Municipal solid waste (MSW) management is a globally recognized environmental issue. The concepts of sustainability and the circular economy have progressed MSW management system from basic disposal ...to recycling and resource recovery. Life cycle assessment (LCA) is the technique that has been widely used to analyse MSW management system. However, the reliability of results is deeply influenced by the methodology, quality of data, and robustness of the analyses. This raises two questions: how to improve the quality of LCA work, and how to select the appropriate MSW management strategy for practice? To answer these questions, we have conducted a critical review of 79 scientific studies from 36 low-to-high income countries. The review examines the scientific community's application of LCA to MSW management and identifies the best practices to follow for a good-quality study. Then after categorically assessing the results of the studies, a ranking of appropriate MSW management scenarios is made. Results reveal that the objective of an LCA study is subjective but a decisive factor that defines the procedure of subsequent steps. Differences are found among the practitioners, especially in study boundaries, selection of impact categories, choice of input data and analysis methods. Sensitivity analysis is critical for producing reliable results but was not performed in around 38% of the studies. Our analysis also reveals that the integration of recycling, treatment and disposal technologies is the most appropriate strategy. The choice of technologies and their performance, however, depends on the technological and socio-economic background of the studied region.
Display omitted
•Critical review on LCA of MSW management from low to high-income countries•Indications for best practices in LCA application and MSW management are established.•Selection of study boundaries and impact categories define the depth of an LCA study.•Input data quality with sensitivity and uncertainty analyses increase the reliability of results.•IWMS with resource recovery methods is the most sustainable waste management strategy.
The low structural stability of hydrogen‐bonded organic frameworks (HOFs) is a thorny issue retarding the development of HOFs. A rational design approach is now proposed for construction of a stable ...HOF. The resultant HOF (PFC‐1) exhibits high surface area of 2122 m2 g−1 and excellent chemical stability (intact in concentrated HCl for at least 117 days). A new method of acid‐assisted crystalline redemption is used to readily cure the thermal damage to PFC‐1. With periodic integration of photoactive pyrene in the robust framework, PFC‐1 can efficiently encapsulate Doxorubicin (Doxo) for synergistic chemo‐photodynamic therapy, showing comparable therapeutic efficacy with the commercial Doxo yet considerably lower cytotoxicity. This work demonstrates the notorious stability issue of HOFs can be properly addressed through rational design, paving a way to develop robust HOFs and offering promising application perspectives.
An ultra‐robust hydrogen‐bonded organic framework with high BET surface area and acid‐assisted crystalline recovery was developed through several rational design strategies. With periodic integration of photoactive pyrene in the framework, this material can efficiently encapsulate the drug doxorubicin for synergistic chemo‐photodynamic therapy, showing low cytotoxicity and prominent therapeutic efficacy.
When the number of projections does not satisfy the Shannon/Nyquist sampling requirement, streaking artifacts are inevitable in x-ray computed tomography (CT) images reconstructed using filtered ...backprojection algorithms. In this letter, the spatial-temporal correlations in dynamic CT imaging have been exploited to sparsify dynamic CT image sequences and the newly proposed compressed sensing (CS) reconstruction method is applied to reconstruct the target image sequences. A prior image reconstructed from the union of interleaved dynamical data sets is utilized to constrain the CS image reconstruction for the individual time frames. This method is referred to as prior image constrained compressed sensing (PICCS). In vivo experimental animal studies were conducted to validate the PICCS algorithm, and the results indicate that PICCS enables accurate reconstruction of dynamic CT images using about 20 view angles, which corresponds to an undersampling factor of 32. This undersampling factor implies a potential radiation dose reduction by a factor of 32 in myocardial CT perfusion imaging.
Extracellular polymeric substances (EPS) of aerobic (AerAOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) are expected to have a significant impact on the performance of autotrophic nitrogen ...removal in engineered systems. However, there are a few investigations of the EPS of AerAOB and AnAOB, and the results are contradictory. In this study, photometric measurements indicated that the EPS of AerAOB- (31.74 ± 1.48 mg/g-VSS, volatile suspended solids) and AnAOB-enriched cultures (30.12 ± 1.52 mg/g-VSS) contained more polysaccharides than did conventional activated sludge from a municipal wastewater treatment facility (10.76 ± 0.83 mg/g-VSS). In addition, the EPS of the AnAOB-enriched culture was dominated by proteins, leading to a considerably higher protein/polysaccharide ratio (2.64 ± 0.12) than those of the AerAOB-enriched culture (0.56 ± 0.03) and conventional activated sludge (1.96 ± 0.09). Characterization using Fourier transform infrared spectroscopy (FTIR) revealed the dominance of amide bands and/or polysaccharide-associated bands in the EPS of AnAOB and AerAOB. These results corroborate the data from the photometric measurements. In addition, the EPS of AnAOB (23.1% ± 1.2%) and AerAOB (21.9% ± 1.1%) had a higher portion of α-helices, which is the key protein secondary structure that determines flocculation or cell aggregation, in the amide I band than that of activated sludge (16.7% ± 0.8%). X-ray photoelectron spectroscopy (XPS) characterization also revealed significantly different functionalities among the EPS of the three mixed cultures; e.g., O-(C,H), which indicates the presence of polysaccharides, was richer in the EPS of AerAOB, whereas protonated amines, which are commonly found in amino acids and amino sugars, accounted for a large portion of the EPS of AnAOB. The results of this study can potentially expand our knowledge of the microbial aggregates responsible for autotrophic nitrogen removal.
Display omitted
•EPS extracted from AerAOB- and AnAOB-enriched culture was studied.•AerAOB- and AnAOB- contained more polysaccharides than conventional sludge.•EPS of AnAOB-enriched culture was dominated by proteins.•α-Helix was an important protein secondary structure of EPS of AnAOB and AerAOB.•Different functionality among the EPS of the three cultures was found.
Microscale cell carriers have recently garnered enormous interest in repairing tissue defects by avoiding substantial open surgeries using implants for tissue regeneration. In this study, the highly ...open porous microspheres (HOPMs) are fabricated using a microfluidic technique for harboring proliferating skeletal myoblasts and evaluating their feasibility toward cell delivery application in situ. These biocompatible HOPMs with particle sizes of 280–370 µm possess open pores of 10–80 µm and interconnected paths. Such structure of the HOPMs conveniently provide a favorable microenvironment, where the cells are closely arranged in elongated shapes with the deposited extracellular matrix, facilitating cell adhesion and proliferation, as well as augmented myogenic differentiation. Furthermore, in vivo results in mice confirm improved cell retention and vascularization, as well as partial myoblast differentiation. These modular cell‐laden microcarriers potentially allow for in situ tissue construction after minimally invasive delivery providing a convenient means for regeneration medicine.
Highly open porous microspheres (HOPMs) are conveniently designed using a microfluidic setup and evaluated for their feasibility toward minimally invasive cell delivery‐based tissue regeneration. These biocompatible HOPMs with interconnected paths facilitate a high cell proliferation rate, and partial differentiation of skeletal myoblasts. These modular cells‐laden microcarriers provide a convenient means for in situ repair of tissue defects and applications in regenerative medicine.
The slow rate of extracellular electron transfer (EET) of electroactive microorganisms remains a primary bottleneck that restricts the practical applications of bioelectrochemical systems. ...Intracellular NAD(H/
) (i.e., the total level of NADH and NAD
) is a crucial source of the intracellular electron pool from which intracellular electrons are transferred to extracellular electron acceptors via EET pathways. However, how the total level of intracellular NAD(H/
) impacts the EET rate in Shewanella oneidensis has not been established. Here, we use a modular synthetic biology strategy to redirect metabolic flux towards NAD
biosynthesis via three modules: de novo, salvage, and universal biosynthesis modules in S. oneidensis MR-1. The results demonstrate that an increase in intracellular NAD(H/
) results in the transfer of more electrons from the increased oxidation of the electron donor to the EET pathways of S. oneidensis, thereby enhancing intracellular electron flux and the EET rate.
Despite their advantageous morphological attributes and attractive physicochemical properties, mesoporous silica nanoparticles (MSNs) are merely supported as carriers or vectors for a reason. ...Incorporating various metal species in the confined nanospaces of MSNs (M‐MSNs) significantly enriches their mesoporous architecture and diverse functionalities, bringing exciting potentials to this burgeoning field of research. These incorporated guest species offer enormous benefits to the MSN hosts concerning the reduction of their eventual size and the enhancement of their performance and stability, among other benefits. Substantially, the guest species act through contributing to reduced aggregation, augmented durability, ease of long‐term storage, and reduced toxicity, attributes that are of particular interest in diverse fields of biomedicine. In this review, the first aim is to discuss the current advancements and latest breakthroughs in the fabrication of M‐MSNs, emphasizing the pros and cons, the confinement of various metal species in the nanospaces of MSNs, and various factors influencing the encapsulation of metal species in MSNs. Further, an emphasis on potential applications of M‐MSNs in various fields, including in adsorption, catalysis, photoluminescence, and biomedicine, among others, along with a set of examples is provided. Finally, the advances in M‐MSNs with perspectives are summarized.
Despite their captivating physicochemical properties, mesoporous silica nanoparticles are only supported as carriers. To enrich their performance, various metal species are encapsulated in their nanospaces for diverse functionalities. This review provides an overview highlighting the attractive features of these innovative constructs and a synopsis of the current advancements and latest breakthroughs in their potential catalytic and various biomedical applications.
The electrolyte additive plays an important role in determining the crucial properties of batteries such as cycling stability and safety. Compared to material development, research on electrolyte and ...interphase is still in the early stage for sodium ion batteries (SIBs). Herein, for the first time, succinic anhydride (SA) is investigated as a synergistic filming additive to fluoroethylene carbonate (FEC), and the lifespan of the dual‐additive Na/Na0.6Li0.15Ni0.15Mn0.55Cu0.15O2 (NLNMC) cell is significantly improved, maintaining capacity retention of 87.2% over 400 cycles at 1 C rate. For comparison, the batteries with only one of the two additives or without any additive show much inferior electrochemical performance. After the addition of SA, the interphase layer on the surface of cycled NLNMC material becomes uniform and stable, which contains more oxygen‐rich organic species and less NaF. Additionally, the addition of SA also has an impact on the interphase layer in the sodium anode part as indicated by electrochemical impedance spectroscopy (EIS) and energy dispersive spectrometer (EDS) results. Moreover, the online differential electrochemical mass spectrometry (OEMS) tests show the dual‐additive cell has less CO2 generation during the initial two cycles compared to that with only FECs which demonstrates another advantage of SA for practical application.
For the first time, succinic anhydride (SA) is applied as a synergistic electrolyte additive for fluoroethylene carbonate (FEC) in sodium ion batteries. The coexistence of SA and FEC regulates the interphase layer both on the cathode and anode. Optimized electrochemical performance of Na/Na0.6Li0.15Ni0.15Mn0.55Cu0.15O2 (NLNMC) is achieved in the dual‐additive cell with 87.2% of capacity retention after 400 cycles at a 1 C rate.
Rational design and controllable synthesis of well‐defined nanostructures with high stability and Pt‐like activity for hydrogen evolution reaction (HER) are critical for renewable energy conversion. ...Herein, a unique pyrolysis strategy is demonstrated for the synthesis of RhPx nanoparticles (NPs) in N, P co‐doped thin carbon nanoshells (RhPx@NPC nanoshells) that display high electrocatalytic activity and stability over a wide pH range. This strategy involves simultaneous phosphorization and pyrolysis processes that can produce highly‐dispersed RhPx NPs within N, P co‐doped carbon nanoshells and at the same time induce thinning of carbon nanoshells from inside out. The resulting RhPx@NPC nanoshells not only possess Pt‐like activity for HER with low overpotentials to achieve 10 mA cm−2 (22 mV in 0.5 m H2SO4, 69 mV in 1.0 m KOH, and 38 mV in 1.0 m phosphate buffered saline (PBS)) but also provide long‐term durability in a wide pH range. The remarkable HER performance of RhPx@NPC nanoshells is ascribed to the high surface area, abundant mesoporosity, strong catalyst–support interaction, ultrathin carbon encapsulation, and N, P co‐doping. This work provides an effective strategy for designing heterostructured electrocatalysts with high catalytic activity and stability desired for reactions that may occur under harsh conditions.
A unique pyrolysis strategy is demonstrated for the synthesis of RhPx nanoparticles in N, P co‐doped carbon nanoshells that display high electrocatalytic activity and stability over a wide pH range. This strategy involves simultaneous phosphorization and pyrolysis processes that can produce highly dispersed RhPx nanoparticles within carbon nanoshells and induce thinning of carbon nanoshells from the inside out.
PDF
