Highly Porous Hydroxyapatite/Graphene Oxide/Chitosan Beads as an Efficient Adsorbent for Dyes and Heavy Metal Ions Removal

Abstract

Dye and heavy metal contaminants are mainly aquatic pollutants. Although many materials and methods have been developed to remove these pollutants from water, effective and cheap materials and methods are still challenging. In this study, highly porous hydroxyapatite/graphene oxide/chitosan beads (HGC) were prepared by a facile one-step method and investigated as efficient adsorbents. The prepared beads showed a high porosity and low bulk density. SEM images indicated that the hydroxyapatite (HA) nanoparticles and graphene oxide (GO) nanosheets were well dispersed on the CTS matrix. FT-IR spectra confirmed good incorporation of the three components. The adsorption behavior of the obtained beads to methylene blue (MB) and copper ions was investigated, including the effect of the contact time, pH medium, dye/metal ion initial concentration, and recycle ability. The HGC beads showed rapid adsorption, high capacity, and easy separation and reused due to the porous characteristics of GO sheets and HA nanoparticles as well as the rich negative charges of the chitosan (CTS) matrix. The maximum sorption capacities of the HGC beads were 99.00 and 256.41 mg g−1 for MB and copper ions removal, respectively.

Chitosan-Functionalized-Graphene Oxide (GO@CS) Beads as an Effective Adsorbent to Remove Cationic Dye from Wastewater

“…During this decade, various adsorbent materials were investigated as effective adsorbents to remove Methylene blue (MB)-dye from wastewater [ 5 , 6 , 7 , 8 , 9 ]. However, many types of these adsorbent materials have some restrictions to use in wastewater purification [ 7 ], and therefore several efforts were made to develop excellent adsorption materials with economic and eco-friendly properties derived from natural resources [ 7 , 10 ]. Chitosan (CS), a natural biopolymer, is an example of promising adsorbent material derived from natural resources; therefore, it has gained great attention due to its properties.…”

“…Chitosan (CS), a natural biopolymer, is an example of promising adsorbent material derived from natural resources; therefore, it has gained great attention due to its properties. The chemical structure of chitosan (CS) contains several active groups, such as amino- (-NH 2 ) and hydroxyl- (-OH) groups, which serve as coordination sites for various pollutants; therefore, it is considered as an efficient adsorbent material for wastewater treatment [ 10 ]. Recently, many works have been investigated to modify the chitosan to enhance its efficiency in removing dyes and other pollutants from wastewater [ 2 , 3 , 7 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

“…The chemical structure of chitosan (CS) contains several active groups, such as amino- (-NH 2 ) and hydroxyl- (-OH) groups, which serve as coordination sites for various pollutants; therefore, it is considered as an efficient adsorbent material for wastewater treatment [ 10 ]. Recently, many works have been investigated to modify the chitosan to enhance its efficiency in removing dyes and other pollutants from wastewater [ 2 , 3 , 7 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Modification of CS with carboxymethyl to synthesize a novel cross-linked O-CM-chitosan hydrogel adsorbent materials to remove the MB dye [ 2 ].…”

Synthesis of a Magnetic Carnation-like Hydroxyapatite/Basic Calcium Carbonate Nanocomposite and Its Adsorption Behaviors for Lead Ions in Water

“…Calcium contained compounds, such as calcium alginate (C 18 H 24 CaO 19 ) [ 11 ], calcium carbonate (CaCO 3 ) [ 12 ], calcium silicate hydrate (xCaO·SiO 2 ·yH 2 O) [ 13 , 14 ], and hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) [ 15 , 16 , 17 ], are usually used as solid-phase extraction adsorbents for heavy metal ions. For these adsorbents, calcium ions play a key role in the solid-phase extraction-adsorption process by replacing heavy metal ions of aqueous solutions.…”

“…Since these solid-phase extraction adsorbents come from calcium-enriched compounds, they can provide more calcium ions to replace heavy metal ions of aqueous solutions, and then they have higher adsorption efficiency for heavy metals [ 13 , 14 , 16 ]. Therefore, as a calcium-enriched compound, hydroxyapatite (HAP) contains ten calcium atoms in a unit cell and has excellent adsorption property for various heavy metal ions [ 15 , 16 , 17 , 18 , 19 ]. As a relevant phase of calcium carbonate, basic calcium carbonate (BCC) (Ca 3 (CO 3 ) 2 (OH) 2 ·H 2 O), which has three calcium atoms in a unit cell, is also a calcium-enriched compound.…”