Functionalized Cellulose Aerogel Beads for Heavy Metal Ions Removal | Chunxia Tang

Presentation abstract: Water pollution is a serious issue in the world, which is highly associated with the cumulatively discharge of industry wastewater. Heavy metal ions, such as Cu2+, Pb2+, and Cr6+ are among the major components in the industry wastewater, which can threaten human health due to their high toxicity, non-degradability and bio-accumulation. Absorbents, such as activated carbon and petroleum-based polymers are commonly used absorbents or flocculants. However, their low adsorption capacity, high cost, poor recyclability and non-degradability make them a less attractive choice. Therefore, novel absorbents that satisfy all the practical requirements should be developed for future applications.
Developing bio-based absorbents possessing high removal capacity towards heavy metals is one of the key strategies to manage water pollution worldwide. Cellulose is one of the potential alternatives as it is abundant on earth, renewable and bio-degradable. Functionalized cellulose nanofibrils (CNF) as absorbents have been widely reported for wastewater treatment applications due to their larger specific surface area, abundant surface hydroxyl groups and structural flexibility. However, most of the reported cellulose nanomaterial- based absorbents directly used their single fibril form, which are difficult to recover due to their submicron size. Besides, pristine cellulose nanomaterials have low removal capacity due to the low affinity of hydroxyl groups towards heavy metals.
In my PhD research, functional groups are decorated on CNF to improve their metal ions adsorption capacity followed by assembled into aerogels which can be readily separated from the bulk solution. In one study, we grafted a hyperbranched cationic polymer, PEI on CNF using (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as a crosslinker. The obtained mixture was injected into liquid nitrogen for rapid freezing, followed by sublimation to obtain cellulose aerogel beads (diameter between 3-4 mm). The preparation process is shown in Schematic 1. The chemical structure and composition, morphology, mechanical property, Cu (II) ion adsorption capacity and mechanism as well as regeneration performance of the aerogel beads were investigated. The novelty of this work comprise of: (1) cellulose aerogel beads was used instead of cellulose aerogel monoliths for Cu (II) removal to improve the removal efficiency by reducing copper ion diffusion path length; (2) small beads with larger surface to volume ratio than monoliths that enhanced the adsorption rate; (3) a scalable and simple one pot chemical crosslinking reaction conducted at room temperature and in aqueous solution was proposed; (4) the mechanical performance of the aerogel beads were precisely quantified, and to our knowledge, this is the first reported study; (5) the beads possessed excellent adsorption, regeneration and mechanical property, which is very promising for packed column adsorption.

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Please share your paper. Now i am working of cellulose aerogel