Extremely Fast and Efficient Removal of Congo Red Using Cationic-Incorporated Hydroxyapatite Nanoparticles (HAp: X (X = Fe, Ni, Zn, Co, and Ag))

Abstract

Congo red (CR) is a stable anionic diazo dye that causes allergic reactions with carcinogenic properties. The rapid removal of CR using cation-incorporated nanohydroxyapatite (pristine HAp: X (X = Fe, Ni, Zn, Co, and Ag)) was investigated. The pristine and cation ion-doped HAp adsorbents were coprecipitated and subjected to hydrothermal and ultrasound treatments and subsequent microwave drying. The dopant ions significantly engineered the crystallite size, crystallinity, particle size (decreased 38–77%), shape (a rod to sphere modification by the incorporation of Ag+, Ni2+, and Co2+ ions), and colloidal stability (CS) of the adsorbent. These modifications aided in the rapid removal of the CR dye (98%) within one minute, and the CR adsorption rate was found to be significantly higher (93–99%) compared to previously reported rates. Furthermore, the kinetic, Langmuir, Freundlich, and DKR isotherms and thermodynamic results confirmed that the CR adsorption on the HAp was due to the strong chemical adsorption process. The order of the maximum CR adsorption capacity was Fe-HAp > HAp > Ag-HAp > Co-HAp > Zn-HAp. Whereas the CR regeneration efficiency was Fe-HAp (92%) > Ag-HAp (42%) > Ni-HAp (30%), with the other adsorbents exhibiting a poor recycling efficiency (1–16%). These results reveal Fe-HAp as a potential adsorbent for removing CR without the formation of byproducts.

Accelerating Cd2+ adsorption using hydroxyapatite nanoparticles engineered by combination of ultrasound and microwave treatment

“…09-0432 (Fig. 1a), indicating the polycrystalline nature of the hexagonal structure of the HAp phase [15][16][17]. This suggests that the hydrothermal, ultrasonication, microwave drying, and their combination significantly influence crystallinity and crystallite size.…”

“…6a). The adsorbent pHpzc was calculated from the pH drift method [16,17,30], as shown in Fig. 6b, and it found to be 6.9 ± 0.1, 7 ± 0.1, and 7 ± 0.1 of HAp-M, HAp-UM, and HAp-HUM, respectively.…”

Nickel‐ion substituted hydroxyapatite matrices for metal‐affinity chromatographic purification of recombinant proteins

“…The replacement of C sites with various metal ions (e.g., Sr 2+ , Ag 2+ , Mg 2+ , Zn 2+ , Mn 2+ , Co 2+ , and Y 3+ ) has been reported for various applications, but the structural incorporation of Ni 2+ in HAp is very uncommon in existing literature [13]. Earlier reports on metal-substituted HAp materials have focused on biomaterials and water-treatment applications [14][15][16][17]. There are a few reports on batch adsorption studies with recombinant proteins [5,7,18].…”

Construction of Oxygen Vacancies of Zr-Doped CeO2 with Enhanced Dye Adsorption Performance

“…Therefore, the removal of these substances is crucial to safeguard the environment and public health against their deleterious effects. A number of methods have been used to remove CR dye from wastewater, including photocatalytic (redox) reactions, flocculation, coagulation, ion exchange, reverse osmosis, membrane filtration, and adsorption [9][10][11][12][13][14]. Compared to other techniques, the adsorption technique is best suited for practical applications, since it offers advantages such as operational simplicity, cost-effectiveness, and the generation of non-toxic byproducts, making it widely employed in dye wastewater treatment [15][16][17].…”