# Fewer Dimensions for Higher Thermal Performance: A Review on 2D Nanofluids
## 5 Life Cycle Assessment
### Molybdenum Disulfide  
The industrial production of MoS\({}_{2}\) nanomaterials may raise concerns regarding environmental and health impacts. To mitigate these concerns, Hachbach et al. [178] applied the LCA method to the scaled-up production of MoS\({}_{2}\)-engineered nanomaterials using the solvothermal process. The method was undertaken through the combined use of Aspen Plus and from cradle-to-gate LCIA IMPACT 2002+ considering 1 kg of MoS\({}_{2}\). The results demonstrated that most of the impact categories were linked with the production and inherent sub-processes of the lithium hydroxide. The EIs were analyzed to identify the fundamental problems and to propose technological routes to reduce, or even eliminate, the environmental burdens. The impact assessment was carried out with the aid of the 2002+ impact inferring method. The impact 2002+ LCIA approach proposes the implementation of a midpoint/damage route, linking all types of LCI results through 14 midpoint categories [179]. The researchers fundamentally focused on the categories of resourcesand energy consumption, given that the production of MoS\({}_{2}\)-engineered nanomaterials demands a high amount of energy and resource use. To achieve an improved understanding of the EIs and corresponding solutions to mitigate them, it is necessary to assess the contribution of every process in the impact category. Among the investigated impact categories, it has already been demonstrated that the ecotoxicities and non-carcinogen impacts derived only from the existence of aluminum emissions to the water originated from the production of lithium hydroxide according to the Ecoinvent database. The impact category of land use summarized the EIs closely linked with the tasks of human occupation, reshaping, and exploration of the land, and this can refer to the time of extended occupation on the land or to the change in the type of land that contributes to the emission of CO\({}_{2}\)[180]. In this sense, the authors considered that the land EI originated from the occupation of the forest, implementation of industrial and traffic areas, and dumpsites. The climate change impact fundamentally originated from the release of greenhouse gases, namely CO\({}_{2}\) and methane. The CO\({}_{2}\) emanated mainly from the production of steam with 42.6 kg CO\({}_{2}\) eq. and electricity consumption with 347.7 kg CO\({}_{2}\) eq., which surpassed the CO\({}_{2}\) generated by the land use of 0.03 kg CO\({}_{2}\) eq. Similarly, methane production contributed to the climate change category with 1.03 kg CO\({}_{2}\) eq., which was generated in the steam production from natural gas. The impact of mineral extraction dealt with the extraction of the molybdenum itself as the component for the precursor (NH\({}_{4}\))\({}_{6}\)Mo\({}_{7}\)O\({}_{24}\). The extraction of molybdenum may result in wastes containing concentrations of up to 4000 mg/kg of molybdenum, resulting in the contamination of the soil, sediment, and water. The findings were consistent with those reported in [180] which, for the same WS\({}_{2}\) and boundaries of the involved system, confirmed that this was the principal contributor to a major part of the considered impacts, being responsible for more than 64% of the sum of the impact categories. Molybdenum is widely recognized as an essential trace metal for almost all organisms due to its role as a cofactor in diverse enzymes. Nonetheless, when present in high doses, molybdenum can be toxic [181]. In the referred study, the origins of the already mentioned chemical compounds were various. The extraction of the mineral processes impacted the environment through the extraction of pure molybdenum, and the climate change impact was generated mainly through the production of steam and electricity.