A comprehensive understanding of the waste cotton supply chain and different end-of-life options is essential to promote cotton recycling and reuse. This study analyzed global and US data to understand the quantity, current sources, and destinations of waste cotton. Globally, 11.6 million metric tons of waste cotton are generated per year during cotton garment production. This study also reviewed different options for recycling both pre-consumer and post-consumer cotton waste via chemical and mechanical processes. Different applications of waste cotton were compared to their virgin counterparts from technical, environmental, and economic perspectives. Unlike most previous studies, this research included applications that are not traditional textile products (e. g., biofuels and composites), shedding light on potential new markets for waste cotton that will not compete with virgin cotton.

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Dissolving pulp (DP) is a specialty pulp product from a variety of lignocellulosic biomass (i.e., hardwoods (HW) and softwoods (SW)) with a broad range of applications. Conducting life cycle assessment (LCA) for DP end applications (e.g., textile products, specialty plastics) is challenging due to the lack of life cycle inventory (LCI) data and environmental information associated with different grades. This research addresses this challenge using process simulations to generate LCI for different DP grades (e.g., acetate and viscose) made from HW and SW, respectively. The LCA results show that biomass feedstock directly affects the environmental impacts of DP. For instance, HW acetate grade has higher global warming potential than SW acetate but lower environmental impacts in other categories related to ecosystems and human health. This HW versus SW comparison has similar results for viscose DP in all impact categories except eutrophication. Additionally, a hotspot analysis identifies that on-site emissions and chemicals are the main contributors to the environmental impacts across all grades in this study. The results and LCI data generated in this work provide critical information to support future LCA and sustainability assessment for end-products derived from DP.

Wood-based fluff pulp (FP) is the primary raw material for indispensable commodities, including hygienic products. FP substantially contributes to global warming due to the high manufacturing energy demand. Despite FP's importance, the environmental implications of its manufacture have not been transparently explored. The present study provides the carbon footprint for FP cradle-to-manufacturing gate based on process simulation and environmental life cycle assessment The simulation tracks the anthropogenic and biogenic carbon across the mill's areas. In addition, the implications of switching energy sources and key operational conditions are evaluated. The results show that 1 kg of FP produces 1.102 kg CO 2 -equiv. Most of the biogenic carbon fed to the mill (52%) is used to produce steam and electricity. The study shows that switching from natural gas to residual biomass wood pellets represents a reduction of 13.4% of the CO 2 -equiv emissions. This benefit is increased if wood pellets are used to achieve electrical power self-sufficiency, and even more benefit can be realized if the mill produces 20% surplus electricity to the grid. A critical parameter for global warming potential is the incoming biomass lignin content; the pulping of biomass with higher lignin content produces a black liquor with higher heating value and more solids burned in the recovery boiler, reducing the demand for external energy and thus reducing fossil-based greenhouse gas emissions.