Preparation and Characterization of a Starch‐Based Adsorbent for the Effective Removal of Environmental Pollutants Hg (II)

Abstract

In this work, a dialdehyde starch cysteine (DASC) Schiff base is synthesized by the reaction of dialdehyde starch (DAS) and l-cysteine, and subsequently tested to remove Hg (II) from aqueous solution using the batch method. It is also characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscope (SEM), Brunner-Emmet-Teller (BET) measurements, and X-ray photoelectron spectroscopy (XPS) techniques. The results reveal that the DASC is a kind of starch-based Schiff base containing thiol group, which holds excellent adsorption capacity for Hg (II) due to the interaction between sulfur atoms and Hg (II). At 25°C, the equilibrium can be achieved within 2 h and the maximal adsorption capacity of DASC with the substitution degree of 1.14 can be reached at 884.6 mg g −1 at initial pH 5. A relatively high temperature is favorable for the adsorption process of Hg (II). The kinetic and isotherm data are well fitted with the linear forms of pseudo-second order equation and Freundlich model. Additionally, the DASC shows good regenerative adsorption efficiency of 87.07% after four recycles. Owing to the advantages of economical, eco-friendly, high adsorption capacity, and recyclability, DASC may provide valuable information for the treatment of Hg (II) contaminated water.

In situ crosslinked Schiff base biohydrogels containing Carica papaya peel extract: application in the packaging of fresh berries

“…Such thermal behaviour for DAS has been reported previously. 40,52–54 From the TG curves in Fig. 5B, it could be seen that the decomposition temperature for the hydrogels loaded with the C. papaya peel extract is higher than that of the neat CsDAS hydrogel.…”

Chestnut shell‐like hollow spheres of C/Co3O4 nanoparticles as adsorbent for the removal of Congo red in wastewater

“…Three critical points of adsorbents are fatal, involving structure adjustment, ease preparation and cost control 24–26 . Nano‐materials with hollow structure are considered ideal adsorbents for the removal of pollutants due to their large surface area, porous structure and cavities 27,28 .…”

“…23 Three critical points of adsorbents are fatal, involving structure adjustment, ease preparation and cost control. [24][25][26] Nanomaterials with hollow structure are considered ideal adsorbents for the removal of pollutants due to their large surface area, porous structure and cavities. 27,28 Carbon materials have drawn a lot of attention in the field of water treatment, including carbonaceous aerogels, carbon nanotubes and so forth, for their large surface area and porous structure.…”