Exploring Arsenic Adsorption at low Concentration onto Modified Leonardite
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The removal of As(V) from aqueous solutions by leonardite loaded with ferric ions (Fe-leonardite) has been investigated. The influence of pH, contact time, and arsenate concentration on the adsorption process were evaluated. Batch kinetic studies showed that equilibrium time was reached at 24 h of contact time. Equilibrium data obtained with low initial arsenate concentrations (10–400 ppb) were fitted to both Langmuir and Freundlich models, and the maximum adsorption capacity was estimated to be 322 μg g−1. Arsenic sorption was evaluated in continuous mode to reproduce industrial applications and to determine the conditions where the process was controlled by either mass transfer or reaction rate. A maximum sorption capacity of 905 μg g−1 was obtained in continuous experiments. These results indicate that Fe-leonardite is a great potential material for removing arsenate at low initial concentrations from contaminated water.
KeywordsArsenic Sorption Leonardite Iron-coated sorbent Column test
We thank undergraduated students Zoe Alique and Nuria Torras for their collaboration.
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