Molybdenum disulfide co-catalysis boosting nanoscale zero-valent iron based Fenton-like process: Performance and mechanism.

The conventional Fenton process has the drawbacks of low efficiency of Fe3+/Fe2+ conversion, low utilization of H2O2, and narrow range of pH. In this paper, molybdenum sulfide (MoS2) was used as a co-catalyst to boost the nanoscale zero-valent iron (nZVI) based heterogeneous Fenton-like process for the degradation of Rhodamine B (RhB). The catalytic performance, influences of parameters, degradation mechanism, and toxicity of intermediates were explored. Compared with the conventional like-Fenton process, the existence of MoS2 accelerated the decomposition of H2O2 and the RhB degradation rate constant of MoS2/nZVI/H2O2 reached more than six times that of nZVI/H2O2. In addition, the effective pH range of MoS2/nZVI/H2O2 was broadened to 9.0 with 84.9% of RhB being removed within 15 min. The co-catalytic system of MoS2 and nZVI was stable and had high reusability according to the results of four consecutive runs. Quenching tests and electron paramagnetic resonance (EPR) demonstrated that hydroxyl radical (·OH), superoxide anions (·O2-), and singlet oxygen (1O2) were all involved in MoS2/nZVI/H2O2. Compared with nZVI/H2O2 system, MoS2 not only increased the corrosion of nZVI but also accelerated the conversion of Fe3+/Fe2+. ECOSAR analysis suggested that the overall acute and chronic toxicity of the degradation products decreased after treatment. Hence, this MoS2 co-catalytic nZVI based Fenton-like process can be used as a promising alternative for the treatment of organic wastewater.

A novel Fe/Mo co-catalyzed graphene-based nanocomposite to activate peroxymonosulfate for highly efficient degradation of organic pollutants.

A novel 3D α-FeOOH@MoS2/rGO nanocomposite was successfully fabricated by a simple in situ hydrothermal method. It is a highly efficient heterogeneous catalyst in activation of peroxymonosulfate (PMS) for rapid degradation of rhodamine B (RhB), with 99.9% of RhB removed within 20 min. The introduction of rGO contributes to uniform dispersion and sufficient contact of α-FeOOH and MoS2 nanosheets. Highly active Mo(IV) enhances the reduction of Fe(III), improves Fe(III)/Fe(II) conversion and promotes the generation of O21, which ensures an improved catalytic activity. MoS2/rGO hybrid can effectively solve the problem of material reunion and make α-FeOOH exhibit excellent catalytic performance. The α-FeOOH@MoS2-rGO/PMS system is a co-catalytic system based on the active components of α-FeOOH and MoS2. The main reactive oxygen species in the α-FeOOH@MoS2-rGO/PMS system are O21, SO4.- and ⋅O2-, which contribute to a high reactivity over a wide range of pH (5-9). Besides, this system is highly resistant to anions (Cl-, SO42-) and natural organic matter (humic acid), and can be widely used for degradation of common organic pollutants. The α-FeOOH@MoS2/rGO is a promising Fenton-like catalyst for refractory organic wastewater treatment.

RNA-Seq Analysis of Aboveground and Underground Parts of Biomass Sorghum Was Performed to Evaluate Its Suitability for Environmental Remediation.

"Alto2" is a new biomass sorghum variety, which has the characteristics of fast growth, high growth, and strong cadmium (Cd) resistance, so it has the application prospect of soil remediation plants. In order to reveal the Cd resistance mechanism of this plant and pave the way for genetic breeding and cultivation of efficient remediation plants in the future, in this research, through the determination of Cd content in various tissues of sorghum under Cd stress and the physicochemical response combined with RNA-Seq analysis, the mechanism of Cd resistance of "Alto2" was initially revealed. The results show biomass sorghum "Alto2" was mainly connected with aboveground and underground parts through the MAPK signaling pathway and plant hormone signaling pathway, and transmit stress signal in response to Cd stress. Chelase and metal-binding proteins may be the functional genes mainly responsible for Cd enrichment and transport and regulated by stress signals. However, the expression of aboveground transporters was not significant. This may be because Cd in biomass sorghum is mainly concentrated in the underground part and is enriched by the chelation of secondary metabolites from plant roots by the cell wall leading to inhibition of aboveground transporter expression. The results of this study indicate that the biomass sorghum "Alto2" on Cd has high resistance, but the lack of the aboveground enrichment of transportability requires further research to improve the Cd transportability of this plant.

Enhanced elimination of Cr(VI) from aqueous media by polyethyleneimine modified corn straw biochar supported sulfide nanoscale zero valent iron: Performance and mechanism.

A novel polyethyleneimine modified corn straw biochar supported sulfide nanoscale zero-valent iron (S-nZVI@PBC) was developed to enhance Cr(VI) removal from aqueous media. The characteristics of morphology, chemical composition, and functional groups of S-nZVI@PBC, as well as its kinetics and mechanism for Cr(VI) removal were explored. Characterization verified S-nZVI was successfully loaded onto PEI modified biochar. The adsorption process was well represented pseudo-second-order model (R2 = 0.990) and Langmuir isotherm model (R2 = 0.962), indicating it was a monolayer chemical adsorption process. The Cr(VI) removal was affected by pH and achieved the maximum when pH = 3.0, which may be ascribed to the better corrosion of nZVI and release of Fe(II) from the S-nZVI@PBC in acidic condition. The primary mechanisms were adsorption, reduction, and co-precipitation. S-nZVI@PBC exhibited higher stability and reusability than nZVI, which makes it more promising in environmental application. Overall, S-nZVI@PBC is of great potential for treating Cr(VI)-containing wastewater.