Guangming Li

Feedstock quality and unequal process services complicate comparisons of waste flexible-film recycling routes. We linked records from 52 recyclers and 166 flows with 60 composition observations and separate polyethylene (PE) pelletization and mixed-feed (MIX) molding records. PE scenarios distinguished fixed feed from equal retained pellet output; MIX scenarios compared treatment of the same feed without assuming equivalent product function. Twelve PE batches yielded 38,226 kg of pellets from 40,796 kg of feed, with pooled electricity use of 439.8 kWh/t pellets. Industrial dry-cleaning electricity was treated as a threshold variable. At the MIX-06 reference setting, the covered climate impact of the extrusion reference exceeded molding by 23.5 kg CO₂-eq/t feed; this difference ranged from −58.2 to 129.7 kg CO₂-eq/t across engineering scenarios. Additional relative molding transport removed the climate and L2 cost margins at 150.5 and 34.0 km. L2 includes priced direct inputs, labor, maintenance and annualized equipment costs. Monthly throughput weighting yielded a candidate recorded flow interval of 2728.7–6605.2 t before deployment constraints. Route rankings depend on specified services, quality, capacity and feed supply. Unquantified services limit industrial interpretation, and unresolved resale links prevent interpreting regional endpoints as deduplicated physical savings.

Cleaning-induced mass changes depend on which films enter the post-cleaning weighing. This study quantifies that dependence using 84 model film runs in an established pulsed gas–solid apparatus and a laboratory stirred water reference. The count-matched weighing criterion retained 26 runs (31.0%): 24.0% of dry cleaning runs and 88.9% of stirred water reference runs. Ten of 21 groups had no eligible gravimetric observation. In one incomplete recovery run, assigning the mean initial clean film mass to the unweighed piece gave a scenario contribution of 19.5 percentage points of the unrestricted gravimetric index, illustrating potential bias without correcting the observation. Optical normalization denominators ranged from 68.0 to 76.2 percentage points; separately selected films introduced a conditional sampling uncertainty component of 0.33–0.99 percentage points in optical recovery. At 120 s, the nominal 5 g polyethylene (PE) configuration had 15.2 percentage point lower mean optical recovery than the 3 g configuration despite similar film count recovery. Reporting recovery-dependent coverage alongside each endpoint keeps laboratory comparisons tied to the film populations actually measured.

Waste three-way catalysts (TWCs) and waste LiCoO ₂ batteries represent critical environmental challenges due to hazardous components yet contain high-value resources, and their recycling has garnered widespread attention. We propose a novel ‘waste-to-waste’ synergistic recycling where spent LiCoO ₂ batteries reconstruct mineral phases of waste TWCs, enabling co-recovery of platinum group metals and Li/Co without traditional oxidants. However, the environmental performance of this process still requires further analysis. A comprehensive life cycle assessment using the CML2001 framework evaluated seven impact categories across three core phases: carbothermal reduction, oxidation calcination and HCl leaching. The process achieves net-negative environmental impact with significant benefits in abiotic depletion potential elements (−0.062 kg Sb eq.), acidification potential (−120 g SO ₂ eq.) and eutrophication potential (−1.09 g phosphate eq.). Compared to the individual recycling of lithium-ion batteries, this synergistic recycling process can reduce CO ₂ emissions by approximately 75% or more. Oxidation calcination and HCl leaching are the main phases contributing to environmental burdens. Specifically, electricity consumption, the input of HCl and silicate cement are key factors generating environmental load. Therefore, exploring methods to improve heating efficiency in the oxidation calcination and HCl leaching phases, increasing the proportion of renewable energy in power generation, reducing the use of HCl and seeking environmentally friendly alternatives to silicate cement are crucial to mitigating the environmental impact of this process. Overall, the synergistic recycling process proposed in this study is environmentally friendly and aligns with the goals of a circular economy.

This review aims to evaluate the carbon mitigation potential of waste tire (WT) pyrolysis through a life cycle assessment (LCA) perspective, with a focus on clarifying methodological differences across studies. The scope of the review covers the three main pyrolysis products—tire pyrolysis oil (TPO), recovered carbon black (rCB), and tire pyrolysis gas (TPG)—and their roles in two interconnected mitigation pathways: (i) material substitution, where TPO can displace fossil diesel (≈2.7–3.2 kg CO₂e/kg) and rCB can replace virgin carbon black (≈1.8–2.2 kg CO₂e/kg), and (ii) energy self-sufficiency, where TPG (≈30–40 MJ/m³) offsets external fuels. Unlike earlier reviews that emphasized technical feasibility, this study synthesizes comparative LCA evidence to explain why reported mitigation factors vary widely, highlighting the influence of system boundaries, substitution ratios, and product quality. Harmonizing these conventions provides a consistent basis for cross-study comparison and positions WT pyrolysis as a strategic contributor to circular economy and decarbonization agendas.

The global accumulation of waste tires (WTs), exceeding 25 million tons annually, presents both environmental challenges and opportunities for sustainable resource recovery. Pyrolysis has emerged as a leading thermochemical technology for WT management, converting rubber waste into valuable products—tire pyrolysis oil (TPO), tire pyrolysis gas (TPG), and recovered carbon black (rCB)—while mitigating greenhouse gas (GHG) emissions. This review systematically evaluates pyrolysis-based carbon reduction mechanisms through three interconnected pathways: (1) material substitution, where TPO displaces fossil diesel (2.7-3.2 kg CO2e/kg) and rCB replaces virgin carbon black (1.8-2.2 kg CO2e/kg); (2) energy self-sufficiency, leveraging TPG’s high calorific value (30-40 MJ/m3) to eliminate 60-100% of external energy demand. A comparative analysis of recent life cycle assessment (LCA) studies shows that optimized pyrolysis systems can effectively reduce CO2 emissions, with emission reduction effects exceeding those of traditional treatment methods such as incineration or landfill. Furthermore, technological innovations such as catalytic upgrading and policy instruments like carbon credit recognition are discussed as enablers for industrial scalability. The study concludes that pyrolysis is not only a feasible waste-to-resource solution but also a strategic component in global decarbonization and circular economy initiatives.

Amidst global climate change, carbon emissions across the edible vegetable oil supply chain are critical for sustainable development. This paper systematically reviews the existing literature, employing life cycle assessment (LCA) to analyze key factors influencing carbon footprints at stages including cultivation, processing, and transportation. It reveals the differential impacts of fertilizer application, energy structures, and regional policies. Unlike previous reviews that focus on single crops or regions, this study uniquely integrates global data across major edible oils, identifying three critical gaps: methodological inconsistency (60% of studies deviate from the requirements and guidelines for LCA); data imbalance (80% concentrated on soybean/rapeseed); weak policy-technical linkage. Key findings: fertilizer emissions dominate cultivation (40–60% of total footprint), while renewable energy substitution in processing reduces emissions by 35%. Future efforts should prioritize multidisciplinary integration, enhanced data infrastructure, and policy scenario analysis to provide scientific insights for the low-carbon transformation of the global edible oil industry.

The rapid development of the global energy industry has driven an escalating worldwide demand for lithium resources. As a major lithium source, salt lake brines contain abundant divalent ions that hinder efficient lithium extraction. Compared with conventional lithium recovery technologies, nanofiltration membranes emerge as an energy-efficient and environmentally friendly alternative. Over the past decade, interfacial polymerization has been widely adopted to fabricate nanofiltration membranes for lithium–magnesium separation, with studies confirming the superior performance of positively charged membranes in distinguishing monovalent and divalent cations. This review systematically summarizes recent advancements in positively charged nanofiltration membranes synthesized via interfacial polymerization for lithium–magnesium separation, categorizing the design strategies into five distinct approaches. The correlations between intrinsic membrane structural characteristics and separation performance are critically analyzed. Furthermore, current challenges and future research directions are discussed to provide new perspectives for developing high-performance positively charged composite nanofiltration membranes. This work aims to inspire innovative designs and accelerate the practical implementation of nanofiltration technology in lithium extraction from salt lake brines.

Waste tires (WTs) pose significant environmental challenges due to their massive volume, with millions of tons generated globally each year. Improper disposal methods, such as illegal burning, further aggravate these issues by releasing substantial quantities of greenhouse gases (GHGs) and toxic pollutants into the atmosphere. To mitigate these impacts, the adoption of environmentally friendly resource recovery technologies and a thorough evaluation of their environmental benefits are crucial. Against this backdrop, this research reviews life cycle assessment (LCA)-based analyses of WT recycling technologies, focusing on their environmental performance and contributions to GHG emission reduction. Key recycling pathways, including pyrolysis, rubber reclaiming, and energy recovery, are evaluated in terms of their carbon emissions, alongside an in-depth analysis of carbon reduction opportunities across various stages of the recycling process. Based on these findings, this paper proposes feasible recommendations and identifies future trends for advancing WT resource recovery. The objectives are to (1) systematically review the existing LCA research findings and technological pathways for WT resource recovery; (2) evaluate the advantages and disadvantages of current technologies from the perspective of carbon emission reduction; and (3) explore future trends, proposing optimization pathways and recommendations for technological development.