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The effects of calcium-to-silicon ratio on the properties of fly ash (FA)-based tobermorite and its removal performance of Zn2+ and Mn2+ were studied. The calcium-to-silicon ratio had a significant effect on the structural properties of the tobermorite samples. The specific surface area, pore volume, and average pore size of mesoporous tobermorite samples with different calcium-to-silicon ratios (0.8TOB, 1.2TOB, and 1.6TOB) were much larger than those of FA, and those of 1.2TOB were the largest, which were 53.29 m2/g, 0.448 cm3/g, and 30.50 nm, respectively. The removal efficiencies of Zn2+ and Mn2+ by 1.2TOB were 84.19% and 47.67%, respectively, which were much higher than those of 0.8TOB (60.62% and 42.41%), 1.6TOB (46.69% and 24.31%), and FA (4.13% and 6.95%). The adsorption of Zn2+ and Mn2+ by 0.8TOB, 1.2TOB, and 1.6TOB was corresponding to the pseudo-second-order kinetic model and Langmuir isotherm model. Particularly, 1.2 TOB showed the highest maximum adsorption capacities of Zn2+ and Mn2+ calculated from the Langmuir model, which were 129.70 mg/g and 82.09 mg/g, respectively. Moreover, the adsorption mechanisms might be due to the combination with –OH and the interlayer adsorption of the samples. This research provides new insight into the fly ash-based adsorbents towards Zn2+ and Mn2+ in wastewater. [ABSTRACT FROM AUTHOR]

The two-dimensional electrochemical Y2C's low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation. [ABSTRACT FROM AUTHOR]

The two-dimensional (2D) transition metal thiophosphates family CdPS3 and CdPSe3 are supposed to explore pressure-relevant structural and electronic behaviors as support to build 2D spintronic devices. The pressure-induced phase transition and electronic properties of CdPX3 are investigated up to 40 GPa using first-principles calculation. CdPS3 undergoes reversible phase transitions at around 1.5 GPa and 25 GPa from C2/m structure to structure and then to P 3 ¯ 1 m structure, while the reversible phase transitions of CdPSe3 are found at approximately 13 GPa from R 3 ¯ structure to P 3 ¯ 1 m structure, reflected in the lattice constant mutation and cell volume collapse. The computed metallization transition is found at about 25 GPa and 13 GPa owing to energy band closure for CdPS3 and CdPSe3, respectively. As anisotropy increases with pressure, the enhanced metallic property is accompanied by the inter- and intra-layer sliding atom pairs induced by phase transition. The paper is conducive to considering the phase transition and metallization of CdPX3-type family under extreme conditions. [ABSTRACT FROM AUTHOR]

Photoacoustic imaging and laser induced breakdown spectroscopy are two technologies that have been developed very rapidly in the imaging field in recent years, and have great potential in medical imaging. When the laser irradiates the tissue, both the photoacoustic signals and plasma are generated on the surface of the tissue. The photoacoustic signal carries the characteristic information of light absorption in the tissue, and the characteristic spectrum of the plasma can also trace the element information in the tissue. This paper summarizes the research background and imaging principle of the two technologies, and further demonstrates the possibility of a combination of the two technologies by analyzing the photoacoustic imaging and LIBS imaging modes, and introduces their applications in the fields of pathological section imaging and tissue metal element tracing. Finally, we discuss and prospect the bimodal imaging system combining the two technologies, which is expected to play an important role in the field of medical diagnosis and imaging. [ABSTRACT FROM AUTHOR]