Issue 24, 2017, Issue in Progress

Characterization of KOH modified biochars from different pyrolysis temperatures and enhanced adsorption of antibiotics

Abstract

Poplar biochars from pyrolysis at temperatures of 300, 500 and 700 °C were modified with KOH and characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and nitrogen adsorption–desorption isotherm studies. Adsorption experiments were carried out on the modified biochars to remove tetracycline (TC) from aqueous solution. The results showed that KOH modification could increase or decrease TC adsorption onto biochars depending on the different pyrolysis temperatures. Maximum adsorption capacities (qe,m) of TC in modified biochar from a low pyrolysis temperature of 300 °C increased up to 21.17 mg g−1 relative to 4.30 mg g−1 in unmodified biochar of 300 °C (final TC concentrations were 8.83 and 25.70 mg L−1, respectively). In contrast, qe,m decreased from 7.37 and 11.63 mg L−1 to 4.97 and 7.13 mg L−1 in biochars from higher pyrolysis temperatures of 500 and 700 °C with and without modification, respectively, even with an increase in SBET. The adsorption ability of biochar can remain over a wider range of pH in modified biochar relative to unmodified biochar. Further analysis indicated that there was a strong linear regression relationship between qe,m and total functional oxygen groups using Bohem titration (n = 6, R2 = 0.84), whereas no significant relationship was observed between qe,m and SBET in this experiment. The result suggested that KOH modification of biochar from a low pyrolysis temperature can enhance TC adsorption and can be used over a wide range of pH, which may be a good choice for disposal of organic pollutants in aqueous solution.

Graphical abstract: Characterization of KOH modified biochars from different pyrolysis temperatures and enhanced adsorption of antibiotics

Supplementary files

Article information

Article type
Paper
Submitted
07 Dec 2016
Accepted
24 Feb 2017
First published
06 Mar 2017
This article is Open Access
Creative Commons BY license

RSC Adv., 2017,7, 14640-14648

Characterization of KOH modified biochars from different pyrolysis temperatures and enhanced adsorption of antibiotics

H. Huang, J. Tang, K. Gao, R. He, H. Zhao and D. Werner, RSC Adv., 2017, 7, 14640 DOI: 10.1039/C6RA27881G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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