{Study on the removal of no from flue gas by wet scrubbing using NaClO3} J. Serb. Chem. Soc. 84 (10) 1183–1192 (2019) UDC 66.074+546.172.6:66.08.3+ JSCS–5256 546.33’131:66.095.828 Original scientific paper 1183 Study on the removal of NO from flue gas by wet scrubbing using NaClO3 DEQI SHI, GUOXIN SUN and YU CUI* School of Chemistry and Chemical Engineering, University of Jinan, No. 336, West of Nan Xinzhuang, Jinan, 250022, Shangdong, P. R. China (Received 5 March, revised and accepted 17 May 2019) Abstract: In order to remove nitric oxide (NO) from flue gas, from small coal- -fired boilers, it is necessary to exploit the cost-effective wet denitration tech- nology. The absorption of NO with sodium chlorate solution was studied. The effects of experimental conditions, such as temperature, NaClO3 concentration, type of acid, mole ratio of NaClO3 to hydrogen ions, on NO removal rate were investigated, and the optimal conditions were established. As the effect of tem- perature on denitration was related to the type of acid used, the temperature required for sulfuric acid was high, and the temperature required for nitric acid was low. The optimal mole ratio between NaClO3 and the two types of acids was the same. The reaction products were analyzed by ion chromatography. The reacted solution could be recycled after the removal of sodium chloride. The reaction mechanism and the total chemical reaction equation of NaClO3 denitration were deduced. The thermodynamic derivations showed that this oxidation reaction could proceed spontaneously and the reaction was very thor- ough. NaClO3 exhibited high NO removal efficiency and its denitration cost was much lower than sodium chlorite. Keywords: nitrogen oxides; oxidation; absorption; NaClO3; denitration. INTRODUCTION Air pollution caused by the burning of fossil fuels is increasingly serious, and the NOx emitted by the fuels can lead to atmospheric ozone depletion, acid rain1,2 and visibility problems, through a series of complex reactions with water and oxygen.3 Denitration methods such as selective catalytic reduction (SCR) and selec- tive non-catalytic reduction (SNCR) have been extensively studied proved to be a great success in large power plants. However, due to the high cost of SCR and the low efficiency of SNCR, industrial denitration process4 is still immature in * Corresponding author. E-mail: chm_cuiy@ujn.edu.cn https://doi.org/10.2298/JSC190305053S ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. 1184 SHI, SUN and CUI the practical application of small coal-fired boilers.5,6 In addition, the ammonia denitration efficiency is low due to the large temperature difference of flue gas from small boilers. These technologies can not be applied to the treatment of dusty flue gases in steel, ceramics and cement plants. A large amount of dust in the flue gas can easily block the catalyst channel and cause catalyst poisoning. The development of efficient denitration technology is of great significance to environmental protection in various countries. The wet denitration technology is less affected by temperature in removing dust. It requires less investment and is suitable for coal-fired boilers in oil wells and remote areas. Therefore, it is necessary to develop economical and efficient wet denitration technology.7–11 Wet denitration technology is one of the most popular technologies in indus- trial scale in recent years. The method uses a strong oxidant to oxidize NO to nitrogen dioxide (NO2),12,13 which can be absorbed by water or alkaline solution. Up to now, a varity of oxidants, such as ClO2,14 KMnO4/NaOH,15 NaClO2,16–18 NaClO2/NaOH,19–21 NaClO2/(NH2)2CO,22 H2O223,24 and water-soluble ferrous- -chelating agents,25 may be included. Among these oxidants, NaClO2 showed better oxidation performance and the industrial application test was carried out. However, the treatment cost of the system was too high to be a practical NOx control process. In order to reduce the denitration cost and improve the denitration efficiency, NaClO3 was used to remove NOx from simulated flue gas in this paper. One molecule of NaClO3 can oxidize more NO than the one of commonly used NaClO2, while the price of NaClO3 is only one third of NaClO2. The reacted liquid could be reused after removing NaCl from the solution. Therefore, deve- loping the denitration technology with NaClO3 has a good prospect for the wet denitration of industrial flue gas. However, there are few basic researches on NaClO3 denitration technology. In this research, a new denitration solution made of NaClO3 was used for the removal of NO in a bubble reactor. Various influencing factors on the removal efficiency of NO were measured, in order to determine the optimal experimental conditions. The reaction mechanism and the total chemical reaction equation for denitration using NaClO3 were deduced. This method might be applied to an ind- ustrial scale denitration process. EXPERIMENTAL Materials The analytical grade reagents used in experiment were H2SO4 (95–98 wt. %) and HNO3 (65–68 wt. %), obtained from Laiyang Chemical Reagent Factory, China. NaClO3 (purity > 99 wt. %) was obtained from Tianjin Chemical Reagent Factory, China. Standard gases, N2 (99 %) and NO/N2 (2.02 vol. ‰ NO) span gas, were obtained from Oxygen Co., Ltd., China. Reverse osmosis water was applied to prepare the solutions. ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. REMOVAL OF NO BY WET SCRUBBING 1185 Experimental setup The experimental system of this research consists of three parts: a flue gas simulation section, a bubble reactor and a nitrogen oxide analyzer. A schematic diagram of the experi- mental device is shown in Fig. 1. Fig. 1. Schematic diagram of the experimental setup. Nitrogen and NO/N2 were obtained from cylinders and metered through mass flow con- trollers. The total flow of blended gas was kept at 160 mL/min. The simulated flue gas was then introduced into the mixer and NO was diluted to 800 ppm. The absorption experiments were performed in a bubbling reactor. The temperature of the absorbing liquid (solution vol- ume = 500 mL; liquid height = 12 cm) was controlled by a water bath. The solution was stir- red magnetically and the simulated flue gas entered the bubbling reactor. The concentration of NOx was continuously recorded by flue gas analyzer. In order to protect the flue gas analyzer, the gas coming from the reactor passed through a drying tube containing anhydrous calcium chloride and a scrubber with phosphoric acid. Data analysis When the simulated flue gas flowed through the aqueous solutions of NaClO3, NO reacted with the oxidant and was removed. The removal efficiency of NO in % was defined as: in out in NO NOx f NO 100 C C E C − = (1) where Ef is the efficiency of NO removal, CNOin and CNOxout represent the inlet and outlet gas concentrations, respectively. The denitration rate was calculated by the integral method. RESULTS AND DISCUSSION Contrast study in different systems NaClO3 was used to remove NO in a bubble reactor and a series of compar- ative experiments were carried out under different conditions. The result is shown in Fig. 2. NO removal efficiency was 29.11 % in water, 28.82 % in H2SO4 solution and 29.63 % in HNO3 solution. The removal efficiency of NO was only 29.52 % by NaClO3 solution without the presence of acid, which was just similar to water. However, the removal efficiency of NO achieved 84.40 % by the com- ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. 1186 SHI, SUN and CUI bination of 0.50 % NaClO3 and 0.60 mol/L HNO3. Similarly, the removal effi- ciency of NO in the mixed solution of NaClO3 and H2SO4 reached 86.17 %. The results showed that NaClO3 combined with acid significantly promoted the rem- oval of NO. Fig. 2. Contrast study of denitration in different systems. Effect of temperature The reaction temperature was an important factor affecting the denitration effect. Experiments were carried out under the conditon of room temperature to 80 °C. It could be seen from Fig. 3a that the concentration of outlet NOx gradu- ally decreased when the temperature rose from 30 to 80 °C in NaClO3/H2SO4 sys- tem. Considering the accelerating evaporation of water with the increase of tem- perature, the optimal temperature in practical application was chosen to be 80 °C. Fig. 3. Effect of temperature on NO removal efficiency. However, for NaClO3/HNO3 system, the denitration efficiency decreased rapidly from 85.14 to 54.83 % with the temperature from 40 to 80 °C (Fig. 3b), which was contrary to the NaClO3/H2SO4 system. Therefore, 40 °C was selected as the optimal temperature for NaClO3/HNO3 system. The optimal temperature ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. REMOVAL OF NO BY WET SCRUBBING 1187 was close to the operating temperature of wet flue gas desulfurization (WFGD), which was very conducive to the joint operation of desulfurization and denit- ration process. Effect of NaClO3 concentration The effect of NaClO3 concentration on NO absorption efficiency was carried out to ascertain the optimal NaClO3 concentration and the results were shown in Fig. 4. The removal efficiency of NO in NaClO3/H2SO4 system increased sharply with an increment of NaClO3 concentration at first, and then grew slowly. When the concentration of NaClO3 was 0.50 %, the NO removal efficiency reached 83.53 %. This can be explained from two aspects: chemical reaction and physical properties. The chemical reaction can improve the removal efficiency of NO, but the viscosity of denitration liquid increases with the increment of NaClO3 con- centration, therefore, the liquid diffusion coefficient and solubility of NO decrease. Fig. 4. Effect of NaClO3 concentration on NO removal efficiency: H2SO4 concentration, 0.30 mol/L, HNO3 concentration, 0.60 mol/L. The effect of NaClO3 concentration on NO absorption efficiency in NaClO3/ /HNO3 system indicated that NO absorption efficiency increased sharply from 35.48 to 91.65 % with NaClO3 concentration rising from 0.05 to 0.50 %. But the change was not obvious when NaClO3 concentration exceeded 0.50 %. So the optimal NaClO3 concentration was chosen to be 0.50 %. Effect of NaClO3 to H+ mole ratio and type of acid The influence of NaClO3 to H+ mole ratio on the removal efficiency of NO was studied, and the result was shown in Fig. 5. A significant increment of the NO removal efficiency from 53.30 to about 87.32 % was observed when the mole ratio of NaClO3 to H+ varied from 1:2.13 to 1:8.50. When the mole ratio of NaClO3 to H+ was 1:12.76, the maximum absorption efficiency of NO was about 91.68 %. This indicated that the oxidizing ability of NaClO3 gradually increased with the increase of acid intensity.26,27 With the further increase of molar ratio, the removal efficiency of NO did not change much. ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. 1188 SHI, SUN and CUI Fig. 5. Effect of molar ratio of NaClO3 to H + and type of acid on NO removal efficiency. The type of acid was also a factor affecting NO absorption. It could be seen from Fig. 5 that the absorption efficiency of NO by H2SO4 was slightly higher than by HNO3 at the same molar ratio. Analysis of products in solution In order to deduce the reaction mechanism, the results of ion chroma- tography (IC) analysis of the products are given in Table I. Nitrites were not found, while the main anions in the absorbent solution were nitrates and chlorides. This indicates that the NOx directly oxidize to nitrates. The Cl– comes from the reduced chlorate. Table I. Products of denitration; A1 – 1:12.76 (H2SO4); A2 – 1:17.01 (H2SO4); A3 – 1:12.76 (HNO3); A4 – 1:17.01 (HNO3) Medium CNO3- / mg L -1 CCl- / mg L -1 A1 85.03 24.243 A2 80.12 21.205 A3 – 24.240 A4 – 22.066 Denitration reaction mechanism It was worth pointing out that the solution remained clear and transparent rather than yellow-green during the denitration process using NaClO3 solution, indicating that no chlorine dioxide (ClO2) was generated. This was different from the phenomenon of removing NOx from simulated flue gas by acidic NaClO2 sol- ution.28,29 ClO2 is a very harsh gas and even very small amount of ClO2 can be detected. In a mass concentration of 0.025 % NaClO2 and 0.12 % H2SO4 solut- ion, it could be observed clearly that the solution was yellow-green. However, the solution of a mass concentration of 0.40 % NaClO3 and 2.55 % H2SO4 rem- ained colourless, proving that no ClO2 existed. The process involved numerous ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. REMOVAL OF NO BY WET SCRUBBING 1189 chemical reactions. The mechanism of NO absorption by NaClO3 may be as fol- lows: NaClO3 + H+ ↔ Na+ + HClO3 (2) 13NO + 6HClO3 + 5H2O → 6HCl + 3NO2 + 10HNO3 (3) 3NO2 + H2O → 2HNO3 + NO (4) 2NO + H2O + HClO3 → HCl + 2HNO3 (5) 2NO + H2O + NaClO3 + H+ → Na+ + HCl + 2HNO3 (6) NaClO3 + 2NO + H2O → 2HNO3 + NaCl (7) The reported denitration mechanism with NaClO2 is shown in Eqs. (8)–(12), in which ClO2 is produced in the reaction process, which possesses a potential hazard for the actual use: 8NaClO2 + 8H+ → 6ClO2 + Cl2 + 4H2O + 8Na (8) 5NO + 2ClO2 + H2O → 2HCl + 5NO2 (9) 5NO + ClO2 + 3H2O → HCl + 5HNO3 (10) 5NO + 3ClO2 + 4H2O → 3HCl + 5HNO3 (11) 3NaClO2 + 4NO + 2H2O → 4HNO3 + 3NaCl (12) Reacting 1.00 kg of NO requires 2.26 kg NaClO2, but only 1.77 kg NaClO3 calculated with Eqs. (7) and (12). In addition, the price of NaClO3 is one third of NaClO2. In other words, the cost of NaClO3 process is about a quarter of the cur- rent cost of NaClO2 wet denitration technology. Due to the high rate of denit- ration and low cost, the denitration technology with NaClO3 has a good industrial application prospect for the wet denitration of industrial flue gas. Chemical thermodynamics The thermodynamic data of chemical reactions are important for assessing the extent of the reaction (Eq. (7)). Data calculations of the thermodynamic para- meters were conducted and the enthalpy change of reaction (ΔrHm(T)), Gibbs energy change of reaction (ΔrGm(T)) and chemical reaction equilibrium constant (K ) of Eq. (7) were obtained. The thermodynamic data of related substances in this research were given in Table II.30 TABLE II. Standard formation enthalpy, standard formation Gibbs function, standard entropy and calorific capacity Substance Δf Hm / kJ mol -1 Δf G m / kJ mol -1 Sm / J mol -1 K-1 Cp / J mol -1 K-1 HNO3 (aq) –207.36 –111.34 146.4 –86.6 NaClO3 (aq) –344.09 –269.91 221.3 111.3 NaCl (aq) –407.27 –393.17 115.5 –90.0 NO (g) 91.29 87.60 210.76 29.85 H2O (l) –285.83 –237.14 69.95 75.35 ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. 1190 SHI, SUN and CUI ΔrHm(T) at different temperatures have been calculated based on the Eqs. (13) and (14): r m f m f m( ) (products) (reactants)H T H Hγ γΔ = Δ − Δ  (13) r m r m r p.m 289.15 ( ) d T H T H C TΔ = Δ + Δ (14) r p.m p.m p.m(products) (reactants)C C Cγ γΔ = −  (15) The results of Eq. (14) were ΔrHm = –374.65 kJ/mol, ΔrHm (313.15 K) = = –382.29 kJ/mol and ΔrHm (353.15 K) = –402.68 kJ/mol. The results show that ΔrHm, ΔrHm (313.15 K) and ΔrHm (353.15 K) values of the chemical reaction are negative, which indicates that the reaction between NO and NaClO3 is exothermic. Therefore, the chemical equilibrium for this reaction is unfavourable at high temperatures from the thermodynamics point of view. However, the reaction rate is generally affected by the temperature, and the react- ion rate increases at high temperatures. The effect of temperature on the removal efficiency of NO showed there was an optimal reaction temperature at which NO could be removed quickly. This was the result of a combination of chemical ther- modynamics and kinetics. ΔrGm(T) at 298.15, 313.15 and 353.15 K was calcul- ated by Eqs. (16) and (17): r m f m f m(products) (reactants)G G Gγ γΔ = Δ − Δ  (16) r m r m r m r p.m r r m 298.15 ( ) ( ) 298.15 d T m G T H T S T C H T S T T T Δ = Δ − Δ = Δ = Δ − Δ −  (17) The results of Eq. (17) were ΔrGm = –284 kJ/mol, ΔrGm (313.15 K) = = –279.33 kJ/mol and ΔrGm (353.15 K) = –267.21 kJ/mol. The chemical reaction equilibrium constant (K ) of Eq. (7) was given as follows: ln G RT KΔ = − (18) The results of Eq. (18) for K are 1049.78, 1046.60 and 1039.52. The results showed that ΔrGm, ΔrGm (313.15 K) and ΔrGm (353.15 K) of the chemical reaction were high negative values, compared to –40 kJ/mol, and K values calculated were far greater than 105.31 From these thermodynamic deriv- ations, we can suggest that this oxidation reaction can proceed spontaneously and the reaction is very thorough. In the actual operation, the reason why the denit- ration rate did not reach 100 % should be that the residence time was short, res- ulting in insufficient reaction. ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. REMOVAL OF NO BY WET SCRUBBING 1191 CONCLUSIONS NaClO3 is a promising absorbent for the removal of NO from flue gas. The denitration efficiency increased with temperature from 30 to 80 °C in NaClO3/ /H2SO4 system. However, for NaClO3/HNO3 system, the denitration efficiency decreased with temperature from 40 to 80 °C. The NO removal efficiency inc- reased with NaClO3 and acid concentrations. The optimal mole ratio of NaClO3 to H+ was 1:12.76. The NO removal efficiency was 91.86 %. The cost of NaClO3 process was about a quarter of the NaClO2 wet denitration technology. The react- ion product was NaCl and could be recovered. Therefore, NaClO3 method may be an alternative way to solving the problem of denitration of dusty flue gas small boilers produced intermittently. Acknowledgements. The authors would like to thank Talent Training Program in Western Shandong Province (2017GRC5227). И З В О Д СТУДИЈА О УКЛАЊАЊУ NO ИЗ ЕМИСИЈЕ МОКРИМ СКРУБИНГОМ ПОМОЋУ NaClO3 DEQI SHI, GUOXIN SUN и YU CUI School of Chemistry and Chemical Engineering, University of Jinan, No. 336, West of Nan Xinzhuang, Jinan, 250022, Shangdong, P. R. China За уклањање азот-моноксида (NO) из гасне емисије малих котлова на угаљ, неоп- ходно је употребити економичну технологију влажне денитрације. Проучавана је апсорпција NO помоћу раствора натријум-хлората. Установљени су утицаји експери- менталних услова као што су температура, концентрација NaClO3, врста киселине, молски однос NaClO3 према водоничним јонима – на брзину уклањања NO, и утврђени оптимални услови. Како је утицај температуре био повезан са врстом киселине, темпе- ратура потребна за сумпорну киселину (H2SO4) била је висока, а температура потребна за азотну киселину (HNO3) ниска. Оптимални молски однос NaClO3 према овим двема киселинама био је исти. Продукти реакције анализирани су јонском хроматографијом. Реакциони раствор се могао рециклирати након уклањања натријум-хлорида. Изведен је закључак о механизму и укупној једначини реакције NaClO3 денитрације. Добијени термодинамички резултати показали су да је ова оксидациона реакција спонтана и врло темељна. NaClO3 је показао високу ефикасност уклањања NO, а трошак денитрације је био много нижи него помоћу натријум-хлорита. (Примљено 5. марта, ревидирано и прихваћено 17. маја 2019) REFERENCES 1. R. F. Sawyer, Symp. (Int.) Combustion 18 (1981) 1 (http://dx.doi.org/10.1016/S0082- 0784(81)80006-9) 2. M. J. Prather, J. A. Logan, Symp. (Int.) Combustion 25 (1994) 1513 (http://dx.doi.org/10.1016/S0082-0784(06)80796-4) 3. J. H. Ye, J. Shang, Q. Li, W. W. Xu, J. Liu, X. Feng, T. Zhu, J. Hazard. Mater. 271 (2014) 89 (http://dx.doi.org/10.1016/j.jhazmat.2014.02.011) 4. B. R. Deshwal, S. H. Lee, J. H. Jung, B. H. Shon, H. K. Lee, J. Environ. Sci.-China 20 (2008) 33 (http://dx.doi.org/10.1016/S1001-0742(08)60004-2) 5. H. K. Lee, B. R. Deshwal, K. S. Yoo, Korean J. Chem. Eng. 22 (2005) 208 (http://dx.doi.org/10.1007/BF02701486) ________________________________________________________________________________________________________________________Available on line at www.shd.org.rs/JSCS/ (CC) 2019 SCS. 1192 SHI, SUN and CUI 6. W. Y. Sun, S. L. Ding, S. S. Zeng, S. J. Su, W. J. Jiang, J. Hazard. Mater. 192 (2011) 124 (http://dx.doi.org/10.1016/j.jhazmat.2011.04.104) 7. N. D. Hutson, R. Kryzynska, R. K. Srivastava, Ind. Eng. Chem. Res. 47 (2008) 5825 (http://dx.doi.org/10.1021/ie800339p) 8. A. Pourmohammadbagher, E. Jamshidi, H. Aleebrahim, S. Dabir, Ind. Eng. Chem. Res. 50 (2011) 8278 (http://dx.doi.org/10.1021/ie102272x) 9. X. L. Long, Z. L. Xin, M. B. Chen, W. Li, W. D. Xiao, W. K. Yuan, Sep. Purif. Technol. 58 (2008) 328 (http://dx.doi.org/10.1016/j.seppur.2007.05.004) 10. Y. G. Adewuyi, S. O. Owusu, J. Phys. Chem., A 110 (2006) 11098 (http://dx.doi.org/10.1021/jp0631634) 11. B. R. Deshwal, H. K. Lee, J. Environ. Sci.-China 21 (2009) 155 (http://dx.doi.org/10.1016/S1001-0742(08)62244-5) 12. P. Fang, C. P. Cen, Z. X. Tang, P. Y. Zhong, D. S. Chen, Z. H. Chen, Chem. Eng. J. 168 (2011) 52 (http://dx.doi.org/10.1016/j.cej.2010.12.030) 13. Y. Zhao, T. X. Guo, Z. Y. Chen, Y. R. Du, Chem. Eng. J. 160 (2010) 42 (http://dx.doi.org/10.1016/j.cej.2010.02.060) 14. D. S. Jin, B. R. Deshwal, Y. S. Park, H. K. Lee, J. Hazard. Mater. 135 (2006) 412 (http://dx.doi.org/10.1016/j.jhazmat.2005.12.001) H. Chu, T. W. Chien, S. Y. Li, Sci. Total. Environ. 275 (2001) 127 (http://dx.doi.org/10.1016/S0048-9697(00)00860-3) 15. T. Chien, H. Chu, H. Hsueh, J. Environ. Eng. 129 (2003) 967 (http://dx.doi.org/10.1061/(ASCE)0733-9372(2003)129:11(967) 16. T. W. Chien, H. Chu, J. Hazard. Mater. 80 (2000) 43 (http://dx.doi.org/10.1016/S0304- 3894(00)00274-0) 17. H. W. Hsu, C. J. Lee, K. S. Chou, Chem. Eng. Commun. 170 (1998) 67 (http://dx.doi.org/10.1080/00986449808912736) 18. H. Chu, T. W. Chien, B. W. Twu, J. Hazard. Mater. 84 (2001) 241 (http://dx.doi.org/10.1016/S0304-3894(01)00215-1) 19. Y. G. Adewuyi, X. D. He, H. Shaw, W. Lolertpihop, Chem. Eng. Commun. 174 (1999) 21 (http://dx.doi.org/10.1080/00986449908912788) 20. E. Sada, H. Kumazawa, I. Kudo, T. Kondo, Chem. Eng. Sci. 33 (1978) 315 (http://dx.doi.org/10.1016/0009-2509(78)80088-8) 21. J. C. Wei, Y. B. Luo, P. Yu, B. Cai, H. Z. Tan, J. Ind. Eng. Chem. 15 (2009) 16 (http://dx.doi.org/10.1016/j.jiec.2008.07.010) 22. D. Thomas, J. Vanderschuren, Chem. Eng. Sci. 51 (1996) 2649 (http://dx.doi.org/10.1016/0009-2509(96)00131-5) 23. E. B. Myers, T. J. Overcamp, Environ. Eng. Sci. 19 (2002) 321 (http://dx.doi.org/10.1089/10928750260418953) 24. L. Wang, W. Zhao, Z. Wu, Chem. Eng. J. 132 (2007) 227 (http://dx.doi.org/10.1016/j.cej.2006.12.030) 25. B. R. Deshwal, H. D. Jo, H. K. Lee, Can. J. Chem. Eng. 82 (2010) 619 (http://dx.doi.org/10.1002/cjce.5450820323) 26. B. R. Deshwal, H. K. Lee, J. Hazard. Mater. 108 (2004) 173 (http://dx.doi.org/10.1016/j.jhazmat.2003.12.006) 27. E. Sada, H. Kumazawa, I. Kudo, T. Kondo, Ind. Eng. Chem. Res. 18 (1979) 275 (http://dx.doi.org/10.1021/i260070a017) 28. J. J. Kaczur, Environ. Prog. Sustain. 15 (1996) 245 (http://dx.doi.org/10.1002/ep.670150414) 29. J. A. Dean, Lange’s Handbook of Chemistry, Science Press, Beijing, 2003 (in Chinese) 30. D. Z. 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