Applicability of poorly crystalline aluminum oxide for adsorption of arsenate

Abstract

This study examined the characteristics of arsenate adsorption on poorly crystalline oxide (PCAO) which was obtained from recycling of dry sanding powders (DSP) produced during sanding and sawing process in a decorative interior company. After calcinating DSP at 550°C, poorly crystalline oxide (PCAO) was obtained as an adsorbent. From the batch adsorption experiments, arsenate was completely removed up to the concentration of 10 mg/L by PCAO. The stability of PCAO as an adsorbent was evaluated at pH 7 and found that the arsenate adsorbed on PCAO was stable for 24 h. The predominant interaction between arsenate and PCAO was thought to be a strong chemical bond by spectroscopic analysis. The arsenate adsorption behavior onto PCAO was satisfactorily simulated with MINEQL+, suggesting that arsenate formed inner-sphere complexes with the surface of PCAO by chemisorption. Meanwhile, the presence of competitive anions such as PO₄ ³⁻, SO₄ ²⁻ and CO₃ ²⁻ decreased somewhat the removal efficiency of arsenate and the effects of competing anions on the adsorption of arsenate were in the order of PO₄ ³⁻ > SO₄ ²⁻ > CO₃ ²⁻ under pH 6. The application of PCAO to the real mine drainage was also carried out. Although the adsorption of arsenic on the PCAO was slightly decreased rather than that removed from synthetic wastewater due to competitive sorption by multiple ions, it was possible to meet the national discharge standard limit with increasing adsorbent concentration.

Keywords:

• Aluminum oxide
• adsorption
• arsenate
• competitive
• mine drainage

Acknowledgments

This study was partially supported by a grant from Kwangwoon University in 2010 and the Korean Ministry of the Environment as “GAIA Project” and partially by the Ministry of Education, Science Technology (MEST) and Korea Institute for Advancement of Technology (KIAT) through the Human Resource Training Project for Regional Innovation.

Notes

¹Lin and Wu (2001)

¹N.D: Not Detected

²N.A: Not Available

¹National Institute of Standard and Technology (1995).

²present study

¹N.D: Not Detected