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Application of sulfonated carbons for mercury removal in gas processing K. Suresh Kumar Reddy, A. Prabhu, Ahmed Sultan Al Shoaibi, and Chandrasekar Srinivasakannan Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.5b02630 • Publication Date (Web): 23 Feb 2016 Downloaded from http://pubs.acs.org on February 28, 2016

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Application of Sulfonated Carbons for Mercury Removal in Gas Processing K. Suresh Kumar Reddy, A. Prabhu, Ahmed Al Shoaibi*, C. Srinivasakannan Department of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, UAE

ABSTRACT Mercury present in natural gas streams is known to damage aluminum heat exchangers, precious catalyst beds, and health risk to work force, therefore its removal is essential in the natural gas processing industries. The present research work attempts to test various sulfur based adsorbents for elemental mercury adsorption capacity. Towards which sulfur impregnated carbons (SIC) and sulfonated carbons (SC) were synthesized while popular commercially available (Norit, UOP) sulfur based adsorbents were utilized in this study. The adsorption capacities of all the adsorbents were assessed at 30, 50⁰C respectively. An increase in mercury adsorption capacity is attributed to predominance of chemisorption due to the presence of sulfur moiety. Among these adsorbents SC-600 is observed to possess maximum adsorption capacity of 5501 µg/g at 50⁰C temperature even at low sulfur content compared to its counter parts. This is due to the superior adsorbent preparation protocol adopted in SC synthesis which renders the availability of active site in the sorbent for better mercury adsorption. This work may trigger utilization of SC adsorbents for various industrial mercury removal applications. Keywords: Sulfonated carbon, BET Surface area, Sulfur content, Thermal process, Elemental analysis

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INTRODUCTION Mercury present in the liquid and gaseous hydrocarbons from oil and gas fields is the key for major mercury emissions. It is one of the current global burning environmental issues due to rapid industrial growth that drives technology developments for mercury free hydrocarbons. Mercury is a recognized toxin, exposure to mercury can result in adverse human health effects ranging from acute to chronic diseases. Mercury receives global focus due to its continuing and serious harm to both the environment and human health.1 Mercury concentration in the range of 4400µg/m3 (500ppbv) has been reported in wells of Germany.2 The elemental mercury levels in the Southeast Asian countries were reported to be very high as compared to United States and Gulf coast.3 Presence of mercury in natural gas is a serious concern to natural gas processing plants and hence mercury removal unit (MRU) with appropriate adsorbent needs to be installed as an integral part of gas processing plants. Mercury exist in three forms in the nature that includes, oxidized mercury (Hg2+), particulate bounded mercury (Hg (p)) and an elemental mercury (Hg⁰). The high volatility, chemical inertness and water insolubility nature of elemental mercury (Hg⁰) makes it difficult to remove from process streams. Also presence of mercury in process streams leads to corrosion of equipment, poisoning of catalyst and health issues to the work force. Therefore, the effective mercury removal practices are to be developed to reduce elemental mercury emissions to the environment. Due to the magnitude of its impact in gas processing and HSE issues, continued interests on development of better separation methods are being reported. The reported separation methods are either adsorption or photochemical oxidation.6-9 Experimentally generated adsorption isotherms along with kinetics of adsorption would facilitate design of commercial adsorption columns. Recent developments such as Computational Fluid


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Dynamics (CFD)

4, 5

are applied to understand the random and steady state concentration and

temperature profiles within the column, which additionally help to improve the design of adsorption columns. A wide variety of porous carbons were developed for mercury adsorption from natural gas,

6, 10-20

and due to predominant physisorption nature of adsorption phenomenon these

sorbents are inferior in their mercury adsorption capacity. In open literature porous carbons with different surface modifications were widely used for mercury removal due to its high surface area and easiness to modify its surface functional groups.21 Due to the commercial importance of mercury removal in natural gas industries, a wide range of porous carbons impregnated with sulfur, iodine, chlorine, bromine were developed and reported to possess better mercury adsorption capacity.

22-28

Among these adsorbents sulfur impregnated porous carbons were

reported to be superior in elemental mercury removal. 29 These information’s triggered us to develop a new group of mesoporous carbon material known as sulfonated carbon (SC), with sulfur incorporated in the sorbent during the SC synthesis steps rather than impregnating sulfur externally, which may furnish better sorption capacity, low cost and long term stability. Sulfonated carbon adsorbents were synthesized in many ways with suitable oxidizing agents.

30-32

The mesoporous sulfonated carbon materials are prepared via

sulfonation and carbonization.33 To synthesize the mesoporous carbon with high SO3H group density by the controlled carbonization and sulfonation. Although the reports on synthesis of these materials are available in open literature,

34-37

its suitability for different applications were

not explored sufficiently. Presence of reasonable proportion of sulfur in the molecular structure of adsorbent has prompted us to test its utility for mercury removal in comparison with the various sulfur impregnated porous carbon matrix.


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The present research attempts to compare the different forms of the sulfurized adsorbents for assessing the mercury adsorption capacity. Towards which SC and SIC were synthesized adopting optimal experimental conditions as reported in literature.

29, 38

Additionally various

characterization methods were utilized to understand the mechanism of adsorption and the various factor that contribute to enhanced adsorption capacity. EXPERIMENTAL SECTION Preparation methods of sulfur impregnated porous carbon (SIC) and sulfonated carbons (SC) are presented in this section. The powder form of the porous carbon was mixed with an appropriate amount of the elemental sulfur to prepare SIC at an optimum process conditions reported in literature.29 The Sulfonated carbon was synthesized using the sucrose, H2SO4, TEOS and distilled water. Twenty grams of sucrose was dissolving in 20 ml of double distilled water, followed by drop wise addition of 60g of TEOS (5 g/min) under constant stirring for 3 hours to form a miscible gel. After complete mixing, 25 g of H2SO4 (5 g/min) was added drop wise to formed miscible gel. The solution mixture was solidified which turns black due to hydrolysis of sucrose and TEOS after 2 hours. Finally the dry product was dried at 105°C for complete carbonization and sulfonation. The prepared samples were carbonized at different temperatures (300 & 600°C) for 6 hours to form sulfonated carbon - named as SC-300 and SC-600 in the present work. Further details on experimental procedure can be sourced from our earlier publication.38 Nitrogen adsorption/desorption studies were conducted on a Autosorb 1-C, Quanta Chrome Instruments, USA. The surface areas were calculated using Brunauer–Emmett–Teller (BET) method, and the pore parameters were determined from desorption branches by Dubinin– Radushkevich (DR) methods.39 Thermogravimetric analysis of the materials was also carried out


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in the temperature range from 30-800oC at a heating rate 5oC/min on a thermogravimetric analyzer (Perkin Elmer Diamond series) in the presence of nitrogen medium. Scanning electron microscopy images were obtained with FEG-250 SEM instrument (FEI, Holland) at 30 kV with 2.5 K magnification. A 100 mg of adsorbent was placed in a tubular furnace having a length of 100 mm and diameter of 25.4 mm. The tubular furnace was jacketed with a circulation water bath in order to maintain the desired adsorption temperature inside the furnace. The schematic as shown in Fig.1 and detail experimental procedures are clearly stated in our previous reports.39 The various adsorbents were crushed and sieved to a uniform size range of 100 and 200 µm and it is tested for mercury adsorption analysis. A mercury permeation device (VICI Metronics Inc, Santa Clara, CA) was used as a source of mercury vapor generator at desired concentration and flow rate. The desired Hgº concentration was maintained by varying the permeation device temperature (Max 100ºC) and helium flow (Max 1000 cc/min) and mercury adsorption capacity of the adsorbents was measured using automatic mercury analyzer, DMA-80 manufactured by MILESTONE Switzerland. RESULTS AND DISCUSSION The variety of commercially available adsorbents and synthesized adsorbents were tested for mercury adsorption capacity and shown in the Fig.2. In comparison with other adsorbents, SC shows several folds higher mercury adsorption capacity. Sulfur content and BET surface area of sulfur based adsorbents shown in Table 1. These results infer that physico-chemical properties of the adsorbents as clear impact on mercury adsorption capacity. Norit-3 adsorbent with very high sulfur (19.1%) content shows lower mercury adsorption capacity and commercial UOP adsorbent with less sulfur (1.7%) content shows predominant mercury adsorption capacity. The SIC


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adsorbent with 12.3% sulfur content performing equivalent mercury sorption capacity as compared to UOP sorbent and more effective rather than Norit-3. These results reflect that sulfur content solely not an important factor for high mercury adsorption capacity, and also needs proper sulfur distribution in the adsorbent to obtain high mercury sorption capacity. Nevertheless, SC-600 with 2.19% sulfur having 510 m2/g BET surface area shows 5501 µg/g, which the maximum among all the adsorbents is at provided experimental conditions. The virgin activated carbon with surface area of 900 m2/g with an average pore diameter of 2.52 nm was used for SIC preparation. The author aim is to increase the sulfur content and distribution inside the porous network of the virgin carbon. After the successful impregnation of sulfur element, adsorbent average pore diameter has reduced from 2.52 nm to 2.45 nm, while the BET surface area has reduced from 900 to 780 m2/g, possibly due to the blockage of certain proportion of pores. Although the surface area has reduced the mercury adsorption capacity has increased many folds, evidence the better distribution of the sulfur throughout the porous network.39 Sulfonated carbon with around 2.19% sulfur has 10 times more adsorption capacity comparative to commercial UOP adsorbent at 50⁰C, which has 1.7% of sulfur. Although the sulfur content in both materials is comparable, sulfonated carbon has several order of magnitude higher adsorption capacities. This could possibly be attributed to presence of sulfur in the molecular structure of the material rather than physically bound on the porous matrix or could be the form of sulfur attachment to the porous matrix. The elemental analysis (Table 2) additionally indicates presence of high proportion of oxygen content in UOP, SC, which would render the adsorbent to be more acidic. Based on FT-IR analysis of SC presence of sulfur compound


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predominantly in the form of -SO3H groups attached to graphitized rings with a high density of acid sites was reported.38 Although the surface area of the SC is far too low compared to sulphur impregnated porous carbon, the higher adsorption capacity could be attributed to the presence of sulfur molecular structure of the porous matrix and in more reactive form. Additionally a simple material balance does reveal only a low amount of sulphur being utilized for binding with the mercury irrespective of the amount of sulphur present in the adsorbent, indicating ineffective availability of the sulphur atoms to interact with mercury in the SIC. This clearly highlights the importance of the distribution of the sulfur compound in the porous matrix in addition to the form of its presence.29 The mercury adsorption experiments were conducted with 100 mg of adsorbent at different temperature range from 30-70°C. The elemental mercury concentration of 50 µg/m3, with an inert flow of 0.5 L/min was used in these experiments. The mercury adsorption capacities show in the Fig.2 with different temperatures. It is well known that physisorption is an exothermic and hence a decrease in adsorption capacity is expected with increase in temperature. However the SIC, UOP and SC adsorbents showed an increase in the mercury adsorption capacity with increase in the adsorption temperature. It can be attributed to the predominant chemisorption process due to the reaction of sulfur with elemental mercury. However, it should be noted that the increase in adsorption capacity of mercury was observed only until a temperature of 140⁰C with respect to SIC. The decrease in adsorption capacity above 140⁰C was attributed to the agglomeration of sulfur inside the porous structure. This can be tested using EDX analysis at various places and observed a clear non-uniform surface after exposed to more


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than 140⁰C. As discussed above, sulfur present in porous carbon reacts with elemental mercury forming mercury sulfide, which is a stable molecule, as given below, Hg (g) + 1/8 S8 →HgS

(1)

In general, the sulfur impregnated carbon shows higher mercury adsorption capacity with increase in the adsorption temperature, owing to the activation energy requirement for initiation of mercury-sulfur reaction.40-41 At lower temperature, adsorption measurements shows high mercury adsorption capacity for the virgin carbon than the sulfur impregnated carbon, while a decrease in adsorption capacity of virgin carbon was reported with increase in the adsorption temperature. Few researchers reported that mercury adsorption capacity increases with increasing the sulfur content of carbon in the range of 0-13% by weight at an adsorption temperature of 36⁰C.42 The surface areas of sulfur based adsorbents were reduces as sulfur percentage increases and also reported the amount of mercury removed to be less than stoichiometric HgS formation.40 The mercury adsorption capacity of virgin carbon decrease with increase in temperature from 25-140⁰C, while the sulfur impregnated carbon adsorption capacity increased with increase in adsorption temperature until 140⁰C. At higher temperature, after 140°C the mercury adsorption capacity was found to decrease. In the case of SC-600 adsorbent the adsorption capacity at 30 and 50⁰C is 3466, 5501 µg/g respectively, many folds higher than SIC and UOP at lower temperatures. However adsorption of mercury at temperature of 70⁰C was observed significantly reduce to 578 µg/g. This rather unfavorable result could be attributed based on the TGA micrograph which clearly indicates loss of active -SO3H functional group at temperature less than 150⁰C. The nonavailability of -SO3H functional groups deemed to weaken chemisorption contributing to lower mercury adsorption capacity.


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The amount of sulfur and its distribution in the adsorbent is believed to play a vital role in deciding the mercury adsorption capacity. The adsorbent surface characteristic is an important factor that will decide the fate and efficiency of adsorbent for elemental mercury removal. Fig. 3 shows the SEM images of adsorbents at magnification of 10000 times, which reveals the morphology and structure of amorphous carbon. The white spots indicate the deposition of sulfur on the surface of carbon complex.43 SEM images had shown full of black spots representing the presence of carbon moiety.38 The amount of sulfur and distribution of sulfur on the adsorbent surface is estimated by EDX analysis. The EDX analysis was performed at different positions A, B and C as shown in Fig.3. The amount of sulfur was found to be varying only marginally, ensuring uniform distribution of sulfur in adsorbents. The detailed elemental report of all adsorbents was listed in the Table 2. Although the sulfur content in the SC and UOP are of comparable magnitude, the more whiter and uniform presence of white color clearly indicate more even presence of sulfur compound possibly contributing to the higher adsorption capacity. Although SIC shows more whiter color as compare to UOP it can attributed to larger amount (12.3%) sulfur in the porous matrix. CONCLUSION The mesoporous sulfonated carbon (SC) is a new sorbent with high mercury removal capacity than the existing sulfur based adsorbents. The mercury adsorption capacities of SIC, UOP, Norit3, SC-300 and SC-600 were tested at lower temperatures and among those SC was found to have remarkably high adsorption capacity of 5501 µg/g at 50⁰C. The high adsorption capacity of SC was attributed to the presence of –SO3H functional group attached to graphitized rings with a high density of acid sites and uniform distribution in molecular structure of the adsorbent. The adsorption capacity was found to reduce significantly at temperatures above 70⁰C, attributed to


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the removal of -SO3H group. The other adsorbents SC, UOP exhibited increase in adsorption capacity with increase in temperature up to 140⁰C. The reduction in adsorption capacity beyond 140 ⁰C was attributed to the agglomeration of sulfur. The importance of sulfur distribution in the porous matrix at atomic level with appropriate functional groups was identified to be important for increasing the adsorption capacity rather than the high amount of sulfur in the porous carbon matrix. ACKNOWLEDGEMENTS The authors gratefully acknowledge The Petroleum Institute for giving support to work on mercury removal from natural gas processing research. REFERENCES (1) Pavlish, J. H.; Holmes, M. J.; Benson, S. A.; Crocker, C. R.; Galbreath, K. C. Application of sorbents for mercury control for utilities burning lignite coal. Fuel Process. Technol. 2004, 85 (6-7), 563-576. (2) Abbott, J.; Oppenshaw, P. Mercury removal technology and its applications. Proceedings of the Eighty-First Annual Convention Gas Processors Association, 2002. Tulsa, OK. (3) Rios, J. Removal of trace mercury contaminants from gas and liquid streams in the LNG and gas processing industry. Proceedings of the Seventy-Seventh Annual Convention Gas Processors Association, 1998. Tulsa, OK: p. 191. (4) Vegendla, S. N. P.; Geraldine, H.; Marin, GB. Probability density function simulation of turbulent reactive gas-solid flow in a riser. Chem. Eng. Technol. 2009, 32 (3), 492–500. (5) Vegendla S. N. P.; Geraldine, H.; Marin, GB. Probability density function simulation of turbulent reactive gas-solid flow in a FCC riser. AIChE. 2012, 58 (1), 268-284. (6) Vidic, R. D.; Siler, D. P. Vapor-phase elemental mercury adsorption by activated carbon impregnated with chloride and chelating agents. Carbon, 2001. 39(1), 3-14. (7) Granite, E. J.; Pennline, H. W.; Hargis, R. A. Novel Sorbents for Mercury Removal from Flue Gas. Ind. Eng. Chem. Res. 2000, 39 (4), 1020-1029. (8) Granite, E. J.; Pennline, H. W. Photochemical Removal of Mercury from Flue Gas. Ind. Eng. Chem. Res. 2002, 41 (22), 5470-5476.


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(9) McLarnon, C. R.; Granite, E.J.; Pennline, H.W. The PCO process for photochemical removal of mercury from flue gas. Fuel Process. Technol. 2005, 87(1), 85-89. (10) Nolan, P. S.; Redinger, K. E.; Amrhein, G. T.; Kudlac, G. A. Demonstration of additive use for enhanced mercury emissions control in wet FGD systems. Fuel Process. Technol. 2004, 85 (6-7), 587-600. (11) Liu, W.; Vidic, R. D.; Brown, T. D. Optimization of High Temperature Sulfur Impregnation on Activated Carbon for Permanent Sequestration of Elemental Mercury Vapors. Environ. Sci. Technol. 2000, 34 (3), 483-488. (12) Liu, W.; Vidic, R. D.; Brown, T. D. Impact of Flue Gas Conditions on Mercury Uptake by Sulfur-Impregnated Activated Carbon. Environ. Sci. Technol. 2000, 34(1), 154-159. (13) O'Dowd, W. J.; Hargis, R. A.; Granite, E. J.; Pennline, H. W. Recent advances in mercury removal technology at the National Energy Technology Laboratory. Fuel Process. Technol. 2004, 85 (6-7), 533-548. (14) Mei, Z.; Shen, Z.; Yuan, T.; Wang, W.; Han, H. Removal of vapor-phase elemental mercury by N-doped CuCoO4 loaded on activated carbon. Fuel Process. Technol. 2007, 88 (6), 623-629. (15) Diamantopoulou, I.; Skodras, G.; Sakellaropoulos, G. P. Sorption of mercury by activated carbon in the presence of flue gas components. Fuel Process. Technol. 2010, 91 (2), 158-163. (16) Tan, Z.; Sun, L.; Xiang, J.; Zeng, H.; Liu, Z.; Hu, S.; Qiu, J. Gas-phase elemental mercury removal by novel carbon-based sorbents. Carbon. 2012, 50 (2), 362-371. (17) Tan, Z.; Qiu, J.; Zeng, H.; Liu, H.; Xiang, J. Removal of elemental mercury by bamboo charcoal impregnated with H2O2. Fuel. 2011. 90 (4), 1471-1475. (18) Scala, F.; Chirone, R.; Lancia, A. Elemental mercury vapor capture by powdered activated carbon in a fluidized bed reactor. Fuel, 2011, 90 (6), 2077-2082. (19) Karatza, D.; Prisciandaro, M.; Lancia, A.; Musmarra, D. Silver impregnated carbon for adsorption and desorption of elemental mercury vapors. J. Environ. Sci. 2011, 23 (9), 1578-1584. (20) Shen, Z.; Ma, J.; Mei, Z.; Zhang, J. Metal chlorides loaded on activated carbon to capture elemental mercury. J. Environ. Sci. 2010, 22 (11), 1814-1819. (21) Skodras, G.; Diamantopoulou, I.R.; Zabaniotou, A.; Stavropoulos, G.; Sakellaropoulos, G. P. Enhanced mercury adsorption in activated carbons from biomass materials and waste tires. Fuel Process. Technol. 2007, 88 (8), 749-758.


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(22) Liu, W.; Vidic, R. D.; Brown, T. D. Optimization of Sulfur Impregnation Protocol for Fixed-Bed Application of Activated Carbon-Based Sorbents for Gas-Phase Mercury Removal. Environ. Sci. Technol. 1998, 32 (4), 531-538. (23) Lee, S. J.; Seo, Y. C.; Jurng, J.; Lee, T. G. Removal of gas-phase elemental mercury by iodine- and chlorine-impregnated activated carbons. Atmos. Environ. 2004, 38 (29), 4887-4893. (24) Zeng, H.; Jin, F.; Guo, J. Removal of elemental mercury from coal combustion flue gas by chloride-impregnated activated carbon. Fuel, 2004, 83 (1), 143-146. (25) Lee, S. H.; Rhim, Y. J.; Cho, S. P.; Baek, J. I. Carbon-based novel sorbent for removing gas-phase mercury. Fuel. 2006, 85 (2), 219-226. (26) Hutson, N. D.; Attwood, B. C.; Scheckel, K. G. XAS and XPS Characterization of Mercury Binding on Brominated Activated Carbon. Environ. Sci. Technol. 2007, 41 (5), 1747-1752. (27) Morency, J. Zeolite sorbent that effectively removes mercury from flue gases. Filtr. Separat. 2002, 39 (7), 24-26. (28) Hassett, D. J.; Eylands, K. E. Mercury capture on coal combustion fly ash. Fuel. 1999, 78 (2), 243-248. (29) Rashid, K.; Suresh Kumar Reddy, K.; Shoaibi, A. A.; Srinivasakannan, C. Sulfurimpregnated porous carbon for removal of mercuric chloride: optimization using RSM. Clean. Technol. Envir. 2013, 15(6), 1041-1048. (30) Okamura, M.; Takagaki, A.; Toda, M.; Kondo, J. N.; Domen, K.; Tatsumi, T.; Hara, M.; Hayashi, S. Acid-Catalyzed Reactions on Flexible Polycyclic Aromatic Carbon in Amorphous Carbon. Chem. Mater. 2006, 18 (13), 3039-3045. (31) Budarin, V. L.; Clark, J. H.; Luque, R.; Macquarrie, D. J. Versatile mesoporous carbonaceous materials for acid catalysis. Chem. Commun. 2007, 6, 634-636. (32) Xing, R.; Liu, Y.; Wu, H.; Jiang, Y.; He, M.; Wu, P. Novel Solid Acid Catalysts: Sulfonic Acid Group-Functionalized Mesostructured Polymers, Adv. Funct. Mater. 2007, 17 (14), 24552461. (33) Hara, M.; Yoshida, T.; Takagaki, A.; Takata, T.; Kondo, J. N.; Hayashi, S.; Domen, K. A Carbon Material as a Strong Protonic Acid. Angew. Chem. Int. Ed. 2004, 43 (22), 2955-2958. (34) Peng, F.; Zhang, L.; Wang, H.; Lv, P.; Yu, H. Sulfonated carbon nanotubes as a strong protonic acid catalyst. Carbon. 2005, 43 (11), 2405-2408.


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(35) Budarin, V. L.; Luque, R.; Macquarrie, D. J.; Clark, J. H. Towards a Bio-Based Industry: Benign Catalytic Esterifications of Succinic Acid in the Presence of Water. Chem. Eur. J. 2007, 13 (24), 6914-6919. (36) Budarin, V. L.; Clark, J. H.; Luque, R.; Macquarrie, D. J.; Koutinas, A.; Webb, C. Tunable mesoporous materials optimized for aqueous phase esterification. Green Chem. 2007, 9, 992995. (37) Xing, R.; Liu, Y.; Wang, Y.; Chen, L.; Wu, H.; Jiang, Y.; He, M.; Wu P. Active solid acid catalysts prepared by sulfonation of carbonization-controlled mesoporous carbon materials. Micropor. Mesopor. Mat. 2007, 105 (1-2), 41-48. (38) Prabhu, A.; Shoaibi, A. A.; Srinivasakannan, C. A facile synthesis of mesoporous sulfonated carbon and its structural properties. J. Nanosci. Nanotechnol. 2016, 16 (1), 1202-1206. (39) Suresh Kumar Reddy, K., Shoaibi, A. A.; Srinivasakannan, C. Gas-Phase mercury removal through sulfur impregnated porous carbon. J. Ind. Eng. Chem. 2014. 20 (5), 2969-2974. (40) Sinha, R. K.; Walker, P. L. Removal of Mercury by Sulfurized Carbons. Carbon. 1972, 10 (6), 754-756. (41) Krishnan, S. V., Gullett, B. K.; Jozewicz, W. Sorption of Elemental Mercury by Activated Carbons. Environ. Sci. Technol. 1994. 28 (8), 1506-1512. (42) Otani, Y.; Kanaoka, C.; Emi, H.; Uchijima, I.; Nischino, H. Removal of mercury vapor from air with sulfur-impregnated adsorbents. Environ. Sci. Technol. 1988, 22 (6), 708-711. (43) Karatza, D.; Lancia, A.; Musmarra, D.; Zucchini, C. Study of mercury absorption and desorption on sulfur impregnated carbon. Exp. Therm. Fluid. Sci. 2000. 21(1–3), 150-155.


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Fig. 1. Elemental Mercury adsorption setup [39]


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Fig. 2. Mercury adsorption at 50⁰C (Co=50 µg/m3)


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(a)

(b)


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Fig. 3. SEM images of different adsorbents (a) SIC (b) UOP (c) SC


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Table 1 Properties of Sulfur based adsorbents Adsorbent

Sulfur content (%)

SIC UOP Norit-3 SC-300 SC-600

12.3 1.70 19.1 0.28 2.19

Surface area (m2/g)

Average pore diameter (nm)

780 ---612 471 510

2.45 ----2.39 3.08 3.10

Table 2 EDX analysis of sulfur based adsorbents Element C O Al Si S

A 76.29 10.04 0.68 0.67 12.3

B 30.76 46.77 --11.08 1.7

Elemental Report (wt %) C D 75.22 21.05 5.26 76.56 --------19.1 0.28

A= SIC, B= UOP, C=Norit-3, D=SC-300, E= SC-600


E 17.56 78.54 ----2.19

Application of Sulfonated Carbons for Mercury ... - ACS Publications

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