燃料化学学报（中英文）

Chemical composition	w/%
SiO₂	50.35	52.96	54.73	55.13	55.96	60.84	87.45
Al₂O₃	35.16	31.02	30.07	29.98	22.55	21.96	8.98
Fe₂O₃	5.25	7.64	6.17	6.08	4.48	4.77	0.07
CaO	3.83	3.45	3.16	3.12	1.20	1.19	0.67
SO₃	1.66	1.17	0.96	0.66	0.59	0.42	0.60
K₂O	1.60	1.35	1.22	1.09	0.43	0.34	0.11
TiO₂	1.52	1.93	1.88	1.74	1.67	1.83	1.15
P₂O₅	0.18	−	0.05	0.72	0.22	0.245	0.08
Other	0.47	0.48	0.56	0.40	0.98	0.33	0.79
Si/Al ratio	1.43	1.71	1.82	1.85	2.48	2.77	9.74

Chemical composition	w/%
SiO₂	50.35	52.96	54.73	55.13	55.96	60.84	87.45
Al₂O₃	35.16	31.02	30.07	29.98	22.55	21.96	8.98
Fe₂O₃	5.25	7.64	6.17	6.08	4.48	4.77	0.07
CaO	3.83	3.45	3.16	3.12	1.20	1.19	0.67
SO₃	1.66	1.17	0.96	0.66	0.59	0.42	0.60
K₂O	1.60	1.35	1.22	1.09	0.43	0.34	0.11
TiO₂	1.52	1.93	1.88	1.74	1.67	1.83	1.15
P₂O₅	0.18	−	0.05	0.72	0.22	0.245	0.08
Other	0.47	0.48	0.56	0.40	0.98	0.33	0.79
Si/Al ratio	1.43	1.71	1.82	1.85	2.48	2.77	9.74

Sample	Raw ash	3# Si-Al carrier	5# Si-Al carrier	6# Si-Al carrier
Specific surface area /(m²·g⁻¹)	2.16	100.48	286.93	568.04

Sample	Raw ash	3# Si-Al carrier	5# Si-Al carrier	6# Si-Al carrier
Specific surface area /(m²·g⁻¹)	2.16	100.48	286.93	568.04

Sample	Surface atomic concentration/%		Proportion of surface atoms/%
Note: the proportion of surface oxygen atoms in the pre-sulfurized FeLaO sample is O_α/O_α+O_β+O_γ.
Fe₂O_3（fresh）	32.55	−	−	67.44	−	−	44.7
Fe₂O_3（-S）	20.08	−	−	72.39	7.52	−	69.31
La₂O₂CO_3（fresh）	−	−	14.8	85.2	−	−	91.25
La₂O₂CO_3（-S）	−	−	12.14	78.42	9.45	−	88.63
FeLaO_（fresh）	5.47	−	11.06	83.47	−	−	76.84
FeLaO_（-S）	3.39	−	4.77	80.49	11.35	−	53.20
CeLaO_（fresh）	−	9.94	9.28	80.77	−	22.57	73.87
CeLaO_（-S）	−	6.42	4.08	76.01	13.49	28.04	85.21
FeCeLaO_（fresh）	5.64	7.04	7.3	80.01	−	23.98	61.05
FeCeLaO_（-S）	2.89	3.76	4.83	72.58	15.95	30.05	92.83

Sample	Surface atomic concentration/%		Proportion of surface atoms/%
Note: the proportion of surface oxygen atoms in the pre-sulfurized FeLaO sample is O_α/O_α+O_β+O_γ.
Fe₂O_3（fresh）	32.55	−	−	67.44	−	−	44.7
Fe₂O_3（-S）	20.08	−	−	72.39	7.52	−	69.31
La₂O₂CO_3（fresh）	−	−	14.8	85.2	−	−	91.25
La₂O₂CO_3（-S）	−	−	12.14	78.42	9.45	−	88.63
FeLaO_（fresh）	5.47	−	11.06	83.47	−	−	76.84
FeLaO_（-S）	3.39	−	4.77	80.49	11.35	−	53.20
CeLaO_（fresh）	−	9.94	9.28	80.77	−	22.57	73.87
CeLaO_（-S）	−	6.42	4.08	76.01	13.49	28.04	85.21
FeCeLaO_（fresh）	5.64	7.04	7.3	80.01	−	23.98	61.05
FeCeLaO_（-S）	2.89	3.76	4.83	72.58	15.95	30.05	92.83

高耐硫硅铝负载Fe-Ce-La复合吸附剂用于中低温烟气砷捕集

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温航宇 , 侯书阳 , 王凯 , 张凯华 ^* , 张锴

燃料化学学报（中英文） | 2026,54(2): 20250144-328-20250144-341

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燃料化学学报（中英文） 2026 , 54 (2) : 20250144-328 -20250144-341

高耐硫硅铝负载Fe-Ce-La复合吸附剂用于中低温烟气砷捕集

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温航宇, 侯书阳, 王凯, 张凯华^*, 张锴

作者信息

华北电力大学能源动力与机械工程学院热电生产过程污染物检测与控制北京市重点实验室, 北京 102206

通讯作者:

张凯华

High resistance SO₂ adsorbent of Fe-Ce-La oxides @ Si-Al carrier for arsenic capture from middle-low-temperature flue gas

Hangyu WEN, Shuyang HOU, Kai WANG, Kaihua ZHANG^*, Kai ZHANG

Affiliations

Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation, North China Electric Power University, Beijing 102206, China

Corresponding Author:

E-mail: khzhang@ncepu.edu.cn

出版时间: 2026-02-15 doi: 10.1016/S1872-5813(25)60606-2

文章导航

摘要

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开发中低温烟气条件下(<400 ℃) 抗硫性强的烟气脱砷吸附剂，实现燃煤烟气低温脱砷和高效抗硫至关重要。本工作采用共沉淀法制备了五种铁-铈-镧氧化物，并耦合粉煤灰基Si-Al载体制备FeCeLaO/SiO₂-Al₂O₃复合吸附剂。通过TPD、TG、XRF、BET和XPS等对活性组分铁-铈-镧氧化物和Si-Al载体进行表征，进而研究温度、Si/Al比和FeCeLaO负载率对抗硫性的影响。结果表明，SO₂对Fe₂O₃、CeLaO和FeCeLaO脱砷具有促进作用，在400 ℃时，三者的脱砷效率分别从无SO₂时的45.3%、72.5%和81.3%增大到62.6%、80.5%和91.0%。SO₂对La₂O₂CO₃和FeLaO脱砷具有抑制作用，且温度越高，抑制作用越强。Si-Al载体的抗硫中毒能力随Si/Al比的增大而增强，当Si/Al比增大为9.74时，SO₂环境中的脱砷效率比无SO₂时升高了13.9%。引入FeCeLaO活性组分，有利于增强Si-Al载体的抗硫中毒能力。FeCeLaO/SiO₂-Al₂O₃复合吸附剂的强抗硫性来自于活性组分和载体的多重作用：Ce元素对Fe、La、Al等活性组分的保护效应，硫酸化诱导产生了Ce³⁺和表面吸附氧，以及SiO₂较强的表面酸性。

Abstract

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It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions (<400 ℃). In this work, five Fe-Ce-La oxides were prepared by co-precipitation method, and FeCeLaO/SiO₂-Al₂O₃ composite adsorbents were prepared by coupling fly ash-based Si-Al carriers. The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD, TG, XRF, BET and XPS, respectively. The effects of temperature, Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated. Results show that the SO₂ promotes the arsenic removal of Fe₂O₃, CeLaO and FeCeLaO. At 400 ℃, the arsenic removal efficiencies of the three oxides increase from 45.3%, 72.5% and 81.3% without SO₂ to 62.6%, 80.5% and 91.0%, respectively. The SO₂ inhibits the arsenic removal of La₂O₂CO₃ and FeLaO, and the inhibition effect is pronounced at high temperatures. The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio. When the Si/Al ratio is increased to 9.74, the arsenic removal efficiency in the SO₂ environment is 13.9% higher than that in the absence of SO₂. Introducing FeCeLaO active components is beneficial for enhancing the SO₂ poisoning resistance of Si-Al carriers. The strong sulfur resistance of the FeCeLaO/SiO₂-Al₂O₃ composite adsorbent results from multiple factors: protective effects of Ce on Fe, La and Al; sulfation-induced generation of Ce³⁺ and surface-adsorbed oxygen; and strong surface acidity of SiO₂.

Key words

arsenic removal / sulfur resistance / flue gas / Fe-Ce-La oxides / fly ash / 脱砷 / 抗硫 / 烟气 / Fe-Ce-La氧化物 / 飞灰

引用本文

温航宇, 侯书阳, 王凯, 张凯华, 张锴. 高耐硫硅铝负载Fe-Ce-La复合吸附剂用于中低温烟气砷捕集. 燃料化学学报（中英文）, 2026 , 54 (2) : 20250144-328 -20250144-341 . DOI: 10.1016/S1872-5813(25)60606-2

Hangyu WEN, Shuyang HOU, Kai WANG, Kaihua ZHANG, Kai ZHANG. High resistance SO₂ adsorbent of Fe-Ce-La oxides @ Si-Al carrier for arsenic capture from middle-low-temperature flue gas[J]. Journal of Fuel Chemistry and Technology, 2026 , 54 (2) : 20250144-328 -20250144-341 . DOI: 10.1016/S1872-5813(25)60606-2

正文

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China is the world’s largest coal producer and consumer. Conventional pollutants such as NO_x, SO_x and particulate matter generated by coal combustion, as well as heavy metal pollutants such as As, Se, Pb and Hg, seriously harm human health and natural environment^[1−2]. Arsenic, as a heavy metal pollutant, is now attracting more and more attention due to its strong volatility, bio-accumulation in ecosystems, carcinogenicity and teratogenicity to humans^[3−4]. It can also cause arsenic poisoning in selective catalytic reduction (SCR) catalyst of coal-fired power plants, which is reported to be one of the most common causes of SCR catalysts deactivation^[5]. Therefore, it is urgent to strengthen the control of arsenic pollution from coal combustion process. Especially in recent years, the “dual-carbon” goal requires coal-fired power units with high carbon emissions to operate at medium-to-low loads or perform deep peak-shaving^[6−7], which results in a significant decrease in the tail flue gas temperature. For example, the denitrification device’s inlet temperature will drop below 300 °C. Therefore, it is significantly important to develop arsenic pollution control technology under middle-low-temperature flue gas conditions (<400 °C).

Adsorption is currently a mature method for arsenic removal from flue gas^[8−10]. To reduce arsenic poisoning of SCR catalysts, arsenic removal adsorbents are generally added to the flue before the denitrification unit. In this case, the adsorbent can be easily deactivated or its service life can be reduced due to poisoning by high concentration of SO₂ and other substances in the flue gas. Therefore, developing sulfur resistant adsorbents for arsenic removal from middle-low-temperature flue gas is exceedingly desired.

In previous work, the authors developed Fe-rare earth composite oxide adsorbents, including FeLaO, CeLaO and FeCeLaO^[11], which can efficiently remove arsenic from middle-low-temperature flue gas (<400 °C) and can meet the current needs of low load operation or deep peak shaving of coal-fired power units. Especially for the FeCeLaO, the total adsorbed arsenic reaches 583.7 μg/g at 400 ℃, and the arsenic removal efficiency is as high as 89%. Therefore, this work uses Fe-Ce-La oxides as the active component and further couples it with a sulfur resistant carrier to prepare a composite adsorbent, aiming to achieve both low-temperature arsenic removal and high-efficiency sulfur resistance in coal-fired flue gas.

Up to date, only a few studies on the sulfur resistance of arsenic removal adsorbents have been reported. Hu et al.^[12] used the DFT method to study the effect of the SO₂ on the adsorption of As₂O₃ on γ-Al₂O₃ by calculating the adsorption structure, adsorption energy, electron transfer and other characteristics. They found that the SO₂ mainly changed the electron distribution around O atom of the first layer of γ-Al₂O₃ and caused almost all previous As₂O₃ adsorption structures on γ-Al₂O₃ surface to become or stay in chemisorption. Therefore, the SO₂ generally favors the adsorption of As₂O₃ on the γ-Al₂O₃ surface. Li et al.^[13] concluded that the SO₂ has no significant effect on arsenic adsorption on the CaO. Firstly, the reaction rate constant between CaO and gaseous arsenic was greater than that between CaO and SO₂. These indicate that in the initial stage, the SO₂ cannot compete with As₂O₃ for active sites on the CaO surface. Secondly, they demonstrated that calcium sulfate also can adsorb gaseous arsenic. Therefore, even if the CaO surface was fully sulfated, it still had a certain adsorption capacity for gaseous arsenic. However, Chen et al.^[14] showed that the SO₂ inhibited the adsorption process of arsenic on CaO between 300 and 800 °C. This is attributed to the fact that the generated CaSO₃/CaSO₄ occupies the free surface available for arsenic capture, and reduces the arsenic capture ability of the CaO. Zhao et al.^[15] investigated the effect of the SO₂ on the removal of As₂O₃ by Fe₃Mn_xO_y. Results showed that the SO₂ occupied the active sites for As₂O₃ adsorption, consumed lattice oxygen in the adsorbent, and converted it into

${\mathrm{SO}}_4^{2-} $

, thus inhibiting the adsorbent’s ability to remove As₂O₃. These previous studies have well illustrated sulfur resistance in common metal oxide adsorbents for arsenic removal. However, the sulfur resistance and synergistic mechanisms of multi-metal oxide composite adsorbents require further investigation.

Fly ash is a by-product of coal-fired power plants. After alkali fusion^[16], acid washing^[17] and other modification, the silica-alumina glass with high degree of polymerization, quartz, and mullite are depolymerized or destroyed^[18]. The SiO₂ and Al₂O₃ are dissolved in the amorphous matters^[19]. After drying and calcination, the active Si-Al carrier can be obtained, which has the advantages of porosity, large specific surface area and high thermal stability^[20]. Compared with some common carriers such as activated carbon and TiO₂, it has strong surface acidity and can inhibit the adsorption of acid SO₂ in flue gas. Therefore, it may have good SO₂ poisoning resistance.

In this work, a series of Fe-Ce-La oxides were prepared by co-precipitation method, and active Si-Al carriers were obtained by modifying fly ash. Then the FeCeLaO/SiO₂-Al₂O₃ composite adsorbents were prepared. To investigate the effects of Fe, Ce, La and Si/Al ratio on surface properties, the Fe-Ce-La oxides and carriers were characterized using temperature programmed desorption (TPD), thermogravimetry (TG), X-ray fluorescence spectroscopy (XRF), specific surface area analysis (BET), and X-ray photoelectron spectroscopy (XPS). The effects of temperature, SO₂ concentration and Si/Al ratio on the arsenic adsorption performance and sulfur poisoning resistance were also investigated in depth.

1　Experimental procedures and methods

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1.1　Preparation of Fe-Ce-La oxides

Five adsorbents, pure Fe₂O₃, pure La₂O₂CO₃, FeLaO, CeLaO and FeCeLaO, were prepared by co-precipitation method.

1.1.1　Preparation of precursor solution

0.1 mol of Fe(NO₃)₃·9H₂O and La(NO₃)₃·6H₂O were dissolved in deionized water, respectively, and then polyethylene glycol with a mass ratio of 1∶1 to the theoretical yield of the product Fe₂O₃ or La₂O₂CO₃ was added to obtain pure Fe₂O₃ and La₂O₂CO₃ precursor solutions.

0.05 mol Ce(NO₃)₃·6H₂O was dissolved in deionized water, and then 0.05 mol H₂O₂ was added. The mixed solution was stirred for 30 min. Polyethylene glycol with the theoretical yield/mass ratio of the product 1∶1 was added. After stirring and dissolving, 0.05 mol of La(NO₃)₃·6H₂O was added to obtain the precursor solution of CeLaO. 0.1 mol of Fe(NO₃)₃·9H₂O and 0.05 mol of La(NO₃)₃·6H₂O were added to obtain the precursor solution of FeCeLaO.

0.05 mol of La(NO₃)₃-6H₂O was dissolved in deionized water. Polyethylene glycol with a mass ratio of 1∶1 to the theoretical yield of the product was mixed. 0.05 mol of Fe(NO₃)₃-9H₂O was added after stirring and dissolving to obtain a precursor solution of FeLaO.

1.1.2　Preparation of Fe-Ce-La oxides by co-precipitation method

The molar ratio of (NH₄)₂CO₃ to ammonia was ensured to be 1∶1, and diluted with deionized water to prepare a mixed alkaline precipitant with an ammonia concentration of 10%. Then it was added drop by drop to the above five precursor solutions until the pH value was 9.5. Aging at room temperature for 24 h, centrifugal separation, the filter cake was washed sufficiently with deionized water until the pH of the cleaning solution was neutral, after which it was dried at 105 °C. The dried powder was calcined at 500 °C for 5 h, and then was ground for further use.

1.2　Preparation of Si-Al carrier by fly ash activation

A certain amount of fly ash was taken. The particles of equal mass of NaOH or Na₂CO₃ were added and then ground thoroughly (among which samples 1#−5# were NaOH particles and sample 6# was Na₂CO₃ particle). The samples were roasted in muffle furnace at 800 ℃ for 2 h, and were cooled to room temperature.

A hydrochloric acid solution with a volume concentration of 11% was prepared. Its amount was determined based on the molar ratios of n(HCl)/n(NaOH) at 1∶2, 1∶1, 3∶2 and 3∶1, respectively, to perform acid washing for alkali-fused ash. The reaction was conducted at 60 °C with stirring for 80 min. After 10 h settling, the cake was filtered and washed until the supernatant reached neutral pH. The filter cake was dried at 105 °C for 10 h, grounded and labeled as samples 1#−4#.

In order to obtain the Si-Al carrier with great difference in Si/Al ratio, 30% and 60% hydrochloric acid solutions were further prepared. The dosage of hydrochloric acid solution was determined according to the ratio of n(HCl)/n(NaOH or Na₂CO₃) as 2∶1 and 4∶1, respectively. Then the above steps were repeated to obtain 5#−6# samples.

1.3　Preparation of FeCeLaO/SiO₂-Al₂O₃ composite adsorbents

Using the 3# Si-Al carrier with a Si/Al ratio of 1.85 as an example, composite adsorbents with different loading ratios (active component/carrier) were prepared. 25, 10, 5, 2.5 and 1.7 g of the 3# Si-Al sample were weighed and separately added to the FeCeLaO precursor solution. The alkaline precipitant was then added dropwise until pH value = 9.0−10.0. The steps described in Section 1.1 were subsequently repeated to obtain composite adsorbent samples with loading ratios of 1∶5, 1∶2, 1∶1, 2∶1 and 3∶1, respectively.

1.4　Adsorbents characterization

The chemical composition of the active Si-Al carrier was determined by X-ray fluorescence spectrometer (XRF, BRUKER PUMA Series 2, Germany), and its Si/Al ratio was calculated.

The specific surface area of the activated Si-Al carriers was determined using a Micromeritics ASAP 2020 analyzer. The samples were degassed at 300 °C for 1 h before testing in order to remove impurities from the pores. Specific surface area information was obtained from the measured N₂ adsorption isotherms and Brunauer-Emmett-Teller (BET) results.

SO₂-TPD analysis was performed on the Fe-Ce-La oxides and Si-Al carriers using a chemical adsorption analyzer (ChemBET Pulsar TPD/TPR, Quantachrome, USA). The sample was first heated to 400 °C under high-purity N₂ purge and held for 20 min, then exposed to a gas stream containing 2.0×10⁻³ SO₂ and 5% O₂ at 400 °C for 2.5 h to achieve saturation adsorption. Subsequently, the sample was purged with high-purity N₂ for about 40 min until the SO₂ signal disappeared in order to remove reversibly adsorbed SO₂ gas, and then cooled to 50 °C; Finally, temperature-programmed desorption (TPD) was conducted by heating the sample from 50 to 1000 °C at a rate of 10 °C/min, and the data was recorded simultaneously to obtain the TPD curve.

Thermogravimetric (TG) analysis was performed in N₂ atmosphere using Netzsch STA 449 F3 analyzer (Germany), with a nitrogen flow rate of 60 mL/min. The heating rate was 10 °C/min and the sample was heated up to 1200 °C until it no longer lost weight to obtain a TG-DTG curve. The surface atomic states of the adsorbents were analyzed by X-ray photoelectron spectroscopy (XPS, ESCALab 250 Xi, Thermo Fisher, USA) with Al Kα radiation (hv=1486.6 eV). The binding energies were calibrated using the C 1s peak at 284.6 eV as a reference.

1.5　Experimental device and method of SO₂ resistance

The experimental setup for evaluating the sulfur poisoning resistance of the adsorbent during arsenic removal from flue gas was shown in Figure 1. It consists of four parts: a simulated flue gas supply unit, an arsenic source generation unit, an anti-SO₂ poisoning reaction unit, and an exhaust gas treatment unit. The simulated flue gas supply unit provided a mixture of N₂, O₂ and SO₂. The total gas flow rate was maintained at 200 mL/min. The arsenic source generator and adsorbent fixed bed were integrated into the same quartz tube reactor. This reactor was installed inside two small electric furnaces which could be heated separately.

The arsenic source was obtained through the vaporization and decomposition of the As₂O₅/H₂O standard solution (Inorganic Ventures, USA, As (V) concentration 999 ± 5 μg/mL). It was evenly dropped into the small liquid pool through a micro-syringe and then heated to 400 ℃. It is reported that As₂O₅ can lose O and convert to As₂O₃ because of instability near 300 ℃^[21], so heating at 400 ℃ in this study will completely produce As₂O₃ gas. The As₂O₃ vapor was carried by the simulated flue gas through the fixed adsorbent bed located at the bottom of the reactor. Different reaction temperatures could be achieved by adjusting the temperature of the 2# furnace. The simulated flue after adsorption reaction enters the tail gas treatment unit, the escaped arsenic and SO₂ were captured in impingers containing HNO₃ (0.5 mol/L) and NaOH (0.5 mol/L), respectively.

Detailed experimental methods for resistance to sulfur poisoning are as follows:

Firstly, the Fe-Ce-La oxides, activated Si-Al carriers and composite adsorbents were pre-sulfurized so that sulfur poisoning occurred sufficiently in advance. The pre-sulfurization conditions were as follows: the adsorbent dosage was 0.3 g, which was placed in the quartz tube adsorption bed. The quartz tube was put into an electric furnace. The carrier gas composition, flow rate and temperature were adjusted for pre-sulfurization to match the corresponding anti-SO₂ poisoning experimental conditions. After the gas path and temperature stabilized, the pre-sulfurization treatment commenced and lasted for 1.5 h.

Secondly, the As₂O₃(g) removal performance of fresh and sulfur poisoned adsorbents was compared. The flow rates of SO₂, O₂ and N₂ were each adjusted to obtain different component concentrations and the total flow rate was kept at 200 mL/min. Then the furnace 1 was seted to 400 ℃ and the furnace 2 was seted to the different target temperatures. approximately 0.3 g of fresh or sulfur poisoned adsorbent was uniformly placed on the quartz tube bed, and all pipes were connected. After gas flow stabilization, the arsenic source was added dropwise to initiate the reaction. The dosage of arsenic source was 0.4 mL and the reaction time was 90 min.

In order to reduce the experimental error, the above experiments were repeated more than three times under the same conditions.

1.6　Arsenic analysis method

Total arsenic contents of the samples were determined using hydrochloric acid digestion and hydride generation atomic fluorescence spectrometry. The specific procedure was as follows: 0.1 g of sample was digested in 100 mL of 10% hydrochloric acid at 80 °C for 12 h. The total arsenic content in the resulting solution was then measured by AFS-933 Hydride Generation Atomic Fluorescence Spectrometer (Beijing Jitian Instrument Co, Ltd).

The total arsenic removal efficiency (η) was defined as follows:

$ \textit{η}=\frac{{A}{{s}}_{\text{ad}}}{\left[{A}{{s}}_{\text{0}}\left({1-}\textit{α}\right)\right]}{\times 100\%} $

(1)

where As_ad is the total arsenic content in the adsorbent, μg; As₀ is the total amount of added arsenic, μg; α is the ratio of the sum of arsenic adhered to the reactor wall and non-volatilized arsenic to the total arsenic input, %.

2　Results and discussion

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2.1　XRF and BET analysis

The composition of Si-Al carriers obtained from fly ash activation is shown in Table 1. The total contents of SiO₂ and Al₂O₃ in the raw ash are approximately 85.51%, and the Si/Al ratio is 1.43. With the increase of acid concentration and n(HCl)/n(NaOH or Na₂CO₃) molar ratio during the activation treatment, the Al₂O₃ content is gradually reduced, the Si/Al ratio is significantly increased, and the concentration of impurities such as SO₃ is significantly reduced. When the hydrochloric acid concentration is 60% and the n(HCl)/n(Na₂CO₃) molar ratio is 4∶1, the Si/Al ratio of the obtained 6# Si-Al carrier is 9.74, which is approximately 7 times the Si/Al ratio of the original ash, and the sum of the impurity contents such as SO₃ is only 2.83%. These indicate that high-concentration acid washing significantly enhances the Si/Al ratio while effectively removing most impurities from fly ash, including Fe and Ca components that possess adsorption activity toward As₂O₃. The increase of Si/Al ratio is favorable to enhance the surface acidity, thereby inhibiting competitive SO₂ adsorption in flue gas and reducing pore blockage induced by sulfate precipitation. These combined effects potentially enhance the adsorbent’s sulfur poisoning resistance.

Table 2 shows the variation of specific surface area of raw fly ash and activated Si-Al carrier. As the concentration and dosage of acid increase during the acid-washing process, the specific surface area of the Si-Al carriers significantly increases. Among them, the 6# Si-Al carrier exhibits the largest specific surface area, reaching 568.04 m²/g. This fully meets the requirements for use as an adsorbent or carrier to enhance adsorption capacity.

2.2　SO₂-TPD analysis

SO₂-TPD measurements were carried out on oxides FeLaO, CeLaO and FeCeLaO, as well as pure oxides Fe₂O₃ La₂O₂CO₃ as comparison. As is shown in Figure 2, the five adsorbents exhibit different desorption peaks. Desorption peaks between 50−500 °C correspond to SO₂ release from adsorbent surfaces or pores^[22]. FeLaO and pure La₂O₂CO₃ exhibit minimal low-temperature SO₂ adsorption, likely due to their limited specific surface area and poor sulfur affinity^[11]. The 600−800 °C desorption peak for Fe₂O₃ is attributed to iron sulfate decomposition^[23], while La₂O₂CO₃ shows a peak at 805 °C from lanthanum sulfate decomposition. FeLaO displays dual peaks at 736 and 770 °C, which are attributed to the decomposition of lanthanum sulfate or iron sulfate，suggesting that both Fe and La elements in FeLaO may have been sulfated.

CeLaO exhibits a characteristic peak at 867 °C assigned to cerium sulfate decomposition. No desorption peak corresponding to lanthanum sulfate is detected, indicating that Ce in CeLaO preferentially reacts with SO₂, thereby protecting La from sulfation. For FeCeLaO, peaks at 658, 789 and 946 °C correspond to decomposition of Fe₂(SO₄)₃, La₂(SO₄)₃ and Ce(SO₄)_2, respectively^[24]. The dominant cerium sulfate peak indicates severe sulfation of Ce, while small iron/lanthanum sulfate peaks suggest mild sulfation of Fe and La. This confirms Ce’s protective role in CeLaO and FeCeLaO systems, shielding Fe and La active sites from sulfur poisoning.

SO₂-TPD tests were also carried out on Si-Al carriers and composite adsorbents as shown in Figure 3. Desorption peaks between 50−500 °C belong to the desorption of SO₂. Peaks between 500−600 °C for 3#, 5# and 6# carriers are attributed to iron sulfate decomposition^[25−26].

These peaks diminish with increasing Si/Al ratios due to decreasing Fe content and increasing surface acidity, and thereby weaken sulfation. The 775 °C peak for 3# carrier originates from decomposition of Al₂(SO₄)₃, while these peaks disappear at high Si/Al ratios. For composite adsorbents, desorption peaks at or above 703 °C stem from decomposition of Ce(SO₄)₂.

2.3　TG analysis

TG analysis was employed to identify the sulfate species formed on the SO₂ poisoned adsorbents and the variation of sulfation degree with temperature or Si/Al ratio.

Figure 4 shows the weight loss peaks of fresh Fe₂O₃ and pre-sulfurized Fe₂O₃ at different temperatures. Fresh Fe₂O₃ has almost no weight loss peaks, while SO₂ poisoned Fe₂O₃ exhibits three weight loss peaks. The peak below 200 °C is attributed to the evaporation of surface adsorbed water. The peak around 430 °C may be attributed to the decomposition of the hydrogen sulfate. The peak between 500 and 800 °C is ascribed to the decomposition of the iron sulfate^[23,27]. The degree of SO₂ poisoning in Fe₂O₃ initially increases and then decreases with the increasing of the pre-sulfidation temperature. At 300 °C, the mass loss of the iron sulfate reaches 3.17%, indicating the maximum degree of sulfation. As the temperature continues to rise (>300 °C), the degree of sulfur poisoning is weakened. Possible reasons for this are as follows: (1) a weakening of SO₂ adsorption on the Fe₂O₃ surface, and (2) the decomposition of the formed iron sulfate^[28].

Figure 5 shows the weight loss peaks of fresh La₂O₂CO₃ and pre-sulfurized La₂O₂CO₃ at different temperatures. The weight loss peak between 650 and 800 °C is attributed to the decomposition of La₂O₂CO₃ into La₂O₃ and CO₂. The weight loss peak around 1200 °C is ascribed to the decomposition of La₂(SO₄)₃^[29]. When the pre-sulfidation temperatures are 300, 400 and 500 °C, the mass losses of La₂(SO₄)₃ decomposition are 2.12%, 3.56%, and 7.04%, respectively. These indicate that the higher the temperature, the more severe the sulfur poisoning of La₂O₂CO₃.

Figure 6 shows the TG-DTG curves of FeLaO. The weight loss peak at 460 °C is attributed to the decomposition of LaCO₃OH into La₂O₂CO₃, H₂O and CO₂^[30]. The weight loss peaks at 600−1000 °C may be due to the decomposition of La₂O₂CO₃ or Fe₂(SO₄)₃, as their decomposition temperatures are similar. The weight loss peak at 1200 °C is attributed to the decomposition of La₂(SO₄)₃. With increasing presulfidation temperature, the weight loss corresponding to the former peak gradually decreases, while that corresponding to the latter peak gradually increases. The mass loss of La₂(SO₄)₃ is 3.38%, 4.63% and 9.67% when the temperatures were 300, 400 and 500 °C, respectively. It indicates that the sulfur poisoning of FeLaO becomes more severe overall with increasing temperature.

Figure 7 shows the TG-DTG curves of CeLaO. The weight loss peaks below 200 °C are attributed to the evaporation of adsorbed water. The weight loss peaks around 500−750 °C are caused by the decomposition of LaCO₃OH or La₂O₂CO₃. The weight loss peaks around 850 and 1200 °C are ascribed to the decomposition of Ce₂(SO₄)₃ and La₂(SO₄)₃, respectively. When the pre-sulfidation temperature are 300, 400 and 500 °C, the mass loss of cerium sulfate increases gradually, with values of 1.91%, 2.11% and 4.98%, respectively. The mass loss of La₂(SO₄)₃ also gradually increases, with values of 2.96%, 3.51% and 5.05%, respectively.

These indicate that both Ce and La undergo sulfation simultaneously. However, compared with FeLaO, the sulfation degree of La in CeLaO is less severe. This is attributed to the presence of Ce, which inhibits the sulfation of La to some extent.

Figure 8 shows the TG-DTG curves of FeCeLaO. Compared with the fresh adsorbent, the sulfur poisoned adsorbents exhibits three weight loss peaks around 800, 920 and 1200 °C, which are attributed to the decomposition of Ce(SO₄)₂, Ce₂(SO₄)₃ and La₂(SO₄)₃, respectively^[31−32]. When the pre-sulfidation temperatures are 300, 400 and 500 °C, the mass loss of cerium sulfate increases sequentially, reaching 1.42%, 4.11% and 6.19%, respectively. In contrast, the weight loss of lanthanum sulfate is relatively small, and the weight loss of iron sulfate is almost not observed. These indicate that Ce element preferentially reacts with SO₂, inhibiting the sulfation of Fe and La components. Therefore, Ce plays a protective role by preventing the active sites of Fe and La from sulfur poisoning.

Figure 9 shows the TG-DTG curves of fresh Si-Al carriers. For all samples with different Si/Al ratios, the weight loss peaks below 200 °C are attributed to the evaporation of surface-adsorbed water and internal bound water.

The weight loss peaks around 1200 °C are attributed to the slow decomposition of residual crystalline phases such as anhydrite.

Figure 10 shows the TG-DTG curves of sulfur poisoned Si-Al carriers. Compared with the fresh samples, the weight loss curve of SO₂-poisoned raw ash remains basically unchanged, indicating that it is difficult for the raw fly ash to adsorb SO₂ gas or undergo sulfation reaction. For the 3#, 5# and 6# carriers, the weight loss peaks at 500−800 °C are ascribed to the decomposition of iron sulfate. Peaks at around 1000 °C are attributed to the decomposition of CaSO₃ or Al₂(SO₄)₃. As the Si/Al ratio increases, the weight loss of each carrier gradually decreases. This indicate that the acid washing treatment removes the alkaline metal oxides in the fly ash, leading to increasing surface acidity and reducing sulfation degree.

2.4　XPS analysis

X-ray photoelectron spectroscopy (XPS) was performed to determine the surface element chemical states of the fresh and SO₂ poisoned Fe-Ce-La oxides, and the results were shown in Table 3.

Figure 11 shows the XPS spectra of Fe 2p before and after sulfation of each adsorbent. Two peaks are detected around 710.2 and 723.8 eV, corresponding to Fe 2p_3/2 and Fe 2p_1/2, respectively. The Fe in all three adsorbents is Fe³⁺, and the valence state of Fe remains unchanged before and after sulfur poisoning. The Fe 2p_3/2 orbital of FeLaO splits into three peaks, with the peaks centered at 710.1 and 712.5 eV are attributed to Fe³⁺.

The peak centered at 714.7 eV is attributed to Fe³⁺ bound to −OH^[33−34]. Compared to fresh adsorbents, both Fe 2p_3/2 and Fe 2p_1/2 peaks of the sulfur poisoned adsorbent shifts to high binding energies, which is attributed to the inductive effect of

${\mathrm{SO}}_4^{2-} $

. The strong electronegativity of

${\mathrm{SO}}_4^{2-} $

has a strong attraction for electrons, resulting in a decrease in the electron density around Fe³⁺ ions.

Figure 12 shows the O 1s XPS spectra before and after sulfur poisoning. The peaks at 531.3−532.3 eV are attributed to the surface chemisorbed oxygen (O_α), while the peaks at 529.2−530.3 eV are ascribed to lattice oxygen species (O_β)^[35]. The O 1s of FeLaO is splited into three peaks, with the peak centered at 535.0 eV identified as O_γ, attributed to oxygen in −OH or

${\mathrm{SO}}_4^{2-} $

^[36−37].

As shown in Table 3, the O_α/O_α+O_β ratios for Fe₂O₃, CeLaO and FeCeLaO are 44.7%, 73.87% and 61.05% respectively. After SO₂ poisoned, 69.31%, 85.21% and 92.83%, indicating a significant rise in surface-adsorbed oxygen content, with FeCeLaO exhibiting the greatest increase. The added surface oxygen species are mainly derived from S−OH generated by

${\mathrm{SO}}_4^{2-} $

hydrolysis^[38] and oxygen vacancies provided by the formed Ce^3+[39]. Surface oxygen exhibits greater mobility than lattice oxygen, thereby enhancing the oxidative adsorption reactivity toward As₂O₃. In contrast, the surface oxygen ratios of La₂O₂CO₃ and FeLaO decrease by 2.62% and 23.64%, respectively, after sulfur poisoning, suggesting a reduction in their oxidative adsorption activity for As₂O₃.

The XPS curves of La in La₂O₂CO₃ (a), FeLaO (b), CeLaO (c) and FeCeLaO (d) before and after pre-sulfidation are shown in Figure 13. The La 3d_3/2 peak appears at 835.1 eV and the La 3d_5/2 peak appears at 852.1 eV, with an energy separation of about 16.8 eV between the two peaks. Each main La 3d peak corresponds to a satellite peak. These results regarding the binding energy and multiple splitting peak are consistent with existing reports on La³⁺^[40−41]. Compared to fresh adsorbents, four sulfur poisoned adsorbents exhibit various degrees of blue shift in their La 3d peaks, indicating the formation of S-O-La bond^[42−43], namely the generation of La₂(SO₄)₃.

Figure 14 shows the Ce 3d spectral curves for CeLaO and FeCeLaO. Eight characteristic peaks are fitted: v, v', v'', v''' are attributed to Ce 3d_5/2 spin orbitals, u, u', u'', u''', u''' are ascribed to Ce 3d_3/2 spin orbitals. Among them v, v'', v''', u, u'', u''' correspond to Ce⁴⁺, v', u' correspond to Ce³⁺. Before SO₂ poisoned, the Ce³⁺/Ce³⁺+Ce⁴⁺ ratios in CeLaO and FeCeLaO are 22.57% and 23.98%. After SO₂ poisoned the ratios increase to 28.04% and 30.05%. Sulfation significantly increases the proportion of Ce³⁺, which facilitates the generation of oxygen vacancies and enhances surface chemisorbed oxygen^[11,44], thereby promoting the oxidative adsorption of As₂O₃.

Figure 15 shows the S 2p XPS spectra of the adsorbents after sulfur poisoning. Distinct S 2p curves are detected on all adsorbents, indicating that sulfation occurrs on them. The characteristic peaks located near 170 and 168.8 eV belong to S 2p_1/2 and S 2p_3/2 in

${\mathrm{SO}}_4^{2-} $

(or

${\mathrm{HSO}}_4^- $

)^[37,45]. No spectral signatures of S⁴⁺ compounds such as

${\mathrm{SO}}_3^{2-} $

${\mathrm{HSO}}_3^- $

are observed.

2.5　Sulfur poisoning resistance of active component Fe-Ce-La oxides

Figure 16 shows the arsenic removal efficiency of sulfur poisoned Fe₂O₃ in the temperatures of 200−600 °C and under SO₂ concentration of 1000. The arsenic removal efficiency of fresh Fe₂O₃ is also represented in the figure for comparison. The arsenic removal efficiency of Fe₂O₃ is significantly higher with SO₂ than that without SO₂. At temperatures of 200, 300, 400, 500 and 600 ℃, the arsenic removal efficiency increases by 8.2%, 23.9%, 17.4%, 17.3% and 7.6%, respectively. This can be attributed to the sulfation of Fe₂O₃ in the SO₂ atmosphere, which generates abundant

${\mathrm{SO}}_4^{2-}/{\mathrm{HSO}}_4^- $

species on the surface. These species also possess effective capabilities for oxidizing and adsorbing As₂O₃^[46−47]. The most significant improvement in arsenic removal efficiency occurs between 300 and 500 °C. This indicates that the Fe₂O₃ exhibits the strongest resistance to sulfur poisoning at this temperature range.

However, excessively high temperature (>500 ℃) causes the decomposition of the iron sulfate salt active sites, weakening their promoting effect on arsenic removal. These findings are in agreement with the TG results of Fe₂O₃ before and after pre-sulfation.

Figure 17 and Figure 18 show the arsenic removal efficiency of pre-sulfurized La₂O₂CO₃ and FeLaO. Their arsenic removal efficiency in the presence of SO₂ is significantly reduced compared with that in the absence of SO₂. At 200, 300, 400 and 500 ℃, the arsenic removal efficiency of pre-sulfurized La₂O₂CO₃ decreases by 2.1%, 4.6%, 10.2% and 18.8%, respectively, while pre-sulfurized FeLaO decreases by 2.8%, 5.1%, 9.0% and 15.1%. It shows that La₂O₂CO₃ and FeLaO exhibit poor sulfur poisoning resistance. The higher the temperature, the worse the resistance to sulfur poisoning.

Based on the TG and SO₂-TPD analyses, La reacts with SO₂ to form La₂(SO₄)₃, and the newly generated La₂(SO₄)₃ exhibits no activity for adsorbing As₂O₃. XPS results further indicate that the sulfation of La leads to a reduction in the surface adsorbed oxygen ratio (O_α/O_α+O_β), suppressing oxidation and adsorption activity.

Consequently, the arsenic removal efficiency decreases. This is in agreement with the findings of Peralta et al.^[48]: K/La₂O₃ catalyst undergoes sulfation and forms inactive La₂(SO₄)₃ at 400 °C in flue gas containing 1.0×10⁻³ SO₂, which results in complete catalyst deactivation.

Figure 19 and Figure 20 show the arsenic removal efficiency of pre-sulfurized CeLaO and FeCeLaO. The arsenic removal efficiencies of both CeLaO and FeCeLaO are significantly enhanced with SO₂ than those without SO₂. At adsorption temperatures of 200, 300, 400 and 500 °C, pre-sulfurized CeLaO shows efficiency improvements of 3.3%, 5.3%, 8.0% and 9.8%, respectively, and pre-sulfurized FeCeLaO indicates increases of 2.3%, 5.1%, 9.7% and 11.2%, respectively. At 400 ℃, the efficiency reaches 80.5% for CeLaO and 91.0% for FeCeLaO. These findings align with the TPD and XPS results.

TPD analysis reveals that Ce preferentially reacts with SO₂ in flue gas, thereby protecting Fe and La active sites. XPS results show that after sulfation, both Ce³⁺ ratio (Ce³⁺/Ce³⁺+Ce⁴⁺) and surface adsorbed oxygen content (O_α/O_α+O_β) increase significantly. These synergistic effects collectively enhance arsenic removal efficiency.

2.6　Sulfur poisoning resistance of Si-Al carrier

In order to investigate the resistance of active Si-Al carriers with different Si/Al ratios to SO₂ in flue gas, the experiments were carried out at 400 °C and 5.0×10⁻⁴ SO₂, and the results are shown in Figure 21. Compared with the fresh adsorbent, the pre-sulfurized Si-Al carriers exhibit progressively enhanced resistance to sulfur poisoning as the Si/Al ratio increases. The arsenic removal efficiency of original fly ash after SO₂ poisoning is 30.7%, which is basically the same as that of fresh fly ash. When the Si/Al ratio is 1.85, the arsenic removal efficiency of SO₂ poisoned Si-Al carrier is 54.5%, which decrease by 24.2% compared with the fresh carrier. As the Si/Al ratio further increases, the difference in arsenic removal efficiency between them progressively narrows. At a Si/Al ratio of 2.77, the difference is only approximately 3%. When the Si/Al ratio is 9.7, the arsenic adsorption efficiency of the pre-sulfurized carrier reaches the maximum value of 74.6%, which is 13.9% higher than the arsenic removal efficiency of the fresh carrier. Therefore, increasing Si/Al ratio in the carrier promotes enhancing sulfur resistance in the adsorbent.

The possible reason is that as the Si/Al ratio increases, the content of alkali metal oxide in active Si-Al carrier decreases, both the content of SiO₂ and the surface acidity increase. This inhibits the adsorption of SO₂ from flue gas and weakens the competitive adsorption between SO₂ and gaseous As₂O₃, thereby preventing the formation of metal sulfates that would otherwise cause active site depletion or pore blockage. At the same time, the increase in the Si/Al ratio can obtain a large specific surface area. Therefore, the ability to resist sulfur poisoning is enhanced.

2.7　Sulfur poisoning resistance of FeCeLaO/SiO₂-Al₂O₃

The 3# Si-Al oxide with Si/Al ratio of 1.85 was used as the carrier to prepare the composite adsorbents with different loading ratios. The effect of FeCeLaO loading ration on sulfur resistance was investigated at 400 ℃ and under 5.0×10⁻⁴ SO₂. The results are shown in Figure 22.

For the pure Si-Al carrier (0 loading ratio), the arsenic removal efficiency decreases by 24.2% after sulfur poisoning. As the loading ratio increases to 1∶5, 1∶2, 1∶1, 2∶1 and 3∶1, the arsenic removal efficiency of SO₂ poisoned adsorbents is 73.3%, 84.7%, 93.2%, 88.2% and 83.9%, respectively. Compared with the corresponding fresh adsorbents, these efficiencies still decline, decreasing by 10.8%, 5.5%, 3.6%, 2.3% and 1.4%, respectively. However, the degree of the decline in arsenic removal efficiency has gradually narrowed. This demonstrates that incorporating FeCeLaO active components is beneficial to enhance the sulfur poisoning resistance of the adsorbent. Furthermore, as the loading ratio increases, the degree of sulfur resistance improvement becomes more pronounced. Especially when the loading ratio exceeds 1∶2, the decrease in arsenic removal efficiency of the pre-sulfurized adsorbent is less than 5%; When the loading ratio is 1∶1, the removal efficiency of sulfur poisoned adsorbent is still as high as 93.2%. Therefore, the FeCeLaO/SiO₂-Al₂O₃ composite adsorbent is undoubtedly a low-cost adsorbent with superior sulfur resistance for arsenic removal.

The reason for this phenomenon is as follows: after introducing the FeCeLaO active component, as its loading ratio increases, the content of Ce component increases. The Ce element preferentially reacts with SO₂, thereby protecting the Fe and La active components as well as the Al component in the carrier from sulfur poisoning. This prevents the loss of active sites and thus enhances the resistance to sulfur poisoning. It is precisely due to the protective effect of Ce components and the surface acidity of SiO₂ that the composite adsorbent FeCeLaO/SiO₂-Al₂O₃ retains high adsorption efficiency and demonstrates excellent SO₂ resistance in SO₂-containing environments.

3　Conclusions

收起

This study aims to develop superior arsenic removal adsorbents in the middle-low-temperature region which could be applied efficiently even in the presence of SO₂. The as-prepared CeLaO, FeCeLaO and FeCeLaO/fly ash derived SiO₂-Al₂O₃ can exhibit arsenic removal efficiencies of 80.5%, 91.0% and 93.2% respectively at 400 °C in the SO₂ atmosphere, which not only have a low arsenic removal temperature window (≤400 ℃), but also have a strong resistance to sulfur toxicity.

The Si-Al carrier with a specific surface area as high as 568.04 m²/g used in this study is derived from coal fly ash. Notably, it does not require additional silicon-aluminum sources, and has advantages of strong sulfur resistance and low-cost. This approach provides a pathway for the resource utilization of coal fly ash.

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SIGNES-PASTOR A J, VIOQUE J, NAVARRETE-MUNOZ E M, et al. Inorganic arsenic exposure and neuropsychological development of children of 4-5 years of age living in Spain[J]. Environ Res, 2019, 174: 135−142.

NACHMAN K E, GINSBERG G L, MILLER M D, et al. Mitigating dietary arsenic exposure: Current status in the United States and recommendations for an improved path forward[J]. Sci Total Environ, 2017, 581−582: 221−236.

MUKHERJEE S, SRIVASTAVA S K. Trace elements in high-sulfur Assam coals from the Makum coalfield in the northeastern region of India[J]. Energy Fuels, 2005, 19(3): 882−891.

CHENG K, WANG Y, TIAN H, et al. Atmospheric emission characteristics and control policies of five precedent-controlled toxic heavy metals from anthropogenic sources in China[J]. Environ Sci Technol, 2015, 49(2): 1206−1214.

LI X, LI J, HE X, PENG Y, CHANG H. Poisoning mechanism and regeneration process of the denitration catalyst[J]. Chem Ind Eng Prog, 2015, 34: 4129−4138.

BURKE M J, STEPHENS J C. Political power and renewable energy futures: A critical review[J]. Energy Res Social Sci, 2018, 35(7/8): 78–93.

BIRD L, LEW D, MILLIGAN M, et al. Wind and solar energy curtailment: A review of international experience[J]. Renewable Sustainable Energy Rev, 2016, 65: 577−586.

WINTER R M, MALLEPALLI R R, HELLEM K P, et al. Determination of As, Cd, Cr, and Pb species formed in a combustion environment[J]. Combus Sci Technol, 1994, 101: 45−58.

MERCEDES D A-S, M ROSA M N-T. Retention of trace elements using fly ash in a coal gasification flue gas[J]. J Chem Technol Biotechnol, 2002, 77: 396−402.

RAJA A, JADHAV R A, HIMANSHU G, et al. Mechanism of selenium sorption by activated carbon[J]. Can J Chem Eng, 2000, 78: 168−174.

ZHANG K, HU L, WANG C, et al. Middle-low-temperature oxidation and adsorption of arsenic from flue gas by Fe-Ce-based composite catalyst[J]. Chemosphere, 2022, 288(1): 132425.

HU P, WENG Q, LI D, et al. Effects of O₂, SO₂, H₂O and CO₂ on As₂O₃ adsorption by gamma-Al₂O₃ based on DFT analysis[J]. J Hazard Mater, 2021, 403: 123866.

LI Y, TONG H, ZHUO Y. Simultaneous removal of SO₂ and trace As₂O₃ from flue gas: Mechanism, kinetics study, and effect of main gases on arsenic capture[J]. Environ Sci Techno, 2007, 41(8): 2894−2900.

CHEN D, HU H, XU Z, et al. Findings of proper temperatures for arsenic capture by CaO in the simulated flue gas with and without SO₂[J]. Chem Eng J, 2015, 267: 201−206.

ZHAO S, WANG Y, XIE X, et al. Arsenic removal from Coal-fired flue gas by MnO₂ coated magnetic flower-like Fe₃O₄ composites: Experimental and DFT study[J]. Chem Eng J, 478 (2023) 147481.

QU P, GAO X, WANG Q, et al. Study on alkali hydrothermal treatment of fly ash and its adsorption properties[J]. Shanxi Chem Ind, 2021, 41(6): 1−2,9.

SOMERSET V S, PETRIK L F, WHITE R A, et al. Alkaline hydrothermal zeolites synthesized from high SiO₂ and Al₂O₃ co-disposal fly ash filtrates[J]. Fuel, 2005, 84(18): 2324−2329.

ZHAO Y, ZHANG J, LIU J, et al. Experimental study on fly ash capture mercury in flue gas[J]. Sci China Tech Sci, 2010, 40(4): 385−391.

ZHAO Y, ZHANG J, WANG Z, et al. Study on mineralogy and micro-structure of high-calcium fly ash[J]. J Eng Thermophysics, 2008, (8): 1427−1430.

QI L, WANG X, WANG W, et al. Mercury removal from coal combustion flue gas by pyrite-modified fly ash adsorbent[J]. Environ Sci Pollut Res Int, 2022, 29(26): 39228−39238.

ZHANG Y, WANG C, LIU H. Experiment and mechanism research on gas-phase As₂O₃ adsorption of Fe₂O₃/γ-Al₂O₃[J]. Fuel, 2016, 181: 1034−1040.

DONG W K, KWANG H P, HEON P H, et al. The role of molybdenum on the enhanced performance and SO₂ resistance of V/Mo-Ti catalysts for NH₃-SCR[J]. Appl Surf Sci, 2019, 481: 1167−1177.

YA Y, WEI T, DONG Q, et al. Insight into the SO₂ resistance mechanism on γ-Fe₂O₃ catalyst in NH₃-SCR reaction: A collaborated experimental and DFT study[J]. Appl Catal B: Environ, 2021, 281: 119544.

CHEN Y, JIANG Y, LI W, et al. Adsorption and interaction of H₂S/SO₂ on TiO₂[J]. Catal Today, 1999, 50: 39−47.

WEI Y, CHEN P, HOU X, et al. SO₂ poisoning mechanism of Fe-Mn/TiO₂ catalyst for low-temperature NH₃ deniteation[J]. J Funct Mater, 2021, 52(4): 4132-4139+4146.

YU Y, CHEN C, MA M, et al. SO₂ promoted in situ recovery of thermally deactivated Fe₂(SO₄)₃/TiO₂ NH₃-SCR catalysts: From experimental work to theoretical study[J]. Chem Eng J, 2019, 361: 820−829.

LEE T, BAI H. Metal sulfate poisoning effects over MnFe/TiO₂ for selective catalytic reduction of NO by NH₃ at low temperature[J]. Ind Eng Chem Res, 2018, 57(14): 4848−4858.

KWON D W, NAM K B, HONG S C. The role of ceria on the activity and SO₂ resistance of catalysts for the selective catalytic reduction of NO_x by NH₃[J]. Appl Catal B: Environ, 2015, 166−167: 37−44.

LIU R, YANG Y, ZHU T, et al. Role of NO and SO₂ in mercury oxidation over a La₂O₃/Fe₂O₃ catalyst with high thermal stability[J]. J Environ Sci China, 2021, 109: 36−44.

LEE M H, JUNG W S. Hydrothermal synthesis of LaCO₃OH and Ln³⁺-doped LaCO₃OH powders under ambient pressure and their transformation to La₂O₂CO₃ and La₂O₃[J]. Bull Korean Chem Soc, 2013, 34(12): 3609−3614.

ZHOU Y, SU B, REN S, et al. Nb₂O₅-modified Mn-Ce/AC catalyst with high ZnCl₂ and SO₂ tolerance for low-temperature NH₃-SCR of NO[J]. J Environ Chem Eng, 2021, 9(5): 106323.

CHANG H, CHEN X, LI J, et al. Improvement of activity and SO₂ tolerance of Sn-modified MnO_x-CeO₂ catalysts for NH₃-SCR at low temperatures[J]. Environ Sci Technol, 2013, 47(10): 5294−5301.

SHWAN S, JANSSON J, OLSSON L, et al. Chemical deactivation of H-BEA and Fe-BEA as NH₃-SCR catalysts—effect of potassium[J]. Appl Catal B: Environ, 2015, 166−167: 277−286.

THOMAS J E, JONES C F, SKINNER W M. The role of surface sulfur species in the inhibition of pyrrhotite dissolution in acid conditions[J]. Geochimica et Cosmochimica Acta, 1998, 62(9): 1555−1565.

ZHAO L, LI C, LI S, et al. Simultaneous removal of elemental mercury and NO in simulated flue gas over V₂O₅/ZrO₂-CeO₂ catalyst[J]. Appl Catal B: Environ, 2016, 198: 420−430.

LIU J, DU Y, LIU J, et al. Design of MoFe/Beta@CeO₂ catalysts with a core−shell structure and their catalytic performances for the selective catalytic reduction of NO with NH₃[J]. Appl Catal B: Environ, 2017, 203: 704−714.

YANG S, GUO Y, YAN N, et al. Nanosized cation-deficient Fe-Ti spinel: A novel magnetic sorbent for elemental mercury capture from flue gas[J]. ACS Appl Mater Interfaces, 2011, 3(2): 209−217.

WEI L, CUI S, GUO H, et al. DRIFT and DFT study of cerium addition on SO₂ of manganese-based catalysts for low temperature SCR[J]. J Mol Catal A: Chem, 2016, 421: 102−108.

ZHANG L, QU H, DU T, et al. H₂O and SO₂ tolerance, activity and reaction mechanism of sulfated Ni–Ce–La composite oxide nanocrystals in NH₃-SCR[J]. Chem Eng J, 2016, 296: 122−131.

WU Q, LIU M, JAEGERMANN W. X-ray photoelectron spectroscopy of La_0.5Sr_0.5MnO₃[J]. ACS Mater Lett, 2005, 59(12): 1480−1483.

PAWLAK D A, ITO M, OKU M, et al. Interpretation of XPS O (1s) in mixed oxides proved on mixed perovskite crystals[J]. J Phys Chem B, 2002, 106: 504−507.

SU J, LYU T, YI H, et al. Superior arsenate adsorption and comprehensive investigation of adsorption mechanism on novel Mn-doped La₂O₂CO₃ composites[J]. Chem Eng J, 2020, 391: 123623.

LIU X, ZONG E, HU W, et al. Lignin-derived porous carbon loaded with La(OH)₃ nanorods for highly efficient removal of phosphate[J]. ACS Sustainable Chem Eng, 2018, 7(1): 758−768.

WANG H, QU Z, XIE H, et al. Insight into the mesoporous FexCe_1−xO_2−δ catalysts for selective catalytic reduction of NO with NH₃: Regulable structure and activity[J]. J Catal, 2016, 338: 56−67.

FERRIZZ R M, GORTE R J, VOHS J M. TPD and XPS investigation of the interaction of SO₂ with model ceria catalysts[J]. Catal Lett, 2002, 82(1/2): 123−129.

XINGS J, WANG C, HUANG Y, et al. A comprehensive exploration about the effects of O₂, SO₂ and NO on As₂O₃ adsorption over Cu/γ-Al₂O₃ SCR catalyst: A DFT study[J]. Chem Eng Sci, 2022, 248: 117260.

XING J, WANG C, HUANG Y, et al. Mechanism of the arsenic adsorption over Cu/γ-Al₂O₃ SCR catalyst: An experimental combined theoretical analysis[J]. Chem Eng Sci, 2022, 254: 117610.

PERALTA M A, ULLA M A, QUERINI C A. SO₂ influence on the K/La₂O₃ soot combustion catalyst deactivation[J]. Catal Today, 2008, 133−135: 461−466.

2026年第54卷第2期

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doi: 10.1016/S1872-5813(25)60606-2

接收时间：2025-07-16
首发时间：2026-09-23
出版时间：2026-02-15

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收稿日期：2025-07-16
修回日期：2025-08-19

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华北电力大学能源动力与机械工程学院热电生产过程污染物检测与控制北京市重点实验室, 北京 102206

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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Chemical composition	w/%
SiO₂	50.35	52.96	54.73	55.13	55.96	60.84	87.45
Al₂O₃	35.16	31.02	30.07	29.98	22.55	21.96	8.98
Fe₂O₃	5.25	7.64	6.17	6.08	4.48	4.77	0.07
CaO	3.83	3.45	3.16	3.12	1.20	1.19	0.67
SO₃	1.66	1.17	0.96	0.66	0.59	0.42	0.60
K₂O	1.60	1.35	1.22	1.09	0.43	0.34	0.11
TiO₂	1.52	1.93	1.88	1.74	1.67	1.83	1.15
P₂O₅	0.18	−	0.05	0.72	0.22	0.245	0.08
Other	0.47	0.48	0.56	0.40	0.98	0.33	0.79
Si/Al ratio	1.43	1.71	1.82	1.85	2.48	2.77	9.74

Chemical composition

w/%

raw ash

1# sample

2# sample

3# sample

4# sample

5# sample

6# sample

SiO₂

50.35

52.96

54.73

55.13

55.96

60.84

87.45

Al₂O₃

35.16

31.02

30.07

29.98

22.55

21.96

8.98

Fe₂O₃

5.25

7.64

6.17

6.08

4.48

4.77

0.07

CaO

3.83

3.45

3.16

3.12

1.20

1.19

0.67

SO₃

1.66

1.17

0.96

0.66

0.59

0.42

0.60

K₂O

1.60

1.35

1.22

1.09

0.43

0.34

0.11

TiO₂

1.52

1.93

1.88

1.74

1.67

1.83

1.15

P₂O₅

0.18

−

0.05

0.72

0.22

0.245

0.08

Other

0.47

0.48

0.56

0.40

0.98

0.33

0.79

Si/Al ratio

1.43

1.71

1.82

1.85

2.48

2.77

9.74

Sample	Raw ash	3# Si-Al carrier	5# Si-Al carrier	6# Si-Al carrier
Specific surface area /(m²·g⁻¹)	2.16	100.48	286.93	568.04

Sample

Raw ash

3# Si-Al carrier

5# Si-Al carrier

6# Si-Al carrier

Specific surface area /(m²·g⁻¹)

2.16

100.48

286.93

568.04

Sample	Surface atomic concentration/%		Proportion of surface atoms/%
Note: the proportion of surface oxygen atoms in the pre-sulfurized FeLaO sample is O_α/O_α+O_β+O_γ.
Fe₂O_3（fresh）	32.55	−	−	67.44	−	−	44.7
Fe₂O_3（-S）	20.08	−	−	72.39	7.52	−	69.31
La₂O₂CO_3（fresh）	−	−	14.8	85.2	−	−	91.25
La₂O₂CO_3（-S）	−	−	12.14	78.42	9.45	−	88.63
FeLaO_（fresh）	5.47	−	11.06	83.47	−	−	76.84
FeLaO_（-S）	3.39	−	4.77	80.49	11.35	−	53.20
CeLaO_（fresh）	−	9.94	9.28	80.77	−	22.57	73.87
CeLaO_（-S）	−	6.42	4.08	76.01	13.49	28.04	85.21
FeCeLaO_（fresh）	5.64	7.04	7.3	80.01	−	23.98	61.05
FeCeLaO_（-S）	2.89	3.76	4.83	72.58	15.95	30.05	92.83

Sample

Surface atomic concentration/%

Proportion of surface atoms/%

Fe³⁺

Ce³⁺+Ce⁴⁺

La³⁺

S⁶⁺

Ce³⁺/Ce³⁺+Ce⁴⁺

O_α/O_α+O_β

Note: the proportion of surface oxygen atoms in the pre-sulfurized FeLaO sample is O_α/O_α+O_β+O_γ.

Fe₂O_3（fresh）

32.55

−

67.44

−

44.7

Fe₂O_3（-S）

20.08

−

72.39

7.52

−

69.31

La₂O₂CO_3（fresh）

−

14.8

85.2

−

91.25

La₂O₂CO_3（-S）

−

12.14

78.42

9.45

−

88.63

FeLaO_（fresh）

5.47

−

11.06

83.47

−

76.84

FeLaO_（-S）

3.39

−

4.77

80.49

11.35

−

53.20

CeLaO_（fresh）

−

9.94

9.28

80.77

−

22.57

73.87

CeLaO_（-S）

−

6.42

4.08

76.01

13.49

28.04

85.21

FeCeLaO_（fresh）

5.64

7.04

7.3

80.01

−

23.98

61.05

FeCeLaO_（-S）

2.89

3.76

4.83

72.58

15.95

30.05

92.83