Preparation of biomorphic Ni–Al LDHs using cotton from discarded T–shirt as a template and the adsorption capability for Congo red

Abstract

Biomorphic Ni-Al layered double-hydroxide (LDH) nanosheets with 3D hierarchical structures were synthesized with cotton from discarded T-shirt as templates. The as-prepared samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetry-differential thermal analysis, scanning electron microscopy, and energy-dispersive X-ray diffraction. Adsorption of Congo red (CR) by calcined Ni-Al layered double hydroxides (CLDH) from aqueous solution was investigated in detail. Different conditions were evaluated, including solution pH, amount of adsorbent, initial CR concentration, contact time, and temperature. The adsorption kinetics and equilibrium isotherms of the CLDH were studied by use of pseudo-first-order and pseudo-second-order kinetic models, and the Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. Equilibrium isotherms of uptake of CR by CLDH were a good fit to the Freundlich equation, and the adsorption kinetics of CR followed a pseudo-secondorder kinetic model. These results suggest that CLDH may be effective adsorbents for the removal of anionic dyes from wastewater.

Synthesis of Nanocrystalline Mg-Al Hydrotalcites in the Presence of Starch—the Effect on Structure and Composition

“…The method is considered particularly attractive owing to the low cost, renewable nature, biodegradable character, and environmental compatibility of natural reagents. A literature search shows that synthesis of Ht with the use of sacrificial biotemplates is a very recent tendency, with research concentrating so far on the hard templating syntheses, in which the nanostructure of rigid biomaterials was replicated in the final Ht product [10][11][12][13][14][15][16][17][18][19]. In most works cellulosic polymers of various provenience have been used in the capacity of sacrificial biotemplates.…”

“…In most works cellulosic polymers of various provenience have been used in the capacity of sacrificial biotemplates. In such a way formation of biomorphic hierarchical Mg-Al, Zn-Al and Ni-Al Ht was achieved, the materials proving to be excellent adsorbents of a variety of substances, including bovine serum albumin, oil, dyes and antibiotics [11,[13][14][15][16]18]. Zhang et al [12] demonstrated that advanced Zn-Al Ht/Al 2 O 3 composites with tunable compositions and micro/nanostructures could be grown by structure replication of cellulose fibers.…”