Methane can be stored by metal-organic frameworks (MOFs). However, there remain challenges in the implementation of MOFs for adsorbed natural gas (ANG) systems. These challenges include thermal management, storage capacity losses due to MOF packing and densification, and natural gas impurities. In this review, we discuss discoveries about how MOFs can be designed to address these three challenges. For example, Fe(bdp) (bdp 2− = 1,4-benzenedipyrazolate) was discovered to have intrinsic thermal management and released 41% less heat than HKUST-1 (HKUST = Hong Kong University of Science and Technology) during adsorption. Monolithic HKUST-1 was discovered to have a working capacity 259 cm 3 (STP) cm −3 (STP = standard temperature and pressure equivalent volume of methane per volume of the adsorbent material: T = 273.15 K, P = 101.325 kPa), which is a 50% improvement over any other previously reported experimental value and virtually matches the 2012 Department of Energy (Department of Energy = DOE) target of 263 cm 3 (STP) cm −3 after successful packing and densification. In the case of natural gas impurities, higher hydrocarbons and other molecules may poison or block active sites in MOFs, resulting in up to a 50% reduction of the deliverable energy. This reduction can be mitigated by pore engineering. of 9.2 MJ L −1 , which is 70% less than that of gasoline [2,15]. However, carrying an extremely pressurized tank raises safety concerns in vehicles in the case of accidents and has an energy cost associated with compression. Furthermore, CNG, which is the established and predominant technology for NGVs, has a driving range of 350-450 km as compared to 400-600 km for gasoline-powered vehicles [16]. Based on this, there is a need to develop gas storage technology beyond that which is already established in real life applications. Further improvements in natural gas storage for NGV technology should seek to improve driving range to decrease time at the pump and the corresponding number of required tank recharges. Increasing driving range would be helpful to implement the technology in areas where natural gas filling stations are not as abundant. In addition, the CNG tank that holds the fuel takes up cargo space and technological advancements that decrease the volume of the natural gas fuel tank are beneficial. Another approach to store natural gas is LNG, which has an energy density of 22.2 MJ L −1 . Some drawbacks of LNG are the energy and cost associated with liquefaction (−162 • C), which present major technological obstacles [17,18] Lastly natural gas can be stored as ANG. Fairly large volumetric capacities of 4-6 MJ L −1 at pressures of around 35 bar at room temperature for different adsorbents were achieved [19]. The presence of sorbent materials in high pressure tanks reduces the pressure requirement of the tanks, making storage and delivery safer and allows for the use of single-stage compressors. ANG may increase the driving range and decrease the volume required of the fuel tank to achieve a specific driving dis...

The massive production of Polyurethane foam from various products generates an extensive amount of waste, mostly in the form of dust that is emitted while cutting, trimming, or grinding the foam. In this research, the polyurethane dust (PUD) waste is incorporated into unsaturated polyester resin (UPR) to fabricate a heat insulation composite material to be used in construction. Filler percentages ranging from 10% to 50% were used to make the UPR-PUD composite materials. The thermal and mechanical properties of the material were studied in order to evaluate the ability of the composites for this type of application. Thermogravimetric Analysis and Differential Scanning Calorimeter tests were applied to determine the thermal stability of the material. In addition, the microstructure of the prepared composites and the incorporation of PUD filler into the polyester matrix were investigated by Scanning Electron Microscopy, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) analysis. The FTIR and XRD analyses suggested that adding PUD improved the curing process of unsaturated polyester and enhanced its crystalline structure. The experimental results showed promising thermal insulation capability, with low thermal conductivity in the range of 0.076 to 0.10 and low water retention. Moreover, the composites exhibited compression strength between 56 and 100 MPa and tensile strength between 10.3 and 28 MPa, much higher than traditional thermal insulators and many building materials.