In this study, Mn-C composites using different MnO2 contents and solid carbon material were prepared to explore the synchronous removal performance of nutrients and SMX. Higher nitrate removal performance (97-98 %) with quickest nitrate removal rate (4.97 mg N L -1h- 1) was obtained in Mn\_20 systems. The increased Mn content and Mn-P compound were observed via surface characteristics, indicating the involvement of MnOx in pollutants removal, particularly for higher phosphorus removal (84-89 %) via Mn-P precipitation and BioMnOx adsorption. Nevertheless, compared to systems based on Mn\_0 composites (74 %), systems with Mn-C composites presented lower SMX reduction efficiency (34-51 %), which might be attributed to the large Mn(II) accumulation, impairing certain microbes and lower the MnOx function. Higher abundance of genera affiliated to Bacter-oidetes\_vadinHA17 and Rhodocyclaceae was observed in the Mn-C composites, as well as the gathering of Geo-bacter and Desulfovibrio as keystone taxa, responsible for the removal of nitrate and SMX and microbial interactions. Besides, the increase of sulfonamide ARGs was closely related to the predominant microbes in the Mn-C composites, which acted as the hosts of ARGs. This study broadens the knowledge of Mn-C composites in synergetic removal of nutrients and organics, and supports the potential application of manganese oxide in wastewater treatment.
The urban infrastructures of municipal solid waste (MSW) disposal play important roles in carbon reduction and building sustainable cities. China, with the world's largest MSW generation, has witnessed a relatively slow and spatially uneven transition progress of MSW disposal management. This study analysed the MSW disposal management transition and its determinants in Chinese cities of different sizes. Furthermore, the carbon reduction potential of MSW disposal management transition was estimated under different settings of policy reform. The results indicate that the MSW disposal management transition has made faster progress in cities with larger sizes, which could be ascribed to larger contradiction between city development and public service. The prediction results suggest that 73.13%–287.28% of carbon emission could be reduced by various policy reforms compared with the baseline scenario without policy intervention. Moreover, technological transformation should be specially underlined in mega cities, and household sorting should be specially underlined in medium cities.
Balancing clean water and economic growth remains challenge to achieve the Sustainable Development Goals (SDGs) issued by the United Nations. In this study, the water quality impacts and cost-effectiveness analysis of catchment actions were integrated by a new proposed watershed management framework (WAM-SDGs). The source appointment and control practices were incorporated based on physical-based model and heuristic al gorithm. The tradeoffs between different targets were balanced using multiple attribute decision-making (MADM) and Pareto score approaches. The method was tested in two paired catchments including typical urban and agricultural catchments in China. The results indicated that 1) the cost-effectiveness and reliability of catchment action was improved by 4% and 3.3% compare to traditional methods. 2) The restriction of urban pollution is mainly attributable to strong spatial heterogeneity, while that of agricultural pollution control is attributed to lack of investment. 3) For water quality improvement, sources and sinks of pollutants are quantified and used as priority areas for catchment action. Due to high pollution intensity and control reliability, urban catchments should be given priority and agricultural catchments are more cost-effectiveness when fund is no longer a limiting factor. The economic-based and water-quality-based protection strategies are suggested for urban and agricultural catchment, respectively. This new framework could be extended to other catchments for global sustainable development.
In this work, we propose a novel framework for density forecast combination by constructing time-varying weights based on time-varying features. Our framework estimates weights in the forecast combination via Bayesian log predictive scores, in which the optimal forecast combination is determined by time series features from historical information. In particular, we use an automatic Bayesian variable selection method to identify the importance of different features. To this end, our approach has better interpretability compared to other black-box forecasting combination schemes. We apply our framework to stock market data and M3 competition data. Based on our structure, a simple maximum-a-posteriori scheme outperforms benchmark methods, and Bayesian variable selection can further enhance the accuracy for both point forecasts and density forecasts.
As novel photocatalysts, covalent organic frameworks (COFs) have potential for water purification. Insufficient exciton dissociation and low charge mobility in COFs yet restricted their photocatalytic activity. Excitonic dissociation and charge transfer in COFs could be optimized via regulating the donor–acceptor (D–A) interactions through adjusting the number of donor units within COFs, yet relevant research is lacking. By integrating the 1,2,4-triazole or bis-1,2,4-triazole unit with quinone, we fabricated COF-DT (with a single donor unit) and COF-DBT (with double donor units) via a facile sonochemical method and used to decontaminate emerging contaminants. Due to the stronger D–A interactions than COF-DT, the exciton binding energy was lower for COF-DBT, facilitating the intermolecular charge transfer process. The degradation kinetics of tetracycline (model contaminant) by COF-DBT (k = (12.21 ± 1.29) × 10–2 min–1) was higher than that by COF-DT (k = (5.11 ± 0.59) × 10–2 min–1) under visible-light irradiation. COF-DBT could efficiently photodegrade tetracycline under complex water chemistry conditions and four real water samples. Moreover, six other emerging contaminants, both Gram-negative and Gram-positive strains, could also be effectively eliminated by COF-DBT. High tetracycline degradation performance achieved in a continuous-flow system and in five reused cycles in both laboratory and outdoor experiments with sunlight irradiation showed the stability and the potential for the practical application of COF-DBT.
With the developing technologies of artificial intelligence and the Internet of Things, intelligent IoT (iIoT) is prevailing currently. Design and implementation of integrated IoT nodes with continuous perception capability are indispensable to realize various smart terminal devices, which would also be vital to reduce the power consumption, improve the real-time performance, and enhance the security/privacy of the IoT system. In this paper, we present the architecture of “Sensing with Computing” and its chip design for smart sensing applications, which would support multi-modal perception signal processing with multi-dimension extension ability. Specially, we explore the analog/mixed-signal circuit designs and algorithm-hardware co-design methodologies for perception signal processing, and we also study the multi-modal integration of novel sensors and their interface technologies. Additionally, some multi-modal smart sensing systems with “Sensing + Computing in Memory” mixed-signal chips would be fabricated, which would support typical always-on smart sensing tasks.
After the Kigali Amendment (KA) came into effect, HCFC-22 plants are obliged to limit HFC-23 emissions. Therefore, the study of cost-effective mitigation pathways for HFC-23 is important for the sustainable implementation of KA in China and other HCFC-22 producing countries. This study constructed an inventory of HFC-23 by-production, emissions, and abatement for HCFC-22 plants in China from 2006 to 2020, and predicted the costs and climate benefits of HFC-23 abatement in China's compliance with the KA between 2021 and 2060. Results showed that HFC-23 emissions from HCFC-22 plants in China contributed about 60% of the growth in global atmospheric mole fraction of HFC-23 observed by Advanced Global Atmospheric Gases Experiment (AGAGE) from 2007 to 2020. Furthermore, China's cumulative HFC-23 abatement was about 109 kt (1613 Mt CO2-eq) from 2006 to 2019, accounting for 53% of total by-production, which allowed the global atmospheric mole fraction and radiative forcing of HFC-23 in 2020 to avoid an uplift of 9.2 × 10−9 and 1.7 mW m−2, respectively, contributing to climate change mitigation. Under the baseline of the Kigali Amendment, less emission (LE), and resource utilization (RU) scenarios, the cumulative HFC-23 abatement from 2021 to 2060 would be 683 ± 29 kt (10107 ± 431 Mt CO2-eq), 694 ± 29 kt (10277 ± 427 Mt CO2-eq), and 702 ± 29 kt (10385 ± 426 Mt CO2-eq), respectively. The cumulative net abatement costs for the KA, LE, and RU scenarios would be 5.0 ± 0.2, 2.9 ± 0.2, and −2.7 ± 0.2 billion CNY (2021 prices), respectively. In the future, applying resource utilization technology to reduce HFC-23 emissions can achieve both climate and economic benefits.
Halogenated pharmaceuticals exhibit high toxicity if released to natural environment, and dehalogenation is a key process for their degradation. In this study, a reductive and directional dehalogenation technique, heterogenous formic acid (HCOOH) catalytic activation system, was proposed for diclofenac (DCF) dechlorination and detoxification. A functional material of Pd nanocluster decorated graphitic carbon nitride (Pd/g-C3N4) was developed for HCOOH activation. Although the optimized material (Pd1/g-C3N4) showed lower HCOOH decomposition rate (k1 = 0.287 ± 0.017 min−1) than the pristine Pd particles (k1 = 0.401 ± 0.031 min−1), it processed higher DCF degradation efficiency (97.9% within 30 min) than Pd particles. The enhancement mechanism was revealed by both experiments and theoretical calculations. Firstly, the six-fold cavities of g-C3N4 acted as anchor sites, which offered strong coordination environment for Pd nanoclusters. Secondly, the strong coordination environment of Pd led to upshifted d-band center of Pd 4d with enhanced bonding state, and then promoted HCOOH adsorption on Pd/g-C3N4, thus facilitating HCOOH decomposition through formate pathway rather than carboxyl pathway. Thirdly, Pd/g-C3N4 ensured HCOOH selectively decomposed as dehydrogenation reaction, which generated more H* (adsorbed H on Pd) than the dehydration reaction. The H* was proved to be the dominant reductive species for DCF hydrodechlorination. Moreover, the toxicities of DCF dechlorination products were greatly reduced.
