Optimization and mechanisms of As(III) removal from aqueous solution using Fe-MCM-41 immobilized on GAC. Issue 2 (April 2018)

• Record Type: Journal Article
• Authors: Wantala, Kitirote; Keawbuddee, Chatkamol; Sthiannopkao, Suthipong; Chanpiwat, Penradee
• Is Part Of: Journal of environmental chemical engineering. Volume 6:Issue 2(2018)
• Page Start: 2191
• Page End: 2199
• Publication Date: 2018-04
• Subjects: Arsenic -- Fe-MCM-41/GAC -- Box-Behnken design -- Adsorbent loading -- Adsorption isotherm -- Physisorption; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2018.03.014
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: Loading of Fe-MCM-41 on GAC can enhance As(III) removal efficiency about 20%. As was adsorbed to form a multi-layer on the surface of adsorbent by physisorption. High removal was found in solution with low pH, low As and high adsorbent loading. The presence of NO3 − and SO4 2− reduced the As removal efficiency about 25%–50%. Increasing Fe 3+ and Mn 2+ concentrations caused up to 40% increase in As removal. Abstract: Groundwater contaminated with high arsenic (As) concentration has become a global problem of health concerns for many decades. Therefore, a removal of As is an urgent action needed for countries where the groundwater is a main source of drinking water. The objectives of this work were to study i) the removal mechanisms and effects of solution pH, adsorbent loading, and initial concentration on As adsorption by Fe-MCM-41/GAC and ii) the interference effects of anions and cations on the adsorption process. The Box-Behnken Design (BBD) based on Response Surface Methodology (RSM) was applied for the batch experimental designs. Comparing to GAC, higher adsorption rate and capacity were found in the Fe-MCM-41/GAC. The experimental results which fit well to Freundlich isotherm confirmed a multi-layer adsorption on adsorbent surface. The maximum adsorption capacity of Fe-MCM-41/GAC was 133 μg g −1 . The sorption energy of As(III) ranging from 0.0415 to 0.0451 kJ mol −1 indicating that As(III) adsorption process on Fe-MCM-41/GAC is a physisorption. The adsorption was a rate controlling step for As(III) removal. The increases in solution pH and initial As(III) concentration caused a reduction in the removal efficiency. While, higher adsorbent loading resulted in an increase in removal efficiency. For the interference effects, 25% and 50% reduction in the removal efficiencies were found when NO3 − and SO4 2−, respectively, were increased from 500 to 1000 μg L −1 . In contrast, 40% and 10% increases in removal efficiencies were found when Fe 3+ and Mn 2+, respectively, were increased to 1000 μg L −1 .