Aminolytic Depolymerisation of Polyethylene Terephthalate Wastes using Sn doped ZnO Nanoparticles

Poly(ethylene terephthalate) (PET) is one of the most consumed polymers because of its excellent thermal and mechanical properties. By increasing in PET production and since the disposal of PET waste has growing to be a major global environmental issue each year. Chemical recycling is a most successful method to achieve circular economy in the PET utilizing industries. Current research work aims to complete depolymerization of waste PET from soft drink bottles by the aminolysis method to produce bis (2-hydroxy ethylene) terephthalamide (BHETA) in the presence of Sn doped ZnO. To evaluate catalytic activity, pure and Sn2+ doped ZnO nanoparticles prepared using different Sn2+ molar ratios at 0.5, 1.0 and 2.0 mol% and calcined at 500 0C for 1h. The synthesized catalysts characterised using FT-IR, XRD, and UV-vis spectroscopy. The surface morphology and percentage doping obtained from SEM and SEM-EDS, respectively. We have observed a reduction in optical band gap and crystallite size of ZnO due to tin doping. Aminolytic depolymerization of PET waste using ethanolamine promoted by Sn doped ZnO effectively under conventional thermal method. Increase in the yield of the BHETA observed with respect to increasing doping percentage of Sn and 1-2 mol% Sn doped ZnO nanoparticles afforded over 90% of BHETA. Structure and purity of BHETA, depolymerised product characterized by FT-IR, 1HNMR, 13C NMR, and MS.

Developing the Debris Incinerator Vessel as a New Solution for Managing Marine Debris in Small Islands of Indonesia

Marine debris has been considered a global environmental issue, yet its impacts on each country are varied. Indonesia as an archipelagic country comprises thousands of islands and vast marine territory. The marine debris has threatened many sectors, such as marine endangered species protection, coastal ecosystem, and human livelihood (e.g., sea transportation, tourism, fisheries). The government of Indonesia has implemented various efforts to address this marine debris issue, which include applying recent methods and prototypes from global partners. Based on these approaches, we learn that there are three key success factors to clean marine debris in a very large area of Indonesia, i.e.: good understanding of marine debris dispersion in Indonesian water, sufficient budget, and good coordination among stakeholders. Hence, the Marine Research Centre developed a prototype vessel design in 2021 to manage marine debris, particularly surround small islands, which in Indonesia is called “Kapal Insinerator Sampah” or Debris Incinerator Vessel (DIV). This vessel will focus on managing the waste generated by local inhabitants and marine debris stranded on small islands.

Investigating the toxicity of tropical reservoir sediments using the Allium test

Water pollution is a global environmental issue, and aquatic sediments are important compartments that might act as sinks or sources of contaminants. Once in the environment, inorganic contaminants such as metals can cause cytogenotoxic effects that damage genetic material and harm the aquatic community. Biological assays such as the Allium test can be used to investigate potential cytogenotoxicity of contaminated sediments based on the alterations of cell cycle indexes and chromosomal aberration frequencies. Therefore, we aimed to assess the toxicity of sediments from four Brazilian reservoirs using the Allium test. Sediments were sampled and elutriates were prepared in a simulating sediment resuspension in the water column. The Allium test was applied to the elutriates, and the metals copper, chromium, cadmium, lead, zinc, and iron were quantified. The elutriates derived from reservoir sediments were able to reduce the mitotic and anaphase index, increase the prophase and metaphase index, and boost chromosomal aberrations compared to the negative control. The cytogenotoxic effects observed may be linked to the presence of copper, zinc, and iron. Therefore, our results showed that the Allium test was a sensitive tool for warning the occurrence of genotoxic contaminants in sediment elutriates from four Brazilian reservoirs.

Evaluating Marine Debris Trends and the Potential of Incineration in the Context of the COVID-19 Pandemic in Southern Bali, Indonesia

Highlight Research:The potential calorific value of marine debris obtained from calculating the total waste is 12.05 MJ/kg, which still falls within the incinerator application's standard criteria. AbstractMarine debris, a global environmental issue today, is a major threat to Bali’s seas which are famous for its natural beauty and aggravated by the spread of COVID-19 pandemic. This study aimed to determine the characteristics of marine debris in Bali Island, especially in the southern region and to analyze the feasibility of incineration as one of the waste treatment processes. This research was conducted by utilizing secondary data and literature reviews from related previous studies. Water content and caloric value were measured directly using the ASTM E 790-15 and ASTM D 5865-11a standards. Marine debris generation from 2013 to 2019 tends to decrease from 1.22 kg/km.day to 0.46 kg/km.day. Organic waste (59.4%) comprised the largest marine debris followed by plastic waste (13.4%) and diapers (11.9%). Thermal technology such as incineration can be introduced to treat marine debris. The standard application of incinerator technology is moisture content and caloric value. The water content of marine debris is reportedly 54.56%, therefore, further preliminary processing is needed, especially for waste with high moisture content, such as diapers and organic waste. The potential calorific value of marine debris during the COVID-19 pandemic obtained from calculating the total waste was 12.05 MJ/kg which still did not meet the incinerator application's standard criteria.

Life cycle assessment on automotive bumper: Scenario analysis based on End-of-Life vehicle recycling system in Japan

In the last three decades, the increased use of plastics is rapidly becoming a global environmental issue, resulting in growing landfills, pollution of surrounding atmosphere, and possible greenhouse effect. The automotive industry, as a major demander of plastic materials, is starting to take responsibility on sustainable actions. Japan, as the world’s top tier car manufacturing and dealing country, has been taking attempts to the proper dealings of used auto-plastic. This research aims to find out current situation of auto-plastic recycling industry after these attempts. Furthermore, this research compares pros and cons of each treatment and methods under treatment environmentally as well as economically from the point of recycling operators using life cycle assessment. Bumper is chosen as the target to represent auto-plastic because of their homogeneity of composition and relatively large share of weight among all auto-plastic parts. The result shows that material recycling amount is decreasing along with recent promotion demonstration. Top reason is that material recycling even reduces carbon emissions, costs far more than energy recovery, and that subsidy is given to energy recovery but not material recycling worsens the situation. Besides that, lack of cooperation between stakeholders on the demand of secondary plastic is impeding material recycling. Also, better scheme on how to separate auto-plastic and what kind would be separated should be noticed by the policymaker.

Environmental Issue in the Caucasus Mountains: Prospects for Solving the Issue

The modern stage in the development of civilization is characterized by the growth of contradictions between society and nature. In this regard, the study, the assessment, and the protection of biological and current landscape diversity have become a serious global environmental issue. The search for solutions is not merely an item of theoretical significance, but also great practical importance. This is not only a matter of the increasing pressure on various components of the anthropogenic environment and even on an entire ecosystem. At the same time, particularly regarding reform, there has been a clear shortage of theoretical and experimental studies of ecological systems at the regional and local levels. The Caucasus is noted for its high biodiversity and is among 200 priority regions. The North Caucasus is an integral part of the whole Caucasus, and currently is one of Russia’s most densely populated and developed regions. The region is facing a serious problem of developing a set of measures to maintain biological diversity, preserve biological resources, as well as optimize environmental management. Contemporary international studies (for example, the Johannesburg Memorandum, 2002) do not provide adequate tools for achieving the ideals of sustainable development, especially from a regional perspective. Classical ecology makes it possible to identify and formulate problems that threaten biodiversity. However, realistic and constructive proposals for their implementation have not yet been developed. The purpose of the study is to assess the current state of the ecosystems of the Caucasus Mountains for the development of ecological networks as the basis for the conservation of biological diversity.

The Impact of Public Deliberation on Climate Change Opinions Among U.S. Citizens

Governance of climate change has become a major global environmental issue in the 21st century, and in the absence of wider citizen engagement poses risks of global proportions. Much of the current climate governance debate, unfortunately, is limited to scientists, politicians, and interest groups. With few exceptions, everyday citizens are spectators at best, their views, if not absent, are dismally represented in policy processes. To close the widening gap between citizens and policymakers, thereby increasing the sense of ownership of environmental policies by ordinary people, several methods of citizen engagement for global environmental governance have emerged. The effectiveness of these methods, however, relies upon the ability of citizens to deliberate meaningfully, especially in issues such as climate change. We conducted a study in conjunction with World Wide Views on Climate and Energy, a global citizen consultation that aims to solicit carefully considered public views on pressing issues, to determine whether American citizens are receptive to deliberation, and to ascertain what effect it had on their opinions, if any, could be observed. Along with the descriptive analysis, we performed a non-parametric Wilcoxon signed-rank test of selected pre-and post-event opinions of the participants from the US. Our study revealed that providing US citizens with the opportunity to engage in deliberation resulted in increased awareness regarding climate change and greater trust in science, technology, and international agreements. The change in opinion was more pronounced among people whose political orientation titled to the right or who considered themselves as neutral. Citizen’s opinions, especially after the event, resulted in less polarized views towards the global consensus on climate change. This finding suggests that US citizens are receptive to scientific information if it is communicated in an appropriate manner – a characteristic necessary for the creation of deliberative democratic governance on socially contested issues.

Micro and Nanoplastics Identification: Classic Methods and Innovative Detection Techniques

Micro and nanoplastics are fragments with dimensions less than a millimeter invading all terrestrial and marine environments. They have become a major global environmental issue in recent decades and, indeed, recent scientific studies have highlighted the presence of these fragments all over the world even in environments that were thought to be unspoiled. Analysis of micro/nanoplastics in isolated samples from abiotic and biotic environmental matrices has become increasingly common. Hence, the need to find valid techniques to identify these micro and nano-sized particles. In this review, we discuss the current and potential identification methods used in microplastic analyses along with their advantages and limitations. We discuss the most suitable techniques currently available, from physical to chemical ones, as well as the challenges to enhance the existing methods and develop new ones. Microscopical techniques (i.e., dissect, polarized, fluorescence, scanning electron, and atomic force microscopy) are one of the most used identification methods for micro/nanoplastics, but they have the limitation to produce incomplete results in analyses of small particles. At present, the combination with chemical analysis (i.e., spectroscopy) overcome this limit together with recently introduced alternative approaches. For example, holographic imaging in microscope configuration images microplastics directly in unfiltered water, thus discriminating microplastics from diatoms and differentiates different sizes, shapes, and plastic types. The development of new analytical instruments coupled with each other or with conventional and innovative microscopy could solve the current problems in the identification of micro/nanoplastics.

Graphene-Based Photo-Fenton Catalysts for Pollutant Control

Water pollution is a global environmental issue with multi-dimensional influences on human life. Some strategies, such as photo-Fenton reaction, have been employed to remove recalcitrant pollutants. Two-dimensional (2D) graphene and its three-dimensional (3D) configurations have attracted considerable attention as emerging carbon-based catalysts in photo-Fenton fields owing to their alluring properties in electron transfer, reactant adsorption, and light response. This review summarizes the recent developments in 2D and 3D graphene-based catalysts for photo-Fenton reactions. Their structures, characteristics, activity, and mechanisms are discussed. The conclusions and outlooks are proposed for the profound understanding of challenges and future directions.

The effect of microplastics on the growth of Paralichthys Olivaceus

In recent years, microplastics (MPs) pollution have become a global environmental issue, which aroused concern about their potential toxicity to marine organisms. However, due to the gradual depletion of natural resources, it had been rapidly developed in aquaculture. Therefore, this article studied the effect of polystyrene (PE) on the growth of Paralichthys Olivaceus. The surface of PE was rough and average size was 197.3 ± 11.2 μm. The contact angle of PE was 100.3 ± 2.5 °, which indicated that PE had a hydrophobic surface. PE exposure had no significant effect on the body length growth of fish, but compared with CK treatment, the weight growth of fish in PE treatment group was slower, which increased by 36.3% on the 28th day, but only increased by 10.9% in PE treatment group, indicating that PE could inhibit the growth of fish. PE led to the decrease of oxygen consumption rate of fish. On the 7th, 21st and 28th day, the oxygen consumption rate of fish decreased by 7.9%, 25.4% and 41.1%, respectively. Based on the above results, we concluded that marine MPs could inhibit the growth of the benthic economic fish, which would disturb the balance of the marine ecosystem.