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Lithium silicate (Li 4 SiO 4) has good stability, high theoretical carbon dioxide (CO 2) adsorption capacity, and low regeneration temperature. It has great potential in the field of CO 2 adsorption. However, it is difficult to achieve the theoretical value in practical applications and a narrow temperature window for adsorption. Therefore, further research in this area is urgently needed. In this study, experimental and simulation methods were used to investigate the effects of single doping and co-doping with K, Na, Be, Ca, and Al metals on the adsorption performance and adsorption temperature window of Li 4 SiO 4. Single doping with K, Na, or Al makes CO 2 easier to be adsorbed on the Li 4 SiO 4 (010) surface by increasing the charge transfer from the Li 4 SiO 4 surface to CO 2. Co-doping with K and Al increases the adsorption energy of CO 2 on the Li 4 SiO 4 (010) surface, enhances hybrid peaks, and broadens the temperature range for CO 2 adsorption on the Li 4 SiO 4 surface. It exhibits stable cyclic adsorption performance under low CO 2 (15% CO 2 , N 2 balance) concentration, and more electron transfer facilitates the formation of carbonate species on the Li 4 SiO 4 (010) surface at lower temperatures, thereby improving its CO 2 adsorption performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • S-doped ZTC was prepared by CVD method using C 2 H 2 and H 2 S as C and S precursor. • Sulfur bonded to the S-doped ZTC framework was active site for Hg0 capture. • DFT calculation was used to reveal the adsorption mechanism of Hg0. • S-doped ZTC has good thermal stability and regeneration characteristics. Elemental mercury is harmful to humanity and the ecological environment. It is a simple and feasible method to capture elemental mercury by carbon-based adsorbents. The purpose of this work is to develop zeolite-templated carbon with and without sulfur (ZTC and S-doped ZTC) and to explore their mercury adsorption performance. ZTC and S-doped ZTC were synthesized by chemical vapor deposition (CVD) method and their mercury adsorption performance were tested at 30 and 150 °C. Among all ZTC samples, BEA-ZTC-HS exhibited highest mercury removal efficiency (MRE) whose initial value was 99.99% (150 °C) and 97.39% (30 °C) and decreased to 96.63% and 89.15% after one hour mercury adsorption. The physical and chemical properties of the ZTC samples were characterized by various methods to explain the high MRE of BEA-ZTC-HS. The experimental results shown that BEA-ZTC-HS replicated the crystal structure of BEA zeolite faithfully and exhibited regular microporous structure and doesn't have obvious elemental sulfur whose existence could block the micropores in ZTC. This was helpful to the mass transfer of Hg0 in ZTC. Moreover, the chemical properties of BEA-ZTC-HS shown that the introduced sulfur were mainly bonded to the carbon framework of ZTC in the form of thiophene, sulfone, sulfoxide and sulfonic acid. Those sulfur-containing functional groups provided main active sites for mercury capture and exhibited higher activity at 150 °C. Finally, Density Functional Theory (DFT) was used to reveal the adsorption mechanism of ZTC and S-doped ZTC on Hg0. Due to its good properties of regeneration, higher MRE, good thermal stability and low cost, BEA-ZTC-HS has a wide prospect for industrial application in the wide temperature ranges compared to the activated carbon injection technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption of Hg2+and Hgorg in gasoline by thiophene-carbon was explored. • Acidic site and pore size of zeolite has effect on the structure of templated carbon. • Property concentration of ThM promoted ordered structure and functional groups. • S = O and C-O functional groups showed excellent mercury adsorption capacity. A simple synthesis of thiophene-functional zeolite-templated carbons (ZTCs) is proposed to remove ionic mercury (Hg2+) and organic mercury (Hgorg) from gasoline. Microporous zeolite (Beta) and mesoporous zeolite (MCM-41) were used to prepare porous carbon by impregnating with 2-thiophenemethanol (ThM) to explore the influence of template type on the quality of templated carbon. The amount of strong acidic sites in MCM-41 zeolite was more than Beta zeolite which promoted the catalytic polymerisation of the ThM in the pores structure of the zeolite and highly templated carbon was obtained. The impregnation concentration of ThM on the structure and functional groups of the samples was explored. It was found that increasing the concentration of ThM properly can promote the filling of zeolite pores by ThM and form more ordered templated carbons. In addition, the increased ThM promoted the formation of the S = O and C-O oxygen-containing functional groups. The optimal impregnation concentrations of ThM were 25% for B-Al (25%-B-Al-ZTC) and 75% for M−Al (75%-M−Al−ZTC). The 75%-M−Al−ZTC with sufficient S = O and C-O oxygen-containing functional groups showed excellent mercury adsorption capacity (617.49 μg/g) and a high intra-particle diffusion rate (294.10 h−1). The simultaneous adsorption of Hg2+ and Hgorg was also conducted and it was found that Hgorg had competitive adsorption for Hg2+ which led the total adsorption capacity to decrease. In addition, the 25%-B-Al-ZTC and 75%-M−Al−ZTC adsorbents had good regeneration ability and the adsorption capacity remained over 75% and 71% for Hg2+ and Hgorg after five desorption-sorption cycles, respectively. Thus, the new adsorbents with stable and efficient Hg removal performance have the potential for practical application by oil refineries. [ABSTRACT FROM AUTHOR]

• The adsorption mechanism between Hg (II) in gasoline and KI-13X was explored. • The Hg (II) adsorption amount of zeolite increased by 18 times after 2% KI loaded. • KI was impregnated into microspores more than on the surface of the sorbent. • There were two main active sites for I atom in the zeolite for mercury capture. Mercury (Hg) removal from natural gas condensates is a hot topic due to its importance in petroleum refineries. Unfortunately, though much attention has been paid to the adsorption efficiency of sorbents in industry, mercury adsorption mechanisms are rarely addressed. This paper studies the adsorption mechanisms of zeolite 13X impregnated with potassium iodide (KI) on ionic mercury (Hg(II)) from gasoline. The effects of different KI loading amounts, initial mercury concentrations, and adsorption times of mercury removal were investigated by adsorption experiments. The adsorption efficiency increased from 15% to 91%, and the adsorption amount increased by 18 times after the addition of pristine zeolite loaded with 2% KI. The preferential adsorption sites of potassium (K), iodine (I), and Hg atoms in zeolite were calculated by the grand-canonical Monte Carlo (GCMC) method. The center of the super cage (center 1) and interface between the super cages (center 2) provided the main I active sites for Hg capture. In addition, the adsorption energies between I and Hg were analyzed by density functional theory (DFT), and partial density of states (PDOS) analysis indicated that Hg interacts strongly with I in the super cage. Hence, during the adsorption process, mesopores served as an entrance for active materials. Hg(II) in gasoline diffused to the micropore channels via mesopores and were captured by I, forming HgI 2. These results cast a new light on the development of novel sorbents for mercury removal. [ABSTRACT FROM AUTHOR]

• A mixed molecular dynamics system of asphaltene adsorbed rock surface, water, and CO 2 established. • Asphaltene-adsorbed rock surface changes from strong water- to CO 2 -wetting as CO 2 density rises. • Water wettability decrease caused by asphaltene adsorption is adsorption thickness-independent. • Water wettability on the asphaltene-adsorbed rock surface decreases slightly with inorganic salt ions increases. The reactions between CO 2 slugs and crude oil induce a substantial amount of asphaltene precipitation and adsorption on the rock surface during the CO 2 alternative water flooding process. When the subsequent water slug passes through the core pores after asphaltene adsorption, it will displace the previous CO 2 slug. The wettability of water and CO 2 on the asphaltene-adsorbed rock surface will directly determine the magnitude and direction of the capillary force of the two media, which in turn affects their flow resistance and flow pattern analysis. In this paper, the systems of CO 2 /water/sandstone and CO 2 /water/asphaltene adsorption sandstone were established by molecular dynamics simulation technology. The effects of asphaltene adsorption, thickness of the asphaltene adsorption layer, CO 2 density, mass fraction and type of salt in water on the wettability of water on sandstone surfaces were studied. The results reveal that asphaltene adsorption significantly reduces the wettability of water on the original powerful water-wetting sandstone surface, making it easier to see how CO 2 density affects the wettability of water on the asphaltene-adsorbed sandstone surface. The increased CO 2 density will continue to lower the wettability of water on the asphaltene-adsorbed sandstone surface, even causing it to become wet with CO 2. The adsorption thickness of asphaltene does not affect the wettability of water and CO 2 on the asphaltene-adsorbed sandstone surface, and just a layer of 5A-thick asphaltene adsorption can significantly reduce the wettability of water on sandstone surfaces. Furthermore, a rise in salinity in water has a detrimental impact on the wettability of water on the asphaltene-adsorbed sandstone surface, with divalent salts having a stronger negative effect than monovalent salts. [ABSTRACT FROM AUTHOR]

Abstract: Soil protection from heavy metal contamination requires scientific assessment on the linkage between site-specific pollutant discharge and environmental effects. However, this kind of linkage is usually disregarded due to the lack of assessment tools in environmental policies, e.g., some developed coastal cities in China have forced their highly polluting industries out to less developed interior areas without consideration of the impacts from pollution transfer. This paper developed a soil adsorption fraction (SAF) model to characterize the emissions-to-adsorption relationship between heavy metal emission and the adsorption by soil. Case studies were carried out for two adjacent southern cities in China, i.e., Guangzhou and Shaoguan. The results indicated that the average SAF of cadmium was 5.38×10−3 for Shaoguan and 1.28×10−3 for Guangzhou, i.e., cadmium released from Shaoguan threatened the soil environment 4.2 times of that from Guangzhou. Further analysis showed the polluting pathway and abundance of water resources were the main influencing factors on SAF. Soil contamination will be exaggerated by relocating heavy metal polluting industries from coastal areas to interior areas. The results should be useful to prompt site-specific policies on heavy metal pollution control. [Copyright &y& Elsevier]