Environmental impact of cellulose carbamate fibers from chemically recycled cotton

The goal of this study was to assess the environmental impact of cellulose carbamate fiber production, using discarded cotton textiles as raw material, and compare the results to reference cotton and viscose fibers. Life cycle inventory and assessment was conducted for two production process scenarios within a cradle-to-gate system. Carbon footprint, water use, and water scarcity footprint were assessed. The results show that the carbon footprint of a cellulose carbamate factory integrated with a pulp mill, and that recycles water and chemicals in energy-intensive operations, is comparable to viscose production in Europe. Cellulose carbamate fiber production consumes less than 2% and 25% of the water consumed by cotton and viscose fiber production, respectively. For a factory located in Äänekoski in Finland, the water scarcity footprint was 15 m3 water eq. per 1000 kg carbamate fiber. For Augsburg, Germany, a likely alternative location, the water scarcity footprint was 18 m3 water eq. per 1000 kg carbamate fiber. Carbon footprint and local impact of water use give information that can be utilized to determine optimal locations for a carbamate factory. The study also indicated that discarded cotton textiles can be used as a cellulosic feedstock without increasing the carbon footprint and water use compared to the commercial viscose process. Additionally, by using cellulose carbamate technology, occupational health risks and the environmental burden of carbon disulfide and hydrogen sulfide emissions from viscose process vents can be avoided.