Photocatalytic degradation of acid alizarin black (AAB) dye (C.I. 21725) in aqueous solution was investigated using UV light in the presence of hydrogen peroxide (H2O2) as a catalyst at different operating conditions. The operating conditions were concentration of catalyst dosage (0.1, 0.2 and 0.3 mL of 30 % H2O2), initial concentration of AAB dye (100, 150 and 200 mg/L) and pH (3.3, 6.84 and 10.8). It was found that the increasing of catalyst concentration enhanced the dye decolourisation. Hydrogen peroxide exerted positive effects on the AAB removal whilst the initial concentration of AAB negatively affected its removal. It was also found that the removal efficiency of AAB increased with the pH value close to neutral (pH 7), while a reversed trend was observed at acidic and basic medium

Haydar A. Mohammad Salim

Sabir A. Mohammad Salih

Sherwan M. Simo

Science Journal of University of Zakho

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Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              329HOMOGENEOUS PHOTOCATALYTIC DEGRADATION OF ACID ALIZARIN BLACK USING HYDROGEN PEROXIDE  Haydar A. Mohammad Salim, Sabir Ayob Mohammad Salih and Sherwan M. Simo Dept. of Chemistry, Faculty of Science, University of Zakho, Kurdistan Region-Iraq. (Accepted for publication: November  11,  2014)  ABSTRACT Photocatalytic degradation of acid alizarin black (AAB) dye (C.I. 21725) in aqueous solution was investigated using UV light in the presence of hydrogen peroxide (H2O2) as a catalyst at different operating conditions. The operating conditions were concentration of catalyst dosage (0.1, 0.2 and 0.3 mL of 30 % H2O2), initial concentration of AAB dye (100, 150 and 200 mg/L) and pH (3.3, 6.84 and 10.8). It was found that the increasing of catalyst concentration enhanced the dye decolourisation. Hydrogen peroxide exerted positive effects on the AAB removal whilst the initial concentration of AAB negatively affected its removal. It was also found that the removal efficiency of AAB increased with the pH value close to neutral (pH 7), while a reversed trend was observed at acidic and basic medium.   KEY-WORDS: Photocatalytic, AOPs, catalyst, wastewater, H2O2.  INTRODUCTION any modern techniques of treatment have been used over the last few decades to treat and purify water. Ozonation and photolysis techniques, for example, have been used successfully to degradate and reduce a range of organic and biological pollutants (Rice and Browning, 1981, Rice and Hoff, 1981, Barakat et al., 2005). However, stronger oxidant are produced (i.e. radicals) when these techniques are combined with some additives such as hydrogen peroxide and catalysts, and these processes together with additives are called Advanced Oxidation Processes (AOPs) (Glaze et al., 1987). AOPs are typically based on redox reactions as a result of gaining and losing electrons by radicals and organic molecules, respectively (Rice and Netzer, 1983). Among AOPs, in recent years, homogeneous photocatalysis methods have received a great attention in degrading or reducing organic pollutant (Al-Ekabi et al., 1991).   It is estimated that, in textile industries, more than 10 % of the dye is lost during the process of dyeing and discharged as effluent (Weber and Stickney, 1993). Since the existence of small quantities of dyes (even bellow 1 part per million) is clearly visible, the discharge of those coloured water pollutants in the environment is a considerable non aesthetic pollution source. Through hydrolysis, oxidation or other chemical reactions taking place in the phase of wastewater, wastes of dyes can also produce dangerous by-products and eutrophication (Zollinger, 1991, Tang et al., 1997). Therefore, dye effluents decolourisation has received increasing attention. In liquid phase, addition of hydrogen peroxide (H2O2), as oxidant, is an accepted technique to accelerate photocatalytic oxidation. For photocatalytic oxidation of water phase, the hydrogen peroxide effect was extensively investigated. Addition of moderate H2O2 concentration was found to be significantly accelerate degradation of dyes and aromatic compounds (Barakat et al., 2005, Mart'yanov et al., 1997, Balcioglu and Inel, 1996, Dionysiou et al., 2004). This study outlines the results achieved for the degradation of acid alizarin black (AAB) in the presence of H2O2. Various operating parameters were studied in this research including initial AAB concentration, amount of H2O2 and pH.   METHODOLOGY Materials Acid alizarin black (AAB) was purchased from Hopkin and Williams LTD, UK and used as received. A stock solution of AAB (1000 mg/L) was prepared on a daily basis in distilled water and other concentrations (100, 150 and 200 mg/L) were prepared by dilution the stock solution of AAB. The prepared stock solution was covered by aluminum foil and kept in dark. Hydrogen peroxide (H2O2) was purchased from ALPHA, India and used as received without further treatment. UV lamp with 254 nm (12 watt) was purchased from SEMTEC, China. Experimental procedures A closed semi-batch reactor, as shown in Fig. 1, was used in this study. A 500 mL, at a specific concentration, of the AAB solution was charged MJournal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              330into the reactor, this solution prepared from the stock solution by dilution. 30 % of H2O2 at a spesific volume (0.1, 0.2 and 0.3 mL) was added to the AAB solution. The volume of the reactor was 600 mL. It is made from PYREX glass and fitted with a sample port. The reactor was equipped with a plunging tube in which a SEMTEC 12 watt lamp was placed horizontally. A glass syringe with 5 mL volume was used, at a specific schedule, to collect samples. The pH values (3.23, 6.84, and 10.8) of these solutions were adjusted using 0.1M of NaOH and 0.1M of HNO3. The pH of the solution was determined using pH meter (EUTECH, Malaysia). Visible spectrophotometer (Jenway, 6700) was used to analyse the collected samples.      Fig. (1) Photocatalytic reactor  RESULTS AND DISCUSSION Effect of initial H2O2 concentration  The effect of H2O2 concentration on AAB decolourisation was studied and the results are shown in Fig.2. The figure shows the decolourisation of AAB solution in the presence of H2O2. The other experiment conditions were kept constant (AAB concentration was set to 100 mg/L, pH 6.84, and room temperature 24oC). Various volume of H2O2 (0.1, 0.2 and 0.3 mL) were used. Fig. 2 also shows how the increasing catalyst amount increases the removal efficiency. After 30 min reaction time, the decolourisation rate of AAB increased when the amount of H2O2 increased, due to the formation of highest amount OH● radicals when more H2O2 volume was used.  Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              331 Fig. (2) AAB removal by using different amount of H2O2 at 30 min ([AAB]o = 100 mg/L, Temperature= 24 oC, Volume = 500 mL, pH= 6.84)  After 5 min of the reaction (see Fig. 3), the removal percentage of AAB increased and reached 59 %, after using 0.1 mL of H2O2. However, the removal percentage enhanced and reached 81 % and 84.5 % when the volume of H2O2 increased to 0.2 and 0.3 mL, respectively. The removal efficiency of AAB was recorded the highest removal percentage when 0.3 mL of (H2O2)wasused.   Fig. (3) AAB removal percentage at various amount of H2O2 at 5 min ([AAB]o = 100 mg/L, Temperature= 24 oC, Volume = 500 mL, pH= 6.84)   Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              332Effect of initial AAB concentration  The effect of initial AAB concentration on the decolourisation rate of AAB was studied using UV light in the presence of H2O2. The results show that increasing the initial concentration of AAB reduced the decolourisation rate (see Fig. 4). The rate constant, k', was found to decrease linearly with increased initial AAB concentration. When AAB concentration increased from 100 to 200 mg/L, the decolourisation percentage of AAB at 5 min reaction time decreased from 81 % to 21 %, respectively (see Fig. 5). The dye loss, according to the following equation, was observed as a function of time and data were fitted to a pseudo first order rate model (Bali et al., 2004, Esplugas et al., 2002).       The plot of ln (C/Co) versus time gives a straight line with k' = - slope (k', as seen from figure, depends on the H2O2 concentration), so the reaction follows a pseudo-first order scheme. Table 1 and Table 2 show the effect of dye concentration and amount of H2O2 on rate constant. Table (1): Effect of AAB concentration on a pseudo-first order kinetic for the degradation of AAB  [AAB] (mg/L) k' (min-1) R2 100 0.2483 0.9608 150  0.1511 0.9808 200 0.0844 0.994  Table (2): Effect of  H2O2 amount on a pseudo-first order kinetic for the degradation of AAB                Fig. (4): Effect of initial AAB concentration on solution decolourisation at 60 min (Temperature= 23 oC, Volume= 500 mL, pH= 6.84)   H2O2 Volume (mL) k' (min-1) R2 0.1 0.1953 0.984 0.2 0.2327 0.9608 0.3 0.3052 0.9865 Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              333 Fig. (5) AAB removal percentage at various concentrations of AAB at 5 min (Temperature= 23 oC, Volume = 500 mL, pH= 6.84)  Effect of pH      The process of AAB removal is higher at pH close to 7 compared to AAB removal in acidic and basic medium.  As shown in Fig. 6, the removal percentage improved from 94 to 97 % when pH changed from 3.3 to 6.84, respectively. However, the improvement decreased from 97 to 95.4 % when pH increased from 6.84 to 10.8, respectively.   Fig. (6) Effect of pH on AAB removal percentage at 30 min (Temperature= 23 oC, Volume = 500 mL)      Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              334CONCLUSIONS Photocatalytic degradation, in the presence of H2O2, of AAB under different operating conditions was studied in this research. The operating conditions were initial dye concentration, amount of H2O2 and pH. The most effective improvements on the degradation of AAB were recorded with initial AAB concentration of 100 mg/L. It was also found that the increasing of H2O2 quantity enhance the reaction rate of AAB decolourisation. The removal efficiency of AAB was favourable in the neutral medium more than the acidic and basic medium. The removal percentage reached the maximum value at pH close to 7.   REFERENCES@ -AL-EKABI, H., SAFARZADEH-AMIRI, A., SIFTON, W. & STORY, J. 1991. Advanced technology for water purification by heterogeneous photocatalysis. International Journal of Environment and Pollution, 1, 125-136. -BALCIOGLU, I. A. & INEL, Y. 1996. Photocatalytic degradation of organic contaminants in semiconductor suspensions with added H2O2. Journal of Environmental Science and Health - Part A Environmental Science and Engineering and Toxic and Hazardous Substance Control, 31, 123-138. -BALI, U., ÇATALKAYA, E. & ŞENGÜL, F. 2004. Photodegradation of Reactive Black 5, Direct Red 28 and Direct Yellow 12 using UV, UV/H2O2 and UV/H2O2/Fe2+: a comparative study. Journal of Hazardous Materials, 114, 159-166. -BARAKAT, M. A., TSENG, J. M. & HUANG, C. P. 2005. Hydrogen peroxide-assisted photocatalytic oxidation of phenolic compounds. Applied Catalysis B: Environmental, 59, 99-104. -DIONYSIOU, D. D., SUIDAN, M. T., BAUDIN, I. & LAÎNÉ, J. M. 2004. Effect of hydrogen peroxide on the destruction of organic contaminants-synergism and inhibition in a continuous-mode photocatalytic reactor. Applied Catalysis B: Environmental, 50, 259-269. -ESPLUGAS, S., GIMÉNEZ, J., CONTRERAS, S., PASCUAL, E. & RODRı́GUEZ, M. 2002. Comparison of different advanced oxidation processes for phenol degradation. Water Research, 36, 1034-1042. -GLAZE, W. H., KANG, J. W. & CHAPIN, D. H. 1987. The Chemistry of Water Treatment Processes Involving Ozone, Hydrogen Peroxide and Ultraviolet Radiat. International Ozone Association, 9, 335-352. -MART'YANOV, I. N., SAVINOV, E. N. & PARMON, V. N. 1997. Photocatalytic Oxidation of Methyl Viologen in an Aqueous Suspension of TiO2 in the Presence of Oxygen and Hydrogen Peroxide. The Effect of the Solution pH and H2O2 Concentration on the Reaction Rate. Kinetics and Catalysis, 38, 70-76. -RICE, E. W. & HOFF, J. C. 1981. Inactivation of Giardia lamblia cysts by ultraviolet irradiation. Appl Environ Microbiol, 42, 546-7. -RICE, R. G. & BROWNING, M. E. 1981. Ozone treatment of industrial wastewater, Park Ridge, N.J., Noyes Data Corp. -RICE, R. G. & NETZER, A. 1983. Handbook of Ozone Technology and Applications, Vol 1, Rice,Rg, Netzer,A. Journal American Water Works Association, 75, 64-64. -TANG, W. Z., ZHANG, Z., AN, H., QUINTANA, M. O. & TORRES, D. F. 1997. TiO2/UV photodegradation of azo dyes in aqueous solutions. Environmental Technology, 18, 1-12. -WEBER, E. J. & STICKNEY, V. C. 1993. Hydrolysis kinetics of Reactive Blue 19-Vinyl Sulfone. Water Research, 27, 63-67. -ZOLLINGER, H. 1991. Color chemistry: syntheses, properties, and applications of organic dyes and pigments, VCH.  @@@@ @@Journal of University of Zakho, Vol. 2(A) , No.2, Pp 329-335, 2014              335@@@bäìí›ÙŽïm@ŽõŠò‡äbè@bÙŽî‹i@•òŠ@ŽôåîŠaïÜó÷@Žô’‹m@bÌbîíil@ŽôïèbäìŠ@@bäbåï÷ŠbØí÷@ŠììˆμuìŠ‡îbè@õ‡ïØ @@Zón‚íq åïÜíØóÄ@ ŽôÄ†‡Žï@a@•òŠ@ ŽôåîŠaïÜó÷@ Žô’‹m@bÌbîíi@bäìí›ÙŽïm(AAB, C.I. 21725)@@ ŽôïèbäìŠ@ ŽõŠò‡äbè@bÙŽî‹i@ómbè@ç‹Ø@ a†@ôÄb÷@ ŽôØónŽîìb÷@ Äbä†@ a‡ï“Ðóåi@ Šó@ bÙ“ïm@ bäbåï÷ŠbÙi@ bäìíióè@lììˆìIμuìŠ‡îbè@õ‡ïØí÷@ ŠH2O2@ H@ÛòìŠbØîóòŠ@ ŽôØŠò‡äbè äóu@³ÜŒaìbïu@oŽîŠa†‹Ø@ ‡mbè†@ÚŽïq@ ŽôåïÜíØóÄ@ ŽôÄ@ æŽïî@ õŠbØ@ æŽï‚ì†Šbi@ Næ@I 0.3, 0.2, 0.1Ýà@ˆ@ÝïH2O2 %30@HŽônîóqˆ@@ßó †@õŠóîŠbØŽônîóq@@ôîbmòŠóI@l200, 150, 100HÜ@OâÍÝà@@bÌbîíi@ŽôîAAB@@ìpH@I@õónŽîìb÷@ŽõSNS@LVNXT@LQPNXH@bä‹Øò‡ŽîŒ@l@ŽôåïÜíØóÄ@ŽôÄˆ@´î†@ómbè@NŽônîóq@Šò‡äbè@ŽôîŠbÙîŠbè@õ@ bÌbîíi@ ŽôäòŠ@ bäŽîˆ@ ŠóÜ@póØ†AAB@ NŠò‡äbèôåïuìŠ‡îbè@ õ‡ïØí÷@ Šììˆ@ Žñ@@ æŽïàb−ó÷@ Ûò‡åèóäbÅïmòŒíq@@ça†@ bÌbîíi@ bäŽîˆ@ ŠóÜAAB@@ bäbåï÷ŠbÙi@l@ Ž¶@ ŽônîóqôîbmòŠó@@ ŽôîAAB@@ bØóä‹ÙŽïmŠbØóäbÅïnŽïŽïä@@ŽôÄ@ bäŽîˆ@ ŠóÜ@‹ØNŽôÌbîíi@è@ bòìŠóè@´î†@ ómb@ bÌbîíi@ bäŽîˆ@oŽï’†@ òŠò‡äbè@Óó÷AAB@@ Žôîbèói@ ßóØ†@póØò‡ŽîŒpH@@íi@oïi@ÚîŽïäbmìbè@IpH 7HNa†@ônÑm@ì@•‹m@a‡äóÄbä†@óîóäaìó›Žïi@oïi@Šbî†@Žõ†@Ž¶óiL@@@@@@@@@ãa‡ƒnhi@†íÿa@æîŠaïÜc@àby@óÍj—Ü@ð÷í›Üa@ïÑznÜa@Šíè‡mìia@‡ïØμuìŠ‡ï@@@@ó–þ©a Šíè‡m@ óaŠ†@ @@ †íÿa@ æîŠaïÜc@àby@ óÍj—Ü@ ð÷í›Üa@ ïÑznÜa(AAB, C.I. 21725)@@ð÷b¾a@ ßíÝa@ À@ †íuíiì@ óïvÑåjÜa@ ×íÐ@ óÉ’ÿa@ ãa‡ƒnhiμuìŠ‡ïa@ ‡ïØìi (H2O2)@aíÉØ@ ÞàòÑ«@@ óÜby@ ÀÄóÑÝn¬@Óì‹@NI@ðè@óaŠ‡Üa@ë‰@ÞáÉÜa@Óì‹Ä@oäbØìPNQ@LPNR@LPNS@ÝàÝï @æàSP@@EH2O2a@óÈ‹§@H@ðÜìÿa@ïØÜaì@ÑIQPP@LQUP@LRPP@HÜ@OâÍÝà@@ßa@Îj—ÜAAB@@ìpH@I@ßíÝaSNS@LVNXT@LQPNXH‡uì@‡Ôì@N@@óaŠ‡Üa@ë‰è@À@æà@ŒÉî@Ña@ïØ‹m@ò†bîŒ@çc@çíÝÜa@óÜaŒgóÍj—Ü AAB @N@μuìŠ‡ïa@‡ïØìi@ßa@óÍj–@óÜaŒg@À@óïib°g@w÷bnä@oÈcAAB@@ß@ðÜìÿa@ïØÜa@çc@μy@ÀAAB@NóÍj—Üa@ë‰è@óÜaŒg@À@bïjÝ@p‹qdm  @ßa@óÍj–@óÜaŒg@òöbÑØ@çc@b›îc@μjmAAB@aŒ†@ óáïÔ@ Êà@ppH@jî‹Ôb@@ ¶gß†bÉnà@IpH 7H@ L@Æy@ íÜ@μy@ÀÛíÝÜa@ð›àb¨a@ÂíÜa@À@ðÙÉÜa@@ìNñ‡ÈbÕÜa@@@@

Homogeneous Photocatalytic Degradation of Acid Alizarin Black Using Hydrogen Peroxide

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Homogeneous Photocatalytic Degradation of Acid Alizarin Black Using Hydrogen Peroxide

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