Association between drinking status and risk of kidney stones among United States adults: NHANES 2007-2018.

OBJECTIVE: This study aimed to investigate the relationship between drinking status and kidney stones occurrence among United States (US) adults who consume alcohol. METHODS: We conducted a cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES 2007-2018). Questionnaires yielded information on alcohol consumption and kidney health. Drinking status was categorized into four groups-former, mild, moderate, and heavy-based on alcohol consumption patterns. The aim was to explore the relationship between drinking status and the prevalence of kidney stones occurrence. For this analysis, we examined a group of individuals diagnosed with kidney stones. With survey weights applied, the total weight of the group was 185,690,415. RESULTS: We used logistic regression to measure the relationship between drinking status and the likelihood of developing kidney stones. In a fully adjusted model, former drinkers were less likely to have previously experienced kidney stones (OR 0.762, 95% CI 0.595-0.977, P < 0.05). In subgroup analysis, heavy alcohol consumption was associated with a significantly reduced likelihood of kidney stones occurrence in various populations. The adjusted odds ratios (with 95% confidence intervals) of kidney stones risk for heavy alcohol consumption were 0.745 (0.566-0.981) for young individuals, 0.566 (0.342-0.939) for older individuals, 0.708 (0.510-0.981) for individuals of white race, 0.468 (0.269-0.817) for individuals with underweight/normal BMI, 0.192 (0.066-0.560) for widowed people, 0.538 (0.343-0.843) for smoking individuals, 0.749 (0.595-0.941) for individuals without a cancer history, and 0.724 (0.566-0.925) for individuals without a stroke history. CONCLUSIONS: In US adults who consume alcohol, a negative linear relationship is apparent between drinking status and the prevalence of kidney stones, with heavy drinking showing a lower prevalence compared to former drinkers. However, the causal relationship between drinking status and kidney stones requires further investigation in future research endeavors.

Hg0 Conversion over Sulfureted HPMo/γ-Fe2O3 with HCl at Low Temperatures: Mechanism, Kinetics, and Application in Hg0 Removal from Coal-Fired Flue Gas.

Recently, sulfureted metal oxides have been developed for the catalytic oxidation of Hg0 to HgCl2 using HCl as an oxidant at low temperatures, and they exhibit excellent Hg0 removal performance. Owing to the lack of reaction mechanisms and kinetics, further improvement in their performance for Hg0 conversion is extremely restricted. In this study, the reaction mechanism of Hg0 conversion over sulfureted HPMo/γ-Fe2O3 with HCl at low temperatures was investigated using Hg balance analysis and transient reaction. The chemical adsorption of Hg0 as HgS and the catalytic oxidation of Hg0 to HgCl2 both contributed to Hg0 conversion over sulfureted HPMo/γ-Fe2O3. Meanwhile, the formed HgCl2 can adsorb onto sulfureted HPMo/γ-Fe2O3. Then, the kinetics of Hg0 conversion, Hgt adsorption, and HgCl2 desorption were developed, and the kinetic parameters were gained by fitting the Hg balance curves. Subsequently, the inhibition mechanism of H2O and SO2 on Hg0 conversion over sulfureted HPMo/γ-Fe2O3 was determined by comparing the kinetic parameters. The kinetic model suggested that both HgCl2 resulting from Hg0 oxidation and unoxidized Hg0 can be completely adsorbed on sulfureted HPMo/γ-Fe2O3 with a moderate mass hourly space velocity. Therefore, sulfureted HPMo/γ-Fe2O3 can be developed as a reproducible sorbent for recovering Hg0 emitted from coal-fired power plants.

Highly efficient Cr (VI) removal from electroplating wastewater by regenerable copper sulfides: Mechanism and magical induction effect for Cr resource recovery.

The current sorbents used to remove Cr (VI) from electroplating wastewater are faced with some challenges including the difficulty in separating, regenerating, and safely disposing of adsorbed Cr species. To address these challenges, CuSx/TiO2 was developed to recover Cr (VI) from electroplating wastewater. CuSx/TiO2 had superior performance in removing Cr (VI), with the rate and capacity of approximately 9.36 mg g-1 h-1 and 68.8 mg g-1 at initial pH 4.0, respectively. Additionally, Cu2+ released from CuSx/TiO2 during Cr (VI) removal would come back to its external surface as the Cu(OH)2 precipitate at initial pH 4.0, which helped to prevent the generation of secondary pollution. The Cu(OH)2 precipitate would be decomposed into CuOx after calcination, which would then be transformed back into CuSx by re-sulfuration for regeneration. Hence, CuSx showed a magical induction effect on Cr (VI) recovery, and Cr (VI) from electroplating wastewater might be gradually enriched as Cr2O3 in the sandwich between CuSx and TiO2 through multiple regenerations and removals, which could be considered as a chromium ore resource for industrial applications when the amount of enriched Cr2O3 reached more than 30 wt%. Overall, CuSx/TiO2 showed great potential as a promising sorbent for Cr (VI) removal from electroplating wastewater.

Interaction between drinking and dietary inflammatory index affects prostate specific antigen: a cross-sectional study.

BACKGROUND: Numerous studies have shown that the dietary inflammatory index (DII) is associated with adverse health effects. However, the relationship between DII and prostate cancer (PCa) remains controversial. Although alcohol is included in DII as a dietary factor, the various adverse health effects of alcohol consumption are not only related to inflammation. On the other hand, it has been a long-standing debate whether alcohol consumption is linked to the risk of PCa. Therefore, to clarify whether drinking affects the relationship between DII and PCa, we evaluated the correlation between DII and prostate-specific antigen (PSA) based on the National Health and Nutrition Examination Survey (NHANES) database. METHODS: We used data from the NHANES spanning from 2005 to 2010 to analyze the relationship between PCa and DII. Out of the 31,034 NHANES participants, we enrolled 4,120 individuals in our study, utilizing dietary intake data from a twenty-four-hour period to determine DII scores. Demographic data, physical and laboratory test results were collected to compare between low PSA and high PSA groups, and to calculate the odds ratio between both groups, we employed a logistic regression analysis. RESULTS: In this cross-sectional investigation of PCa, drinkers and non-drinkers had different relationships between DII and PSA levels (OR: 1.2, 95% Cl: 1-1.44 vs. OR: 0.98, 95% Cl: 0.9-1.07), and DII and abstaining from alcohol were effective in reducing the incidence of PSA (p-value for significant interaction = 0.037). CONCLUSION: The results of our study suggest that drinking may influence the relationship between DII and PSA levels. DII is likely to be a reliable indicator for estimating PSA levels among non-drinkers, who may limit their intake of pro-inflammatory ingredients to lower the incidence and death of PCa.

Novel Counteraction Effect of H2O and SO2 toward HCl on the Chemical Adsorption of Gaseous Hg0 onto Sulfureted HPW/γ-Fe2O3 at Low Temperatures: Mechanism and Its Application in Hg0 Recovery from Coal-Fired Flue Gas.

In this work, sulfureted phosphotungstic acid-grafted γ-Fe2O3 (HPW/γ-Fe2O3) was investigated as a regenerable monolithic sorbent to recover gaseous Hg0 upstream of wet flue gas desulfurizations (FGDs), and the effects of HCl, SO2, and H2O on the chemical adsorption of Hg0 onto sulfureted HPW/γ-Fe2O3 were investigated with Hg balance analysis and kinetic analysis. Hg0 conversion over sulfureted HPW/γ-Fe2O3 was remarkably promoted in the presence of HCl, and most Hg0 was catalytically oxidized to HgCl2. Moreover, the chemical adsorption of Hg0 was notably restrained as the key species for Hg0 transformation to HgS (i.e., S22-) was rapidly oxidized by Cl*. However, the effect of HCl on Hg0 conversion over sulfureted HPW/γ-Fe2O3 was almost counteracted by H2O and SO2 as they competed with physically adsorbed Hg0 and S22- for the consumption of Cl*. Therefore, the chemical adsorption of Hg0 onto sulfureted HPW/γ-Fe2O3 in the presence of SO2 and H2O was slightly inhibited by HCl, and only a small amount of HgCl2 was formed. Moreover, sulfureted HPW/γ-Fe2O3 exhibited a moderate ability for gaseous HgCl2 adsorption. As a result, sulfureted HPW/γ-Fe2O3 showed excellent performance in recovering Hg0 from the flue gas upstream of the FGDs for the centralized control of Hg0 emitted from coal-fired plants.

Simultaneous Adsorption of Gaseous Hg0 and Hg(II) by Regenerable Monolithic FeMoSx/TiO2: Mechanism and its Application in the Centralized Control of Hg Pollution in Coal-Fired Flue Gas.

FeMoSx/TiO2 was investigated as a regenerable sorbent to simultaneously adsorb Hg0 and Hg(II) from coal-fired flue gas for the centralized control of Hg pollution discharged from coal-fired power plants. The performance of FeMoSx/TiO2 for Hg(II) and/or Hg0 adsorption was evaluated on a fixed-bed reactor at 80 oC, and the mutual interference between Hg0 adsorption and Hg(II) adsorption was analyzed using individual adsorption, simultaneous adsorption, and two-stage adsorption. FeMoSx/TiO2 displayed an excellent capacity for individual Hg0 adsorption (41.8 mg g-1) and a moderate capacity for individual Hg(II) adsorption (0.48 mg g-1). Two types of adsorption sites were present on FeMoSx/TiO2 for gaseous Hg adsorption (S0 and FeS2/MoS3 sites). X-ray photoelectron spectroscope and kinetic analyses demonstrated that Hg0 and Hg(II) could adsorb onto S0 sites, whereas only Hg0 was adsorbed onto FeS2/MoS3 sites. As Hg0 competed with Hg(II) for the S0 sites, the amount of Hg(II) adsorbed slightly decreased by 16% in the presence of Hg0. However, Hg0 adsorption onto the FeS2/MoS3 sites predominated over the Hg0 adsorption onto FeMoSx/TiO2 and it was not inhibited in the presence of Hg(II). Therefore, the amount of Hg0 adsorbed on FeMoSx/TiO2 was only decreased by 2% in the presence of Hg(II).

Novel Promotion of Sulfuration for Hg0 Conversion over V2O5-MoO3/TiO2 with HCl at Low Temperatures: Hg0 Adsorption, Hg0 Oxidation, and Hg2+ Adsorption.

In this work, the commercial selective catalytic reduction (SCR) catalyst V2O5-MoO3/TiO2 was sulfureted with H2S to improve both its capability for elemental mercury (Hg0) removal at low temperatures and its resistance to SO2 and H2O. Hg0 removal over both V2O5-MoO3/TiO2 and sulfureted V2O5-MoO3/TiO2 involved the catalytic oxidation of Hg0 to HgCl2 and the chemical adsorption of gaseous Hg0; therefore, the effect of sulfuration on Hg0 chemical adsorption and the catalytic oxidation of Hg0 to HgCl2 over V2O5-MoO3/TiO2 and its resistance to SO2 and H2O were investigated using Hg balance analysis. Kinetic analysis showed that the rates of the chemical adsorption and oxidation of Hg0 were both in direct proportion to the concentration of physically adsorbed Hg0. The physical adsorption of gaseous Hg0 on V2O5-MoO3/TiO2 was remarkably promoted after sulfuration, and the physical adsorption of gaseous Hg0 over sulfureted V2O5-MoO3/TiO2 was scarcely inhibited by SO2 and H2O. Therefore, the performance of V2O5-MoO3/TiO2 for Hg0 removal and its resistance to SO2 and H2O were both improved after sulfuration. Even more remarkably, sulfureted V2O5-MoO3/TiO2 can adsorb gaseous HgCl2, which resulted from Hg0 oxidation. Therefore, sulfureted V2O5-MoO3/TiO2 showed an excellent performance to recover Hg0 from coal-fired power plants, which can then be converted to liquid Hg.

Different Design Strategies for Metal Sulfide Sorbents to Capture Low Concentrations of Gaseous Hg0 in Coal-Fired Flue Gas and High Concentrations of Gaseous Hg0 in Smelting Flue Gas.

Capturing gaseous Hg0 using regenerable metal sulfides is a promising technology to recover gaseous Hg0 from both coal-fired flue gas (CFG) and smelting flue gas (SFG) for the centralized control. Gaseous Hg0 concentration in SFG is 2-3 orders of magnitude higher than that in CFG; therefore, the design strategy of metal sulfides for capturing gaseous Hg0 from CFG is quite different from that from SGF. In this work, the structure-activity relationship of metal sulfides to capture Hg0 was investigated according to the remarkable difference in MoO3 loading on sulfureted FeTiOx to capture low/high concentrations of gaseous Hg0. The rate of Hg0 adsorption onto metal sulfides was mainly related to the amounts of adsorption sites and S22- on the surface, the affinity of adsorption sites to gaseous Hg0, and the gaseous Hg0 concentration. Meanwhile, the capacity for Hg0 adsorption was approximately equal to the less of the amount of adsorption sites and S22- on the surface. Furthermore, capturing low concentrations of gaseous Hg0 from CFG required the metal sulfide sorbents having more adsorption sites with strong affinity to gaseous Hg0, while capturing high concentrations of gaseous Hg0 from SFG required the sorbents with enough adsorption sites.

Faster electron injection and higher interface reactivity in g-C3N4/Fe2O3 nanohybrid for efficient photo-Fenton-like activity toward antibiotics degradation.

Two different morphologies of Fe2O3 involving nanodots and nanosheets were deposited on g-C3N4 nanosheets by simple in-situ deposition and impregnation-hydrothermal methods, respectively. Structural effect of Fe2O3 on photo-Fenton-like activity and charge transfer at the interface in these two g-C3N4/Fe2O3 hybrids were studied. Detail characterizations on charge transfer kinetics revealed that g-C3N4/nanodot-Fe2O3 structure showed faster electron injection rate and higher injection efficiency (≈0.084 ns-1 and ≈27.5%) than g-C3N4/nanosheet-Fe2O3 counterpart (≈0.054 ns-1 and ≈19.5%). Stronger intimate junction between g-C3N4 nanosheets and Fe2O3 nanodots was believed to be the reason for faster and more efficient electron injection. In addition, stronger interaction with tetracycline and higher reactivity with H2O2 at the interface were observed for g-C3N4/nanodot-Fe2O3 compared with g-C3N4/nanosheet-Fe2O3. Thereby, under visible light stimulation, g-C3N4/nanodot-Fe2O3 demonstrated higher photo-Fenton-like tetracycline removal efficiency and rate (≈87% and ≈0.037 min-1) than g-C3N4/nanosheet-Fe2O3 (≈57% and ≈0.016 min-1). Furthermore, g-C3N4/nanodot-Fe2O3 junction can remain robust catalytic performance under various conditions (recycle experiment, real environment, different initial pHs and temperatures, anion coexistence, and other contaminants removal) and possible tetracycline degradation pathways were proposed. This study provided deep insights into structure-activity relationship and electron transfer between g-C3N4 and nanostructured Fe2O3, which can open a new avenge to develop Fe2O3-based photo-Fenton catalysts with high efficiencies for antibiotic wastewaters remediation.

Outstanding Performance of Magnetically Separable Sulfureted MoO3/Fe-Ti Spinel for Gaseous Hg0 Recovery from Smelting Flue Gas: Mechanism and Adsorption Kinetics.

To replace the hazardous and complicated Boliden-Norzink technology, the technology of Hg0 recovery from smelting flue gas by a magnetic and reproducible sulfureted MoO3/Fe-Ti spinel was employed to keep the produced H2SO4 free of Hg. The sulfureted MoO3/Fe-Ti spinel showed excellent performance in capturing gaseous Hg0, with an average adsorption rate of 93.3 µg g-1 min-1 and an adsorption capacity of 66.3 mg g-1 at 60 °C, which were much better than those of most of the other reported sorbents. Meanwhile, the sulfureted MoO3/Fe-Ti spinel exhibited excellent superparamagnetism and magnetization of 19.9 emu g-1, which ensured that it could easily be magnetically separated without a specialized precipitator or the molding of pulverous sorbents to monolithic sorbents. To investigate the promotion mechanism of MoO3 loading on Hg0 adsorption onto the sulfureted Fe-Ti spinel, the Hg0 adsorption kinetic parameters of the sulfureted MoO3/Fe-Ti spinel and sulfureted Fe-Ti spinel, resulting from the fitting of the adsorption breakthrough curves based on the kinetic model, were compared. The promotion of MoO3 loading was attributed to the remarkable increase in the adsorption sites on the sulfureted Fe-Ti spinel for Hg0 physical adsorption, which was mainly related to the formation of the MoS3 layer.

Novel Synergistic Effect of Fe and Mo in FeMoSx/TiO2 for Recovering High Concentrations of Gaseous Hg0 from Smelting Flue Gas: Reaction Mechanism and Kinetics.

There is a high demand for developing a more effective and environment-friendly technology to substitute the complicated and hazardous Boliden-Norzink technology for recovering gaseous Hg0 from smelting flue gas. In this work, a low-cost and reproducible sorbent (FeMoSx/TiO2) was developed to recover gaseous Hg0 from smelting flue gas. FeMoSx/TiO2 exhibited a superior ability for capturing high concentrations of Hg0, with an adsorption rate of 72.2 µg g-1 min-1 and a capacity of 41.8 mg g-1 at 60 °C. These were generally larger than the sums of those of FeSx/TiO2 and MoSx/TiO2. The kinetic model of Hg0 adsorption by FeSx/TiO2, MoSx/TiO2, and FeMoSx/TiO2 were constructed according to the adsorption mechanism. Then, the structure-activity relationship of FeMoSx/TiO2 for Hg0 capture was determined by comparing the kinetic parameters. The intrinsic adsorption of Hg0 by MoSx/TiO2 (i.e., physically adsorbed Hg0 was oxidized by MoS3 to HgS) was inhibited marginally after FeSx was incorporated. However, another Hg0 adsorption route (i.e., physically adsorbed Hg0 was oxidized by FeS2 to HgS) appeared on FeMoSx/TiO2. Its rate was significantly higher than that of FeSx/TiO2. Thus, a novel synergistic effect of Fe and Mo in FeMoSx/TiO2 for Hg0 capture was observed.

Significant Enhancement of Gaseous Elemental Mercury Recovery from Coal-Fired Flue Gas by Phosphomolybdic Acid Grafting on Sulfurated γ-Fe2O3: Performance and Mechanism.

The existing technologies to control Hg emissions from coal-fired power plants can be improved to achieve the centralized control of Hg0 emissions, which continue to pose a risk of Hg exposure to human populations. In this work, MoSx@γ-Fe2O3, formed by the sulfuration of phosphomolybdic acid (HPMo)-grafted γ-Fe2O3, was developed as a magnetic and regenerable sorbent to recover gaseous Hg0 from coal-fired flue gas as a cobenefit to the use of wet electrostatic precipitators. The thermal stability of γ-Fe2O3 was notably enhanced by HPMo grafting; thus, the magnetization of MoSx@γ-Fe2O3 hardly decreased during the application. The kinetic analysis indicates that the chemical adsorption of gaseous Hg0 was mainly dependent on the amounts of surface S22- and surface adsorption sites. Although the amount of S22- on sulfurated γ-Fe2O3 decreased after HPMo grafting, the amount of surface adsorption sites significantly increased due to the formation of a layered MoSx structure on the surface. Therefore, the ability of sulfurated γ-Fe2O3 to capture Hg0 was improved considerably after HPMo grafting. Furthermore, low concentrations of gaseous Hg0 in coal-fired flue gas can be gradually enriched by at least 1000 times by MoSx@γ-Fe2O3, which facilitates the recovery and centralized control of gaseous Hg0 in flue gas.

Acceleration of Hg0 Adsorption onto Natural Sphalerite by Cu2+ Activation during Flotation: Mechanism and Applications in Hg0 Recovery.

The rate of gaseous Hg0 adsorption onto natural sphalerite increased by approximately 1.9-7.7 times after Cu2+ activation during flotation of the natural sphalerite to remove impurities. Via a new pathway involving CuS, physically adsorbed Hg0 was oxidized by CuS to HgS on natural sphalerite after Cu2+ activation. In a similar intrinsic ZnS pathway, physically adsorbed Hg0 was oxidized by ZnS to HgS. The rate of the CuS pathway for Hg0 capture was generally significantly larger than that of the intrinsic ZnS pathway. Thus, Hg0 adsorption onto natural sphalerite was notably accelerated after Cu2+ activation. However, the kinetic analysis indicated that the capacity of natural sphalerite for Hg0 capture did not vary. Because the properties of the activated sphalerite for Zn smelting were barely degraded after Hg0 capture, the spent activated sphalerite for Hg0 capture can be reused for Zn smelting. Moreover, most of the gaseous Hg0 captured by activated sphalerite can be recovered eventually as liquid Hg0 in the condenser unit of Zn smelters. Thus, Hg0 recovery by activated sphalerite is a cost-effective and environmentally friendly technology to recover Hg0 from Zn smelting flue gas, thus replacing the complex and dangerous Boliden-Norzink process.

Balance between Reducibility and N2O Adsorption Capacity for the N2O Decomposition: CuxCoy Catalysts as an Example.

CuxCoy (CuO-Co3O4 mixed oxides) catalysts were prepared via co-precipitation for the N2O decomposition reaction. They exhibited a higher N2O decomposition activity than that of pure CuO and Co3O4 because of the balance of the redox property and N2O adsorption capacity. Co3O4 presented a large number of surface oxygen vacancies, increasing the N2O chemical adsorption as "□-Co-ON2" on the catalyst surface, whereas CuO was dispersed around Co3O4 and presented high reducibility on the interface of Co3O4-CuOx for the N-O break of N2O, healing oxygen vacancies by leaving one oxygen atom in the vacancy. Based on kinetic studies, the rate constant of N2O decomposition was related to the number of surface vacancy sites ([Mn+]) and the rate of N-O break (k3), whereas the rate-determining step is the N-O break. Therefore, the N2O decomposition rate is first order to the N2O concentration. Overall, both the density functional theory calculations and kinetic results indicate that the quantities of adsorption and activation sites derived from the interaction between Co and Cu (dual-function mechanism) were accounted for the excellent N2O decomposition performance of CuxCoy catalysts.

Outstanding Performance of Recyclable Amorphous MoS3 Supported on TiO2 for Capturing High Concentrations of Gaseous Elemental Mercury: Mechanism, Kinetics, and Application.

Hg0 capture by sorbents was a promising technology to control Hg0 emission from coal-fired power plants and smelters. However, the design of a high performance sorbent and the predicting of the extent of Hg0 adsorption were both extremely limited due to the lack of adsorption kinetics and structure-activity relationship. In this work, the adsorption kinetics of gaseous Hg0 onto MoS3/TiO2 was investigated and kinetic parameters were obtained by fitting breakthrough curves. According to the kinetic parameters, the removal efficiency, the adsorption rate and the capacity for Hg0 capture were accurately predicted. Meanwhile, the structure-activity relationship of metal sulfides for gaseous Hg0 adsorption was built. The chemical adsorption rate of gaseous Hg0 was found to mainly depend on the amount of surface adsorption sites available for the physical adsorption of Hg0, the amount of surface S22- available for Hg0 oxidation and gaseous Hg0 concentration. As MoS3/TiO2 showed a superior performance for capturing high concentrations of Hg0 due to the large number of surface adsorption sites for the physical adsorption of gaseous Hg0, it has promising applications in recovering Hg0 from smelting flue gas.

Outstanding Resistance of H2S-Modified Cu/TiO2 to SO2 for Capturing Gaseous Hg0 from Nonferrous Metal Smelting Flue Gas: Performance and Reaction Mechanism.

The utilization of H2SO4, produced using SO2 from nonferrous metal smelting flue gas as a source of S, is extremely restricted due to Hg contamination; therefore, there is great demand to remove Hg0 from smelting flue gas. Although the ability of Cu/TiO2 to capture Hg0 is excellent, its resistance to H2O and SO2 is very poor. In this study, Cu/TiO2 was treated with H2S to improve its resistance to H2O and SO2 for capturing Hg0. The chemical adsorption of Hg0 on Cu/TiO2 was primarily through the HgO route, which was almost suppressed by H2O and SO2 due to the transformation of CuO into CuSO4. Besides the HgO route, the HgS route also contributed to the chemical adsorption of Hg0 on modified Cu/TiO2. As the CuS on modified Cu/TiO2 was inert to H2O and SO2, the chemical adsorption of Hg0 on modified Cu/TiO2 through the HgS route was barely inhibited. Meanwhile, the HgS route was predominant in the chemical adsorption of Hg0 on modified Cu/TiO2. Therefore, modified Cu/TiO2 exhibited an excellent resistance to H2O and SO2, and its Hg0 capture capacity from simulated flue gas was up to 12.7 mg g-1 at 100 °C.

H2S-Modified Fe-Ti Spinel: A Recyclable Magnetic Sorbent for Recovering Gaseous Elemental Mercury from Flue Gas as a Co-Benefit of Wet Electrostatic Precipitators.

The nonrecyclability of the sorbents used to capture Hg0 from flue gas causes a high operation cost and the potential risk of exposure to Hg. The installation of wet electrostatic precipitators (WESPs) in coal-fired plants makes possible the recovery of spent sorbents for recycling and the centralized control of Hg pollution. In this work, a H2S-modified Fe-Ti spinel was developed as a recyclable magnetic sorbent to recover Hg0 from flue gas as a co-benefit of the WESP. Although the Fe-Ti spinel exhibited poor Hg0 capture activity in the temperature range of flue gas downstream of flue gas desulfurization, the H2S-modified Fe-Ti spinel exhibited excellent Hg0 capture performance with an average adsorption rate of 1.92 µg g-1 min-1 at 60 °C and a capacity of 0.69 mg g-1 (5% of the breakthrough threshold) due to the presence of S22- on its surface. The five cycles of Hg0 capture, Hg0 recovery, and sorbent regeneration demonstrated that the ability of the modified Fe-Ti spinel to capture Hg0 did not degrade remarkably. Meanwhile, the ultralow concentration of Hg0 in flue gas was increased to a high concentration of Hg0, which facilitated the centralized control of Hg pollution.

Elemental Mercury Oxidation over Fe-Ti-Mn Spinel: Performance, Mechanism, and Reaction Kinetics.

The design of a high-performance catalyst for Hg0 oxidation and predicting the extent of Hg0 oxidation are both extremely limited due to the uncertainties of the reaction mechanism and the reaction kinetics. In this work, Fe-Ti-Mn spinel was developed as a high-performance catalyst for Hg0 oxidation, and the reaction mechanism and the reaction kinetics of Hg0 oxidation over Fe-Ti-Mn spinel were studied. The reaction orders of Hg0 oxidation over Fe-Ti-Mn spinel with respect to gaseous Hg0 concentration and gaseous HCl concentration were approximately 1 and 0, respectively. Therefore, Hg0 oxidation over Fe-Ti-Mn spinel mainly followed the Eley-Rideal mechanism (i.e., the reaction of gaseous Hg0 with adsorbed HCl), and the rate of Hg0 oxidation mainly depended on Cl• concentration on the surface. As H2O, SO2, and NO not only inhibited Cl• formation on the surface but also interfered with the interface reaction between gaseous Hg0 and Cl• on the surface, Hg0 oxidation over Fe-Ti-Mn spinel was obviously inhibited in the presence of H2O, SO2, and NO. Furthermore, the extent of Hg0 oxidation over Fe-Ti-Mn spinel can be predicted according to the kinetic parameter kE-R, and the predicted result was consistent with the experimental result.

Recyclable Naturally Derived Magnetic Pyrrhotite for Elemental Mercury Recovery from Flue Gas.

Magnetic pyrrhotite, derived from the thermal treatment of natural pyrite, was developed as a recyclable sorbent to recover elemental mercury (Hg0) from the flue gas as a cobenefit of wet electrostatic precipitators (WESP). The performance of naturally derived pyrrhotite for Hg0 capture from the flue gas was much better than those of other reported magnetic sorbents, for example Mn-Fe spinel and Mn-Fe-Ti spinel. The rate of pyrrhotite for gaseous Hg0 capture at 60 °C was 0.28 µg g min-1 and its capacity was 0.22 mg g-1 with the breakthrough threshold of 4%. After the magnetic separation from the mixture collected by the WESP, the spent pyrrhotite can be thermally regenerated for recycle. The experiment of 5 cycles of Hg0 capture and regeneration demonstrated that both the adsorption efficiency and the magnetization were not notably degraded. Meanwhile, the ultralow concentration of gaseous Hg0 in the flue gas was concentrated to high concentrations of gaseous Hg0 and Hg2+ during the regeneration process, which facilitated the centralized control of mercury pollution. Therefore, the control of Hg0 emission from coal-fired plants by the recyclable pyrrhotite was cost-effective and did not have secondary pollution.

Mechanism of N2O formation during the low-temperature selective catalytic reduction of NO with NH3 over Mn-Fe spinel.

The mechanism of N2O formation during the low-temperature selective catalytic reduction reaction (SCR) over Mn-Fe spinel was studied. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and transient reaction studies demonstrated that the Eley-Rideal mechanism (i.e., the reaction of adsorbed NH3 species with gaseous NO) and the Langmuir-Hinshelwood mechanism (i.e., the reaction of adsorbed NH3 species with adsorbed NOx species) both contributed to N2O formation. However, N2O selectivity of NO reduction over Mn-Fe spinel through the Langmuir-Hinshelwood mechanism was much less than that through the Eley-Rideal mechanism. The ratio of NO reduction over Mn-Fe spinel through the Langmuir-Hinshelwood mechanism remarkably increased; therefore, N2O selectivity of NO reduction over Mn-Fe spinel decreased with the decrease of the gas hourly space velocity (GHSV). As the gaseous NH3 concentration increased, N2O selectivity of NO reduction over Mn-Fe spinel increased because of the promotion of NO reduction through the Eley-Rideal mechanism. Meanwhile, N2O selectivity of NO reduction over Mn-Fe spinel decreased with the increase of the gaseous NO concentration because the formation of NH on Mn-Fe spinel was restrained. Therefore, N2O selectivity of NO reduction over Mn-Fe spinel was related to the GHSV and concentrations of reactants.