Arsenic removal from real arsenic-bearing groundwater by adsorption on iron-oxide-coated natural rock (IOCNR)
Journal
Desalination
Journal Volume
280
Journal Issue
1-3
Pages
72-79
Date Issued
2011
Author(s)
Abstract
This study used iron-oxide-coated natural rock (IOCNR) an adsorbent of arsenic from real arsenic-bearing groundwater collected from the Lanyang Plain, North Eastern Taiwan. SEM and EDX were applied to characterize the as-prepared adsorbent. Batch adsorption studies were conducted at 25±2°C. A 15gL-1 dose of adsorbent removed ~75% of the total arsenic from the real sample when the initial arsenic concentration was 40μgL-1 and the pH was 7.5 (reduced to 10μgL-1, the maximum contaminant level (MCL)). The contact time was 6h and the agitation speed 180rpm. Adsorption followed the Langmuir isotherm and the maximum adsorptive capacity of IOCNR was 0.36mgg-1. The dimensionless parameter (RL) and Gibbs free energy (δGo) changes suggested that the process is favorable and spontaneous. The adsorption process followed the first-order reaction kinetic model better than the other three kinetic models, and film-diffusion was the rate-limiting step. Arsenic removal efficiency of the exhausted and NaOH-regenerated IOCNR decreased in the second-cycle operation. Arsenic removal efficiency of IOCNR was comparable to that of the commercially available patented adsorbent LEWATIT FO36. © 2011 Elsevier B.V.
SDGs
Type
journal article