Enhanced mercury adsorption capacity by sulfurization of activated carbon with SO2 in a bubbling fluidized bed reactor

Asasian, Neda; Kaghazchi, Tahereh; Faramarzi, Amirhasan; Hakimi-Siboni, Ahmad; Asadi-Kesheh, Reza; Kavand, Mohammad; Mohtashami, Seyed-Abolfazl

doi:10.1016/j.jtice.2013.10.012

Cited by 48 publications

(32 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the work, the largest drop belonged to AC-DMDS which was produced using a liquid sulfurizing agent at room temperature. In contrast, in the case of AC-SO 2 , applying a gaseous sulfurizing agent and high-temperature treating led to the lowest porosity blockage in spite of introduction of the same amount of sulfur Kaghazchi 2012, 2013b;Asasian et al 2014). The weakness of SACs in physisorption of pollutants and their slower initial adsorption rate compared to the parent AC could be attributed to the limited porosity of the sorbents.…”

Section: Resultsmentioning

confidence: 99%

“…which usually exist in wastewaters as interfering ions. This is exactly the reason of the improved selectivity of the sulfurized adsorbents toward mercury (Asasian et al 2014).…”

Section: Introductionmentioning

confidence: 85%

“…Ranganathan and Balasubramanian sulfurized a coconut shell-based AC by mixing and shaking of AC with a sodium sulfide solution (0.5 %) for 1 h. The mercury equilibrium adsorption capacity of the virgin one was 40 mg/g which increased to 60 mg/g (Ranganathan and Balasubramanian 2002). In the previous works of our group, sulfurization of AC through different methods has been reported Kaghazchi 2012, 2013b;Asasian et al 2014). …”

Section: Introductionmentioning

confidence: 90%

“…The second method was a two-step sulfurization procedure including (1) AC impregnation in the molten elemental sulfur at 145°C for 30 min with the sulfur-to-carbon ratio (SCR) of 4:1, and (2) stabilization of the physically sorbed sulfur by heat treating of the solid mixture at 600°C for 30 min in a muffle furnace under an inert atmosphere (Asasian and Kaghazchi 2013b). In the third method, AC was contacted with a stream of sulfur dioxide (SO 2 ) diluted in N 2 (concentration of 4 % vol/vol) in a bubbling fluidized bed reactor at 700°C for 60 min (Asasian et al 2014). The detailed procedures and the ways of achieving the abovesaid optimal conditions were described in the previous works Kaghazchi 2012, 2013b;Asasian et al 2014).…”

Section: Sulfurization and Characterizationmentioning

confidence: 99%

“…In the third method, AC was contacted with a stream of sulfur dioxide (SO 2 ) diluted in N 2 (concentration of 4 % vol/vol) in a bubbling fluidized bed reactor at 700°C for 60 min (Asasian et al 2014). The detailed procedures and the ways of achieving the abovesaid optimal conditions were described in the previous works Kaghazchi 2012, 2013b;Asasian et al 2014). The SACs were denoted as AC-DMDS, AC-S, and AC-SO 2 , respectively.…”

Section: Sulfurization and Characterizationmentioning

confidence: 99%

See 4 more Smart Citations

Sulfurized activated carbons and their mercury adsorption/desorption behavior in aqueous phase

Asasian

Kaghazchi

2015

Int. J. Environ. Sci. Technol.

View full text Add to dashboard Cite

Sulfurized activated carbons (SACs) are of the most recent forms of modified sorbents with high affinity toward mercury. The adsorption/desorption behavior of SACs has not been studied in detail in liquid phases. The study was carried out with the aim of recognition of similarities and differences in the properties and performances of SACs and activated carbons (ACs) exposing to aqueous-phase mercury. In this study, three different sulfurizing agents including dimethyl disulfide (DMDS), elemental sulfur (S), and sulfur dioxide (SO 2 ) were tested for AC sulfurization (each under the optimal conditions). Sulfurization with DMDS at room temperature led to the formation of elemental sulfur and sulfide/disulfide on the AC surface; however, sulfurization at higher temperatures with SO 2 and powdered S resulted in the formation of more stable organic forms such as thiophene and oxidized sulfur. The equilibrium mercury adsorption capacity of AC-DMDS was so larger than AC and other SACs. On the other hand, the largest surface area drop and consequently the slowest mercury adsorption rate belonged to this sample. However, AC-S and AC-SO 2 led to moderate increase in mercury equilibrium adsorption capacity; they showed several advantages resulted from their extended porosities and more stable sulfur functionalities. The more accelerated adsorption especially at initial stages of contact in batch modes and negligible entry of sulfur compounds into the treating wastewater were of their important advantages. Mercury desorption was also studied and compared using several acidic and potassium halide solvents. The possibility of applicability of SACs in consecutive mercury adsorption/desorption cycles was also investigated.

show abstract

Section: Resultsmentioning

confidence: 99%

“…which usually exist in wastewaters as interfering ions. This is exactly the reason of the improved selectivity of the sulfurized adsorbents toward mercury (Asasian et al 2014).…”

Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 90%

Section: Sulfurization and Characterizationmentioning

confidence: 99%

Section: Sulfurization and Characterizationmentioning

confidence: 99%

See 3 more Smart Citations

Sulfurized activated carbons and their mercury adsorption/desorption behavior in aqueous phase

Asasian

Kaghazchi

2015

Int. J. Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

Study on the Desorption Mechanism of Sulfur Dioxide–Modified Activated Carbon Based on Density Functional Theory

Chen,

Wang,

Liu

et al. 2024

Asia-Pacific J Chem Eng

View full text Add to dashboard Cite

Activated carbon injection technology is the primary method used to control the mercury emissions from coal‐fired power plants. The preparation of sulfur‐loaded carbon‐based adsorbents through SO2 modification of the surface of activated carbon (the primary component) provides an effective solution to enhancing the mercury removal performance of adsorbents. However, there remains a lack of clarity on the adsorption performance and mechanism of mercury on the newly formed active sites of the carbon surface after SO2 sulfur loading modification. In this study, four potential structures of SO2 loaded onto the surface of activated carbon were constructed. Quantum chemical calculation methods were applied to calculate the adsorption process of Hg in these four models, with those important characteristics identified such as bonding properties, adsorption energy, electrostatic potential, and molecular orbitals. As indicated by those results, the adsorption bonds of the SO2‐modified activated carbon were mainly C‐O‐S and C‐S‐C. After the carbon cluster model adsorbed SO2 molecules, the sulfur in SO2 exhibited a strong positive potential that facilitated the loss of electrons from Hg due to the potential difference. Consequently, HgO was firmly adsorbed onto the surface of the carbon cluster. As revealed by the molecular orbital calculations performed after Hg adsorption on the two carbon cluster models, SO2‐modified and elemental sulfur‐modified activated carbons, in the SOAC‐Arm‐1 configuration, there was a clear exchange orbital around the adsorbed Hg atom in the LUMO, with a small HOMO–LUMO energy gap of only 0.01713 eV. At this point, the free electrons on the molecule were prone to orbital transitions, promoting the occurrence of adsorption reactions. The SOAC‐Arm‐3 conformation exhibited the shortest C‐Hg bond length and had an adsorption energy of up to −70.42 kJ/mol, indicating a stronger chemical bonding ability and a higher likelihood of adsorption reactions. These results demonstrate the feasibility of sulfur‐loaded modified activated carbon to mitigate Hg pollution through SO2.

show abstract

Resorcinol formaldehyde xerogels modified with mercapto functional groups as mercury adsorbent

Motahari

Heidari

Motlagh

2015

J of Applied Polymer Sci

View full text Add to dashboard Cite

Resorcinol formaldehyde xerogels are modified by mercaptopropyl-trimethoxysilane during the sol-gel process used to produce the xerogel. The chemical modification is confirmed by Fourier-transform infrared spectroscopy. The xerogel is then used to adsorb mercury ions from aqueous solutions. The effects of the molar ratios of the precursors as well as the catalyst and the modifier are studied on the textural properties of the xerogel and the adsorption efficiency. It is shown that the chemical modification of the resorcinol formaldehyde xerogels creates the chemical sites on the structure of the xerogel to adsorb more mercury ions and increase the adsorption efficiency. At the same time, chemical modification decreases the xerogel surface area which results in a reduction of the mercury adsorption. Therefore, there exists an optimum value for the chemical modification of the xerogel to achieve the highest adsorption efficiency. Adsorption kinetics as well as equilibrium isotherm of xerogels were examined using pseudo-first-and secondorder kinetic equations, and Freundlich and Langmuir isotherm models. The adsorption kinetics was found to follow the pseudosecond-order kinetic equations. The experimental data was also fitted into the Longmuir model more precisely comparing the Freundlich model. Finally, a series of mercury adsorption-desorption tests proved that the optimized mercapto-modified resorcinol formaldehyde xerogel was an efficient reusable adsorbent for mercury ions.

show abstract

Enhanced mercury adsorption capacity by sulfurization of activated carbon with SO2 in a bubbling fluidized bed reactor

Cited by 48 publications

References 41 publications

Sulfurized activated carbons and their mercury adsorption/desorption behavior in aqueous phase

Sulfurized activated carbons and their mercury adsorption/desorption behavior in aqueous phase

Study on the Desorption Mechanism of Sulfur Dioxide–Modified Activated Carbon Based on Density Functional Theory

Resorcinol formaldehyde xerogels modified with mercapto functional groups as mercury adsorbent

Contact Info

Product

Resources

About