Self-assembly of sponge-like kaolin/chitosan/reduced graphene oxide composite hydrogels for adsorption of Cr(VI) and AYR

Heavy metals ions in water have attracted close attention due to their toxicity, non-biodegradability and carcinogenicity [1]. Because lead ions are more harmful to the human body and tend to accumulate in the body, their removal from wastewater is necessary [2]. Adsorption method was extensively used to remove/recover toxic metal ions, owing to its low cost, convenient operation, no secondary pollution and diversified nature [3-5]. Most conventional adsorbents are in powder form, which makes it difficult to collect after adsorption. Graphene and its derivative have become widely used for functional materials [6, 7]. Graphene oxide (GO) with plenty of reactive functional groups including hydroxyl, carboxyl and epoxy groups is obtained by strong oxidation and stripping of graphite. Abundant oxygen-containing functional groups can be used as active sites to adsorb heavy metals. Therefore, GO can be widely used in the field of heavy metal adsorption [8, 9]. However, due to the presence of a large number of hydrophilic groups, GO has good hydrophilicity, which makes it difficult to be separated and recycled after adsorption [10, 11]. Therefore, it is necessary to further modify the GO. It is expected to assemble three-dimensional (3D) aerogels by combining GO with chain-like biomass molecules or polymers. Sodium carboxymethyl cellulose (CMC), a hydrosoluble anion linear biopolymer and semi-synthetic derivative of cellulose, is obtained by substituting the 2,3,6-hydroxyl groups of cellulose with a carboxymethyl moiety [12]. Because of its low cost, nontoxic, renewable, biodegradable and modifiable characteristics, CMC is considered a biocompatible material and can be used for drug delivery and tissue engineering. And the CMC aqueous solution still has high viscosity at low concentration, it is widely used as an adhesive in industry. It is also an effective adsorbent for removing metal ions because it contains many active functional groups, including hydroxyl and carboxyl groups that can chelate metal ions and interact with organic compounds. However, it has weak mechanical properties. Therefore, it is difficult to directly assemble GO and CMC to form aerogels with strong mechanical properties. Recent work has demonstrated that during AA reduction of graphene oxide, some oxygen-containing This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

“…Graphene oxide (GO) was synthesized by an improved hummers method [13]. Graphene oxide (GO) was synthesized by an improved hummers method.…”

Section: Methodsmentioning

confidence: 99%

“…functional groups on the GO surface could be removed, which would lead to the aggregation of GO sheets and improve the mechanical strength on a macro scale [13,14].…”

mentioning

confidence: 99%

Facile fabrication of sodium carboxymethyl cellulose/reduced graphene oxide composite hydrogel and its application for Pb(II) removal

Zhang

Huang

et al. 2020

Micro & Nano Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…A number of other additives has been combined with CS/GO, such as kaolin as a filler to enhance the mechanical strength of the hydrogel composite [ 220 ], lignosulfonate for additional binding sites [ 221 , 222 ], triethylenetetramine providing amine groups to enhance adsorption [ 223 ], hydroxyapatite to enhance strength and adsorption capacity [ 224 ] and silica as it contains a number of silanol groups (Si–OH) [ 225 ] and it can be furthermore employed to aid the dispersion of GO within chitosan to give effective adsorbents [ 226 ]. Moreover, other biopolymers have been combined with chitosan to form blends which are then combined with GO to give high performing adsorbents.…”

Section: Chitosan Supportsmentioning

confidence: 99%

Recent Developments in Chitosan-Based Adsorbents for the Removal of Pollutants from Aqueous Environments

et al. 2021

View full text Add to dashboard Cite

The quality of water is continuously under threat as increasing concentrations of pollutants escape into the aquatic environment. However, these issues can be alleviated by adsorbing pollutants onto adsorbents. Chitosan and its composites are attracting considerable interest as environmentally acceptable adsorbents and have the potential to remove many of these contaminants. In this review the development of chitosan-based adsorbents is described and discussed. Following a short introduction to the extraction of chitin from seafood wastes, followed by its conversion to chitosan, the properties of chitosan are described. Then, the emerging chitosan/carbon-based materials, including magnetic chitosan and chitosan combined with graphene oxide, carbon nanotubes, biochar, and activated carbon and also chitosan-silica composites are introduced. The applications of these materials in the removal of various heavy metal ions, including Cr(VI), Pb(II), Cd(II), Cu(II), and different cationic and anionic dyes, phenol and other organic molecules, such as antibiotics, are reviewed, compared and discussed. Adsorption isotherms and adsorption kinetics are then highlighted and followed by details on the mechanisms of adsorption and the role of the chitosan and the carbon or silica supports. Based on the reviewed papers, it is clear, that while some challenges remain, chitosan-based materials are emerging as promising adsorbents.

show abstract

“…Moreover, chitosan is non-toxic, biocompatible and can be used in various forms such as beads, membranes, fibers and sponges. [35,36] Also, as a semi-flexible, hydrophilic and reactive biopolymer, chitosan can be easily modified chemically. [37] Elucidation of adsorption mechanisms is critically important to understanding adsorption processes.…”

Section: Introductionmentioning

confidence: 99%

“…Chitosan displays high metal‐binding affinity in either concentrated or diluted effluents. Moreover, chitosan is non‐toxic, biocompatible and can be used in various forms such as beads, membranes, fibers and sponges . Also, as a semi‐flexible, hydrophilic and reactive biopolymer, chitosan can be easily modified chemically …”

Section: Introductionmentioning

confidence: 99%

Removal of Mercury Ions from Aqueous Solutions by Crosslinked Chitosan‐based Adsorbents: A Mini Review

Zhang

Crini

Lichtfouse

et al. 2020

The Chemical Record

View full text Add to dashboard Cite

Abatement of mercury emissions in air and waters has become a global challenge due to the toxicity of mercury species for life, yet actual remediation techniques are limited. In particular, adsorption of mercury ions onto solids is widely used but most adsorption techniques are not specific, and in turn, removal efficiency is lower. Adsorbents developed so far include activated carbon, clay, bentonite, cellulose and chitosan. Chitosan derivatives have recently attracted research attention for water purification because their molecular frames contain a large amount of À NH 2 and À OH groups that can chelate with metal ions specifically. This manuscript reviews recent advances in chitosan-based adsorbents designed to remove mercury ions from wastewater. Focus is placed on their design, synthesis, characterization, adsorption properties, adsorption mechanisms and applications.

show abstract

Self-assembly of sponge-like kaolin/chitosan/reduced graphene oxide composite hydrogels for adsorption of Cr(VI) and AYR

Cited by 35 publications

References 47 publications

Facile fabrication of sodium carboxymethyl cellulose/reduced graphene oxide composite hydrogel and its application for Pb(II) removal

Facile fabrication of sodium carboxymethyl cellulose/reduced graphene oxide composite hydrogel and its application for Pb(II) removal

Recent Developments in Chitosan-Based Adsorbents for the Removal of Pollutants from Aqueous Environments

Removal of Mercury Ions from Aqueous Solutions by Crosslinked Chitosan‐based Adsorbents: A Mini Review

Contact Info

Product

Resources

About