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•Theory of planned behaviour for waste recycling is built on interview and questionnaire.•Regulatory compliance and Economic incentives determine recycling intention.•Industry ...concerns Regulatory compliance while Public concerns Economic incentives.•Recognition of Accreditation scheme is needed to facilitate closed-loop material flow.
Changing individual’s recycling attitude and behaviour is of utmost importance in achieving sustainable construction and demolition (C&D) waste management, yet it has often been underachieved. To understand the motivations for recycling, this study identifies and prioritizes the key factors that affect C&D waste recycling behaviour of various stakeholders in Hong Kong (i.e., representatives from construction-waste-related organizations, environmental consultants and contractors, and government engineers) in a quantitative manner using statistical tools. Different from traditional C&D waste behavioural determinants studies, this paper utilizes an integrated analytical method through semi-structured interviews and survey questionnaire on the basis of Theory of Planned Behaviour (TPB). Qualitative thematic analysis and quantitative frequency analysis were performed to analyse responses from semi-structured interviews and questionnaires, followed by correlation analysis to quantify the relationships between factors. Results indicated that four key factors: (i) regulatory compliance, (ii) economic incentives, (iii) accreditation scheme, and (iv) logistics and management incentives directly influenced recycling behaviour of individuals. Regulatory compliance was the most determining factor for consultants, contractors, experts, and government officials, whereas economic incentives were of great concern to the public. Under the factor of economic incentives, strong positive relationships were identified between disposal costs and collection and sorting costs, thus increasing waste disposal charging fee may promote recycling behaviour. In comparison, accreditation scheme deserved better recognition to facilitate a closed-loop material flow in the construction industry. These findings help to devise more effective and stakeholder-oriented policy tools to raise awareness and encourage behavioural change towards C&D waste recycling, and assist policy makers to establish regulations and practices for sustainable resource management.
The Annonaceae, the largest family in the early-divergent order Magnoliales, comprises 107 genera and c. 2,400 species. Previous molecular phylogenetic studies targeting different taxa have generated ...large quantities of partially overlapping DNA sequence data for many species, although a large-scale phylogeny based on the maximum number of representatives has never been reconstructed. We use a supermatrix of eight chloroplast markers (rbcL, matK, ndhF, psbA-trnH, trnL-F, atpB-rbcL, trnS-G and ycf1) to reconstruct the most comprehensive tree to date, including 705 species (29%) from 105 genera (98%). This provides novel insights into the relationships of five enigmatic genera (Bocagea, Boutiquea, Cardiopetalum, Duckeanthus and Phoenicanthus). Fifteen main clades are retrieved in subfamilies Annonoideae and Malmeoideae collectively, 14 of which correspond with currently recognised tribes. Phoenicanthus cannot be accommodated in any existing tribe, however: it is retrieved as sister to a clade comprising the tribes Dendrokingstonieae, Monocarpieae and Miliuseae, and we therefore validate a new tribe, Phoenicantheae. Our results provide strong support for many previously recognised groups, but also indicate non-monophyly of several genera (Desmopsis, Friesodielsia, Klarobelia, Oxandra, Piptostigma and Stenanona). The relationships of these non-monophyletic genera-and two other genera (Froesiodendron and Melodorum) not yet sampled-are discussed, with recommendations for future research.
Aim: African-Asian disjunctions are common in palaeotropical taxa, and are typically explained by reference to three competing hypotheses: (1) 'rafting' on the Indian tectonic plate, enabling ...Africa-to-Asia dispersal; (2) migration via Eocene boreotropical forests; and (3) transoceanic long-distance dispersal. These hypotheses are tested using Uvaria (Annonaceae), which is distributed in tropical regions of Africa, Asia and Australasia. Recent phylogenetic reconstructions of the genus show a clear correlation with geographical provenance, indicating a probable origin in Africa and subsequent dispersal to Asia and then Australasia.Ancestral areas and migration routes are inferred and compared with estimates of divergence times in order to distinguish between the prevailing dispersal hypotheses. Location: Palaeotropics. Methods: Divergence times in Uvaria are estimated by analysing the sequences of four DNA regions (matK, psbA-trnH spacer, rbcL and trnL-F) from 59 Uvaria species and 11 outgroup species, using a Bayesian uncorrelated lognormal (UCLD) relaxed molecular clock. The ancestral area of Uvaria and subsequent dispersal routes are inferred using statistical dispersal-vicariance analysis (S-DIVA). Results: Uvaria is estimated to have originated in continental Africa 31.6 Ma 95% highest posterior density (HPD): 38.4-25.1 Ma between the Middle Eocene and Late Oligocene. Two main migration events during the Miocene are identified: dispersal into Madagascar around 17.0 Ma (95% HPD: 22.3-12.3 Ma); and dispersal into Asia between 21.4 Ma (95% HPD: 26.7-16.7 Ma) and 16.1 Ma (95% HPD: 20.1-12.1 Ma). Main conclusions: Uvaria fruits are widely reported to be consumed by primates, and are therefore unlikely candidates for successful long-distance transoceanic dispersal. The other biogeographical hypotheses, involving rafting on the Indian tectonic plate, and dispersal via the European boreotropical forests associated with the Eocene thermal maximum, can be discounted due to incongruence with the divergence time estimates. An alternative scenario is suggested, involving dispersal across Arabia and central Asia via the tropical forests that developed during the late Middle Miocene thermal maximum (17-15 Ma), associated with the ' out-of-Africa' dispersal of primates. The probable route and mechanism of overland dispersal between Africa and Asia for tropical plant groups during the Miocene climatic optimum are clarified based on the Uvaria data.
To close the carbon loop of biomass waste valorization, it is imperative to utilize the unavoidable by-products such as humins, a carbonaceous residue with complex and heterogeneous composition. In ...this study, starch-rich rice waste was effectively converted into value-added chemicals (e.g., 5-hydroxymethylfurfural) under microwave heating at 160 °C using AlCl3 as the catalyst. The solid by-products, i.e., humins, were then valorized as a raw material for fabricating biochar-supported Lewis acid catalysts. The humins were collected and pretreated by AlCl3 as the impregnation agent, followed by carbonization. Detailed characterization revealed several AlO species on the biochar surface plausibly in the amorphous state. The oxygen-containing functional groups of humins might serve as anchoring sites for the Al species during impregnation. The humins-derived biochars exhibited good catalytic activity toward glucose-to-fructose isomerization, a common biorefinery reaction catalyzed by Lewis acids. A fructose yield of up to 14 Cmol% could be achieved under microwave heating at 160 °C for 20 min in water as the greenest solvent. Such catalytic performance was comparable with the previously reported Al-based catalysts derived from wood waste and graphene/graphitic oxide. This study herein highlights humins as a low-cost alternative source of carbon for the preparation of renewable solid catalysts, proposing a novel practice for recycling by-products from food waste valorization to foster circular economy and sustainable development.
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•Valorization of rice waste for HMF production gave humins as a by-product.•Humins-derived biochar catalysts were fabricated via Al impregnation and carbonization.•Biochar catalysts presented AlO species for catalytic glucose-fructose isomerization.•Value-added recycling of humins facilitates a closed carbon loop in biorefineries.
The detection of silica-rich dust particles, as an indication for ongoing hydrothermal activity, and the presence of water and organic molecules in the plume of Enceladus, have made Saturn's icy moon ...a hot spot in the search for potential extraterrestrial life. Methanogenic archaea are among the organisms that could potentially thrive under the predicted conditions on Enceladus, considering that both molecular hydrogen (H
) and methane (CH
) have been detected in the plume. Here we show that a methanogenic archaeon, Methanothermococcus okinawensis, can produce CH
under physicochemical conditions extrapolated for Enceladus. Up to 72% carbon dioxide to CH
conversion is reached at 50 bar in the presence of potential inhibitors. Furthermore, kinetic and thermodynamic computations of low-temperature serpentinization indicate that there may be sufficient H
gas production to serve as a substrate for CH
production on Enceladus. We conclude that some of the CH
detected in the plume of Enceladus might, in principle, be produced by methanogens.
Cushing's disease requires accurate diagnosis, careful treatment selection, and long-term management to optimise patient outcomes. The Pituitary Society convened a consensus workshop comprising more ...than 50 academic researchers and clinical experts to discuss the application of recent evidence to clinical practice. In advance of the virtual meeting, data from 2015 to present about screening and diagnosis; surgery, medical, and radiation therapy; and disease-related and treatment-related complications of Cushing's disease summarised in recorded lectures were reviewed by all participants. During the meeting, concise summaries of the recorded lectures were presented, followed by small group breakout discussions. Consensus opinions from each group were collated into a draft document, which was reviewed and approved by all participants. Recommendations regarding use of laboratory tests, imaging, and treatment options are presented, along with algorithms for diagnosis of Cushing's syndrome and management of Cushing's disease. Topics considered most important to address in future research are also identified.
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•Green co-solvent systems enhanced cellulose depolymerization and product yield.•Maximum 32% of levulinic acid (LA) yielded in GVL/H2O solvent at 200 °C.•GVL/H2O system maintained ...high availability of soluble sugars.•Acetone/H2O solvent generated 17 Cmol% of LA at a lower temperature (180 °C)•Higher temperature induced polymerization of sugars in acetone/H2O solvent.
Lignocellulosic wastes constitute a significant portion of the municipal solid waste, which should be valorised for the synthesis of value-added chemicals to achieve circular bioeconomy. This study evaluates the use of γ-valerolactone (GVL) and acetone as green co-solvents to produce levulinic acid (LA) from lignocellulosic paper towel waste at different temperatures using dilute H2SO4. At the highest reaction temperature (200 °C), H2O-only system achieved ~15 Cmol% of LA at maximum. while GVL/H2O and acetone/H2O co-solvent systems enhanced the depolymerisation of paper towel waste and the subsequent conversion to LA, with the highest yield amounted to ~32 Cmol%. Acetone/H2O solvent system generated ~17 Cmol% LA at a lower temperature (180 °C), while higher temperature induced polymerisation of soluble sugars and intermediates, hindering further conversion to LA. In contrast, the availability of soluble sugars was higher in the GVL/H2O system, which favoured the production of LA at higher temperatures.
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•Brønsted acidity was developed via metal hydrolysis and by-product formation.•Lewis acid sites of metal ions catalyzed hydrolysis and dehydration.•Catalytic performance was primarily ...determined by electrochemical properties.•HMF and glucose (∼54–73%) could be yielded from cooked rice and bread crust.
This study aimed to transform food waste into a value-added chemical, hydroxymethylfurfural (HMF), and unravel the tangled effects induced by the metal catalysts on each single step of the successive conversion pathway. The results showed that using cooked rice and bread crust as surrogates of starch-rich food waste, yields of 8.1–9.5% HMF and 44.2–64.8% glucose were achieved over SnCl4 catalyst. Protons released from metal hydrolysis and acidic by-products rendered Brønsted acidity to catalyze fructose dehydration and hydrolysis of glycosidic bond. Lewis acid site of metals could facilitate both fructose dehydration and glucose isomerization via promoting the rate-limiting internal hydride shift, with the catalytic activity determined by its electronegativity, electron configuration, and charge density. Lewis acid site of a higher valence also enhanced hydrolysis of polysaccharide. However, the metals also catalyzed undesirable polymerization possibly by polarizing the carbonyl groups of sugars and derivatives, which should be minimized by process optimization.
Solid wastes containing potentially toxic elements (PTEs) are widely generated around the globe. Critical concerns have been raised over their impacts on human health and the environment, especially ...for the exposure to PTEs during the transfer and disposal of the wastes. It is important to devise highly-efficient and cost-effective treatment technologies for the removal or immobilisation of PTEs in solid wastes. However, there is an inadequate overview of the global flow of PTEs-contaminated solid wastes in terms of geographical distribution patterns, which is vital information for decision making in sustainable waste management. Moreover, in view of the scarcity of resources and the call for a circular economy, there is a pressing need to recover materials (e.g., precious metals and rare earth elements) from waste streams and this is a more sustainable and environmentally friendly practice compared with ore mining. Therefore, this article aims to give a thorough overview to the global flow of PTEs and the recovery of waste materials. This review first summarises PTEs content in various types of solid wastes; then, toxic metal(loid)s, radioactive elements, and rare earth elements are critically reviewed, with respect to their patterns of transport transformation and risks in the changing environment. Different treatments for the management of these contaminated solid wastes are discussed. Based on an improved understanding of the dynamics of metal(loid) fates and a review of existing management options, new scientific insights are provided for future research in the development of high-performance and sustainable treatment technologies for PTEs in solid wastes.
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•Solid waste streams contain metal(loid)s, radioactive elements, and rare earth elements.•Potentially toxic elements in solid wastes threaten the environment.•Current technologies for recovery and treatment of solid wastes are critically reviewed.•Sustainable waste management is necessary for future development.
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