the dosage of spent tea leaves, the degradation rate of MB increases gradually, but when the tea dosage of 4.0g/L, the reduction rate of MB decreases slightly. The optimum dosage of STL was 3.2 g/L in the combined treatment employing both PDP and STL.(2) The degradation rate of MB increases as the tea mesh increases gradually, that is, the smaller the particle size of tea, the better effect of methylene degradation. k as possible as G50% have the same trend.(3) With the initial concentration of MB increases, the more molecules in the MB solution, the more chances in reaction molecules and the oxidation particles. Meanwhile, competition between molecules and oxide particles is intense. So the reaction concentration increased, the net removal of MB increased, but k and G50% declined.(4) pH in the high-voltage pulse response is an important factor. In our study, we selected three gradients, the acidic conditions (pH= 4), neutral (pH= 7) and alkaline conditions (pH= 10), but in the combination process, pH had little effect on the degradation rate of MB. (5) The study found that spent tea leaves in the combined treatment process are not only as an adsorption, but also a catalyst. And the tea can be reused in the experiment that is the regeneration of tea.(6) High voltage discharge has little effect on pore structure and surface chemistry of spent tea leaves. To the pore structure, total pore volume decreased slightly for used spent tea leaves, the reason is a decrease in the macrospore volume while an increase in the mesopore volume of the STL. Results of Fourier-transform infrared spectral suggest that no new peaks occurred in the case of used STL.