Multiscale levels CO2 decouple reinforcement in China.

Decoupling economic growth from CO2 emissions is imperative for China. Meanwhile, establishing a consistent and comprehensive decoupling inventory that includes national (N), regional and provincial (RP), and city and county (CC) levels is essential for further policy formulation. This research aims to investigate the decoupling status using the "N-RP-CC" approach while considering changes in decoupling trends at the different levels. A combination of the Tapio decoupling model and cluster analysis is employed to study the decoupling's spatiotemporal characteristics and trends. The study first calculates the decoupling value for "national, 7; regions, 30; provinces, 1501 CCs" in China, 2006-2017. The results show that there continues to be an improvement in the decoupling trend at the national level. Conversely, the regional scale exhibits a more vulnerable decoupling trend compared to the national level, with weak and extended negative decoupling observed in northeastern and northern China. Moreover, provincial heterogeneities are increasingly evident, with poor decoupling statuses appearing in Jilin, Heilongjiang, Liaoning, and Xinjiang, as well as many central provinces. Additionally, although more than half of CCs exhibit weak decoupling during most years, seven different states of decoupling were also identified during the time frame. These findings further indicate that spatiotemporal heterogeneities extend beyond RP scales within CCs. Taking the Yangtze River as a boundary line reveals a severe situation in northern areas along with rapid development trends observed in southern regions. Finally, we clustered 1414 CCs based on their industrial proportions for 2017 which further highlights increasingly prominent heterogeneities that should be carefully considered. Based on these findings, policy recommendations such as spatial organization and optimization and technique investment are proposed to achieve CO2 emission decoupling under the N-RP-CC levels.

Microwave- and ultrasonic-assisted synthesis of 2D La-based MOF nanosheets by coordinative unsaturation degree to boost phosphate adsorption.

The metal or metal clusters and organic ligands are relevant to the selectivity and performance of phosphate removal in MOFs, and the electron structure, chemical characteristics, and preparation method also affect efficiency and commercial promotion. However, few reports focus on the above, especially for 2D MOF nanomaterials. In this work, two 2D Ln-TDA (Ln = La, Ce) nanosheets assembled via microwave- and ultrasonic-assisted methods are employed as adsorbents for phosphate (H2PO4 -, HPO4 2-) removal for the first time. Their microstructure and performance were characterized using XRD, TEM, SEM, AFM, FTIR, zeta potential, and DFT calculations. The prepared 2D Ln-TDA (Ln = La, Ce) nanosheets exposed more adsorption sites and effectively reduced the restrictions of mass transfer. Based on this, the Langmuir model was employed to estimate the maximum adsorption capacities of the two kinds of nanosheets, which reached 253.5 mg g-1 and 259.5 mg g-1, which are 553 times and 3054 times larger than those for bulk Ln-TDA (Ln = La, Ce), respectively. Additionally, the kinetic data showed that the adsorption equilibrium time is fast, approximately 15 min by the pseudo-second-order model. In addition, the prepared products not only have a wide application range (pH = 3-9) but also offer eco-safety in terms of residuals (no Ln leak out). Based on the XPS spectra, FTIR spectra and DFT calculations, the main adsorption mechanisms included ligand exchange and electrostatic interactions. This new insight provides a novel strategy to prepare 2D MOF adsorbents, achieving a more eco-friendly method (microwave- and ultrasonic-assisted synthesis) for preparing 2D Ln-based MOF nanosheets by coordinative unsaturation to boost phosphate adsorption.

Integrated ABR and UASB system for dairy wastewater treatment: Engineering design and practice.

This work designed and assessed the engineering performance of dairy wastewater treatment by an integrated system consisting of an anaerobic baffled reactor (ABR) and an upflow anaerobic sludge blanket (UASB). With fats adsorbed and decomposed, proteins were first denatured coagulated into solids in the ABR treatment process, and this process created suitable conditions for sludge retention in the sludge bed of the UASB. As a result, the combined system achieved a substantial reduction in excess sludge from 3 to 5 t/d to 3 t/m, notable biogas generation, and 98% COD removal, while the other pollutants in the effluent met relevant standards. In addition, the system attained an excellent performance in terms of the energy consumption and water treatment agent amount. Two active plants achieved operation costs lower than 0.5 kW h/t, while stable operations under ambient temperature conditions lasted longer than three years. Engineering practices both technically and economically affirmed the potential of the proposed system for dairy wastewater treatment.

A Hydrothermal Synthesis of Fe3O4@C Hybrid Nanoparticle and Magnetic Adsorptive Performance to Remove Heavy Metal Ions in Aqueous Solution.

Advanced core-shelled material with a high specific area has been considered as an effective material to remove heavy metal from aqueous solutions. A core-shelled Fe3O4@C hybrid nanoparticle aggregates with environmental-friendly channel in the study. Moreover, the higher exposure of adsorption sites can be achieved for the special configuration that higher Brunauer-Emmet-Teller (BET) surface area reaches up to 238.18 m2 g-1. Thus, a more efficiently heavy metal ion removal is obtained, Pb (II), Cd (II), Cu (II), and Cr (VI) up to 100, 99.2, 96.6, and 94.8%, respectively. In addition, the products are easy to be separated from the aqueous solutions after adsorption, due to the relative large submicrometer size and the enhanced external magnetic fields introduced by the iron-based cores. We provide an ideal mode to remove heavy metal ions using core-shelled Fe3O4@C under the water treatment condition. A new approach is clarified that core-shell nano/micro-functional materials can be synthesized well on large scales which are used in many fields such as environmental remediation, catalyst, and energy.

Preparation of PPy-Coated MnO2 Hybrid Micromaterials and Their Improved Cyclic Performance as Anode for Lithium-Ion Batteries.

MnO2@PPy core-shell micromaterials are prepared by chemical polymerization of pyrrole on the MnO2 surface. The polypyrrole (PPy) is formed as a homogeneous organic shell on the MnO2 surface. The thickness of PPy shell can be adjusted by the usage of pyrrole. The analysis of SEM, FT-IR, X-ray photoelectron spectroscopy (XPS), thermo-gravimetric analysis (TGA), and XRD are used to confirm the formation of PPy shell. Galvanostatic cell cycling and electrochemical impedance spectroscopy (EIS) are used to evaluate the electrochemical performance as anode for lithium-ion batteries. The results show that after formation of MnO2@PPy core-shell micromaterials, the cyclic performance as anode for lithium-ion batteries is improved. Fifty microliters of PPy-coated caddice-clew-like MnO2 has the best cyclic performances as has 620 mAh g-1 discharge specific capacities after 300 cycles. As a comparison, the discharge specific capacity of bare MnO2 materials falls to below 200 mAh g-1 after 10 cycles. The improved lithium-storage cyclic stability of the MnO2@PPy samples attributes to the core-shell hybrid structure which can buffer the structural expansion and contraction of MnO2 caused by the repeated embedding and disengagement of Li ions and can prevent the pulverization of MnO2. This experiment provides an effective way to mitigate the problem of capacity fading of the transition metal oxide materials as anode materials for (lithium-ion batteries) LIBs.

Effects of Fe(III) on biofilm and its extracellular polymeric substances (EPS) in fixed bed biofilm reactors.

The effects of Fe(III) on the biofilm mass and activity, the biofilm micromorphology as well as the composition and functional groups characteristics of extracellular polymeric substances (EPS) in biofilm were investigated in laboratory-scale fixed bed biofilm reactors. The results showed that 2 mg/L of Fe(III) promoted the biofilm mass and improved the biofilm activity, but 16 mg/L of Fe(III) adversely affected biofilm development. Scanning electron microscopy (SEM) study indicated a high concentration (16 mg/L) of Fe(III) led to significant reduction of the filaments, great promotion of the EPS secretion in biofilm. The result of the EPS composition suggested 2 mg/L of Fe(III) increased soluble EPS and loosely bound EPS which contributed to the microbial aggregation, while 16 mg/L of Fe(III) promoted tightly bound EPS production unfavourable for substrate mass transfer. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis demonstrated that Fe(III) exerted a significant influence on the -CONH- groups of proteins and the C-O groups of polysaccharides in EPS. This study reveals that Fe(III) influences biofilm development and activity not only by directly impacting the microbial physiology but by indirectly affecting the EPS constituents, and it helps to provide theoretical guidance for iron ion containing wastewater treatment.