Degradation Of Methylene Blue Wastewater By Titanium Dioxide Activated Carbon Coupled With Low Temperature Plasma

In this paper,nano TiO₂ was loaded on granular activated carbon to get TiO₂-GAC by the powder sintering method,then we analyzed the specific surface area,pore volume,surface groups and the adsorption performance of the TiO₂-GAC and GAC by scanning electron microscopy,micro analyzer,Boehm titration,FTIR Spectrometer.Next,degrading the methylene blue dye wastewater by TiO₂-GAC coupled with DBD plasma to analyz the synergistic effect of activated carbon adsorption,photocatalytic oxidation,DBD plasma oxidation technology and the the effects of the discharge voltage,the initial electrical conductivity,the TiO₂-GAC adding quantity on the degradation.Then coming up with the possible decomposition pathways of methylene blue molecular on the basis of analysing the intermediate product by GC/MS.Finally,regenerating the TiO₂-GAC adsorpting methylene blue saturated by DBD plasma.The experiment concluded following results:?1?Because of the load of TiO₂,The BET more specific surface area decreased by 9.56%,the total pore volume decreased by 12.29%,the average pore diameter increased by 3.34%;the number of acidity groups such as carboxyl fell by 12.78%.?2?The adsorption rate and adsorption capacity of TiO₂-GAC was lower than GAC;The increasing of temperature was conducive to the methylene blue adsorption of TiO₂-GAC and GAC.The biggest methylene blue adsorption capacities of TiO₂-GAC were respectively 108.70mg/g,123.46 mg/g and 135.14 mg/g when the temperature reached respectively 288.15 K,298.15 K,308.15 K,respectively 3.26%,3.26%,8.64% lower than the GAC.Langmuir isotherm equation and the secondary reaction kinetics model had a better expression for that adsorption process,chemical adsorption is the most important adsorption mechanism of the adsorption process.?3?Compared with GAC,TiO₂-GAC had a better synergy with DBD plasma for the degradating of methylene blue,but the synergistic strength decreased along with the reaction of reactant concentration decline gradually.When degrading 100 ml methylene blue wastewater?100 mg/L?by 2g TiO₂-GAC or GAC coupled with DBD plasma,the degradation rate of TiO₂-GAC,GAC are 21.35% and 21.35% respectivelywhen experiment go on for 5 min at the condition of 8mm plate spacing,9KHz discharge frequency,11 KV discharge voltage,and the synergistic strength were60.89 and 26.27 respectively.Experiments for 40 min,the degradation rate were98.38% and 95.22% respectively,but the synergistic strength were-8.56 and-15.04 respectively.The methylene blue simulated wastewater degradation by TiO₂-GAC adsorption coupled DBD plasma oxidation increased along with the increasing of discharge voltage and TiO₂-GAC dosage,the improvement of initial conductivity has a dual effect on the degradation.When the methylene blue was degradated by TiO₂-GAC adsorption coupled DBD plasma oxidation,the N-C and S-N key were attacked by active particle firstly with the generation of SO42-?NO3-and Biphenylene,then there came to lots of benzene ring opening intermediate products such as“8-Hexadecenal,14-methyl-,?Z?-”,4-phenyltridecane,they were finally oxidized to CO₂ and H2 O.?4?The DBD plasma had a better regeneration effect for TiO₂-GAC than GAC,especially in the early stage of the regeneration.The regeneration rate of TiO₂-GAC was 4.53% 13.31% higher than GAC in the 2 g wet TiO₂-GAC or GAC?about 40%moisture content?regeneration experiment under the condition of 10 KHZ discharge frequency,“10 mm-10 kv” “plate spacing-discharge voltage”.The discharge voltage and plate spacing influence the regeneration of methylene blue from two positive and negative aspects respectively;.The DBD plasma regeneration effect of TiO₂-GAC increased along with the increasing of discharge frequency,decreased along with the decreasing of the number of regeneration.The carbon loss rate increased when the number of regeneration increases,especially after 3 times.Wet TiO₂-GAC had a better regeneration effect than dry TiO₂-GAC.