Preparation of Electrospun Hydroxyapatite-Glass Fibers for Removal of Cadmium (Cd +2 ) and Lead (Pb +2 ) from Aqueous Me
- PDF / 1,025,324 Bytes
- 13 Pages / 547.087 x 737.008 pts Page_size
- 82 Downloads / 187 Views
Preparation of Electrospun Hydroxyapatite-Glass Fibers for Removal of Cadmium (Cd+2) and Lead (Pb+2) from Aqueous Media José Hafid Roque-Ruiz & Jesús Alberto Garibay-Alvarado & Nahum Andrés Medellín-Castillo & Simón Yobanny Reyes-López
Received: 3 June 2020 / Accepted: 14 September 2020 # Springer Nature Switzerland AG 2020
Abstract Hydroxyapatite-silica fibers were prepared by sol-gel process and electrospinning, and their capacity for adsorption of cadmium and lead ions in aqueous solution was studied. The samples were characterized by SEM, FTIR, TGA, DSC, BET, and XRD. The composite consists on a network of continuous rough fibers with mean diameter of 150 ± 40 nm after thermal treatment. The fibers present a mesoporous structure with pore size of 15.75 nm. Fourier transformed infrared spectroscopy and X-ray diffraction demonstrated the presence of crystalline hydroxyapatite and amorphous silica. Adsorption process is represented by Freundlich isotherm, while the adsorption kinetics follow the pseudo-second-order model. The capacity shown by the fibrous material for the removal of lead ions (466.98 mg/g) was five times higher than the capacity observed for the adsorption of cadmium (93.30 mg/g). Therefore, the hydroxyapatite-silica electrospun fibers represent a suitable material for the efficient removal of lead and cadmium ions from aqueous solution. J. H. Roque-Ruiz : J. A. Garibay-Alvarado : S. Y. Reyes-López (*) Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Envolvente del PRONAF y Estocolmo s/n, 32310 Ciudad Juarez, Chihuahua, Mexico e-mail: [email protected] e-mail: [email protected] N. A. Medellín-Castillo Centro de Investigación y Estudios de Posgrado, Facultad de Ingeniería, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava No. 8, 78210 San Luis Potosi, Mexico
Keywords Adsorption . Electrospinning . Hydroxyapatite . Isotherm . Kinetics . Sol-gel
1 Introduction Water pollution by heavy metals is generated by different anthropogenic activities, such as the fabrication of batteries and pigments, mining, smelting, and galvanization processes. Some of the most important heavy metals for environmental science include cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg) due to their abundance and toxicity (Fu and Wang 2011). Heavy metals are not biodegradable and tend to accumulate in tissues of different organisms, representing a serious threat for the environment and for human health. Therefore, different technologies have been developed to remove heavy metals from industrial discharges. The most common are chemical precipitation, ion exchange, coagulation-flocculation, flotation, and electrochemical techniques. However, most of these generate high volumes of sludge, while electrochemical processes are expensive. Consequently, the interest on adsorption as an efficient and low-cost alternative for removal of different pollutants present in aqueous media has increased. Furthermore, adsorption is a reversible process and the material can be potentially reu
