This study was aimed to analyze the thallium pollution and assess the potential ecological risks in the vicinity of coal mines in Henan province, China. We studied 90 surface farmland soil samples from 9 representative coal mines. The Tl concentrations were determined and the potential ecological risks were evaluated. Investigations revealed the farmland soils were modestly contaminated and the trace elements in coal mining areas transferred to the surface soils. Soil Tl contents and potential ecological risks in coal mining areas were significantly increased compared with the original soils which came from the villagers’ mud houses built 40 years ago. The soil Tl concentrations ranged from 0.25 to 0.77(mean = 0.46) mg∙kg⁻¹, which were higher than the original level (0.42 mg∙kg⁻¹). The potential ecological risk index of Tl ranged from 24.00 to 73.2 (mean 44.08), representing a moderate pollution level as a whole of the soils in Henan. In general, high Tl concentrations and high potential ecological risk were found around SHQ and DTG. The soil Tl concentrations exceed the original level and pose noticeable ecological risks.

Hierarchically porous Ce/TiO₂/graphitic carbon microsphere composites (xCe/TiO₂/GCM, where x = 0.2, 1.0, 2.0, 5.0 mmol·L^–1) were prepared for the first time by using a simple colloidal crystal template and characterized by X-ray diffraction, nitrogen adsorption and desorption, scanning electron microscopy, and ultraviolet–visible diffuse reflectance spectra. In addition, the photocatalytic activity of CO₂ reduction by H₂O under simulated solar irradiation was studied. The results showed that the Ce/TiO₂/GCM composite material was characterized by large porosity, high concentration of metal compounds and graphitized carbon matrix, and the content of acetone solvent having a great impact on its form. In terms of the photocatalytic CO₂ reaction, the CH₄ and CO productions were 4.587 and 357.851 μmol·g^–1, respectively. The 2Ce/TiO₂/GCM photocatalyst gave the highest production rate for three products. Under simulated solar irradiation, the Ce/TiO₂/GCM has excellent photocatalytic activity in the photoreduction of CO₂ from H₂O, which was related to the special composition and the Ce/TiO₂/GCM structure.

NH₂-Fe₂O₃ and NH₂-Fe₂O₃/chitosan (NH₂-Fe₂O₃/CS) with excellent physical properties and high adsorption capacities for several heavy metal ions were synthesized using a one-pot hydrothermal method. The materials were characterized by scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Physicochemical properties were determined by the Fourier transform infrared spectra (FTIR) and nitrogen adsorption analysis (Brunauer–Emmett–Teller (BET) method). The results of the characterization studies show that the material is uniformly dispersed and has good crystallinity and well-defined porous particles. The material is mesoporous, and the particles have a specific surface area of 55.41–233.03 m²·g⁻¹, a total pore volume of 0.24–0.54 cm³·g⁻¹, and a diameter of 3.83–17.56 nm. Additional results demonstrate that NH₂-Fe₂O₃ and NH₂-Fe₂O₃/CS are effective adsorbents for the removal of heavy metal ions from solution. In a ternary system, the order of their selective adsorption was determined to be Pb(II) > Cu(II) > Cd(II), and the adsorption rate of Pb(II) was much higher than that of Cu(II) and Cd (II). The metal ion adsorption capacity of NH₂-Fe₂O₃ and NH₂-Fe₂O₃/CS makes them promising adsorbents for wastewater cleanup.

The novel recyclable and biodegradable absorbents NH₂-Fe₂O₃ and NH₂-Fe₂O₃/oxidation-activated carbon (NH₂-Fe₂O₃/OAC) with great physical properties and high adsorption for uptake heavy metal ions were synthesized in this work. The NH₂-Fe₂O₃ samples were prepared via one-pot hydrothermal methods, typically, FeCl₃6H₂O, ethylene glycol and sodium acetate anhydrous were directly dissolved under stirring, followed by x mL of DETA and 0.1 g of SDS at room temperature (x = 0.5, 1, 2, 3, 4 and 5 mL). The as-prepared NH₂-Fe₂O₃ were added into the mixture of oxidation-activated carbon, followed by the cation surfactant CTAB. After reflux condensation, the composites were washed, dried and labeled name NH₂-Fe₂O₃/OAC. Systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD), physicochemical properties were all indicated obviously in this paper. The high adsorption rates of the adsorbents achieved over 88.11 % and 98.25 % towards Pb(II). In the ternary solution, the studied heavy metals revealed selective removal sequence: Pb(II) > Cu(II) > Cd(II).