Abstract:

In this study, the reuse potential of drinking water treatment sludge as an adsorbent was investigated for the removal of arsenic and antimony. A sludge-derived adsorbent, zirconium oxide-coated sludge, was produced by using thermal treatment and zirconium oxide coating processes, and characterization of the adsorbent was investigated. The results showed that zirconium oxide-coated sludge was mainly amorphous and had a high surface area (170 m2g-1). Batch adsorption tests were performed to specify the optimum conditions for arsenic removal. The study revealed that the removal of As (T) was best achieved at pH 3. The initial arsenic concentration descended from 50 μgL-1 to the 0.25 μgL-1 at contact time, 180 min, with the adsorbent dose of 1 gL-1. The isotherm data fitted fine to the Freundlich isotherm model, and adsorption capacity was found to be 7.38 mgg-1. The pseudo-second order model fitted well with the experimental data (R2≥ 0.999). Column performance for arsenic and antimony removal in a fixed bed under continuous flow conditions was also studied. The adsorption process behavior was described successfully by Thomas and Yoon–Nelson models, indicating that the models were suitable for a zirconium oxide-coated sludge fix-bed column design.

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