Porous Titanium Scaffolds with Mechanoelectrical Conversion and Photothermal Function: A Win-Win Strategy for Bone Reconstruction of Tumor-Resected Defects.

Bone metastases severely threaten the lives of patients. Although surgical treatment combined with adjuvant chemotherapy significantly improves the survival rate of patients, tumor recurrence, or metastasis after surgical resection and bone defects caused by surgical treatment remain major challenges for clinicians. Given the abovementioned clinical requirements, barium titanate-containing iron-coated porous titanium alloy scaffolds have been proposed to promote bone defect repair and inhibit tumor recurrence. Fortunately, in vitro and in vivo experimental research confirms that barium titanate containing iron-coated porous titanium alloy scaffolds promote osteogenesis and bone reconstruction in defect repair via mechanoelectric conversion and inhibit tumor recurrence via photothermal effects. Furthermore, the underlying and intricate mechanisms of bone defect repair and tumor recurrence prevention of barium titanate-containing iron-coated porous titanium alloy scaffolds are explored. A win-win strategy for mechanoelectrical conversion and photothermal functionalization provides promising insights into bone reconstruction of tumor-resected defects.

Electron structure modulation and bicarbonate surrounding enhance Fenton-like reactions performance of Co-Co PBA.

Although several strategies have been developed to improve the efficiency of heterogeneous Fenton-like reactions, investigating the relationship among the electronic properties of the catalyst surface, the complex water matrix and catalytic activity remains challenges. Herein, the electron density of the active site Co(II) in Co Prussian blue analogs (Co-PBAs) is proved to be modulated by the anion source method. The elevated electron density of Co(II) and the higher metallicity of the catalyst lead to an increase in electron transport efficiency as revealed by X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), and density functional theory (DFT) calculations. Furthermore, the negative shift of the D-band center of Co(II) can effectively release intermediates to avoid catalyst poisoning. Bicarbonate has been demonstrated to activate peroxymonosulfate (PMS) by weakening the peroxide bond. Its activation mechanism involves free radical mechanism and non-radical mechanism: the first step is the generation of HCO4-, then it is further hydrolyzed to generate •OH and 1O2, and the other is HCO4- interact with Co(III) to form Co(IV)=O. In addition, the degradation pathways of target contaminants p-nitrophenol and toxicity verification of intermediate products have been investigated. This study provides guidance for the research of Fenton-like reactions.

Insights into the mechanism of enhanced peroxymonosulfate degraded tetracycline using metal organic framework derived carbonyl modified carbon-coated Fe0.

Tetracycline (TC) is a commonly used antibiotic that has gained wide spread notoriety owing to its high environmental risks. In this study, rich carbonyl-modified carbon-coated Fe0 was obtained by pyrolysis of MIL-100(Fe) in an Ar atmosphere, and used to activate peroxymonosulfate (PMS) for the degradation of tetracycline in water. The roles of Fe0, carbon and surface carbonyl on PMS activation were investigated. Fe0 continuously activated PMS, acted as a sustained-release source of Fe2+, and could effectively activate PMS to produce SO4•-, O2•- and •OH. Carbon was found to do responsible for electron transportation during the activation of PMS and slow down the oxidation of Fe0. The carbonyl group on the carbon surface layer was the active site of 1O2, which explains the enhanced performance for TC degradation. When Ca = 0.1 g/L and C0 = 0.4 mM, TC degradation rate reached 96%, which was attributed to the synergistic effect of radicals (i.e., SO4•-, O2•-, •OH) and non-radical (i.e., 1O2). Finally, the degradation pathway was proposed by combining density functional theory (DFT) calculations with liquid chromatography-mass spectrometry (LC-MS), toxicities of the intermediate products were also evaluated. All results show that carbonyl-modified carbon-coated Fe0 possesses promising capacity for the removal of antibiotics from water.

Bicarbonate-enhanced iron-based Prussian blue analogs catalyze the Fenton-like degradation of p-nitrophenol.

P-nitrophenol (PNP), a widely used compound, is harmful to the environment and human health. In this study, four iron-based Prussian blue analogs (PBAs) were prepared by coprecipitation (Co-Fe PBA, Mn-Fe PBA, Cu-Fe PBA and Fe-Fe PBA). The Co-Fe PBA exhibited high peroxymonosulfate (PMS) activation performance for PNP degradation, removing over 90% of PNP in 60 min at an optimal pH of 7, temperature at 30 ℃, initial concentration of 20 mg/L, PBA dose of 0.2 g/L and PMS dose of 1 g/L. The physicochemical properties of the Co-Fe PBA were investigated by various characterization methods. The catalytic activity of PBA and the influence of various process parameters and water quality on the catalytic reaction were investigated to elucidate the mechanism of p-nitrophenol degradation by PBA-activated persulfate. Moreover, the mechanism of accelerated degradation of PNP under HCO3- conditions and the role of major reactive oxides were determined by EPR measurement methods and free radical trapping experiments. HCO3- was found to directly activate PMS to produce reactive oxygen species, and 1O2, ∙OH and SO4∙- were all greatly increased. This work presents a promising green heterogeneous catalyst for the degradation of emerging contaminants (ECs) in real wastewater with natural organic matter and coexisting anions by PMS activation.

In-situ fabrication of a spherical-shaped Zn-Al hydrotalcite with BiOCl and study on its enhanced photocatalytic mechanism for perfluorooctanoic acid removal performed with a response surface methodology.

Perfluorooctanoic acid (PFOA), a widely used compound, is harmful to the environment and human health. In this study, a facile one pot solvothermal method of integrating BiOCl with Zn-Al hydrotalcite to form spherical-shaped BiOCl/Zn-Al hydrotalcite (B-BHZA) sample is reported. The characteristics and main factors affecting photocatalytic PFOA and photocatalytic mechanism of BiOCl/Zn-Al hydrotalcite (B-BHZA) are systematically investigated. It is found that spherical-shaped B-BHZA possesses abundant defects and a larger surface area of 64.4 m2 g-1. The factors affecting photocatalytic removal PFOA (e.g., time, pH, initial concentration and dosage) are investigated by modeling the 3D surface response. The removal rate of PFOA is over 90 % in 6 h under UV light at an optimal pH of 2, an initial concentration of 500 µg/L and a dose of dosage 0.5 g/L. The main mechanism occurs by photo-generated h+ oxidation and synergistic effects from the photocatalysis process. Though investigating the intermediates of PFOA degradation and F-, a possibility was proposed that h+ initiated the rapidly decarboxylation of PFOA. The unstable perfluoroheptyl group is formatted and further conversed to short chain perfluorocarboxylic acid. This study provides a new insight for the preparation of highly efficient photocatalysts to the treatment of halogenated compounds in UV system.

Ultrasonic degradation of nitrosodipropylamine (NDPA) and nitrosodibutylamine (NDBA) in water.

Nitrosodipropylamine (NDPA) and nitrosodibutylamine (NDBA), two highly toxics and carcinogenic disinfection by-products, cannot be efficiently removed by conventional water treatment processes, while the ultrasound treatment was developed as a promising alternative. In this work, nitrosodipropylamine (NDPA) and nitrosodibutylamine (NDBA) are degraded by ultrasound treatment. Greater than 99% of NDPA and NDBA mixing solution could be decomposed within 60 min at neutral pH under optimal ultrasound power and frequency settings of 100 W and 600 kHz, respectively. Free radical reactions (OH•) played a significant role and the reaction sites were predominately at the bubble interface. The degradation of both NDPA and NDBA exhibited pseudo-first-order degradation kinetics, and the rate constant kapp was influenced by a number of factors including ultrasonic frequency, power, initial concentration, initial pH, various anions and cations frequently present in drinking water, hydroxyl radical scavengers, and water matrices, especially the promoting effect of various anions and cations and water matrices. The results of this study suggest the potential for ultrasound treatment as a method for removing NAms from water.

Insights to perfluorooctanoic acid adsorption micro-mechanism over Fe-based metal organic frameworks: Combining computational calculation with response surface methodology.

Adsorption performance, interfacial interaction mechanism and contribution of pores concerning PFOA adsorption to Fe-based metal-organic frameworks (MOFs) including Fe-BTC, MIL-100-Fe and MIL-101-Fe are investigated using experiments and computational calculation at molecular level even electronic level. Fe-BTC (418 mg/g) with more Lewis acid sites demonstrates higher adsorption capacity of PFOA in comparison with MIL-100-Fe (349 mg/g) and MIL-101-Fe (370 mg/g). Adsorption isotherms and kinetics indicate presence of monolayer adsorption and chemisorption in adsorption process. The pH dependence of PFOA adsorption to Fe-based MOFs is statistically revealed by experiments and analysis of variance of response surface methodology (RSM). XPS spectra of MOF-PFOA corroborate that decreasing binding energy of Fe2p and increasing binding energy of F1s, suggesting the presence of Lewis acid/base complexing (LAB) and hydrophobic interaction in adsorption process. Differential charge demonstrates that Fe center and benzene of organic ligands are respectively electron acceptor and donor in adsorption process. Electronic level mechanism finds that LAB complexing dominates adsorption process due to highest overlap of electron cloud. Smaller pores such as triangle and pentagonal pores of Fe-based MOFs contribute to the load of PFOA, while larger hexagonal one enable PFOA to enter into cages, as revealed by computational calculation.

Highly effective adsorption removal of perfluorooctanoic acid (PFOA) from aqueous solution using calcined layer-like Mg-Al hydrotalcites nanosheets.

To study the influence factors of calcined layer-like Mg-Al hydrotalcites nanosheets adsorbing perfluorooctanoic acid (PFOA) in aqueous solution, Mg-Al hydrotalcite (HMA) nanosheets were prepared by one-step hydrothermal synthesis. The effect of calcination temperature on adsorption properties and structure of HMA (CHMA-x, x means different calcination temperature) was investigated. The prepared samples were systematically characterized by the Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and nitrogen adsorption-desorption isotherms. The adsorption isotherms and kinetics showed the adsorption equilibrium reached within 2 h, and the factors, such as adsorption dosage, pH, and cycles were investigated. It was found that CHMA with 600 °C displayed a uniformly morphology, higher surface area about 106.3 m2/g, and excellent adsorption properties (1969 mg/g). The equilibrium adsorption data perfectly fitted to the pseudo-second-order kinetic model (R2 = 0.999) and the Freundlich model (R2 = 0.994). The main mechanism of CHMA adsorbing PFOA might be the "memory effect." This study provided a new insight to prepare highly effective adsorbents in water treatment.