An understanding of the impacts regarding different phases of inorganic materials on heavy metal removal is indispensable, owing to the intrinsic structure of materials that can affect its properties. In this study, the distinct adsorption behaviors of heavy metals (Pb(II) and Cu(II)) on different phases of MoS 2 (metallic phase (1T) and semiconducting phase (2H)) were theoretically and experimentally investigated. According to the computational results, both Pb(II) and Cu(II) have formed more stable complexes on 1T-MoS 2 compared to those on 2H-MoS 2 due to the lower adsorption energy (E ad ). This phenomenon indicates that Pb(II) and Cu(II) were more preferably adsorbed onto 1T-MoS 2 . Based on the results of the computational studies, two-dimensional (2D) MoS 2 nanosheets with identical 1T and 2H phases were synthesized via a facile hydrothermal reaction. As we surmised, 1T-MoS 2 achieved excellent Pb(II) and Cu(II) adsorption capacities, which were 147.09 and 82.13 mg/g at 298 K, respectively, compared to those of 2H-MoS 2 (i.e., 64.16 and 50.74 mg/g at 298 K). Moreover, 1T-MoS 2 has shown other superior properties, such as (i) ultrafast adsorption kinetics and (ii) great anti-interference activity toward other existing cations, compared to 2H-MoS 2 . Extensive computations and characterizations of MoS 2 −Pb and −Cu adsorption complexes illustrated that the active S sites were indispensable for heavy metal adsorption. Overall, for the first time, we provide evidence that 1T-MoS 2 is more functional in heavy metal removal compared to 2H-MoS 2 , which can guide and expand the applications of MoS 2 -based adsorbents in environmental remediation.

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Increasing numbers of cement furnaces have applied selective catalytic reduction (SCR) units for advanced treatment of NO in the flue gas. However, the SCR catalysts may face various poisons, such as acidic, alkaline, and heavy metal species, in the fly ash. In this work, we studied the deactivation mechanisms of multipoisons (Ca, Pb, and S) on the CeO2–WO3/TiO2 catalyst, using the in situ diffuse reflectance infrared Fourier transform spectroscopy method. Calcium promoted the conversion of Ce­(III) to Ce­(IV) and, thus, (i) suppressed the redox cycle, (ii) decreased the NO adsorption (monodentate NO3 – and bridged NO2 –), and (iii) enriched the Lewis acid sites. Pb­(IV) blocked Ce2(WO4)3, aggravating the electronegativity of W6+, which inhibited (i) the binding stability of tungsten and ammonia species, (ii) bridged NO3 – (bonded to tungsten), and (iii) the Brønsted acid sites. The multipoisoning processes enriched O2– by repairing partial surface oxygen defects, which suppressed O2 2– and O–. Sulfur occupied the surface base sites and formed PbSO4 after Ce2(WO4)3 was saturated.