查看更多>>摘要：Pressures on the current plastic waste management infrastructure has made the growth of new sustainable recycling capacities crucial. Pyrolysis is an emerging thermochemical technology that may be utilised at a large scale to aid in reaching the EU 2030 targets for plastic waste. Plastic valorisation via this process could gain increased competitiveness with conventional methods through the use of concepts such as 'Design for Recycling', identifying further marketable applications for pyrolysis end co-products. This paper presents a review on the pyrolysis of the most abundant plastic waste polyolefins, low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP), with a focus on the heavy wax products. A sizeable research gap in its known applications outside of the petrochemical and chemical feedstock industries was identified. Furthermore, its potential use in the hot mix asphalt (HMA) layers of flexible roads as an alternative binder material and aggregate is discussed. A plastic-derived bitumen modifier could be a viable solution to the current limitations associated with plastic bitumen modifiers (PMB), while producing asphalt with enhanced rheological properties and failure resistances. Consequently, future trends in research may include obtaining a full understanding of the capacity for pyrolysis products from waste polyolefins in bitumen modification. The key relationships between pyrolysis process parameters and the subsequent product properties, modification mechanisms and binder performance may also be explored. This application pairing process for pyrolysis products from plastic wastes may also be more extensively adopted in sustainable infrastructure, as well as other industries.
查看更多>>摘要：In this study, a green process consisting of NaOH roasting -water leaching -synergistic acid leaching with only low-concentration and green reagents employed, was developed for simultaneously efficient base metals removal and precious metals enrichment from copper anode slime. Results showed that: (1) phases prepared by the first NaOH roasting under the NaOH/slime ratio of 1.0, roasted at 700 degrees C for 2.0 h, was easier to remove base metals but harder to extraction PMs; (2) 76.39% Pb, 79.29% Sn, 87.72% S and 95.20% As were dissolved by the second water leaching; (3) main base metals including 99.68% Cu, 81.99% Ni and 99.94% Sb were removed by the final synergistic acid leaching under H2SO4 of 2.00 mol/L, tartaric acid of 0.33 mol/L, H2O2 of 0.44 mol/L, the solid-liquid ratio of 25 g/L and 80 C. As a result, 99.98% Ag, 99.50% Au and 91.00% Pd were retained with their contents enriched by 517.08%, 330.77%, and 400.00%, respectively. The calculated negative Gibbs Free Energy Changes indicated that the roasting reactions can proceed spontaneously. Moreover, electric potential-pH analysis of the acid leaching unit suggested that the effective removal of Sb and high retention of Ag was attributed to the complexation of tartaric acid and its interaction with H2O2. In addition, the valuable base metals in the leachates were successfully recovered. Therefore, the process could be a novel green technology for simultaneously efficient base metals removal and precious metals enrichment from copper anode slime.
查看更多>>摘要：This paper presents feasibility and benefits of utilizing off-specification fly ash (OSFA), which would have otherwise been landfilled, in preparing ultra-high-performance concrete (UHPC). Effects of mixture design variables, including OSFA content, water-to-binder ratio, and slag content, on compressive and flexural properties of UHPC were tested. Experimental results showed that UHPC with proper combination of OSFA and slag achieved desired compressive and flexural strengths, as well as low autogenous shrinkage and leachability of heavy metals. The underlying mechanisms of property development were investigated through isothermal calorimetry, thermogravimetric analysis, and X-ray diffraction. Results indicated that use of OSFA retarded hydration reactions, but incorporation of slag effectively suppressed adverse effects of OSFA. Economic and environmental analysis showed that use of OSFA greatly reduced the life-cycle cost, carbon footprint, and embodied energy consumption of UHPC. This study develops a new avenue for valorization of OSFA and development of cost-effective and eco-friendly UHPC.
De Weerdt, LoicDe Jaeger, SimonCompernolle, TineVan Passel, Steven...
9页
查看更多>>摘要：Sustainable management of industrial plastic waste is crucial in the transition to a circular economy. Today, most industrial plastic waste is incinerated, whereas it could be recycled. As a consequence, governments increasingly make use of incineration taxes to improve current waste management practices. This paper presents an econometric panel analysis that studies the effects of an incineration tax on industrial plastic waste in Flanders (Belgium). Not only is this study the first econometric analysis on industrial plastic waste management in which firm heterogeneity is explicitly taken into account by including firm-specific characteristics, but this study also provides policymakers with insights into the effectiveness of an incineration tax to change current waste management practices. Empirical estimates imply that heterogeneous firms generate industrial plastic waste in different ways and that heterogeneous firms reduce their waste generation in different ways after the incineration tax rate increases. The estimates also show that the unique decrease of the incineration tax in 2007, did not change waste management practices. These estimates show that firms do not disinvest or indicate that loss aversion theory, i.e. a preference for avoiding losses over acquiring equivalent gains, might apply to firms that are faced with environmental taxation in a waste management context.
Chacon, LisandraLavoine, NathalieVenditti, Richard A.
11页
查看更多>>摘要：Recent surveys have shown that consumers do not know how to recognize sustainable packaging and are misled by the excessive usage of environmental clues by the packaging industry. A better approach to communicate sustainability is therefore needed to promote purchasing towards sustainable products. This study proposes to redesign recycled paper-based containers so that consumers easily recognize visually large contaminants in the paper influencing the consumer to refer to this product as recycled and perceive it as sustainable. To this end, the appearance of recycled containers from old corrugated containers (OCC) was intentionally altered with the addition of processed mixed office waste (MOW) of distinct average aspect ratio (AR) (length divided by width), namely 52 (macro-scale), 72 (micro-scale), and 163 (nano-scale), to produce recycled paperboards with visually noticeable recycled contents. The addition of MOW with the lowest AR resulted in visible particles on the surface of paperboards, evidencing the presence of recycled materials. The mechanical performance with this material, however, decreased. On the other hand, the addition of MOW with the highest AR improved the mechanical properties of the paperboards similar to the addition of nanocellulose but with less obvious cues of it having recycled content in the product. Thus, the combination of low and high AR contaminants is suggested to strategically engineer sustainable packaging with high performance and clear visual clues of recycled content and positive environmental perception.
查看更多>>摘要：The extensive participation of rural residents in household waste classification is indispensable for sustainable development. In comparison with urban residents, rural residents have a scattered living arrangement and possess little knowledge about environmental protection, which hinders the advancement of household waste classification. This study used the extended theory of planned behavior and structural equation modeling approach to identify the driving factors of rural residents' household waste classification in China. An empirical study including 586 rural residents in 9 villages in Sichuan Province was conducted. Results show that the intention and behavior of rural residents' household waste classification are significantly affected by factors such as publicity and education, attitudes, subjective norms, past behavior, and sense of belonging. The results are in line with the findings of existing literature. Notably, publicity and education are critical influencing factors. They not only directly affect the domestic waste classification intention and behavior of rural residents but also exert indirect influence via attitudes, subjective norms, and past behaviors. Moreover, the sense of belonging of villagers has a positive intermediary effect on transforming attitude to intention, past behavior to intention, and publicity and education to behavior. Residents with a lower sense of belonging are more easily affected by the classification behavior of people around them, whereas those with a higher sense of belonging directly transform received publicity and education to behavior. Therefore, strengthening publicity and education on waste classification and enhancing residents' sense of belonging are paths forward to promote household waste classification in China's rural areas. The results of this study are also referable for rural household waste management in other countries.
NSTL
Elsevier