Development of natural attapulgite derived ferromanganese spinel oxides as heterogeneous catalysts for persulfate activation of tetracycline degradation.

Ferromanganese spinel oxides (MnFe2O4, MFO) have been proven effective in activating persulfate for pollutants removal. However, their inherent high surface energy often leads to agglomeration, diminishing active sites and consequently restricting catalytic performance. In this study, using Al-MCM-41 (MCM) mesoporous molecular sieves derived from natural attapulgite as a support, the MFO/MCM composite was synthesized through dispersing MnFe2O4 nanoparticles on MCM carrier by a simple hydrothermal method, which can effectively activate persulfate (PS) to degrade Tetracycline (TC). The addition of Al-MCM-41 can effectively improve the specific surface area and adsorption performance of MnFe2O4, but also reduce the leaching amount of metal ions. The MFO/MCM composite exhibited superior catalytic reactivity towards PS and 84.3% removal efficiency and 64.7% mineralization efficiency of TC (20 mg/L) was achieved in 90 min under optimized conditions of 0.05 mg/L catalyst dosage, 5 mM PS concentration, room temperature and no adjustment of initial pH. The effects of various stoichiometric MFO/MCM ratio, catalyst dosage, PS concentration, initial pH value and co-existing ions on the catalytic performance were investigated in detail. Moreover, the possible reaction mechanism in MFO-MCM/PS system was proposed based on the results of quenching tests, electron paramagnetic resonance (EPR) and XPS analyses. Finally, major degradation intermediates of TC were detected by liquid chromatography mass spectrometry technologies (LC-MS) and four possible degradation pathways were proposed. This study enhances the design approach for developing highly efficient, environmentally friendly and low-cost catalysts for the advanced treatment process of antibiotic wastewater.

Facilitate the preparation of naturally modified and self-healing superhydrophobic/superoleophilic biochar-based foams for efficient oil-water separation.

Oil spills are sudden, complex, and long-term hazardous, and the existing adsorption materials still have the disadvantages of small selective adsorption capacity, easy secondary contamination, and difficult to repair after breakage in practical applications. Herein, melamine foam (MF) coated by ball milled biochar (BMBC) and natural beeswax (Wax@BMBC@MF) was prepared by a bio-inspired functionalization method and further added with self-healing function (SH-Wax@BMBC@MF) to cope with complex environments, and applied to oil-water separation for oil adsorption. SEM and FTIR results showed that BMBC and natural beeswax nanoparticles successfully encapsulated the smooth surface of the melamine foam skeleton. The loading of natural beeswax increased the foam's ability to absorb oil and organic solvents from 0.6108-1.134 g to 0.850-1.391 g, and the oil-absorbing capacity of the foam remained at 0. 758-1.263 g after being cut by a knife and self-healing. The oil-absorbing capacity of SH-Wax@BMBC@MF remained in the range of 0.936-1.336 g under acid/alkali environment (pH =1-13). The surface functional groups of BMBC improved the surface roughness of the material and strengthen the MF skeleton to adsorb oils and organic solvents by capillary action. The generation of the di-coordinated structure by Fe3+ and catechol group contributed the restoration of SH-Wax@BMBC@MF structure and oil absorption capacity. SH-Wax@BMBC@MF has superiority of superhydrophobic, superoleophilic, self-healing after damage, and environmental friendliness, which provides a promising solution for the treatment of oil spills at sea.

Gas-Pressurized Torrefaction of Lignocellulosic Solid Wastes: Deoxygenation and Aromatization Mechanisms of Cellulose.

A novel gas-pressurized (GP) torrefaction method at 250 °C has recently been developed that realizes the deep decomposition of cellulose in lignocellulosic solid wastes (LSW) to as high as 90% through deoxygenation and aromatization reactions. However, the deoxygenation and aromatization mechanisms are currently unclear. In this work, these mechanisms were studied through a developed molecular structure calculation method and the GP torrefaction of pure cellulose. The results demonstrate that GP torrefaction at 250 °C causes 47 wt.% of mass loss and 72 wt.% of O removal for cellulose, while traditional torrefaction at atmospheric pressure has almost no impact on cellulose decomposition. The GP-torrefied cellulose is determined to be composed of an aromatic furans nucleus with branch aliphatic C through conventional characterization. A molecular structure calculation method and its principles were developed for further investigation of molecular-level mechanisms. It was found 2-ring furans aromatic compound intermediate is formed by intra- and inter-molecular dehydroxylation reactions of amorphous cellulose, and the removal of O-containing function groups is mainly through the production of H2O. The three-ring furans aromatic compound intermediate and GP-torrefied cellulose are further formed through the polymerization reaction, which enhances the removal of ketones and aldehydes function groups in intermediate torrefied cellulose and form gaseous CO and O-containing organic molecules. A deoxygenation and aromatization mechanism model was developed based on the above investigation. This work provides theoretical guidance for the optimization of the gas-pressurized torrefaction method and a study method for the determination of molecular-level structure and the mechanism investigation of the thermal conversion processes of LSW.

Recent developments and perspectives of MXene-Based heterostructures in photocatalysis.

Energy crises and environmental degradation are serious in recent years. Inexhaustible solar energy can be used for photocatalytic hydrogen production or CO2 reduction to reduce CO2 emissions. At present, the development of efficient photocatalysts is imminent. MXene as new two-dimensional (2D) layered material, has been used in various fields in recent years. Based on its high conductivity, adjustable band gap structure and sizable specific surface area, the MXene is beneficial to hasten the separation and reduce the combination of photoelectron-hole pairs in photocatalysis. Nevertheless, the re-stacking of layers because of the strong van der Waals force and hydrogen bonding interactions seriously hinder the development of MXene material as photocatalysts. By contrast, the MXene-based heterostructures composed of MXene nanosheets and other materials not only effectively suppress the re-stacking of layers, but also show the superior synergistic effects in photocatalysis. Herein, the recent progress of the MXene-based heterostructures as photocatalysts in energy and environment fields is summarized in this review. Particularly, new synthetic strategies, morphologies, structures, and mechanisms of MXene-based heterostructures are highlighted in hydrogen production, CO2 reduction, and pollutant degradation. In addition, the structure-activity relationship between the synthesis strategy, components, morphology and structure of MXene-based heterostructures, and their photocatalytic properties are elaborated in detail. Finally, a summary and the perspectives on improving the application study of the heterostructures in photocatalysis are presented.

Vacancy pairs regulate BiOBr microstructure for efficient dimethyl phthalate removal under visible light irradiation.

Developing new photocatalysts to achieve efficient removal of phthalate esters (PAEs) in water is an important research task in environmental science. However, existing modification strategies for photocatalysts often focus on enhancing the efficiency of material photogenerated charge separation, neglecting the degradation characteristics of PAEs. In this work, we proposed an effective strategy for the photodegradation process of PAEs: introducing vacancy pair defects. We developed a BiOBr photocatalyst containing "Bi-Br" vacancy pairs, and confirmed that it has an excellent photocatalytic activity in removing phthalate esters (PAEs). Through a combination of experimental and theoretical calculations, it is proved that "Bi-Br" vacancy pairs can not only improve the charge separation efficiency, but also alter the adsorption configuration of O2, thus accelerating the formation and transformation of reactive oxygen species. Moreover, "Bi-Br" vacancy pairs can effectively improve the adsorption and activation of PAEs on the surface of samples, surpassing the effect of O vacancies. This work enriches the design concept of constructing highly active photocatalysts based on defect engineering, and provides a new idea for the treatment of PAEs in water.

Gas-pressurized torrefaction of lignocellulosic solid wastes: Low-temperature deoxygenation and chemical structure evolution mechanisms.

A novel gas-pressurized (GP) torrefaction realizes deeper deoxygenation of lignocellulosic solid wastes (LSW) to as high as 79% compared to traditional torrefaction (AP) with the oxygen removal of 40% at the same temperature. However, the deoxygenation and chemical structure evolution mechanisms of LSW during GP torrefaction are currently unclear. In this work, the reaction process and mechanism of GP torrefaction were studied through follow-up analysis of the three-phase products. Results demonstrate gas pressure causes over 90.4% of cellulose decomposition and the conversion of volatile matter to fixed carbon through secondary polymerization reactions. Above phenomena are completely absent during AP torrefaction. A deoxygenation and structure evolution mechanism model is developed through analysis of fingerprint molecule and C structure. This model not only provides theoretical guidance for optimization of the GP torrefaction, but also contributes to the mechanism understanding of pressurized thermal conversion processes of solid fuel, such as coal and biomass.

Flue Gas-Enhanced Water Leaching: AAEM Removal from Agricultural Organic Solid Waste and Fouling and Slagging Suppression during Its Combustion.

Alkali and alkaline earth metals (AAEMs) in agricultural organic solid waste (AOSW) contribute to the fouling and slagging during its combustion. In this study, a novel flue gas-enhanced water leaching (FG-WL) method using flue gas as the heat and CO2 source was proposed for effective AAEM removal from AOSW before combustion. The removal rate of AAEMs by FG-WL was significantly superior to that by conventional water leaching (WL) under the same pretreatment conditions. Furthermore, FG-WL also obviously reduced the release of AAEMs, S, and Cl during AOSW combustion. The ash fusion temperatures of the FG-WL-treated AOSW was higher than that of WL. The fouling and slagging tendency of AOSW greatly decreased through FG-WL treatment. Thus, FG-WL is a simple and feasible method for AAEM removal from AOSW and suppressing fouling and slagging during its combustion. Besides, it also provides a new pathway for the resource utilization of power plant flue gas.

Oxygen vacancies assist a facet effect to modulate the microstructure of TiO2 for efficient photocatalytic O2 activation.

Defect engineering is recognized as an effective route to obtaining highly active photocatalytic materials. However, the current understanding of the role of defects in photocatalysts mainly comes from their independent functional analysis, ignoring the synergy between defects and the chemical environment, especially with crystal facets. Herein, oxygen vacancy (VO)-rich TiO2 nanostructures with different dominant exposed facets were prepared, and the microstructural changes induced by the synergy between the VO and facet effect and the performance difference of photocatalytic O2 activation were explored. The results showed that the combination of high concentration VO and the {101} facet is more conducive to improving the photocatalytic performance of TiO2, which is significantly superior to the combination of low concentration VO and the {101} facet as well as the combination of high concentration VO and the {001} facet. The experimental and theoretical results clarified the dependence of each stage of photocatalysis on two factors. Specifically, VO plays a more significant role in energy band regulation, improving the dynamic behavior of photogenerated charges and enhancing the adsorption and activation of O2, while the facet effect made more contributions to reducing the thermodynamic energy barrier of ROS formation and conversion. The excellent ability of O2 activation enables T101-VO to show potential application characteristics in the removal of RhB and bacterial disinfection. This work established a link between defect and facet effects, providing new insights into understanding defect function in photocatalysts.

Discharge of treated Fukushima nuclear accident contaminated water: macroscopic and microscopic simulations.

The diffusion process of the treated Fukushima nuclear accident contaminated water to be discharged into the Pacific Ocean from 2023 is analyzed by two analysis models from macroscopic and microscopic perspectives. Results show that the tritium will spread to the whole North Pacific in 1200 days, which is important to formulate global coping strategies.

Yield prediction of "Thermal-dissolution based carbon enrichment" treatment on biomass wastes through coupled model of artificial neural network and AdaBoost.

The "Thermal-dissolution based carbon enrichment" was proven as an efficient and homogenizing treatment method in converting biomass wastes into similar high-quality carbon materials. However, their yields varied significantly with respect to the different experimental parameters employed. It is therefore imperative to establish the correlation between product yield and experimental parameters for material selection and condition optimization. In this study, Adaboost was coupled with an artificial neural network algorithm to precisely describe the abovementioned correlation. The results demonstrated the effectiveness of this model through its outstanding predicting performance for all the products, especially, the coefficient of determination in predicting the yield of Residue was as high as 0.97. Additionally, the coupling effect of temperature and time was observed. This study not only validates a close correlation between selected experimental parameters and product yields, but also provides a quick and reliable way for material selection and condition optimization.

A Framework for the Automatic Integration and Diagnosis of Building Energy Consumption Data.

Buildings account for a majority of the primary energy consumption of the human society, therefore, analyses of building energy consumption monitoring data are of significance to the discovery of anomalous energy usage patterns, saving of building utility expenditures, and contribution to the greater environmental protection effort. This paper presents a unified framework for the automatic extraction and integration of building energy consumption data from heterogeneous building management systems, along with building static data from building information models to serve analysis applications. This paper also proposes a diagnosis framework based on density-based clustering and artificial neural network regression using the integrated data to identify anomalous energy usages. The framework and the methods have been implemented and validated from data collected from a multitude of large-scale public buildings across China.

Gas-pressurized torrefaction of biomass wastes: The optimization of pressurization condition and the pyrolysis of torrefied biomass.

A novel gas-pressurized (GP) torrefaction with high oxygen removal efficiency at mild temperature was proposed in our previous work. However, the optimal condition of the GP torrefaction and subsequent pyrolysis of the torrefied biomass were not clear. In this work, the effect of pressure on the GP torrefaction and pyrolysis product properties of the torrefied biomass were studied in detail. The results show that the pressure increasing from 1.7 MPa to 5.0 MPa just slightly contributed to further oxygen removal, and 1.7 MPa was thus selected as the optimum pressure. The GP torrefaction significantly improved the product property of biomass pyrolysis compared to the conventional torrefaction (AP torrefaction). The acids content in bio-oil was reduced from 15-20% to less than 5%, and the calorific value of biogas increased to as high as 16.57-19.31 MJ/Nm3. Furthermore, an overall conversion mechanism of combined GP torrefaction and subsequent pyrolysis of biomass was proposed.

Gas-pressurized torrefaction of biomass wastes: Co-gasification of gas-pressurized torrefied biomass with coal.

Co-gasification of coal and biomass offers a relatively cleaner utilization way of fossil fuel. The fuel property improvement of biomass can not only improve the property of syngas but also enhance the synergistic effect during the co-gasification. In our previous work, a novel gas-pressurized (abbreviated as GP) torrefaction was proposed to effectively upgrade the biomass under mild condition. In this work, the co-gasification of GP torrefied biomass and coal were conducted to explore the synergistic effect and kinetics. Significant synergistic effect during the co-gasification was proved. The CO yield of co-gasification increased to as high as 70.70 mol/kg, resulting from the promotion of carbon in coal converting into CO by GPRS. Furthermore, the kinetic model of RPM was most fitting for the co-gasification, and the activation energy of co-gasification was reduced. Thus, the coal gasification was promoted significantly by GP torrefied biomass through obvious synergistic effect during the co-gasification.

Recycling of spent alkaline Zn-Mn batteries directly: Combination with TiO2 to construct a novel Z-scheme photocatalytic system.

Recycling of spent alkaline Zn-Mn batteries (S-AZMB) has always been a focus of attention in environmental and energy fields. However, the current research mostly concentrated in the recovery of purified materials, and ignores the direct reuse of S-AZMB. Herein, we propose a new concept for the first time that unpurified S-AZMB can be used as raw materials for preparation of Z-scheme photocatalytic system in combination with TiO2. A series of characterizations and experiments confirm that the combination with S-AZMB not only extends the response of TiO2 to visible light, but also significantly enhances the separation ability of photogenerated electron-hole pairs. In the toluene removal experiment, the degradation kinetic rate of Z-scheme TiO2@S-AZMB photocatalyst reaches 21.0 and 10.5 times than that of TiO2 and S-AZMB, respectively. More notably, this S-AZMB based Z-scheme photocatalyst can maintain structural and photocatalytic performance stability in cyclic catalytic reactions. We believe that this work not only expands the research concept of recycling S-AZMB, but also provides a new idea for designing highly efficient Z-scheme photocatalysts.

Gas-pressurized torrefaction of biomass wastes: Roles of pressure and secondary reactions.

A gas-pressurized (GP) torrefaction method, proposed in our resent work, can significantly promote the upgrading and oxygen removal of biomass wastes, compared to the traditional torrefaction (AP). However, the mechanism of the GP torrefaction process is not clear. In present work, semi-closed (SC) torrefaction, GP torrefaction, and AP torrefaction were conducted to reveal the roles of pressure and secondary reactions during GP torrefaction quantitatively. The results showed that the pressure significantly promoted the upgrading of biomass during GP torrefaction at 200 °C. The contribution of pressure on the oxygen removal of GP torrefaction at 200 °C was 63.87%. At relatively high temperature of around 250 °C, the promotions were caused by the synergistic effect of pressure and secondary reactions. The contribution of secondary reactions on the oxygen removal was 53.99%. Thus, the process of the GP torrefaction of biomass wastes was preliminarily understood.

Bibliometric review of visual computing in the construction industry.

In the construction area, visuals such as drawings, photos, videos, and 3D models, play a significant role in the design, build and maintenance of a facility, bringing efficiency to generate, transfer, and store information. Advanced visual computing techniques facilitate the understanding of design contents, work plans, and other types of information shared in the construction industry. Automatic visual data collection and analysis provide many possibilities to the construction industry and a large number of works have investigated how visual computing can improve construction management processes and other problems in the construction area. However, a comprehensive literature review is needed. This study uses bibliometric approaches to review the works published to date, and analyses the development of knowledge, significant research results, and trends. The purpose of this study is to help newcomers to this research field understand knowledge structure and formulate research directions, thereby enhancing knowledge development. From this study, it can be concluded that computer vision is a key axis of improvement. Moreover, building information modeling, laser scanning, and other visualization-related techniques are also important in advancing the construction area.

MIL-100(Fe) supported Mn-based catalyst and its behavior in Hg0 removal from flue gas.

A novel magnetic composite catalyst of MnOx loaded on MIL-100(Fe) was prepared for the removal of Hg0 from flue gas, via incipient wetness impregnation followed with calcination at 300 °C. The MIL-100(Fe) supported catalyst showed greater capacity of Hg0 adsorption and oxidation than Fe2O3 supported catalyst at all test temperatures, showing Hg0 removal efficiency of 77.4% at 250 °C with high GHSV of 18,000 h-1. Besides the merit of high BET surface area and developed porous, the ultra-highly dispersed and homogeneous Fe sites on MIL(Fe) significantly promoted Hg0 adsorption and oxidation via the synergy effect with MnOx. Furthermore, the catalyst exhibited magnetic property, which allowed easy separation of the catalyst from fly ash with a recovery of 104%. SO2, H2O and NH3 in flue gas were proved inhibited Hg0 removal via different mechanisms. SO2 and H2O competed and desorbed Hg2+ on the surface of catalyst, while NH3 was more likely to compete adsorption sites with Hg0.

Preparation of activated carbon nanofibers using degradative solvent extraction products obtained from low-rank coal and their utilization in supercapacitors.

In this study, low-rank coal was separated into three solid fractions by a degradative solvent extraction method. The high-molecular-weight extract (termed Deposit) had some outstanding properties such as high carbon content, almost no ash, high aromaticity, good thermoplasticity and high solubility in DMF. Therefore, Deposit with some proportion of polyacrylonitrile (PAN) was used to prepare activated carbon nanofibers by electrospinning and CO2 activation. Moreover, the utilization of these carbon nanofibers as a supercapacitor electrode was preliminarily investigated. The results showed that the specific surface area of the Deposit-based carbon nanofibers (1005 m2 g-1) was significantly higher than that of the nanofibers obtained from pure PAN (688 m2 g-1). TGA simulations showed that this was caused by the different thermal decomposition behaviors of Deposit and PAN during the stabilization and activation processes. In addition, the Deposit-based carbon nanofibers showed a better specific capacitance (192.6 F g-1 at 1 A g-1) and cycling performance (retention rate of 89.8% after 1000 cycles at 5 A g-1) in a 6 M KOH electrolyte. The factors, such as the enhanced surface area and pore volume and decreased average fiber diameter, affected the electrochemical properties of the carbon nanofibers. Thus, it has been proven that the high-molecular-weight extract obtained from low-rank coal by degradative solvent extraction is a promising precursor for the preparation of carbon nanofibers with unique electrochemical properties.

Full Electric Control of Exchange Bias at Room Temperature by Resistive Switching.

Electric control of exchange bias (EB) is of vital importance in energy-efficient spintronics. Although many attempts have been made during the past decade, each has its own limitations for operation and thus falls short of full direct and reversible electrical control of EB at room temperature. Here, a novel approach is proposed by virtue of unipolar resistive switching to accomplish this task in a Si/SiO2 /Pt/Co/NiO/Pt device. By applying certain voltages, the device displays obvious EB in the high-resistance-state while negligible EB in the low-resistance state. Conductive filaments forming in the NiO layer and rupturing near the Co-NiO interface are considered to play dominant roles in determining the combined resistive switching and EB phenomena. This work paves a new way for designing multifunctional and nonvolatile magnetoelectric random access memory devices.

Exposure to nanoscale and microscale particulate air pollution prior to mining development near a northern indigenous community in Québec, Canada.

This study serves as a baseline characterization of indoor and outdoor air quality in a remote northern indigenous community prior to the start of a major nearby mining operation, including measurements of nanoparticles, which has never been performed in this context before. We performed aerosol sample collection and real-time aerosol measurements at six different locations at the Cree First Nation of Waswanipi and the Montviel campsite, located 45 km west of the Cree First Nation of Waswanipi, in the south of the Nord-du-Québec region. High concentrations of airborne nanoparticles (up to 3.98 × 104 ± 8.9 × 103 cm-3 at 64.9-nm midpoint particle diameter) and fine particles (up to 1.99 × 103 ± 1.6 × 102 cm-3 at 0.3-µm midpoint particle diameter) were measured inside a residential home, where we did not find any ventilation or air filtration systems. The most abundant particle sizes by mass were between 0.19 and 0.55 µm. The maximum concentration of analyzed heavy metals was detected at the d50 cut-off particle size of 0.31 µm; and the most abundant heavy metals in the aerosol samples were Al, Ba, Zn, Cu, Hg, and Pb. We concluded that the sources of the relatively high indoor particle concentrations were likely laundry machines and cooking emissions in the absence of a sufficient ventilation system. However, the chemical composition of particles resulting from mining activities is expected to be different from that of the aerosol particles from indoor sources. Installation and proper maintenance of sufficient ventilation and air filtration systems may reduce the total burden of disease from outdoor and indoor air pollution and remediate infiltrated indoor particulate pollution from the mining sources as well.