A novel cost-effective PAN/CNS nanofibrous membranes with rich carboxyl groups for high efficient adsorption of Lanthanum(III) ions

Polyvinylidene fluoride/graphene oxide/polyimide composite high-efficiency PM2.5 filtration nanofiber membranes

Particulate air pollution is a global environmental problem, with PM2.5 being the primary pollutant. One of the most effective ways to remove particles from the air is through filtration. Therefore, high-performance air filters are urgently needed to combat the harm caused by PM2.5. This study uses an electrospinning technique to prepare high-efficiency polyvinylidene fluoride/graphene oxide/polyimide nanofiber membranes. These composite nanofiber membranes demonstrate high filtration efficiency (99.6%), low pressure drop (123 Pa), remarkable thermal stability (450 °C), and excellent mechanical strength (7 MPa). Considering the advantages, these highly efficient nanofiber membranes can find advanced applications in industrial and civil infrastructures.

Effective and selective adsorption of La3+ by a poly-N-isopropylacrylamide phosphoric modified cellulose aerogel

Synthesis diagram of CNC-P-PNIPAM aerogel material.

Synthesis of a New Phosphonate-Based Sorbent and Characterization of Its Interactions with Lanthanum (III) and Terbium (III)

High-tech applications require increasing amounts of rare earth elements (REE). Their recovery from low-grade minerals and their recycling from secondary sources (as waste materials) are of critical importance. There is increasing attention paid to the development of new sorbents for REE recovery from dilute solutions. A new generation of composite sorbents based on brown algal biomass (alginate) and polyethylenimine (PEI) was recently developed (ALPEI hydrogel beads). The phosphorylation of the beads strongly improves the affinity of the sorbents for REEs (such as La and Tb): by 4.5 to 6.9 times compared with raw beads. The synthesis procedure (epicholorhydrin-activation, phosphorylation and de-esterification) is investigated by XPS and FTIR for characterizing the grafting route but also for interpreting the binding mechanism (contribution of N-bearing from PEI, O-bearing from alginate and P-bearing groups). Metal ions can be readily eluted using an acidic calcium chloride solution, which regenerates the sorbent: the FTIR spectra are hardly changed after five successive cycles of sorption and desorption. The materials are also characterized by elemental, textural and thermogravimetric analyses. The phosphorylation of ALPEI beads by this new method opens promising perspectives for the recovery of these strategic metals from mild acid solutions (i.e., pH ~ 4).

Binary Pectin-Chitosan Composites for the Uptake of Lanthanum and Yttrium Species in Aqueous Media

Rare-earth elements such as lanthanum and yttrium have wide utility in high-tech applications such as permanent magnets and batteries. The use of biopolymers and their composites as adsorbents for La (III) and Y (III) ions were investigated as a means to increase the uptake capacity. Previous work has revealed that composite materials with covalent frameworks that contain biopolymers such as pectin and chitosan have secondary adsorption sites for enhanced adsorption. Herein, the maximum adsorption capacity of a 5:1 Pectin-Chitosan composite with La (III) and Y (III) was 22 mg/g and 23 mg/g, respectively. Pectin-Chitosan composites of variable composition were characterized by complementary methods: spectroscopy (FTIR, ¹³C solids NMR), TGA, and zeta potential. This work contributes to the design of covalent Pectin-Chitosan biopolymer frameworks for the controlled removal of La (III) and Y (III) from aqueous media.