Removal of Arsenic in Groundwater Using Fe(III) Oxyhydroxide Coated Sand: A Case Study in Mekong Delta, Vietnam

In Hydrology
Peer-reviewed Article
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Because of its threat to the quality of freshwater resources and human health, arsenic
(As) pollution is important to scientific communities and policymakers around the world. The
Mekong Delta, Vietnam, is one hotspot of As pollution. Its risk assessment of different environmental
components has been well documented; however, very few studies focus on As removal techniques.
Considering this information gap, this study aimed to investigate the performance of an innovative
and low-cost treatment system using Fe(III)-oxyhydroxide (FeOOH) coated sand to remove As(III)
from aqueous solution. Batch and column experiments were conducted at a laboratory scale in order
to study removal kinetics and efficiency. Experimental results indicated that the adsorption isotherm
of As(III) on FeOOH coated sand using Langmuir and Freundlich models have high regression
factors of 0.987 and 0.991, respectively. The batch adsorption experiment revealed that contact time
was approximately 8 h for rough saturation (kinetic test). The concentration of As(III) in effluents
at flow rates of 0.6 L/h, 0.9 L/h, and 1.8 L/h ranged from 1.1 g/L to 1.7 g/L. Results from this
study indicated that FeOOH coated sand columns were effective in removing As(III) from water,
with a removal efficiency of 99.1%. Ultimately, FeOOH coated sand filtration could be a potential
treatment system to reduce As(III) in the domestic water supply in remote areas of the Vietnamese
Mekong Delta.

Nguyen Truong
Pham Van
Huynh Vuong Thu