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A New Approach for Removing Anionic Organic Dyes from Wastewater Based on Electrostatically Driven Assembly
journal contribution
posted on 2016-05-27, 00:00 authored by Sira Sansuk, Somkiat Srijaranai, Supalax SrijaranaiA conceptually new
approach for an efficient removal of anionic
organic dyes from wastewater using layered double hydroxides (LDHs)
through their formation is presented. Acid yellow 25 (AY25) was used
as anionic organic dye model molecules. As a result of the electrostatic
induction, the removal mechanism involved a concurrent incorporation
of AY25 molecules into the interlayer of LDHs during their structural
arrangement, where Mg2+ and Al3+ ions were utilized
to construct the base of LDHs in an alkaline solution. It was found
that the molar stoichiometry of all precursors was a key factor affecting
the removal efficiency. Within 5 min removal time, this method still
maintained high removal efficiency of over 97% and provided a removal
capacity of ∼186 mg g–1, comparable to that
of other LDH-based methods. Also, almost complete dye recovery was
simply achieved by anionic exchange with common anions (Cl–, NO3–, and CO32–). Additionally, the present technique is straightforward, cost-effective,
and environmentally friendly since it avoids the synthesis step of
sorbents, thus significantly saving time, chemicals, and energy. Hence,
this strategy not only exhibits the alternative exploitation of LDHs,
but also provides new insights into the removal of contaminants from
wastewater.