Demineralization of sludge-based adsorbent by post-washing for development of porosity and removal of dyes

Authors

  • Lingjun Kong,

    1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
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  • ShuangHong Tian,

    1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
    2. Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, P. R. China
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  • Rongshu Luo,

    1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
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  • Wei Liu,

    1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
    2. Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, P. R. China
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  • YuTing Tu,

    1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
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  • Ya Xiong

    Corresponding author
    1. Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, P. R. China
    • School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, P. R. China
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Correspondence to: Y. Xiong, School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou, 510275, P. R. China. E-mail: cesxya@mail.sysu.edu.cn

Abstract

Background

There is growing interest in employing sludge-based carbons (SC) from waste treatment as adsorbents. However, the application of SC is limited by its poor porosity caused by large amounts of minerals blocking the pores. It is thus, highly desirable to develop a post-washing process to remove the minerals in SC.

Results

In this paper, SC was washed with deionized water (DW), hydrochloric acid (HCl), citric acid (CA) and a mixed solution of hydrochloric acid and citric acid (HCl-CA), respectively. Results showed that HCl-CA washing had the highest demineralization efficiency (63%), so that HCl-CA washed SC had the lowest ash content (32%) and largest total pore volume (0.455 m3 g-1), and presented the highest adsorption capacities of 319 mg g-1 for acid orange II (AOII) and 250 mg g-1 for methylene blue (MB).

Conclusion

HCl-CA washing has the highest demineralization efficiency. The high efficiency is attributed to the synergetic effects of both protonation and chelation. Demineralization has a strong influence on the development of pore structures, which further influences adsorption capacity. © 2012 Society of Chemical Industry

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