Found 9 results
Article
17 December 2024Upcycling of Waste Poly(ethylene terephthalate) into 2,4-Pyridine Dicarboxylic Acid by a Tandem Chemo-Microbial Process
This study presents a chemo-microbial cascade process for the upcycling of waste poly(ethylene terephthalate) (PET) into valuable compound 2,4-pyridine dicarboxylic acid (2,4-PDCA). Initially, waste PET undergoes efficient hydrolysis to terephthalic acid (TPA) with a high yield of 92.36%, catalyzed by p-toluenesulfonic acid (PTSA). The acid catalyst exhibits excellent reusability, maintaining activity over five cycles. Subsequently, a one-pot, two-step whole-cell conversion system utilizing genetically modified Escherichia coli strains (E. coli PCA and E. coli 2,4-PDCA) converts the generated TPA into 2,4-PDCA. By integrating the PET hydrolysis module with the 2,4-PDCA biosynthesis module, the study achieves an impressive overall efficiency of 94.01% in converting challenging PET waste into valuable 2,4-PDCA. Our research presents a rational design strategy for PET upcycling and 2,4-PDCA synthesis methods. This research provides a systematic approach to PET upcycling, demonstrating its feasibility and potential for industrial application.
Review
09 December 2024Synthesize and Applications of Biodegradable Plastics as a Solution for Environmental Pollution Due to Non-Biodegradable Plastics, a Review
Biodegradable plastics are a potential sustainable alternative to conventional petrochemical-based non-degradable plastics. Due to their lightweight, flexibility, durability, versatile applications, chemical inertness, electrical and heat insulation, and conductivity, plastics have become an essential material for many industries, with annual production currently exceeding 450 million tons. However, these materials are non-biodegradable, leading to detrimental consequences such as the formation of microplastics from improper disposal and the generation of toxic gases, including furans, dioxins, mercury, and polychlorinated biphenyls, from burning plastic waste. This results in environmental pollution, affecting land, water bodies, and the atmosphere. In response, studies where the focus has been on creating bio-degradable polymers such as polylactic acid, polyhydroxy alkanoates, Polycaprolactone, Poly(butylene adipate-co-terephthalate), and Polybutylene succinate, which were extracted from renewable resources or chemically modified as biodegradable polymers. Biodegradable polymers exhibit a wide range of properties and can now be modified to be used in various applications suitable for substituting some conventional plastic products. Thus, the article highlights the critical issue of environmental pollution caused by non-biodegradable plastics and provides a comprehensive overview of the synthesis processes, properties, novel applications, and challenges associated with the use of biodegradable plastics.
Review
01 November 2024Waste Resin Derived Carbon Materials for Sodium-Ion Batteries
As the environmental issues caused by waste resin become increasingly severe, there is an urgent need to develop ways to handle it in a high-value and harmless manner. Turning waste resin into functional carbon materials is a realizable and promising scheme, which could be a trigger to carry forward emerging sustainable battery technologies and applications. However, there are few review articles about the basics and research progress of the waste resin derived carbon materials for sodium-ion batteries. This review article provides a brief overview mainly about resin recycling and the potential usage of the resultant carbon materials for sodium-ion batteries. Specifically, we show the potential improvements in existing research, focusing on utilization of the waste as well as the significance of new routes for resin recycling. This work offers insights for the design of sustainable carbon materials for battery systems.
Review
23 October 2024Chemical Recycling and Upcycling of Waste Plastics: A Review
The indiscriminate disposal of plastic waste represents a significant environmental hazard. Conventional remediation techniques, such as landfilling and incineration, also encounter limitations and are unable to adequately address the pollution issue. Chemical recycling and upcycling represent an effective method for the degradation of plastics into oligomers and subsequent transformation into other product substances. This review provides an overview of the various chemical treatment methods currently in use, from the earliest thermal degradation techniques to the emerging strategies. The conventional techniques for thermal degradation of discarded plastics frequently encounter difficulties due to the necessity for elevated temperatures, substantial energy consumption, and the generation of a heterogeneous product mixture. Significant advances have been made in the fields of catalytic solvolysis, hydrotreating, and oxidative cleavage for the recycling and upcycling of plastics under mild conditions. This review provides a comprehensive overview of the chemical treatment methods currently employed for plastics, with a particular focus on the principles and current developments, as well as the reaction mechanisms involved. Additionally, it offers a detailed introduction to various advanced catalytic technologies and the catalysts utilized. Finally, it presents prospective outlooks for different methods, based on their current development status and the gap between actual needs.
Article
15 October 2024Binder Jetting 3D Printing Utilizing Waste Algae Powder: A Feasibility Study
This paper reports, for the first time in the literature, a preliminary study to investigate the feasibility of utilizing waste algae powder (byproducts of biofuel manufacturing from algae) in binder jetting 3D printing to produce environmentally friendly products. In this study, the algae powder’s morphology and particle size distribution were characterized using scanning electron microscopy and particle size analyzer, respectively, and the flowability was assessed through apparent density and repose angle. The algae powder successfully printed the cylindrical, cubic, and gyroid parts on a binder jetting 3D printer. Results show that it is feasible to print parts with binder jetting 3D printing utilizing waste algae powder. The use of waste algae powder in additive manufacturing offers a novel approach to upcycling waste algae powder into valuable products for various applications such as packaging and construction.
Article
31 May 2024Solid Waste Recycling in Textile Processing Industries: A Case Study of India’s Clothing Hubs
This study investigated the type and amount of solid waste generation from textile wet processing industries and analyzed the disposal and recycling strategies implemented for its utilization. The method involved industrial interactions with textile processing mills. Data was gathered based on a field survey of manufacturing units and their compliance management teams. The solid waste generated in textile processing stages against input raw materials and fuel sources was recorded. The challenges in recycling solid waste are identified and further scope for its valorization is suggested. The results indicate that significant solid waste produced during the wet processing of textiles arises from waste fabric cuttings, combustion of fuels used in processing stages, and sludge generated from the post-effluent treatment. Around 80% of solid waste generated during the wet processing of textiles can find applications in the construction industry. Effective management of solid waste and its potential applications in construction are elaborated in detail.
Review
20 May 2024
Advancements in the Bio-degradation of Plastic Waste into Value-added Chemicals: A
Recent Perspective
Plastics are an essential component of modern life, but the plastic waste has caused significant environmental pollution and economic losses. The effective solution to these problems is the biodegradation and high-value conversion of plastic waste. After biodegradation, plastic waste is broken into smaller molecules and eventually transformed into innocuous substances like water, carbon dioxide and biomass. High-value conversion enables plastic waste to be converted into products with higher economic value and environmental friendliness. Based on this, we summarize the biodegradation methods of bioplastics and analyze the shortage of these methods. Subsequently, we summarize the progress of converting the degradation products into value-added chemicals, comprehensively analyze the advantages and disadvantages of these bioconversion process, and propose some strategies to address these disadvantages. Finally, we analyze the significance of establishing a microbial-based conversion process that integrates the degradation and the conversion, and propose some potential strategies.
Review
02 April 2024Mapping the (in)Effective Enforcement of EU Environmental Law in Greece: Lessons from the EU and Domestic Courts
The effective implementation and enforcement of EU environmental law at national level constitutes a thorny issue with both legal and practical aspects. Greece is among the EU Member States which has historically faced difficulties in complying with the EU environmental acquis due to the poor functioning of the Greek administration, the limited manpower, expertise and resources (especially during the recent period of the economic crisis) for the competent authorities, the lack of political will, the low awareness of environmental problems. In this context, this paper aspires to unpack these enforcement challenges at the national level based on the case law of both the Greek Council of State and the Court of Justice of the European Union. Considering that waste management, nature protection, and water and air quality sectors are recognized as areas with the most significant deficiencies in implementation at the domestic level, the analysis will focus on these four key sectors. To this end, by reviewing the relevant EU and Greek jurisprudence, this paper aspires to identify the disparities between the formal requirements and the practical application of EU environmental regulations in Greece in light of the national political, economic, social, and cultural dynamics.
Article
13 March 2023Reduced Climate Impacts of Dairy Sludge Management by Introducing Hydrothermal Carbonization
Dairies which produce cheese and milk products can, however, produce large volumes of wastewater that require treatment, usually via activated sludge treatment. Disposal of the resulting activated sludge to land is viewed favorably as the sludge is rich in phosphorus (P) and nitrogen (N) and enables nutrient recycling. Nonetheless, sludge management can significantly influence the greenhouse gas (GHG) emissions to the atmosphere. This manuscript has modelled the GHG emissions arising from two sludge management strategies currently adopted by Danish dairies whereby: (i) sludge is stored and later applied to fields; or (ii) sludge is treated by anaerobic digestion (AD), stored, and the digestate will later be applied to fields. This is compared to (iii) an alternative sludge management strategy with treatment by Hydrothermal Carbonization (HTC). HTC is a technologically simple sludge treatment that could lower the cost for dewatering dairy sludge, forming a biochar-like material known as hydrochar. The produced hydrochar can be applied to the land for the purpose of carbon sequestration, P and N recycling. Our calculations indicate that GHG balances of HTC sludge management can result in a net carbon sequestration of 63 kg CO2eq per ton sludge, as opposed to net emissions of 420 and 156 kg CO2eq per ton sludge for strategies (i) and (ii), therefore offering significant reductions GHG emissions for the dairy sector.
