Adsorption desulfurization is a potential new method for deep desulfurization of fuel oil. The development of adsorbents with high adsorption capacity and selectivity is the core of deep adsorption desulfurization. The adsorption behavior of thiophene in MCM-41 mesoporous materials modified by various metal ions was studied in order to understand the adsorption desulfurization process of molecular sieves. The Fe-, Co-, and Zn-modified MCM-41 materials were prepared using a one-step in situ hydrothermal synthesis method. The modified MCM-41 molecular sieves maintained the mesoporous structure, and the metal ions had specific dispersion on the surface of the molecular sieves. Adsorption of thiophene on the surfaces of molecular sieves had both physical and chemical characteristics. The adsorption desulfurization performance of the modified molecular sieve was superior to that of the pure silica molecular sieve. In the simulated gasoline with sulfur content of 220 μg/g, when the amount of adsorbent used was 100 mg, the adsorptive desulfurization performance tended to be in equilibrium, and the optimum adsorption temperature was 30°C. Fe-MCM-41 and MCM-41 molecular sieves reached adsorption equilibrium after ~60 min, but the desulfurization rate of Co-MCM-41 and Zn-MCM-41 still increased slightly. The kinetic simulation results indicated that the pseudo-second-order kinetics adsorption model described well the adsorption process of thiophene on molecular sieves. The molecular sieve Fe-MCM-41 had the best desulfurization performance with an equilibrium adsorption capacity of 14.02 mg/g and the desulfurization rate was ~90%.

Clay minerals, such as layered double hydroxide (LDH) and montmorillonite (MMT), have attracted a great deal of attention for biological applications. Along with the rapid development of nanotechnology, public concern about the potential toxicity of nanoparticles is growing. In the present work, cytotoxicity of LDH and MMT was assessed in terms of inhibition of cell proliferation, generation of oxidative stress, and induction of inflammation response. Moreover, the biokinetics of LDH and MMT were evaluated; biokinetics provides information about in vivo absorption, distribution, and excretion kinetics. The results demonstrated that both LDH and MMT inhibited cell proliferation at relatively large concentrations and after long exposure time compared to other inorganic nanoparticles, although they generated reactive oxygen species (ROS). LDH induced pro-inflammatory cytokines in a size-dependent manner. Biokinetic study revealed that, after single-dose oral administration to mice, both LDH and MMT had extremely slow oral rates of absorption and did not accumulate in any specific organ. All the results suggest great potential of clay minerals for biological application at safe levels.

The aim of the present study was to examine effects of black liquor-montmorillonite (BL-Mnt) complexes on the mechanical and thermal properties of epichlorohydrin rubber. Considering the stability effect of lignin and the barrier property of clay minerals, a significant enhancement of thermo-oxidative aging properties of ECO/BL-Mnt composites was expected. Poly (epichlorohydrin-co-ethylene oxide) (ECO) composites filled with BL-Mnt complex were prepared by mechanical mixing on a two-roll mill. The ECO/BL-Mnt composites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Both XRD and TEM data showed that the filler particles were well dispersed throughout the ECO/BL-Mnt composites. The tensile strength, elongation at break, and 100% modulus of the rubber composite were 14.0 MPa, 457%, and 3.9 MPa, respectively, at a 50% loading of BL-Mnt. The retention of tensile strength was 99% after thermal oxidative aging in an air-circulating oven for 72 h at 100°C. Evidence indicated that ECO/BL-Mnt composites with good mechanical properties and thermo-oxidative aging properties were obtained.

Six-membered ring heterocyclic compounds are widely present in the Earth's surface environments as biological organic molecules composed of soil organic matter including plant and microbial residues, while little is known about their effect on the dissolution of silicate minerals including amorphous silica. To evaluate the effect of these biological molecules on amorphous silica dissolution, dissolution experiments were carried out by the flow-through method using 0.1 g of amorphous silica and 0.1 mM NaCl electrolyte solutions containing 0.0, 0.1, 1.0, or 10.0 mM of the heterocyclic compounds, piperidine (pK = 11.12), pyridine (pK = 5.25), or pyridazine (pK = 2.33), at a pH of 6, 5, or 4. Additionally, adsorption experiments of the compounds on the amorphous silica surface were performed to confirm the adsorption affinity for the amorphous silica surface. The results demonstrated that these heterocyclic compounds enhance the dissolution rate of amorphous silica in the following order: piperidine > pyridine > pyridazine. When 10.0 mM solutions were used, the heterocyclic compounds enhanced greatly the dissolution rate up to enhancement factors of 6.0 to ~14.8, 5.0 to ~14.0, and 1.0 to ~2.6 through an interaction of piperidine, pyridine, and pyridazine, respectively, in the pH range of approximately 6 to ~ 4. The adsorption experiments indicated that the heterocyclic compounds exhibited significant adsorption affinity for the amorphous silica surface as follows: piperidine > pyridine > pyridazine, which was consistent with the order of their effects on the dissolution enhancement. The geochemical calculation revealed that this order of enhancement was in good agreement with the concentrations of cationic species of heterocyclic compounds at corresponding pH conditions. Consequently, the enhancement of amorphous silica dissolution is likely to be influenced by the electrostatic complexation of the cationic species of the heterocyclic compounds with the negative >SiO– sites on the amorphous silica surface.

Aflatoxin contamination of diets results in disease and death in humans and animals. The objective of the present paper was to review the development of innovative enterosorption strategies for the detoxification of aflatoxins. NovaSil clay (NS) has been shown to decrease exposures to aflatoxins and prevent aflatoxicosis in a variety of animals when included in their diets. Results have shown that NS clay binds aflatoxins with high affinity and high capacity in the gastrointestinal tract, resulting in a notable reduction in the bioavailability of these toxins without interfering with the utilization of vitamins and other micronutrients. This strategy is already being utilized as a potential remedy for acute aflatoxicosis in animals and as a sustainable intervention via diet. Animal and human studies have confirmed the apparent safety of NS and refined NS clay (with uniform particle size). Studies in Ghanaians at high risk of aflatoxicosis have indicated that NS (at a dose level of 0.25% w/w) is effective at decreasing biomarkers of aflatoxin exposure and does not interfere with levels of serum vitamins A and E, iron, or zinc. A new spinoff of this strategy is the development and use of broad-acting sorbents for the mitigation of environmental chemicals and microbes during natural disasters and emergencies. In summary, enterosorption strategies/therapies based on NS clay are promising for the management of aflatoxins and as sustainable public health interventions. The NS clay remedy is novel, inexpensive, and easily disseminated.

To apply hydrotalcites more effectively to the problem of dye wastewater, the effects of divalent metal ions on the structure and stability of hydrotalcites, especially on their photocatalytic activity, were compared. In the present study, M/Cr hydrotalcites (M3Cr-CO3-LDHs) (in which M = Mg, Co, Ni, Cu, Zn), where the M/Cr molar ratio was 3, were prepared by the co-precipitation method. The structures and properties were characterized using powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TG-DTA), and UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS). The results showed that five kinds of M3Cr-CO3-LDHs were synthesized successfully, and the layered structure of the samples obtained was regular and the crystal phase was single. When methylene blue (MB) solution was exposed to ZnCr-CO3-LDHs, H2O2, and visible light irradiation, more than 90.67% of the methylene blue (MB) was removed after 140 min. The photocatalytic activity of the samples was in the order: Co3Cr-CO3-LDHs > Mg3Cr-CO3-LDHs > Cu3Cr-CO3-LDHs > Zn3Cr-CO3-LDHs > Ni3Cr-CO3-LDHs. The results of a catalytic mechanism study showed that photocatalytic degradation of MB involved a demethylation reaction, with the reactive species containing •O2-, •OH, and h+.

Photo-assisted selective catalytic reduction (photo-SCR) has been considered as a promising strategy for NOx removal in recent decades. The purpose of the present work was to test the effectiveness of La1–xPrxCoO3, supported on the surface of natural palygorskite (Pal) by a facile sol-gel method, as a photo-SCR for the removal of NOx from wastewaters. The structure, acidity, and the redox property of the prepared La1–xPrxCoO3/Pal nanocomposite were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS), and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations were employed to determine the valence bands. The La1–xPrxCoO3/Pal catalysts were then tested for SCR removal of NOx with the assistance of photo-irradiation. The photo-SCR results revealed that the NOx conversion and the N2-selectivity were greatly improved by this method and reached >95% when carried out at the relatively low temperature of 200°C and with the Pr doping at x = 0.5. The improvements were attributed to the co-precipitation of a PrCoO3 phase as in a solid solution forming a coherent heterojunction of PrCoO3/La0.5Pr0.5CoO3 on the Pal surface.

Chitosan (CTS) modified montmorillonite (Mnt) composites (CTS-Mnt), which have been widely reported for the adsorption of heavy-metal ions and biological dyes, have not been applied to the field of mycotoxin adsorption. The current study was focused on the preparation of CTS-Mnt by calcination as a mycotoxin adsorbent for the efficient removal of aflatoxin B1 (AFB1). The CTS-Mnt samples obtained were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and nitrogen adsorption/desorption analysis. The CTS-Mnt samples prepared at various calcination temperatures exhibited varying structural configurations, surface hydrophobicities, and texture properties. The results revealed that stable CTS-Mnt speciments, obtained at <350°C, displayed superior adsorption capacity for AFB1 from a simulated gastrointestinal tract, increasing from 0.51 mg/g of raw Mnt to 4.97 mg/g. With increased calcination temperature, the effect of pH on the adsorption process of AFB1 becomes negligible. This study demonstrates that the novel CTS-Mnt has tremendous potential as an AFB1 adsorbent.