Catalytic pyrolysis has emerged as a pivotal technology for converting renewable diverse feedstocks (i.e., lignocellulosic biomass, algal biomass, and plastic wastes) into biofuels and chemicals. This review comprehensively examines the reaction kinetics in catalytic pyrolysis, addressing the fundamental gap between lab-scale research and industrial applications. The mechanisms of conventional (i.e., electrical heating) and microwave-assisted catalytic pyrolysis are detailed, highlighting the role of catalysts in altering reaction rates, reaction pathways, and decreasing activation energies. This paper delves into kinetic analysis techniques by comparing the model-free and model-fitting approaches and exploring the emerging role of machine learning in predicting kinetic parameters. In addition, it extensively explores the feedstock specific kinetic models, highlighting the behavior of pseudo-components of lignocellulosic feedstocks, plastic wastes, and their mixtures with a specific focus on synergistic effect during co-pyrolysis. Further, an essential framework to integrate molecular-scale phenomena with reactor-scale process performance was presented by exploring the advanced modelling techniques such as microkinetic modelling using density functional theory (DFT), lumped system analysis using process simulations, and catalyst deactivation kinetics. Despite its promise, challenges such as catalyst deactivation, heat and mass transfer limitations, and feedstock variability remain critical hurdles. This review concludes by identifying future research directions, emphasizing the in-situ characterization, integration of machine learning and artificial intelligence for process optimization, and kinetics of emerging catalyst systems to facilitate the commercial deployment of predictive models for catalytic pyrolysis technologies.

Biodegradable polymers are a promising field of study in the quest for a sustainable circular bioeconomy. They offer a pragmatic alternative to conventional polymers. These polymers are specifically engineered to disintegrate more effectively in natural environments, thereby addressing urgent environmental concerns such as plastic pollution and resource depletion. This review provides a comprehensive analysis of biodegradable polymers, starting with their introduction and the environmental impacts they aim to mitigate. This review categorizes many types of bioplastics, including those obtained from sustainable sources such as plant-based materials and agricultural byproducts. An examination is carried out on the manufacturing techniques of these bioplastics, specifically emphasizing their ability to reduce reliance on fossil fuels and minimize carbon footprints. The study also assesses the biodegradability of these materials, recognizing both their advantages and the challenges they face, such as limited degradation rates and scalability issues. The research showcases the potential of biodegradable polymers in promoting sustainability through the analysis of closed-loop systems and resource efficiency. This strategy encourages the ongoing utilization of resources and reduces the generation of trash, thus enhancing the long-term well-being of the environment and the ability to withstand economic challenges.

In the dual pursuit of achieving the global goal of carbon neutrality and curbing plastic pollution, chemical looping gasification (CLG) technology has emerged a key approach to integrate plastic waste recycling with H2-rich syngas production. This review systematically examines and compares the design strategy (support properties, active metal modification and bimetallic synergy) of oxygen carrier (OC) and the optimization progress of key process parameters (temperature, reactor staging and co-gasification of biomass) in the production of H2-rich syngas from plastic CLG. The findings demonstrate that support optimization and metal synergy can significantly regulate the syngas yield and its H2/CO ratio, while improving the cycle stability of OCs. Temperature and segmented CLG significantly improves the conversion rate and achieve flexible control of the H2/CO ratio. CLG of biomass and plastics can improve the yield and quality of H2-rich synthesis due to the complementary hydrocarbon and the coordinated conversion of tar. However, most studies at present use model plastics as fuel, which highlights the key shortcomings in understanding actual plastic waste, impurities, long-term CLG stability, and systematic economic evaluation. This review aims to provide guidance for the development of stable and selective OC systems and the optimization of CLG systems to achieve sustainable energy conversion of plastic waste.

Activated carbon is a highly porous adsorbent material that is often used to treat wastewater using physical and chemical adsorption. Agricultural and urban biomass waste valorization to activated carbon is a low-cost, renewable solution to commercial adsorbents, and can help prevent waste from tree pruning from being dumped in landfills or openly burned. In this study, the ability of the ground and unground Ficus nitida leaves to efficiently adsorb Rhodamine B dye and total chromium from model aqueous solutions was investigated. Chemical activation was performed using phosphoric acid (H₃PO₄) at different impregnation ratios (1:1, 2:1, and 4:1). Samples obtained as a result of the above activation were labeled G1–G3 (ground) and UG1–UG3 (unground). The adsorption test showed that the samples with the highest activation ratio (G3 and UG3) gave the best results, removing 92% and 94% RhB, respectively, in 20 minutes. After 24 h, sample G3 showed the best efficiency of 73.31% (13.35 ppm remaining) in chromium removal, where the adsorption kinetics were well described by the pseudo-second-order model (R² > 0.98), indicating that there may be some chemical interactions occurring during the adsorption process along with physisorption, and the RhB adsorption isotherms for sample UG3 were well described by the Langmuir isotherm (R² > 0.95). The higher activation ratio and grinding increased the carbon content (up to 90% C for G3), surface functional groups, and textural properties (BET surface area of 699 m²/g and total pore volume of 3.06 cm³/g). Furthermore, reusability tests over five consecutive cycles demonstrated the excellent recyclability of sample G3, retaining removal efficiencies of 80.5% for RhB and 50.2% for total chromium. The results revealed that Ficus nitida leaf-based AC can be used as an efficient, economical, and reusable adsorbent material for sustainable environmental cleanup and water purification systems and will create a circular economy for waste management.