Studies On The Regeneration Of Fe(Ⅲ)NTA Solution

Fe(II)NTA aqueous can be used for simultaneous removal of SO2 and NO,while Fe(II)NTA is easily oxidized to Fe(III)NTA which has no complexation ability for NO by the oxygen from the flu gas.Activated carbon is utilized to catalyze reduction of Fe(III)NTA to Fe(II)EDTA with sulfite to maintain a high NO removal efficiency for a long time.In this study, the adsorption of NTA on activated carbon from the aqueous solutions has been investigated in a batch stirred cell. Experimental results manifest that NTA adsorption rate increases with its concentration in the aqueous solutions, NTA adsorption also increases with temperature. The NTA removal from the solution increases as activated carbon mass increases. The kinetic study shows that NTA adsorption on the activated carbon is in good compliance with the Intraparticle diffusion. The Freundlich equilibrium isotherm models are found to provide a good fitting of the adsorption data.Also we get the thermodynamic parameters of adsorption.In this paper,K2CO3 solution and EDA solution have been researched for the catalytic performance of modified coconut activated carbon in the regeneration of Fe(II)NTA solution.The chemistry of the samples is assessed by the means of FTIR,elementalanalysis,Boehm titration,potentiometric titration,and X-ray photoelectron spectroscopy analysis.The physical structure is characterized by BET.When the modification agent is K2CO3 solution,the optional modification condition is as below:the activated carbon bathed in 2.0mol/L K2CO3 solution for 12 hours and heated at 600℃ for 4 hours.When the modification agent is EDA solution, the optical modified condition as followed:the activated carbon is impregnated in the 5.0mol/L EDA solution for 6 hours and heated to 700℃ for 4 hours,the modified carbon shows the best catalytic performance. By comparison of the catalytic effect of the activated carbon, the catalytic activity of the activated carbon is the result of the chemical properties and physical structure of the activated carbon, and the effect of the chemical properties is more obvious.Continuous experiments are carried out in a fixed-bed reactor to test the catalytic performance of the modified activated carbon for the simultaneous absorption of NO and SO2 into the Fe(II)NTA and Na2SO3 solution.The experimental results demonstrate that the modification of activated carbon by K2CO3 solution and EDA solution,can improve its catalytic performance obviously.With the regeneration of Fe(II)NTA catalyzed by the modified activated carbon,a higher nitric oxide removal efficiency can be maintained for a long time.