Hemp-based adsorbents for sequestration of metals: a review

Environmental Chemistry Letters - With the increasing focus on renewable materials and sustainability issues, the development of non-conventional materials from natural resources and possessing...     

Polylactic acid synthesis,biodegradability, conversion to microplastics and toxicity: a review

Global pollution by plastics derived from petroleum has fostered the development of carbon–neutral, biodegradable bioplastics synthesized from renewable resources such as modern biomass, yet knowledge on the impact of bioplastics on ecosystems is limited. Here we review the polylactic acid plastic with focus on synthesis, biodegradability tuning, environmental conversion to microplastics, and impact on microbes, algae, phytoplankton, zooplankton, annelids, mollusk and fish. Polylactic acid is a low weight semi-crystalline bioplastic used in agriculture, medicine, packaging and textile. Polylactic acid is one of the most widely used biopolymers, accounting for 33% of all bioplastics produced in 2021. Although biodegradable in vivo, polylactic acid is not completely degradable under natural environmental conditions, notably under aquatic conditions. Polylactic acid disintegrates into microplastics faster than petroleum-based plastics and may pose severe threats to the exposed biota.

     

Economic growth,international trade,and the depletion or conservation of renewable natural resources

Conservation of renewable natural resources and promotion of economic growth are both sustainable development goals. Here, we study the interdependency between economic growth, international trade, and the use of renewable natural resources—under alternative institutional settings of either open access or full property rights—in an endogenous growth model. We find that if the resource is depleted over time, consumption growth is reduced. Economic growth and international trade only impact resource use when the resource is harvested under full property rights. Then, widening international trade can lead countries to shift from conservation to depletion. Changes in the institutional setting of resource use in one country may have repercussions on trading partners. Our results indicate potential trade-offs between the sustainable development goals and imply that policies focusing on resource use or trade (e.g., international trade bans or certified trade) are not sufficient to prevent resource depletion.     

An overview of the impacts of changes in common property resources management in the context of globalisation: A case study of India

Socio-economic development of mankind and well-being depend on the environment and the way in which development influences the environment. Thus, environment and development are interdependent. In fact, economic development is closely linked with the development of resources. These resources can be classified into three categories: public goods, semi-public goods (also known as common property resources) and private goods. In poor countries common property resources make a valuable contribution to the sustainable livelihoods of rural populations. The impact of globalisation on the commons shows various patterns of ownership, control, use and misuse. The commons were subjected to degradation as well as conservation in the process of centralized management in India. After the reform period, the administration of natural resources was given significant attention by specialized departments such as the Forest Department and the Revenue Department. All the land, apart from private land, was regarded as state property and controlled by the state. This paper highlights the need to examine the common property resources sector in the context of wider economic policy reform processes in the Indian economy.     

Substitution between biofuels and fossil fuels: Is there a green paradox?

We show that (i) subsidies for renewable energy policies with the intention of encouraging substitution away from fossil fuels may accentuate climate change damages by hastening fossil fuel extraction, and that (ii) the opposite result holds under some specified conditions. We focus on the case of subsidies for renewable resources produced under increasing marginal costs, and assume that both the renewable resources and the fossil fuels are currently in use. Such subsidies have a direct effect and an indirect effect working in opposite directions. The direct effect is the reduction in demand for fossil fuels at any given price. The indirect effect is the reduction in the current equilibrium price for fossil fuels, which tends to increase the amount of fossil fuels demanded. Whether the sum of the two effects will actually result in an earlier or later date of exhaustion of the stock of fossil fuels depends on the curvature of the demand curve for energy and of the supply curve for the renewable substitute.     

Substitution between biofuels and fossil fuels: Is there a green paradox?

We show that (i) subsidies for renewable energy policies with the intention of encouraging substitution away from fossil fuels may accentuate climate change damages by hastening fossil fuel extraction, and that (ii) the opposite result holds under some specified conditions. We focus on the case of subsidies for renewable resources produced under increasing marginal costs, and assume that both the renewable resources and the fossil fuels are currently in use. Such subsidies have a direct effect and an indirect effect working in opposite directions. The direct effect is the reduction in demand for fossil fuels at any given price. The indirect effect is the reduction in the current equilibrium price for fossil fuels, which tends to increase the amount of fossil fuels demanded. Whether the sum of the two effects will actually result in an earlier or later date of exhaustion of the stock of fossil fuels depends on the curvature of the demand curve for energy and of the supply curve for the renewable substitute.     

Models of withdrawing renewable and non-renewable resources based on Odum's energy systems theory and Daly's quasi-sustainability principle

This paper presents a theoretical model of withdrawing resources based on Odum's energy systems diagrams. According to the theory of a general pulsing principle, withdrawing resources changes in time shifting from the initial phases of growth and maturity to the phases of descent and low energy restoration. A simulation was performed in order to hypothesize potential future trends of withdrawing renewable and non-renewable resources and to show some aspects of their sustainability–unsustainability, respectively. According to Odum's theory, after the rapid growth of the last century, our civilization is living in a climax transition phase and it is now approaching a descent phase. A “way down” will be necessary due to the exhaustion of non-renewable and to the limited use of renewable resources. An integrated “renew–non-renew” model was developed by Odum to show how a “business as usual” trend will bring us to a drastic transition to a world that uses scarce renewable resources. Nevertheless, a different choice is possible, based on Daly's concept of quasi-sustainability that can inspire a new model. The latter argued that the exploitation of a non-renewable resource must be paired with a compensating investment in a renewable substitute. Our model shows that we can use non-renewable resources better to considerably improve our capacity of capturing renewable resources in the future. We present this as a necessary condition to address a sustainable environmental policy.     

Durable goods and long-run electricity demand: Evidence from air conditioner purchase behavior

I estimate a dynamic structural model of demand for air conditioners, the most energy-intensive home appliance in the US. The model explores the links between demand for durable goods and expected changes in key attributes: energy efficiency and price. I incorporate expectations explicitly as a feature of the choice setting, and use parameter estimates from the model to calculate durable good demand elasticities with respect to energy efficiency, electricity price, and price of the durable itself. These estimates fill a large gap in the literature, and also shed light on consumer behavior in this setting. Results indicate that consumers are forward-looking and value the stream of future savings derived from energy efficiency.     

Life cycle assessment and sustainable engineering in the context of near net shape grown components: striving towards a sustainable way of future production

Technical product harvesting (TEPHA) is a newly developing interdisciplinary approach in which bio-based production is investigated from a technical and ecological perspective. Society‘s demand for ecologically produced and sustainably operable goods is a key driver for the substitution of conventional materials like metals or plastics through bio-based alternatives. Technical product harvesting of near net shape grown components describes the use of suitable biomass for the production of technical products through influencing the natural shape of plants during their growth period. The use of natural materials may show positive effects on the amount of non-renewable resource consumption. This also increases the product recyclability at the end of its life cycle. Furthermore, through the near net shape growth of biomass, production steps can be reduced. As a consequence such approaches may save energy and the needed resources like crude oil, coal or gas. The derived near net shape grown components are not only considered beneficial from an environmental point of view. They can also have mechanical advantages through an intrinsic topology optimization in contrast to common natural materials, which are influenced in their shape after harvesting. In order to prove these benefits a comprehensive, interdisciplinary scientific strategy is needed. Here, both mechanical investigations and life cycle assessment as a method of environmental evaluation are used.     

Renewable energy,non-renewable energy and sustainable development

The purpose of the present study is to analyse the effects of renewable energy and non-renewable energy on sustainable development. This study is pioneering in this respect because it analyses the effect of renewable energy on adjusted net savings, which is a good sustainable development variable. For this purpose, the data of 40 developed and 73 developing countries were included. According to the estimation results obtained in the study, renewable energy has a positive and statistically significant effect on sustainable development both in developed countries and in developing countries. The impact of renewable energy on sustainable development is greater than the impact of non-renewable energy. In this respect, as the renewable energy amount increases, the level of sustainable development increases. According to these results, the fact that countries use renewable energy more than non-renewable energy sources is extremely important in terms of making progress towards sustainability of development and the 2030 Sustainable Development Goals.     

Quality and Congestion in Environmental Goods: The Road to the Wangapeka

An increasing complaint heard among New Zealand residents is that their enjoyment of local environmental resources is being diminished by increased congestion from foreign visitors. This paper considers a model of vertical differentiation in which foreign high-value and domestic low-value consumers incur congestion costs in using a common resource. We demonstrate that reducing quality in the face of increased foreign demand is optimal absent discriminatory prices (but not otherwise). We also consider the provision of multiple environmental goods and demonstrate that providing differential qualities may be optimal even if domestic consumers do not use the high-quality resources at all.     

Versuchsanlage zur energetischen Beurteilung von Substraten und Kofermentaten für Biogasanlagen

Goal, Scope and Background

Worldwide energy requirements are constantly increasing. Rising prices and the necessity to secure the future energy supply have led the decision-makers in politics and economy to focus on the more intensive use of their own resources. Before the background of possible climatic effects caused by the use of fossil energies, the use of renewable resources as primary energies, with its narrow C-circulation, have gained in importance, particularly in terms of economic aspects. The production of biogas is of specific interest here. It is a sensible ecological investment and a solid source of income for our agriculture.

Material and Methods

The operator uses a complex biological system in a plant with high investment costs. An economic operation is only possible if the process parameters are optimized and the properties of the substrates and the co-ferments are known. For the important determination of the blogas potential, we present an efficient and robust system, which is easy to handle and low cost, that has been developed by the LHL and LLH at the Eichhof. This procedure enables one to make statements on the implementation dynamics and is also suited to judge the fermentation process depending on the size of particles, as the co-ferments are used in a practice-oriented consistency.

Results

With the described fermentation apparatus you can not only assess the potential development of biogas and methane, but also the process of fermentation. The sum-graphs determined allow one to make conclusions on the implementation dynamics and, thus, on the optimization of the process. The advanced equipment makes it possible to determine the process of fermentation and the gas yield under different retention times and digester loads. The determination of the potential of the biogas and also the evaluation of the continuous fermentation are related to a specific correction factor won from the standard.

Discussion

A prerequisite for economic process management is the knowledge of the attainable gas yield and the fermentation process of substrates and co-ferments. A precise calibration is the quality basis for the results achieved with this method, as is the case with other fermentation tests as well. For the tests, a highly homogeneous substrate, which guarantees a continuous biological activity in the digesters, ought to be used. The possibility of determining optimum retention times and digester loads with this equipment makes costly tests with a full scale reactor unnecessary.

Conclusions

All tests run demonstrated that the fermentation apparatus originally developed to determine the biogas yield is absolutely suited to also assess the impact of different digester loads and retention times.

Recommendations

The problem of the suitability and the potential of different materials, the optimum reactor performance and the combination of different processes of energy generation from renewable but also conventional resources will increaseingly become the focus of laboratory tests. The following subjects have to be taken into account:

- Testing different materials on their suitability

- Evaluation security of common and new co-ferments

- Guidelines for mixtures to optimize reactor performance

- Mixtures of different substrates and co-ferments available to a particular operator (also with the help of simulation models)

- Processing changing quantity proportions of plants won from a rotation of crops altered for energy generation

- Other parameters like pre-fermentation, particle size and fer mentation supplements.

Perspective

These tests with a high practical relevance are supposed to contribute to a reliable method of producing biogas, in order to optimize the yield of gas production, but also to find a calibration of less costly procedures like those involving Near Infrared Spectroscopy (NIRS).     

废弃塑料包装物的管理及资源、环境评价

由于塑料包装材料具有明显的资源优势,而获得广泛应用。但塑料材料的原料——石油,目前面临枯竭窘境。同时,塑料包装废弃物的处理存在巨大的环境压力。焚烧包括塑料包装废弃物在内的生活垃圾,用于发电,是日本曾经采取的方法。近年来,因存在难以逾越的生态环境问题,而逐渐废止。工业生态学的材料流的循环利用模式,是解决资源耗尽、废物充斥的理想方法。源头分离是城市固体废弃物资源化的前提条件。按塑料品种分类回收,以材料形式重复利用,保留了塑料的材料价值,还需要解决,再加工过程造成材料力学性能下降的问题。将单一品种塑料转化成单体,不同塑料品种的单体转化率有很大差距,缩合聚合物较高,而PP、PE等则不然。混合塑料的热裂解可获得化工原料和燃料,又达到减少垃圾总量和石油资源循环利用的效果,具有开发潜力。填埋方式占用土地又人为阻碍了有机垃圾回归生物圈。控制性堆肥对避免大量使用化肥、农药造成的生态环境灾难,再建农业生产的可持续性模式,发挥重要作用。生物降解塑料袋对堆肥的实施,具有特殊价值。PET和E-CO在食品包装某些应用领域有优势,而PVC食品包装物的使用和废弃后再利用都存在问题。     

Coalition formation in fisheries with potential regime shift

A system can undergo rapid regime shift in which the growth of natural resources suddenly and permanently declines. We examine how the threat of such a shift alters the strategic management of a common pool renewable resource. We consider exogenous and endogenous threats and examine their effects on both incentives to join a coalition and harvest decisions. We find that an exogenous threat of reduced resource growth may cause the coalition to grow in size, and, perhaps of most interest, we identify conditions under which members of the stable coalition reduce harvest while non-members increase harvest in response to the threat. In contrast, an exogenous threat of total stock collapse may destabilize coalitions, resulting in higher harvest from former members, but reduced harvest by non-members. When the threat of either type of shift is endogenous, the threat of regime shift can induce stable coalitions with more than two members. In particular, we identify cases in which the first best (full cooperation) is sustained as an equilibrium outcome. Finally, we find that the relation between the magnitude of the shift and the size of stable coalitions may be negative.     

Nexus between polymer support and metal oxide nanoparticles in hybrid nanosorbent materials (HNMs) for sorption/desorption of target ligands

Metal oxide nanoparticles like hydrated ferric oxide (HFO) or hydrated zirconium oxide (HZrO) are excellent sorbents for environmentally significant ligands like phosphate, arsenic, or fluoride, present at trace concentrations. Since the sorption capacity is surface dependent for HFO and HZrO, nanoscale sizes offer significant enhancement in performance. However, due to their miniscule sizes, low attrition resistance, and poor durability they are unable to be used in typical plug-flow column setups. Meanwhile ion exchange resins, which have no specific affinity toward anionic ligands, are durable and chemically stable. By impregnating metal oxide nanoparticles inside a polymer support, with or without functional groups, a hybrid nanosorbent material (HNM) can be prepared. A HNM is durable, mechanically strong, and chemically stable. The functional groups of the polymeric support will affect the overall removal efficiency of the ligands exerted by the Donnan Membrane Effect. For example, the removal of arsenic by HFO or the removal of fluoride by HZrO is enhanced by using anion exchange resins. The HNM can be precisely tuned to remove one type of contaminant over another type. Also, the physical morphology of the support material, spherical bead versus ion exchange fiber, has a significant effect on kinetics of sorption and desorption. HNMs also possess dual sorption sites and are capable of removing multiple contaminants, namely, arsenate and perchlorate, concurrently.     

华北平原集约农区种植业生态经济系统的能值分析——以河北沧州为例

从能值的角度出发,以华北平原代表区域——河北省沧州地区2003年统计数据和调查数据为基础,对该地区种植业生态经济系统的能值投入和产出进行首次分析。结果显示:该地区不可更新的工业辅助能占总能值投入的78.5%,可更新的能值投入仅占21.4%(可更新环境资源8.79%、可更新有机12.68%),说明农业生产过渡依赖于外源不可更新辅助能的投入;此外,高系统太阳能值转换率、低净能值产出率和高环境负荷率的特点,表明该地区种植业的科技发展水平比较高,对环境的压力相当大。综合结果说明种植业系统对环境资源的过度利用必然会引起生态环境的破坏。基于此,提出华北平原集约农区种植业生态经济系统可持续发展对策:以优化施肥为基础,合理减少化肥投入为代表,适当降低工业辅助能投入;调整农业增产投入战略,努力解决该地区以水资源短缺为主的作物增产限制因子;改变农业生产中有机能值与无机能值的投入比例,降低系统环境负荷率。     

When is increasing consumption of common property optimal? Sorting,congestion and entry in the commons

First-best pricing or assignment of property rights for rival and non-excludable goods is often infeasible. In a setting where the social planner cannot limit total use, we show that common-property resources can be over or under-consumed. This depends on whether the external benefits of reallocating users to less congested resources outweigh the additional costs imposed by new entrants. Importantly, we show that it may be optimal to encourage consumption of some common property resources. Our results have important implications for settings ranging from fisheries and forestry to recreational demand and transportation.     

A comparison of the water management systems in France and China

This paper compares legal systems for water management in France and China, with a focus on integrated water resources management and regarding in particular the formulation of policies and their implementation. The research shows that China has committed itself to the efficient management of water resources through the development of various policy tools during the current period. This commitment, however, has often been interrupted and distorted by politics, resulting in the neglect of socioeconomic and environmental priorities. France has developed a legislative framework and practical instruments to apply integrated water resources management at the river basin level since the 1960s. This experience and the current implementation of the European Water Framework Directive brings elements that can contribute to Chinese society meeting its water challenges.     

小城镇复合生态系统能值整合研究

运用能值理论和方法,以湖北省小城镇(大悟县)为案例,对其复合生态系统进行研究,以了解系统的能流结构和特点,为系统持续发展提供科学指导。研究结果表明,该系统能值自给率68.42%,对外界依赖性低,经济安全性高;但人均能值用量和能值密度较低,系统经济不发达。不可更新资源占能值总用量63.51%,属于资源消耗型的经济模式,环境压力较大,不利于区域可持续发展,今后应增加可更新资源的利用,提高不可更新资源的利用效率,增加科技投入,促进该区域可持续发展。     

Environmental aspects of biofuels in road transportation

Energy is a vital and growing need for human activities such as transport, agriculture and industry. The transport and agriculture sectors are major consumers of fossil fuel. However, availability of fossil fuels is limited. The use of fossil fuels is of increasing environmental concerns because it produces toxic airborne particulates and greenhouse gases such as CO₂. The increasing industrialization and motorization of the world led to a steep rise for the demand of petroleum-based fuels. Hence, it is necessary to seek alternative fuels, which can be produced from resources available locally within the country such as alcohol, biodiesel and vegetable oils. Biodiesel is defined as the mono alkyl esters of vegetable oils or animal fats. Biodiesel is the best candidate for diesel fuels in the diesel engines. The advantage of biodiesel over gasoline and petroleum/diesel is its eco-friendly nature. This article reviews the production, characterization and current status of biofuels mainly biodiesel along with the environmental impacts of particulate matter, greenhouse gas emissions originated from biodiesel.