Ammonium-functionalized mesoporous silica MCM-41 for phosphate removal from aqueous solutions

Jin Kyu Kang, Jae Hyun Kim, Song Bae Kim, Sang-Hyup Lee, Jae Woo Choi, Chang Gu Lee

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The aim of this study was to investigate the removal of phosphate (P) using ammonium-functionalized MCM-41 (A-MCM-41). Batch experiments were performed with A-MCM-41 under various conditions including the adsorbent dose, reaction time, initial P concentration, and solution pH. The results showed that the phosphate removal in the MCM-41 (initial P conc. = 2 mgP L 1) was negligible with the percent removal of ≤1.0% at the adsorbent dosages between 0.5 and 2.0 g L 1. In the case of A-MCM-41, the percent removal increased from 73.6 to 100% as the adsorbent dose increased from 0.5 to 2.0 g L 1. This indicated an enhancement of the phosphate removal due to the surface modification of the MCM-41 through the functionalization of the ammonium group (NH3 +). The results also demonstrated that the phosphate removal by the MCM-41 was minimal throughout the acidic and alkaline pH conditions (3.1% at pH 3.5; ≤1.0% at pH 5.4–10.7), whereas the phosphate removal by the A-MCM-41 was effective throughout the acidic and neutral pH values (94.7–97.6% at pH 3.5–7.4). In highly alkaline conditions, however, the phosphate removal by the A-MCM-41 was greatly reduced (3.4% at pH 10.7) due to the competition of the hydroxyl groups (OH) with phosphate ions for sorption sites. The results indicated that the pseudo-second-order model was most suitable for describing the kinetic data with the parameter values of qe = 1.86 mgP g 1 and k2 = 183.98 g mgP 1 h 1. The Redlich–Peterson isotherm fits well with the equilibrium data, with the parameter values of KR/aR = 7.90 mgP g 1 and g = 0.83.

Original languageEnglish
Pages (from-to)10839-10849
Number of pages11
JournalDesalination and Water Treatment
Volume57
Issue number23
DOIs
Publication statusPublished - 2016 May 14

Keywords

  • MCM-41
  • Mesoporous silica
  • Phosphate
  • Sorption
  • Surface functionalization

ASJC Scopus subject areas

  • Pollution
  • Water Science and Technology
  • Ocean Engineering

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