Construction of temperature-responsive imprinting cellulose aerogels for separation of neodymium

Abstract

Neodymium ions are of increasing interest in today's market due to their unique magnetic properties. Therefore, adsorption separation of neodymium is extremely valuable both economically and environmentally. In this work, imprinting cellulose aerogels (IHN-HPMC-NIPAM) with temperature responsiveness were prepared using hydroxypropyl methylcellulose (HPMC) and graphene oxide in combination with ion imprinting technology for selective adsorption of rare earth neodymium ions. The microstructure and physicochemical properties of the aerogels were investigated by means of Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Moreover, adsorption experiments were also carried out to study the adsorption performance of aerogels. Based on experimental results, IHN-HPMC-NIPAM exhibits a high adsorption capacity and certain adsorption selectivity for Nd³⁺ ions. Adsorption experiments demonstrated that IHN-HPMC-NIPAM has a selective adsorption effect on neodymium ions in aqueous solutions, with a maximum adsorption capacity of 68.58 mg g⁻¹. Compared with the non-imprinted aerogel, its maximum adsorption capacity for neodymium ions was significantly enhanced, confirming that the introduced ion-imprinting technology played a crucial role in the adsorption process. The cycling experiments indicated that after four adsorption and desorption cycles, the adsorption capacity of IHN-HPMC-NIPAM could still maintain 86% of its initial capacity. The aerogel can be regenerated by temperature, especially due to the introduction of temperature-responsive monomers. The prepared imprinting adsorbent aerogels were highly efficient, green adsorbent materials with great application prospects due to their abundant source of raw materials, simple preparation process, and pollution-free temperature desorption process.