One novel/multifunctional selenium-doped SrFeO3-δ/HNTs composite was fabricated and used for immobilization of gaseous mercury. The composite showed excellent performances for Hg0 removal via adsorption coupled with photocatalytic oxidation in visible-light conditions. The adsorption capacity of 4271.15 μg·g–1, rate of 5.0 μg·g–1·min–1, and removal efficiency of ∼100% were obtained under N2+O2, which was further confirmed by reaction kinetics. SrFeO3-δ was selenized into iron diselenide and a Se–Fe bond with high affinity toward Hg0. In addition, the yielding of •O2– and the separation of photoexcited electrons and holes (h+) promoted the photocatalytic oxidation of mercury. The composite with intrinsic magnetism could be easily recycled for reuse by magnetic separation. Moreover, the composite possessed favorable tolerance to the complicated flue gas. An online lab-built thermal decomposition system demonstrated that the immobilized Hg was primarily HgSe, which exhibited very high stability and low toxicity. Density functional theory (DFT) calculations proved that the composite was half metal with magnetism, indicating that Hg on Se-SrFeO3-δ/HNTs formed the stable structure releasing 1.055 eV. The doping of selenium promoted the charge transfer between O (2p) and Hg (6s), which also favored Hg0 removal. Se-SrFeO3-δ/HNTs with recyclability possess great potentials for Hg0 efficient removal and immobilization/detoxification from flue gas.
Shuo Gao,Chenzhang Liu,Xiaohan Yang,Ziwei Lan,Min Zuo,Ping Yang,Jia Li
Self-driven micro–nanomotors hold great promise for environmental monitoring and remediation. However, developing a nanomotor with dual functions of colorimetric detection and degradation is still a considerable challenge. In this paper, a novel nanomotor with both selective and catalytic activities was synthesized using a combination of natural enzymes and nanozymes. The nanomotor was modeled on natural mineral halloysite nanotubes (HNTs) and had a unique layered structure. MnO2 in the inner layer was the fuel catalytic unit, which achieved actuation by catalyzing hydrogen peroxide (H2O2) to produce oxygen bubbles, and the diffusion coefficient of the nanomotor could reach 2.65 μm2 s−1 in 5% H2O2 solution. Lac/Fe-BTC@NiFe-LDH in the outer layer was the catalytic functional unit, where Lac/Fe-BTC@NiFe-LDH not only exhibited high peroxide-like active enzyme activity, but also provided abundant active sites for the loading of natural laccase. The integration of natural enzymes and nanozymes provided the material with stronger catalytic activity, which could detect the target pollutant minocycline (MC) in water more sensitively and degrade it efficiently, and provided a new idea for the removal of antibiotics from water.
Miaomiao Cui,Demian I. Njoku,Bowen Li,Lihui Yang,Zuankai Wang,Baorong Hou,Ying Li
This article employed a layer-by-layer approach to modify the interfacial boundary of halloysite clay nanotubes (HNTs) using (poly (diallyldimethylammonium chloride)) (PDDA) and poly (styrene sulfonate) (PSS) polyelectrolytes to form core (inhibitor-loaded HNTs)-shell (polyelectrolytes layers (PDDA/PSS)) structured smart microcapsules or micro-containers. Responses of the smart microcapsules to changes in pH (H + ), Cl − , OH − and H 2 O during the release of the loaded inhibitor (2-mecaptobenzothiazole inhibitor (2-MBT)) coupled with the number of PDDA/PSS polyelectrolytes layers ( n ) required to obtain optimal response were characterized. The anticorrosion efficacies of several organic compounds were screened to identify the most suitable inhibitor for the protection of Al alloy 2024 in 3.5 wt.% NaCl. 2-MBT which exhibits the best inhibition efficiency was successfully loaded into the HNTs lumen as demonstrated by TGA and DSC results. The release profiles of 2-MBT reveal that the sensitivity of the smart microcapsules to the various external stimuli decreased in the following order: pH > Cl − > H 2 O > OH − ; and three-layered polyelectrolyte (3n) displays the highest sensitivity amongst the studied layer numbers (n). The release profiles were fitted to the Pappas and Weibull's models which describe the release mechanisms. Compatibility of the smart microcapsules with epoxy coating coupled with the anticorrosion effect on Al alloy 2024 substrate were evaluated by means of long-term salt spray and immersion tests.
危险品化学品经营许可证（带存储）