Template-Free Synthesis of Magnetic La-Mn-Fe Tri-Metal Oxide Nanofibers for Efficient Fluoride Remediation: Kinetics, Isotherms, Thermodynamics and Reusability

Abstract

The occurrence of fluoride contamination in drinking water has gained substantial concern owing to its serious threat to human health. Traditional adsorbents have shortcomings such as low adsorption capacity and poor selectivity, so it is urgent to develop new adsorbents with high adsorption capacity, renewable and no secondary pollution. In this work, magnetic electrospun La-Mn-Fe tri-metal oxide nanofibers (LMF NFs) for fluoride recovery were developed via electrospinning and heat treatment, and its defluoridation property was evaluated in batch trials. Modern analytical tools (SEM, BET, XRD, FTIR) were adopted to characterize the properties of the optimized adsorbent, i.e., LMF11 NFs with a La:Mn molar ratio of 1:1. The surface area calculated via BET method and pHpzc assessed using pH drift method of LMF11 NFs were 55.81 m2 g−1 and 6.47, respectively. The results indicated that the adsorption amount was highly dependent on the pH of the solution, and reached the highest value at pH = 3. The kinetic behavior of defluoridation on LMF11 NFs was dominated by the PSO model with the highest fitted determination coefficients of 0.9999. Compared with the other three isotherm models, the Langmuir model described defluoridation characteristics well with larger correlation coefficients of 0.9997, 0.9990, 0.9987 and 0.9976 at 15 °C, 25 °C, 35 °C and 45 °C, respectively. The optimized LMF11 NFs exhibited superior monolayer defluoridation capacities for 173.30–199.60 mg F−/g at pH 3 at 15–45 °C according to the Langmuir isotherm model. A thermodynamic study proved that the defluoridation by LMF11 NFs is a spontaneous, endothermic along with entropy increase process. In addition, the LMF11 NFs still showed high defluoridation performance after three reused cycles. These findings unveil that the synthesized LMF11 NFs adsorbent is a good adsorbent for fluoride remediation from wastewater owing to its low cost, high defluoridation performance and easy operation.

Metformin-Embedded Biocompatible Chitosan/Poly(vinyl alcohol) Beads with Superior Adsorption Properties toward Lead(II) and Levofloxacin

“…This finding suggests that the chemisorption phenomenon over the whole range of adsorption governs the rate-limiting step. 57 The high R 2 for Pb(II) (0.997) and LFX (0.981) removal obtained from fitting the Elovich model shows a reasonably plausible correlation with empirical kinetic data. This observation implies that the actual solid interfaces are highly energetically heterogeneous and confirms the second-order kinetic model results.…”

In Situ Electrospun Porous MIL-88A/PAN Nanofibrous Membranes for Efficient Removal of Organic Dyes

“…Electrospinning is a fiber fabrication method used to produce long and continuous polymer fibers with diameters in the nano- or micrometer ranges [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. Furthermore, the fibers form stacks during electrospinning, yielding nonwoven membranes [ 33 , 38 ].…”

“…Furthermore, the fibers form stacks during electrospinning, yielding nonwoven membranes [ 33 , 38 ]. Owing to their high porosity and easy preparation, electrospun polymer fibers have recently been integrated with MOFs to shape MOFs into fibers [ 29 , 30 , 31 , 32 ]. For example, Zhao et al proposed a simple method for the uniform growth of porous MIL-100(Fe) on electrospun polyacrylonitrile (PAN) fiber membranes via electrospinning and hydrothermal reactions [ 38 ].…”

Efficient removal of high- or low-concentration copper ions using diethylenetriamine-grafted electrospun polyacrylonitrile fibers

“…[1][2][3][4] Especially, heavy metal ions (e.g., As 2+ , Gd 2+ , Zn 2+ , Cr 3+ , Cu 2+ , and Pb 2+ ) are present in the pollution source and most of these heavy metal ions are toxic and highly accumulative and can enter organisms through bioconcentration of the food chain, [5][6][7][8][9] making the protein and various enzymes in the organism react to make it inactive and even cause poisoning, leading to irreversible damages to the organism. 10,11 In particular, there is a wide range of heavy metal copper sources, such as slag tailings. Processing these large amounts of copper slag requires a large area of land, which may cause pollution of surface water, soil, and groundwater.…”