Energy resource scarcity and sediment pollution perniciousness have become enormous challenges, to which research has been focused on energy recovery and recycle technologies to solve both above problems. The organic matter stored in anoxic sediments of freshwater ecosystem represents a tremendous potential energy source. The system of aquatic plant coupled with sediment microbial fuel cell (AP-SMFC) has attracted much attention as a more feasible, economical and eco-friendly way to remediate sediment and surface water and generate electricity. However, the research on AP-SMFC has only been carried out in the last decade, and relevant studies have not been well summarized. In this review, the advances and prospects on AP-SMFC were systematically introduced. Firstly, the annual publication counts and keywords co-occurrence cluster of AP-SMFC were identified and visualized by resorting to the CiteSpace software, and the result showed that the research on AP-SMFC increased significantly in the last decade on the whole and will continue to increase. The bibliometric results provided valuable references and information on potential research directions for future studies. And then, the research progress and reaction mechanism of AP-SMFC were systematically described. Thirdly, the performance of AP-SMFC, including nutrients removal, organic contaminants removal, and electricity generation, was systematically summarized. AP-SMFC can enhance the removal of pollutants and electricity generation compared with SMFC without AP, and is considered to be an ideal technology for pollutants removal and resource recovery. Finally, the current challenges and future perspectives were summarized and prospected. Therefore, the review could serve as a guide for the new entrants to the field and further development of AP-SMFC application.

Operational energy use and energy-based GHG emissions of air-conditioning in the building sector are increasing aggressively due to occupants’ higher thermal and visual comfort aspirations. Window glazing is the critical building component that affects the thermal performance of the conditioned space. The existing glazing in the buildings allows huge heat gain/loss, leading to additional energy requirements for HVAC systems. Novel laminated glasses with various solar control film interlayers were studied in this article to improve the thermal performance of the conditioned space. Solar-optical properties and thermal indices of proposed laminated glasses were explored to study the potential energy savings and carbon emission mitigations. Thermal loads and energy savings were calculated with the help of a validated mathematical model across three distinct Indian climates (hot, cold, and composite). Substantial reductions in heat gain/loss and energy requirements were found with laminated glasses compared to monolithic clear glass. The laminated glass with reflective solar control film glazing (LGRF) had concluded a cost saving of 100.84 $/year with a payback period of 1.7 years for cold climate in S-E orientation. CO₂ emission mitigation of building with laminated glasses was calculated for the energies conserved with carbon emission factors. The LGRF had reported a carbon emission mitigation of 2.1 tCO₂/year for cold climates and comparable results for hot and composite climates. Daylight performance was carried out with the DesignBuilder simulation tool to assess the daylight accession in building interiors with laminated glasses. The laminated glasses were able to reduce annual energy requirements without greatly affecting the daylight inflow.

Significant hydropower projects have resulted in fragmentation of the rivers and alteration of flow regimes with consequent adverse effects on the river’s ecosystems. To conserve aquatic ecosystems, the minimal desired river flow regime—environmental flows—is advised to maintain in the river system. While maintaining environmental flows, it is equally important to carry out the impact of environmental flows over the hydro-energy generation capacity of hydropower projects. In the present study, the energy generation reduction of provisioning environmental flows has been assessed for five major hydro electric projects on Rivers Bhagirathi and Alaknanda, the two significant head-streams of India’s national river Ganga, located in the Himalayan uplands. The E-Flows assessment done by Tare et al., (2017) is used in the present study, which rationally integrates the ecological and geo-morphological needs of the river. Tare et al., (2017) recommended monthly E-Flows for the upper Ganga basin from ~ 23 to ~ 40% and ~ 29 to ~ 53% of natural flows for the wet and lean periods, respectively. They assessed E-Flows using flow data of the Bhagirathi and Alaknanda rivers for 1972–1982 and 1977–1987, respectively. The annual average reduction in potential energy production due to E-Flows provision in the Alaknanda-Bhagirathi basin is found in between 14.9 and 21.0% for these hydro electric projects. The estimated reduction in energy generation is higher in the lean flow period than in the wet period. This study shows that about 79 to 85% of capacity power generation is possible in the basin after provisioning E-Flows.

Recently, exploring the driving factors behind carbon emission (CE) change in China has achieved increasing attention. As the determinants of CEs are likely to be affected by both spatial and temporal heterogeneities, we propose an extended production-theoretical decomposition analysis (PDA) approach based on global meta-frontier data envelopment analysis (DEA) to resolve heterogeneity problem. Then, by combing the extended PDA and index decomposition analysis (IDA) approaches, CE changes are decomposed into nine factors. And using panel data from China’s 30 provinces during 2005–2015, the main results provide findings as follows. (1) The national total CEs are continuous increasing from 2005 to 2012, and then remain stable in 2012–2015. (2) Potential energy intensity and carbon emission temporal heterogeneity result in reduction of CEs. (3) Economic activity is the dominant driving factor for increasing the CEs, while temporal catch-up effect of carbon emission helps decrease the CEs in almost all provinces.

The international community has generally recognized the key role of developing countries’ cities in reducing carbon emissions, an elemental way to mitigate climate change. However, few have empirically analyzed the impact of market-based instruments such as emission trading system on urban carbon emissions in developing economies. This paper examines the effect of China’s pilot carbon trading markets, the first emission trading system in developing economies, on cities’ carbon intensity. We also explore the mechanism by which the emission trading system achieves its influence. The PSM-DID method is used to analyze the panel data including China’s 273 prefecture-level cities from 2010 to 2016. The results illustrate that the emission trading system significantly decreased pilot cities’ carbon intensity and this effect endured; as time progressed, the reduction effect was increasing. Through mediating effect analysis, we find that the emission trading system reduced the carbon intensity via increasing the proportion of tertiary industry output value in GDP and decreasing the energy intensity. Overall, the empirical results suggest that the Chinese government should drive the establishment and improvement of a national carbon market, proactively adjust industry structure, and consider the possible influence caused by the potential energy rebound effect.

Many studies have shown that the rapid agricultural mechanization development in China led to substantial energy consumption and CO₂ emission growth. To better explain the mechanism behind the decoupling between economic growth and CO₂ emissions, this paper extends the logarithmic mean Divisia index (LMDI) and production-theoretical decomposition (PDA) considering agricultural decoupling from both structural and technical perspectives. The results reveal that (1) China’s agricultural decoupling performance was not ideal. Investment and investment efficiency were the most important factors influencing the decoupling status. The main decoupling obstacle was a higher investment in productivity rather than in energy conservation and carbon reduction. (2) The decoupling status and investment orientation of decoupling efforts among regions were different. Strong negative decoupling statuses frequently occurred in the eastern region, whose main disadvantage was high potential energy intensity. The decoupling status of the central region exhibited expansive features. The decoupling key is to invest more in energy-saving technology rather than in production. The western region changed from weak decoupling to expansive negative decoupling. Both output technology and energy-related factors should be the main investment targets. (3) Weak decoupling and expansive negative decoupling were the most common statuses among provinces. The influence mechanism of drivers exhibited a high spatial heterogeneity at the provincial level. Therefore, the study offered a convincing basis for local governments to formulate low-carbon agricultural development policies by identifying the main decoupling drivers.

The singlet and triplet potential energy surfaces of the HO₂ with CF₂ClO₂ reaction have been probed at the BMC-CCSD/cc-pVTZ level according to the B3LYP/6-311++G(d,p) level obtained geometrical structure. On the singlet PES, the association/dissociation, direct H- abstraction, and SN2 displacement mechanisms have been taken into account. On the triplet PES, SN2 displacement and indirect H- abstraction reaction mechanisms have been investigated and the H- abstraction channel makes more contribution to the CF₂ClO₂ with HO₂ reaction. The rate constants have been computed at 10⁻¹⁰ to 10¹⁰ atm and 200–3000 K by RRKM-TST theory. The results show that at T ≤ 600 K, the generation of IM1 (CF₂ClO₄H) by collisional deactivation is dominant pathway; at high temperatures, the production of P8 (CF₂ClOOH + O₂(³Σ)) becomes predominate. The predicted data for CF₂ClO₂ + HO₂ agrees closely with available experimental value. Moreover, OH radicals act as inhibitors in the CF₂ClOOH→CF₂O + HOCl and CF₂ClOOH→CFClO + HOF reactions. The dominant products for the reaction of CF₂ClOOH + OH are CF₂ClO₂ + H₂O.

Chlorine atoms initiated oxidation reactions are significant for the removal of typical volatile organic compounds (VOCs) in the atmosphere. The intrinsic mechanisms of CH₂=CHCOOH + Cl reaction have been carried out at the CCSD(T)/cc-pVTZ//M06-2X/6-311++G(d,p) level. There are hydrogen abstraction and C-addition pathways on potential energy surfaces. By analyses, the addition intermediates of IM1(ClCH₂CHCOOH) and IM2(CH₂CHClCOOH) are found to be dominant. The secondary reactions of IM1 and IM2 have been discussed in the presence of O₃, O₂, NO, and NO₂. And we have also investigated the degradation mechanisms of ClCH₂CHO₂COOH with NO, NO₂, and self-reaction. Moreover, the atmospheric kinetics has been calculated by the variable reaction coordinate transition–state theory (VRC-TST). As a result, the rate constants show negative temperature and positive pressure dependence. The atmospheric lifetime and global warming potentials of acrylic acid have been calculated. Overall, the current study elucidates a new mechanism for the atmospheric reaction of chlorine atoms with acrylic acid.

To understand the atmospheric chemistry of hydrofluoroethers, we have studied the oxidation of a highly fluorinated compound n-C₂F₅CF(OCH₃)CF(CF₃)₂ (HFE-7300) by OH/Cl oxidants. Here, we have employed M06-2X functional along with a 6-31 + G(d,p) basis set to obtain the optimized structures, various forms of energies, and different modes of frequencies for all species. We have characterized energies of all species on the potential energy surface, and it indicates that H-abstraction from n-C₂F₅CF(OCH₃)CF(CF₃)₂ by Cl atom is kinetically more dominant than the H-abstraction reaction initiated by OH radical. In contrast, the calculated energy change (ΔᵣH°₂₉₈ and ΔᵣG°₂₉₈) results govern that OH-initiated H-abstraction reaction is highly exothermic and spontaneous compared to the Cl-initiated H-abstraction reaction. Rate constants are estimated using transition state theory as well as canonical variation transition state theory at the temperature range 200–1000 K and 1 atm pressure. The calculated rate constants of the H-abstraction channels are found to be in good agreement with the reported experimental rate constant at 298 K. Moreover, we have estimated the atmospheric lifetimes of HFE-7300 for the reaction with OH radical and Cl atom and are found to be 1.75 and 153.93 years, respectively. Additionally, the global warming potentials for HFE-7300 molecule are also estimated for 20-, 100-, and 500-year time horizons. Further, subsequent aerial oxidation of product radical (n-C₂F₅CF(OCH₂)CF(CF₃)₂) in the presence of NO radical is performed, and it produced alkoxy radical via formation of peroxy radical. This alkoxy radical undergoes unimolecular decompositions via two different ways and formed n-C₂F₅CF(OCHO)CF(CF₃)₂ and n-C₂F₅CF(OH) CF(CF₃)₂ products.

A global and systematic theoretical research on the singlet and triplet potential energy surfaces (PESs) of the CH₂ClO₂/CHCl₂O₂ with ClO reactions are done at the CCSD(T)//B3LYP level and accompanied with RRKM computations to forecast the mechanism and distribution of products. The simulation results revealed that, on the singlet PES, products P1 (CHClO + HO₂ + Cl)/P1 (CCl₂O + HO₂ + Cl) from IM1 (CH₂ClOOOCl)/IM1 (CHCl₂OOOCl) are forecasted to the primary products of the CH₂ClO₂/CHCl₂O₂ + ClO reactions, which are initiated by the oxygen atom of ClO radical addition to the terminal-O atom of CH₂ClO₂/CHCl₂O₂ barrierlessly, while other product channels contribute less to the whole reactions owing to higher barriers. Two other isomers, including IM2 (CH₂ClOOClO) and IM3 (CH₂ClOClO₂) for the CH₂ClO₂ + ClO reaction, and three other isomers, including IM2 (CHCl₂OOClO), IM3 (CHCl₂OClO₂), and IM4 (CHCl₂ClO₃) for the CHCl₂O₂ + ClO reaction, could be produced as less significant products. RRKM calculations presented that the initial adducts IM1 (CH₂ClOOOCl)/IM1 (CHCl₂OOOCl) are the primary products at T < 400 K and T < 600 K, respectively, and products P1 (CHClO + HO₂ + Cl)/P1 (CCl₂O + HO₂ + Cl) are dominant the reactions at T ≥ 400 K and T ≥ 600 K, respectively. The atmospheric lifetime of CH₂ClO₂ and CHCl₂O₂ in ClO is around 4.61 and 3.24 h, respectively.