Bimodal porous silica microspheres decorated with polydopamine nano-particles for the adsorption of methylene blue in fixed-bed columns

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• 作者：Taher Ataei-Germi ; Ali Nematollahzadeh ; ^{nematollahzadeha@uma.ac.ir" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Porous silica microspheres ; Polydopamine nano-particle ; Methylene blue ; Separation ; Fixed bed column
• 刊名：Journal of Colloid and Interface Science
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：470
• 期：Complete
• 页码：172-182
• 全文大小：2794 K

文摘

Bimodal meso/macro-porous silica microspheres (MSM) were synthesized by a modified sol-emulsion-gel method and then the surface was coated with polydopamine (PDA) nano-particles of 39 nm in size. Focusing on the encouraging properties of the synthesized adsorbent, such as high specific surface area (612.3 m² g⁻¹, because of mesopores), fast mass transfer (0.9–2.67 × 10⁻³ mL min⁻¹ mg, because of macropores), and abundant “adhesive” functional groups of PDA, it was used for the removal of methylene blue (MB) from aqueous solution in a fixed-bed column. The effect of different parameters such as pH, initial concentration, and flow rate was studied. The results revealed that an appropriate sorption condition is an alkaline solution of MB (e.g., pH 10) at low flow rate (less than 5 mL min⁻¹). Furthermore, the compatibility of the experimental data with mathematical models such as Thomas and Adams-Bohart was investigated. Both of the models showed a good agreement with the experimental data (R² = 0.9954–0.9994), and could be applied for the prediction of the column properties and breakthrough curves. Regeneration of the column was performed by using HCl solution with a concentration of 0.1 M as an eluent.