Font Size: a A A

Plasma Degradation Of Dye By A Nonpulsed Direct Current Glow Discharge In An Aqueous Solution And Synthesis Of Terephthalic Acid

Posted on:2007-01-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:J YanFull Text:PDF
GTID:1101360182986953Subject:Chemistry
Abstract/Summary:PDF Full Text Request
This dissertation consists of two different parts,Part one: Plasma degradation of dye by a nonpulsed direct current glow discharge in an Aqueous Solution;Part two : the synthesis of terephthalic.Recent interest in the application of a nonpulsed direct current glow discharge to the degradation of organic compounds in aqueous solution has grown enormously, mainly because of its high removal efficiency and environmental compatibility. In the reaction zone within the plasma around the anode, H2O vapor molecules was ionized or activated, and then bombard each other to break up by charge transfer, The ultimate result was the production of OH radicals and sometimes H radicals. On the other hand, in the liquid-phase reaction zone near the plasma-anolyte interface, several liquid H2O molecules broke up into H, OH and HO2 by being bombarded by each H2Ogas+. from the anodic plasma. As a mixture of the active species OH, H, H2O2 and H2Ogas+. difused out of the primary zone that was called plasma layer and into the bulk electrolyte, they could interact among themselves and with any active substrate in the solution. Since OH is one of the strongest oxidants that could oxidize many organic pollutants into fatty acids, carbon dioxide or simple inorganic compound, low-temperature glow discharge plasma can be applied in the treatment of organic contaminants in aqueous solution. The present work has studied the degradation of the dye in a highly conductive water solution using the non-pulsed direct current glow discharge plasma technology. The degradation process was observed through Ultraviolet (UV) absorption spectra. The applied voltage, initial pH value, as well as the concentration of the catalyst Fe2+ were investigated for the influence on the degradation of the dye. When the voltage is 900 V, initial pH value is 3, the concentration of Fe2+ is 5 mg/L, the de-colorization rate of the dye with the concentration of 50 mg/L can reach 98%, with the COD removal of 91% within 5 minutes.In the part two of this dissertation ,the new route synthesis of terephthalic was studied, A novel system consisting of AIBN and cobalt salts for the oxidation of p-tolualdehyde to terephthalic acid using molecular oxygen as the oxidant was firstly exploited.The experimental results revealed that the yields of terephthalic acid catalyzed by AIBN/Co(OAc)2/NaBr can reach 90%.
Keywords/Search Tags:direct current glow discharge, degradation, dye, non-pulsed, p-tolualdehyde, terephthalic acid, oxidation
PDF Full Text Request
Related items