Silver Nanoparticle Entrapped Calcium‐Alginate Beads for Fe(II) Removal via Adsorption

Abstract

Summary Silver nanoparticle entrapped calcium‐alginate beads (AgNP‐CAB) were successfully synthesized as adsorbent for effective removal of Fe(II) ions from aqueous solution. The adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction (XRD) and thermogravimetric analysis (TGA). Batch adsorption experiments were used to determine the adsorption capacity. The influence of various factors (such as temperature, pH, adsorbent dosage and contact time) on adsorption behaviour was investigated. The adsorbent thus developed showed higher uptake at pH 4, and adsorption the capacity decreased with increasing temperature. The kinetic results for the adsorption process were interpreted using pseudo‐first order and pseudo‐second order rate equations, as well as Elovich and intra‐particle diffusion models. A good correlation with the pseudo‐second order rate kinetics (R2 = 0.998) could be observed. Adsorption isotherms were fitted to Langmuir, Freundlich, Temkin and Harkins–Jura isotherms whereby the experimental data was found to best fitted for the Langmuir model. The maximum adsorption capacity of adsorbent was found to be 236.40 mg/g.

Adsorption of Ethylenediaminetetraacetic Acid on a Gel-Type Ion-Exchange Resin for Purification of Liquid Waste Containing Cs Ions

“…Based on the higher R 2 and the more similar q e , the pseudo-second-order kinetic model was more suitable than the pseudo-first-order kinetic model. Therefore, we believe that EDTA was adsorbed onto AERs through a chemical interaction rather than a physical one [ 35 ]. The pseudo-second-order kinetic models were applied to the experimental data described in Figure 6 b, which shows the effect of adsorption time on the adsorption capacity of EDTA.…”

“…As such, the EDTA removal was analyzed using Langmuir and Freundlich isotherms, which are representative isotherm models. The Langmuir isotherm suggests that molecules are adsorbed with a monolayer coverage of the surface of adsorbents, which means that adsorption occurs at specific sites on the surface of adsorbents [ 35 ]. The Freundlich isotherm model provides the information on adsorption behavior that occurs with the multilayer coverage of the molecules onto the surface of adsorbents [ 36 ].…”

Green synthesis of silver nanoparticles from Tectona grandis seeds extract: characterization and mechanism of antimicrobial action on different microorganisms

“…They have large surface area to volume ratio due to which they possess optical properties as they are small enough to confine their electrons and produce quantum effects by which their detection becomes easy. Intensive research is being done on silver nanoparticles (AgNPs) owing to their wide range of applications in medical devices (He et al 2013), pharmaceuticals (Kumar et al 2011), clothing (Vigneshwaran et al 2007a), and water purification (Lin et al 2013) due to their antimicrobial properties and also in adsorption of metals and pesticides (Asthana et al 2016;Das et al 2012), sensing of food adulterants (Ping et al 2012), detection of DNA (Thompson et al 2008), etc. Chemical reduction which is the most commonly used method for synthesis of nanoparticles uses an organic solvent, like ethylene glycol (Wiley et al 2004), and reducing agents, like hydrazine (Guzmán et al 2009), sodium borohydride (Song et al 2009), trisodium citrate (Rashid et al 2013), and ascorbate (Qin et al 2010). There was an earnest need for the development of cleaner and safer methods as chemical reduction gives low yield, requires complicated purification and high energy.…”

Microwave-mediated synthesis of silver nanoparticles on various metal-alginate composites: evaluation of catalytic activity and thermal stability of the composites in solvent-free acylation reaction of amine and alcohols

“…For each sample, the 1st stage corresponds to physical weight loss, which is a slow process [21,31]. After 1st stage, weight loss starts through a chemical process, which includes different bond breaking of alginate structure.…”

“…This decomposition stage results in the formation of CO 2 , H 2 O, and other lower molecular weight molecules, and this way, slowly the alginate structure breaks down as temperature increases. Different Agnp-MAs show different behavior with similar temperature treatment [31][32][33].…”