An integrated utilization strategy of printed circuit boards and waste tire by fast co-pyrolysis: Value-added products recovery and heteroatoms transformation

Synergistic atmospheric influence on the co-pyrolysis of antibiotic sludge and waste bicycle tires: Optimal drivers, products, and pathways

Effective management of antibiotic sludge (AS) is essential for disease prevention. This study investigated the co-pyrolysis of AS with polyurethane (PU) and rubber tires (RT), focusing on its key drivers, synergies, resulting products, and atmospheric (N2 versus CO2) dependency. Composite pyrolysis index indicated superior co-pyrolysis properties of AS with PU or RT in the CO2 atmosphere compared with those in the N2 atmosphere. The strongest synergistic effect occurred at an optimal ratio of 75 % AS to 25 % PU (AP31) or 25 % RT (AR31), regardless of the atmosphere. Real-time gas analysis revealed greater product diversity in N2 than in CO2, with AS-derived products predominating. The co-pyrolysis altered AS nitrogen groups, promoting pyrrolic-N and pyridinic-N formation, and accelerated organic sulfur decomposition. Experimental results combined with univariate and multivariate joint optimizations identified the co-pyrolysis pathways of AP31 (650 - 800 °C) and AR31 (600 - 800 °C), respectively, in the CO2 atmosphere as synergistically optimal for maximizing resource recovery while minimizing waste and pollutant generation. This study provides actionable insights into the synergistic co-pyrolysis of AS with PU or RT, facilitating optimized gas emissions, energy recovery, and resource reuse.

Catalysis pyrolysis debromination from waste printed circuit boards: Catalysts selection, parameter effects, products, and mechanisms

As a typical e-waste, waste printed circuit boards (WPCBs), are the most valuable and hazardous components containing all the basic and precious metals as well as toxic substances such as heavy metals, brominated epoxy resins (BERs) and brominated flame retardants (BFRs). Due to their high toxicity and carcinogenicity, effective treatment of BERs and BFRs is the key to achieve the environmental-friendly recycling of WPCBs. Recently, catalysis pyrolysis has proven an efficient and promising approach to removing and recovering bromides from WPCBs. The selection of catalysts and pyrolysis parameters mutually affect the debromination of WPCBs including products and mechanisms. However, there are few studies that focus on analyzing and summarizing the above aspects. Herein, this review first introduces types of catalysts (metals, oxides, hydroxides, molecular sieve, etc.) and figures out that metals are regarded as the most suitable catalysts for WPCBs debromination due to their high efficiency and easy to recycle. Then, the interactive effects of catalyst types and pyrolysis parameters on the debromination efficiency are analyzed, and it was found that temperature ranging from 500 to 600 °C, rapid heating rates, small-size samples and in-situ metals were more suitable for debromination. Moreover, a new idea of in-situ catalysis pyrolysis using self-compositions in WPCBs is highlighted, which point out that the defects of catalysts during the reaction process could promote debromination performance. This review summarizes the key knowledge about catalysis pyrolysis debromination from WPCBs, which will devote to the recycle WPCBs more efficiently and environmental-friendly.

Recent Advancements in Pyrolysis of Halogen-Containing Plastics for Resource Recovery and Halogen Upcycling: A State-of-the-Art Review

Plastic waste has emerged as a serious issue due to its impact on environmental degradation and resource scarcity. Plastic recycling, especially of halogen-containing plastics, presents challenges due to potential secondary pollution and lower-value implementations. Chemical recycling via pyrolysis is the most versatile and robust approach for combating plastic waste. In this Review, we present recent advancements in halogen-plastic pyrolysis for resource utilization and the potential pathways from "reducing to recycling to upcycling" halogens. We emphasize the advanced management of halogen-plastics through copyrolysis with solid wastes (waste polymers, biomass, coal, etc.), which is an efficient method for dealing with mixed wastes to obtain high-value products while reducing undesirable substances. Innovations in catalyst design and reaction configurations for catalytic pyrolysis are comprehensively evaluated. In particular, a tandem catalysis system is a promising route for halogen removal and selective conversion of targeted products. Furthermore, we propose novel insights regarding the utilization and upcycling of halogens from halogen-plastics. This includes the preparation of halogen-based sorbents for elemental mercury removal, the halogenation-vaporization process for metal recovery, and the development of halogen-doped functional materials for new materials and energy applications. The reutilization of halogens facilitates the upcycling of halogen-plastics, but many efforts are needed for mutually beneficial outcomes. Overall, future investigations in the development of copyrolysis and catalyst-driven technologies for upcycling halogen-plastics are highlighted.

Debromination with Bromine Recovery from Pyrolysis of Waste Printed Circuit Boards Offers Economic and Environmental Benefits

Bromine is an important resource that is widely used in medical, automotive, and electronic industries. Waste electronic products containing brominated flame retardants can cause serious secondary pollution, which is why catalytic cracking, adsorption, fixation, separation, and purification have gained significant attention. However, the bromine resources have not been effectively reutilized. The application of advanced pyrolysis technology could help solve this problem via converting bromine pollution into bromine resources. Coupled debromination and bromide reutilization during pyrolysis is an important field of research in the future. This prospective paper presents new insights in terms of the reorganization of different elements and adjustment of bromine phase transition. Furthermore, we proposed some research directions for efficient and environmentally friendly debromination and reutilization of bromine: 1) precise synergistic pyrolysis should be further explored for efficient debromination, such as using persistent free radicals in biomass, polymer hydrogen supply, and metal catalysis, 2) rematching of Br elements and nonmetal elements (C/H/O) will be a promising direction for synthesizing functionalized adsorption materials, 3) oriented control of the bromide migration path should be further studied to obtain different forms of bromine resources, and 4) advanced pyrolysis equipment should be well developed.

A Review on Catalytic Fast Co-Pyrolysis Using Analytical Py-GC/MS

Py-GC/MS combines pyrolysis with analytical tools of gas chromatography (GC) and mass spectrometry (MS) and is a quick and highly effective method to analyse the volatiles generated from small amounts of feeds. The review focuses on using zeolites and other catalysts in the fast co-pyrolysis of various feedstocks, including biomass wastes (plants and animals) and municipal waste materials, to improve the yield of specific volatile products. The utilisation of zeolite catalysts, including HZSM-5 and nMFI, results in a synergistic reduction of oxygen and an increase in the hydrocarbon content of pyrolysis products. The literature works also indicate HZSM-5 produced the most bio-oil and had the least coke deposition among the zeolites tested. Other catalysts, such as metals and metal oxides, and feedstocks that act as catalysts (self-catalysis), such as red mud and oil shale, are also discussed in the review. Combining catalysts, such as metal oxides and HZSM-5, further improves the yields of aromatics during co-pyrolysis. The review highlights the need for further research on the kinetics of the processes, optimisation of feed-to-catalyst ratios, and stability of catalysts and products.