Anisotropic Nanocellulose Aerogel Loaded with Modified UiO-66 as Efficient Adsorbent for Heavy Metal Ions Removal

Abstract

Currently, the preparation of outstanding adsorbents has attracted public concern in environmentally friendly and sustainable pollutant redress. Herein, we report a directional freeze-drying method to prepare a strong and reusable adsorbent by introducing metal-organic framework which modified by ethylene diamine tetraacetic acid (named UiO-66-EDTA) into cellulose nanofiber (CNF) aerogel. Compared to traditional aerogels, the fabricated adsorbent showed a good flexibility and reusability by forming a homogeneous three-dimensional structure. By controlling the concentration of a crosslinkable carboxymethyl cellulose (CMC) solution, we produced aerogels with different pore structures and fibrillar, columnar, and lamellar morphologies. The obtained UiO-66-EDTA/CNF/CMC aerogel (U-EDTACCA) showed an excellent adsorption performance for a total of nine types of heavy metal ions, as the removal efficiency could reach 91%. Moreover, the aerogels could retain 88% of their original shape after five cycles. The aerogel may be an appropriate material for the adsorption of heavy metal ions.

On the mineralization of nanocellulose to produce functional hybrid materials

“…, 267 m 2 g −1 ). 179,182,183 This synthetic approach allows high loadings ( i.e. , 55 wt%) on the foams, but also spun fibers can even support high amounts of mineralized materials with a less brittle and fragile appearance.…”

“…An overall removal efficiency of 91% (98% when tested with individual metal solutions) has been obtained, with a reduction only down to 88% after 5 cycles, further illustrating the reusability of the aerogels. 183 NC has also been hybridized with magnetite nanoparticles for the preparation of aerogels with magnetic properties. Gu and collaborators manufactured aerogels composed of oleic acid, NC, and magnetite nanoparticles for the separation of oil and organic solvents from water.…”

“…These UiO-66/NC hybrids show a higher BET surface area (826 m 2 g À1 ) than those synthesized in situ over nanobers (i.e., 267 m 2 g À1 ). 179,182,183 This synthetic approach allows high loadings (i.e., 55 wt%) on the foams, but also spun bers can even support high amounts of mineralized materials with a less brittle and fragile appearance. Chen et al tested the concept by loading 72 wt% UiO-66 on cellulose acetate bers fabricated at laboratory and pilot scales reaching a BET surface area of 652 m 2 g À1 .…”

Integration of MIL-101-NH2 into Cellulosic Foams for Efficient Cr(VI) Reduction under Visible Light

“…One example reported by Li et al introduced modified UiO-66 into cellulose aerogel and was used for removing heavy metal ions, to obtain an excellent removal efficiency of 91%. 35 In another example, Song et al constructed a type of ZIF-8/TOCN composite membrane with selective filtration of cationic dye. 36 Li et al assembled CDC/TiO 2 /bacterial cellulose film and aerogel with the efficiency of 100% and 84% for Cr(VI) reduction under visible light, respectively.…”

“…Biomass-based porous substrates constructed from alginate, chitosan, or cellulose have emerged as ideal materials. , In particular, nanocellulose with abundant carboxyl and hydroxyl groups has many advantages including being lightweight, cost-efficient, biodegradable, and nontoxic. , Past decades witnessed the development of nanocellulose as a scaffolding matrix (e.g., aerogels, membranes, and foams). − Composite materials constructed by immobilization of MOFs into cellulosic matrix are progressively studied due to excellent performance in water treatment. One example reported by Li et al introduced modified UiO-66 into cellulose aerogel and was used for removing heavy metal ions, to obtain an excellent removal efficiency of 91% . In another example, Song et al constructed a type of ZIF-8/TOCN composite membrane with selective filtration of cationic dye .…”