![Reuse of waste silica as adsorbent for metal removal by iron oxide modification [An article from: Journal of Hazardous Materials]](https://www.ebooknetworking.net/books/B00/0PD/bigB000PDYJVS.jpg)
Reuse of waste silica as adsorbent for metal removal by iron oxide modification [An article from: Journal of Hazardous Materials]
Description
This digital document is a journal article from Journal of Hazardous Materials, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Silica gel is widely used in research laboratories, especially for the purification of organic compounds. Consequently, waste silica gel is generated in increasing amounts. In this work, waste silica was modified by coating its surface with iron oxide aiming to obtain an effective adsorbent for metal removal from wastewater. In the preparation of the adsorbent, the optimal pretreatment temperature and iron concentration were investigated. The coated waste silica was characterized for BET surface area, pore size, specific pore volume and iron content. Iron oxide-coated waste silica was tested for the adsorption of Pb(II), Cu(II), Cd(II) and Ni(II) from solutions in a batch system. The effect of contact time, pH and salt concentration on metal adsorption was investigated. It was found that the adsorption of metals occurred rapidly and reached equilibrium within 30min. The pH suitable for metal adsorption was between 6 and 7 and leaching of iron from the coating was observed only at pH 3 or lower. The presence of salt reduced the adsorption efficiency of the adsorbent. The adsorption behavior followed both Langmuir and Freundlich isotherms (25^oC). Finally, the efficacy of the adsorbents was investigated using aqueous lab waste where removal efficiencies ranging from 62 to 89% were achieved when the initial metal concentrations ranged from 13 to 42mgL^-^1.
Description:
Silica gel is widely used in research laboratories, especially for the purification of organic compounds. Consequently, waste silica gel is generated in increasing amounts. In this work, waste silica was modified by coating its surface with iron oxide aiming to obtain an effective adsorbent for metal removal from wastewater. In the preparation of the adsorbent, the optimal pretreatment temperature and iron concentration were investigated. The coated waste silica was characterized for BET surface area, pore size, specific pore volume and iron content. Iron oxide-coated waste silica was tested for the adsorption of Pb(II), Cu(II), Cd(II) and Ni(II) from solutions in a batch system. The effect of contact time, pH and salt concentration on metal adsorption was investigated. It was found that the adsorption of metals occurred rapidly and reached equilibrium within 30min. The pH suitable for metal adsorption was between 6 and 7 and leaching of iron from the coating was observed only at pH 3 or lower. The presence of salt reduced the adsorption efficiency of the adsorbent. The adsorption behavior followed both Langmuir and Freundlich isotherms (25^oC). Finally, the efficacy of the adsorbents was investigated using aqueous lab waste where removal efficiencies ranging from 62 to 89% were achieved when the initial metal concentrations ranged from 13 to 42mgL^-^1.
