Electro2catalytic oxidation of phenol on Sb2doped SnO 2 2coated Titanium foams electrodes

Transcription

1 Acta Scientiae Circumstantiae Vol. 25,No. 8 Aug., 2005,,,. [J ].,2005,25 (8) : LIU Haiping, LI Ning, ZHOU Derui, et al. Electro2catalytic oxidation of phenol on Sb2doped SnO 2 2coated Titanium foams electrodes [ J ]. Acta Scientiae Circumstantiae,2005,25 (8) : ,,,,, : : : :, ph,. ( HPLC) (COD),,.. : ; ; ; ; : (2005) :X70315 :A Electro2catalytic oxidation of phenol on Sb2doped SnO 2 2coated Titanium foams electrodes LIU Haiping 3, LI Ning,ZHOU Derui, ZHOU Yuhong, LI Deyu Department of applied chemistry, Harbin institute of technology, Harbin Received 14 December 2004 ; received in revised form 1 June 2005 ; accepted 13 June 2005 Abstract : The electrochemical oxidation of Sb2doped SnO 22coated porous titanium anodes on phenol wastewater was studied. Various factors influencing phenolπs oxidation from the anodes was analyzed, such as ph, temperature, salinity of the electrolyte, initial phenol concentration and apparent current density etc. And phenolπs oxidation process and dynamic performance were also discussed. The research results showehat the intermediates of phenol on the anodes during the electrolysis by high performance liquid chromatography ( HPLC), ultraviolet absorption spectroscopy and COD included hydroquinone, benzoquinone, oxalic acid and maleic acid, anhe final product was carbon dioxide. Phenolπs oxidation dynamic performance on the anodes accorded with fitting2first order reaction. The method could be applieo treat high phenol concentration wastewater in high salinity and high acidity. Keywords :porous titanium;sb2doped SnO 2 2coated electrodes ;phenol ;catalytic oxidation ;degradation process, [1 3 ].,, [4,5 ].. E. Fockedey [6 ] -,,. 2,,,. 1 ( Methods) 111, 40 min, ; SnCl 4 5H 2 O2 SbCl 3 30 min, ; ; min, ; , : (1975 ),,,E2mail : com ; 3 ( ) Biography :LIU Haiping (1975 ), female, Ph. D. candidate, E2mail : com ; 3 Corresponding author

2 ,,, 015 cm. Na 2 SO 4. 1 Fig. 1 The schematic map of ECS apparatus 113 COD [7 ] ; 42, 510 nm [8 ] ; TU nm ; Agilent 1100 (HPLC) nm. 2 ( Results) 211, mg L - 1, j = 20 ma cm - 2, = 20, COD.,, 3,,, 310 V, 316.,. 2 COD Fig. 2 The removal rate of COD for the anodic oxidation of phenol 3 SEM Fig. 3 SEM of Porous Ti electrode ph j = 40 ma cm - 2 = 20 6 Ah L - 1, 200 mg L - 1 ph, 1. 1 ph COD Table 1 Effects of different ph on phenol and COD removal rate ph (phenol removal rate) COD (COD removal rate) % 4817 % % 4112 % % 4215 %,, ph [9 ].,, ph,,, (ph = 3, 200 mg L - 1 ) 4. 4,35, 50..,,,,.,,,

3 8 : Fig. 4 Effects of temperature on phenol removal rate,,.,,.,, , :, ( 5). : = 20, j = 40 ma cm - 2,pH = 3. 8 Ah L - 1, mg L - 1, 73 % 86 % 99 %. [2,10 12 ],, :,,,.,,,.,,, Na 2 SO 4,. Na 2 SO 4, : COD, 2 ( ph = 3 = 20, j = 20 ma cm - 2, 2 Ah L - 1 )., COD,.,,.. 2 Na 2 SO 4 COD Table 2 Effects of Na 2 SO 4 concentration on phenol and COD removal rate Na 2 SO 4 (Na 2 SO 4 concentration)π(mol L - 1 ) (phenol removal rate) COD (COD removal rate) % 2714 % % 3111 % % 3715 % mg L - 1 ph = 3 = 21, 6.,,,,.,40 ma cm Fig. 6 Effects of current density on phenol removal rate 3 5 Fig. 5 Effects of initial phenol concentration on phenol removal rate 311, 20 ph = 3 j = 20

4 ma cm - 2, 100 mg L - 1., :, ; ; ;.., ( 7). t = 0 min, K B, ; t = 60 min, K, B ; t = 140 min, K B. HPLC COD,, :,, ;,. [2,10 12 ],,,,, ; [2 ] CO 2. : (1) 312, OH, : 7 Fig. 7 UV spectra of raw and electrochemically treated wastewater 60 min HPLC ( 254 nm), 8. HPLC, :., 210 nm,. 8 60min HPLC (11 ;21 ;31 ;41 ) Fig. 8 HPLC chromatograms of phenol removal 60 mins. After the experiment beginning 260 min, COD 18 mg L - 1,. A : A + B k C (2) = kc n A C m B (3),A ;B ; C ; k ; n m ; C A C B ( t). OH [13 ], OH, : kc m B d C B Π 0 (4) = k, (3) : = k l C n A (5) OH H 2 O OH - [13 ],,,, H 2 O OH -, OH,. OH, : k = kc m B = k C A0 (6), k C A0 ;. n = 1, 1 :

5 8 : 1019 = k C A = k A0 C A (7) C 20, ph = 3, j = 20 ma cm - 2, ( C AO ),, ( C A ) t, - lg ( C A ΠC A0 ) t,, ( 9). k R k Fig. 10 Plot of initial phenol concentration with k,. 4 ( Conclusions) 9 - lg( C A ΠC A0 ) t Fig. 9 Curve of logarithmic concentration ratio ( C A ΠC A0 ) of phenol removal with time ( t) fitted by pseudo2first order model 3 k Table 3 Value of k fitted by pseudo2first order model in different origin concentrations C AO Π(mg L - 1 ) k Πh - 1 n R : - lg( C A ΠC AO ) = k t (6) : lg k = lg k + lg C A0 (8) 3 k C A0, lg k lg C A0, lg k = , = ; R 2 = ( 10).,,. k (7), : = C A0 C A (9) (9),, 1),,. 2) ph Na 2 SO 4.. 3) HPLC COD, :, ; ; ;. 4), : - d C = C ,0 C d t ( References) : [ 1 ] Christos Comninellis1 Electrocatalysis in the Electro2chemical ConversionΠcombustion of Organic Pollutants for Wastewater Treatment [J ]1 Electrochimica Acta, 1994, 39 (11Π12) : [ 2 ] Comninellis Ch, Pulgarin C. Electrochemical Oxidation of Phenol for Wastewater Treatment Using SnO 2 Anodes [ J ]. Journal of Applied Electrochemistry, 1993, 23 : [ 3 ] Wu X W, Zhao G H, Gao T Y. New technique of electrochemical watertreatment2elelctrocatalytic oxidation of bio2refratory organism [J ]. Acta Scientiae Circumstantiae, 2000, 20 ( S1) : ( in Chinese) [ 4 ] Pan H B. The preparation and performance of BaTiO 3 capacitor based on Ti porous[j ]. Development of Ti Industry, 1999 (3) :25 (in Chinese)

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