Synthesis of MOF@aluminum saline slag-based composites for CO2 capture at moderate temperatures

Combining metal–organic framework (MOF) materials and aluminum-containing saline slag residues opens a promising research avenue. This approach reduces the environmental impact of aluminum production by integrating industrial waste in the development of advanced materials that adhere to circular economy principles. It also addresses some inherent stability issues observed in pure MOFs. This study is the first to propose the use of this industrial by-product as a cost-effective and environmentally friendly modulator for controlling the phase transition between MIL-96(Al) and MIL-110(Al). For the first time, novel MOFs composites (MOF@RW1*-n; n = 25, 50, 75% waste) and saline slag waste (RW1*)—a by-product of initial aluminum extraction in an acidic medium—were synthesized in situ by preparing the MOF on RW1* via hydrothermal treatment and subsequently tested as CO2 adsorbents at up to 225 ◦C and 80 kPa. The optimized RW1* content in the composite proved critical in determining the formation of specific crystalline structures (MIL-96(Al) or MIL-110(Al)), ultimately yielding hybrid materials with enhanced textural properties and thermal stability.