废旧塑料回收利用技术的现状及发展趋势

本文详细综述了从３０年代到现在国内外废旧塑料再生利用技术发展的过程及近几年废塑料回收最新技术,对未来废旧塑料回收利用技术的发展趋势进行了预测     

废旧塑料回收利用的现状及发展趋势

本文详细综述了从３０年代到现在国内外废旧塑料再生利用技术发展的过程及近几年废塑料回收最新技术，对未来肇旧塑料回收利用的发展趋势进行了预测。     

废旧塑料改性再生的研究进展

塑料制品作为一种全球范围内广泛使用的商品,几乎已经渗透到了人类生活中的各个方面。同时,快速累积的废旧塑料对陆地和海洋环境产生了一系列的负面影响。值得注意的是,废旧塑料具有资源和废物双重属性。废旧塑料的回收品质和数量的提高,对于资源的高效利用、可持续发展和环境保护具有重大意义。本文介绍了废旧塑料常用的分选方法,综述了近年来国内外废旧塑料化学改性和物理改性的研究进展,并分析了废旧塑料改性再生所面临的问题。     

解决白色污染的技术研究进展

随着经济的发展，废旧塑料大幅增加，所造成的白色污染已经成为了破坏环境的主要因素之一。白色污染主要是由废旧塑料高分子的不可降解性和添加剂的毒害性引起的。目前，各国都在解决白色污染的技术方面进行了大量的研发投入。文章主要综述了可降解塑料的研发和对废旧塑料回收再利用技术的研发两方面的研究进展。     

一种新型碳电极材料的制备及其电化学性质研究

进入21世纪，汽车也成为了主要的交通工具，随着带来的问题是废旧轮胎的增加，然而到目前为止还没有一种有效的方法回收利用这些废旧轮胎，目前的主要处理方法是将轮胎以垃圾形式进行填埋，然而轮胎是很难分解的，因此带来了严重的环境污染问题。目前我国在废旧轮胎回收上还存在技术比较落后，再生产品单一，同时每年全国仍有大量的废旧轮胎不能得以及时回收处理。到目前为止，还没有关于以轮胎粉制作电极材料的报导。合理利用废旧轮胎制备电极材料，既能有效解决黑色污染，又能制备出价值更大的电极材料，带来良好的经济效益。     

氧化镁对聚丙烯/聚氯乙烯脱氯行为的影响

对废旧塑料的回收利用是近年来人们一直关注和不断研究的一个重要课题。将废塑料热裂解为燃料油或单体被认为是最具前景的处理方法之一[1]。当含有PVC的废旧塑料裂解时产生氯化氢气体,严重腐蚀设备;同时也会产生含氯的有机化合物,从而使其裂解生成的液体作为燃料使用时会生成有     

聚苯乙烯的催化裂解研究

由于塑料性质稳定,难以自然降解,其废弃物不仅严重污染环境,更造成了资源浪费.因此,废旧塑料的再资源化对环境保护和可持续发展有着重要意义.废塑料再资源化回收技术是指将废塑料热裂解或催化裂解、回收燃料油和化工原料的技术~([1,2]).     

低温煤焦油与废旧塑料共熔油化的研究

用自制的反应装置研究了预处理后的低温煤焦油与废旧塑料共熔油化所得到的油品的性质，并分别与低温煤焦油和废旧塑料热裂解油品的性质进行了比较，考察了主要工艺条件对共熔油化过程的转化率和产品性质的影响。结果表明，在适当的添加煤焦油后，从废旧塑料热裂解和催化裂解得到的汽油的质量有所提高，但对柴油的质量影响不大。采用低温煤焦油与废旧塑料共熔油化的工艺不仅为“白色污染”的处理开辟了一条新途径，而且扩大了低温煤焦油的应用     

溶剂对聚氯乙烯-聚乙二醇-KOH体系脱氯行为的影响

废旧塑料的回收利用是当今研究的热点之一.据报道,2007年中国聚氯乙烯(PVC)产量高达960万吨[1],如何合理利用相应产生的废旧PVC是一个十分重要的课题.     

废旧锂离子电池正极材料资源化回收与再生

随着电子设备的普及和电动汽车行业的迅速崛起,作为提供能量来源的锂离子电池发挥着重要的作用。以钴酸锂、磷酸铁锂以及三元正极材料为代表的锂离子电池产销量不断增加;与此同时,为了提供更长的续航时间以及续航稳定性,新型锂离子电池材料的研究工作也在不断推进。在此背景下,锂离子电池正极材料的失效、废弃以及资源化回收再生的过程就显得愈发重要,如何在下游解决报废锂离子电池处理的问题也逐渐提上日程。基于此,本文分别从湿法和火法再生两个角度对废旧锂离子电池正极材料的回收和再生过程进行了介绍,包括回收条件优化的方法、较为新颖的回收再生方法以及再生材料的性能等,并总结了回收再生过程的杂质元素,包括铝、铜等元素对再生材料结构和性能的影响以及工业上常用的回收废旧锂离子电池的方法和环境影响。最后对锂离子电池回收的方法进行总结并进行展望。     

Recent advances and challenges in recycling and reusing biomedical materials

Medical waste has increased in the past 3 years as a result of the coronavirus disease 2019 (COVID-19) pandemic. This condition is expected to exacerbate due to the growing healthcare markets and aging population, posing health threats to the public via environmental footprints. To alleviate these impacts, there is an urgent need for medical waste management. This article highlights the drawbacks of current disposal methods and the potential of medical waste reuse and recycling, emphasizing the processes, materials, and chemistry involved in each practice. Further discussion is provided on the chemical and mechanical recycling of plastics as the dominating material in biomedical applications, and possible strategies and challenges in recycling and reusing biomedical materials are explored in this review.     

Advances and approaches for chemical recycling of plastic waste

The global production and consumption of plastics has increased at an alarming rate over the last few decades. The accumulation of pervasive and persistent waste plastic has concomitantly increased in landfills and the environment. The societal, ecological, and economic problems of plastic waste/pollution demand immediate and decisive action. In 2015, only 9% of plastic waste was successfully recycled in the United States. The major current recycling processes focus on the mechanical recycling of plastic waste; however, even this process is limited by the sorting/pretreatment of plastic waste and degradation of plastics during the process. An alternative to mechanical processes is chemical recycling of plastic waste. Efficient chemical recycling would allow for the production of feedstocks for various uses including fuels and chemical feedstocks to replace petrochemicals. This review focuses on the most recent advances for the chemical recycling of three major polymers found in plastic waste: PET, PE, and PP. Commercial processes for recycling hydrolysable polymers like polyesters or polyamides, polyolefins, or mixed waste streams are also discussed.     

Photocatalysis as an Effective Tool for Upcycling Polymers into Value-Added Molecules

Shaping a sustainable future is closely tied to the development of advanced plastic recycling technologies. As global recycling rates remain low, the lion's share of post-consumer plastics is either incinerated or disposed of in landfills. This unbalanced plastic waste management not only poses severe environmental risks, but also entails an irrevocable loss of chemical resources that are embedded in synthetic polymers. To give plastic waste a new life, a series of photocatalytic methods has recently been reported that convert polymers directly into value-added organic molecules. These approaches operate at ambient temperature, show high reactivity/selectivity, and provide alternative reaction pathways as compared to thermal depolymerizations. This Minireview highlights the scientific breakthroughs in upcycling polymers through state-of-the-art photocatalysis under environmentally benign conditions.     

Recycling of polyethylene terephthalate (PET Or PETE) plastics – An alternative to obtain value added products: A review

Waste management is become one of the world's most pressing issues. Plastic is one of the most widely utilised materials in the modern world. Plastic manufacturing and usage have risen globally in recent decades due to its low weight and outstanding mechanical properties. Plastic has a wide range of applications due to such good properties include lightweight, high strength, and extended durability. Because of plastics are non- or low-biodegradable, a vast quantity of plastic waste is generated every day, making waste disposal the most pressing matter globally. Furthermore, improper waste disposal pollutes the environment. An ecologically friendly approach is necessary to locket these issues. One of the solutions is to recycle this sort of garbage. There are many plastic recycling technologies available, however practically all of them have certain restrictions. Chemical recycling of plastic, on the other hand, has been shown to be more efficient than other recycling methods. This article provides a quick overview of chemical recycling of PET post-consumer waste and the synthesis of potentially value-added products such as dye or dyestuffs, bolaform surfactant, bio-degradable polyesters, drug carrier, Metal-organic framework (MOF), bio-degradable polymeric scaffolds, polyurethane foam and coating materials etc.     

Characterization of odorous contaminants in post‐consumer plastic packaging waste using multidimensional gas chromatographic separation coupled with olfactometric resolution

The increasing world population with their growing consumption of goods escalates the issue of sustainability concepts with increasing demands in recycling technologies. Recovery of post‐consumer packaging waste is a major topic in this respect. However, contamination with odorous constituents currently curtails the production of recycling products that meet the high expectations of both consumers and industry. To guarantee odor‐free recyclates, the main prerequisite is to characterize the molecular composition of the causative odorants in post‐consumer plastic packaging waste. However, targeted characterization of odorous trace contaminants among an abundance of volatiles is a major challenge and requires specialized and high‐resolution analytical approaches. For this aim, post‐consumer packaging waste was characterized by sensory analysis and two‐dimensional high resolution gas chromatography coupled with mass spectrometry and olfactometry. The 33 identified odorants represent various structural classes as well as a great diversity of smell impressions with some of the compounds being identified in plastics for the first time. Substances unraveled within this study provide insights into sources of odorous contamination that will require specific attention in the future in terms of screening and prevention in recycling products.     

Chemical Upcycling of Waste Plastics to High Value-Added Products via Pyrolysis: Current Trends,Future Perspectives,and Techno-Feasibility Analysis

Chemical upcycling of waste plastics into high-value-added products is one of the most effective, cost-efficient, and environmentally beneficial solutions. Many studies have been published over the past few years on the topic of recycling plastics into usable materials through a process called catalytic pyrolysis. There is a significant research gap that must be bridged in order to use catalytic pyrolysis of waste plastics to produce high-value products. This review focuses on the enhanced catalytic pyrolysis of waste plastics to produce jet fuel, diesel oil, lubricants, aromatic compounds, syngas, and other gases. Moreover, the reaction mechanism, a brief and critical comparison of different catalytic pyrolysis studies, as well as the techno-feasibility analysis of waste plastic pyrolysis and the proposed catalytic plastic pyrolysis setup for commercialization is also covered.     

Effects of reprocessing of oxobiodegradable and non-degradable polyethylene on the durability of recycled materials

The use of plastics is steadily increasing in our daily lives, and plastics are the fastest-growing component of the waste stream. Although the efficiency of plastic recycling is increasing, plastics are often seen as a permanent environmental problem because of littering. The introduction of oxobiodegradable polyolefins (OBDs), containing prodegradant additives, is considered to be a way to reduce this problem by enabling the fast degradation of plastics in the environment. The prodegradant additives form radicals that attack the polymer chains, causing chain scissions and generation of low molecular mass oxidation products that can be consumed by microorganisms. There is, however, a concern that the prodegradant additives will present a problem if OBD materials end up in the conventional plastic recycling streams. The present study therefore highlights the impact of mixing OBD materials with conventional polyolefins to evaluate the impact on the remaining service life of the recyclates.The study included the use of two different OBDs, mixed in different proportions (10% and 20%) in a conventional polyethylene. The remaining service life of the mixtures was evaluated by monitoring the reduction in tensile strain after exposure to thermo-oxidative degradation at 70 °C, compared with a pure polyethylene. The impact of stabilizer content in the mixtures was also evaluated together with the effect of mixing partially degraded OBDs into the recyclate.The results show that the incorporation of minor fractions of OBD materials in the existing recycling streams will not create a severe effect on the service life of the recyclates as long as the polymer mixture possesses a reasonable degree of stabilization.     

Converting Waste Plastic to Liquid Organic Hydrogen Carriers

The accumulation of waste plastics in landfills and the environment, as well as the contribution of plastics manufacturing to global warming, call for the development of new technologies that would enable circularity for synthetic polymers. Thus far, emerging approaches for chemical recycling of plastics have largely focused on producing fuels, lubricants, and/or monomers. In a recent study, Junde Wei and colleagues demonstrated a new catalytic system capable of converting oxygen-containing aromatic plastic waste into liquid organic hydrogen carriers (LOHCs), which can be used for hydrogen storage. The authors utilized Ru−ReO_x/SiO₂ materials with zeolite HZSM-5 as a co-catalyst for the direct hydrodeoxygenation (HDO) of oxygen-containing aromatic plastic wastes that yield cycloalkanes as LOHCs with a theoretical hydrogen capacity of ≈5.74 wt % under mild reaction conditions. Subsequent efficiency and stability tests of cycloalkane dehydrogenation over Pt/Al₂O₃ validated that the HDO products can serve as LOHCs to generate H₂ gas. Overall, their approach not only opens doors to alleviating the severe burden of plastic waste globally, but also offers a way to generate clean energy and ease the challenges associated with hydrogen storage and transportation.     

碳化硅纳米材料的溶剂热合成

本文综述了溶剂热法制备一系列碳化硅纳米材料的研究,包括一维纳米线、纳米带、纳米棒、二维纳米片及空心球等;同时,碳源过量时可形成碳包覆碳化硅的复合材料。使用废塑料作为碳源合成了碳化硅纳米材料,为废塑料的回收再利用提供了新途径。通过使用碘、硫等添加剂,有效降低了合成温度,显示出溶剂热技术在制备碳化硅方面的独特优势。