Abstract

Wendimagegn Tagesse^1,2* and Brhane Haile^1,3

DOI : http://dx.doi.org/10.13005/ojc/370217

In the current study, the potential sorption of Cr (VI) ions through a zero-valent silver nanoparticle synthesized by a green approach has been studied. The objective of this research was to remove Cr (VI) from aqueous solution using zero-valent silver nanoparticles synthesized from Moringa stenopetala leaves extract. The synthesized silver nanoparticles were characterized using X-ray diffractometer and UV-visible spectrophotometer. The grain size of nanoparticles was found to be 19.5 nm confirming the crystalline structure of the mesosphere and showed the maximum absorption at 419 nm. In order to determine parameters that influence the adsorption mechanism, batch adsorption experiments have been conducted. Results obtained for removal of Cr (VI) ions showed that efficiency of removal improved as adsorbent dosage increased until the equilibrium point reached at 50 minutes. However, as the pH of the solution increased from 1 to 8, and as the Preliminary concentration of Cr increased, removal efficiency decreased. Adsorption isotherms were investigated by applying the models of Langmuir and Freundlich. The Freundlich isotherm can better explain the removal of Cr (VI) ions, offering correlation coefficient values greater than the Langmuir isotherm model. Adsorption kinetics regression results studied by the pseudo-first and second-order models moreover proved that a pseudo-first-order was further accurately represented by the adsorption kinetics. In order to alleviate wastewater problems, the implementation of this approach is able to cost-effective, eco-friendly and publicly viable. To improve its removal effectiveness and compare it with other adsorbents, additional study on surface modification of this adsorbent is required.

Adsorption Isotherm; Green Synthesis; Hexavalent Chromium; Kinetics; Moringa Stenopetala; Silver Nanoparticle

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