Adsorption characteristics of ammonium ion onto hydrous biochars in dilute aqueous solutions

• Published in: Bioresource technology Vol. 272; pp. 465 - 472
• Main Authors: Fan, Ruemei, Chen, Ching-lung, Lin, Jui-yen, Tzeng, Jing-hua, Huang, Chih-pin, Dong, Chengdi, Huang, C.P.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2019
• Subjects: Adsorption; Ammonium; Ammonium Compounds - chemistry; Ammonium Compounds - isolation & purification; Biochar; Charcoal - chemistry; Heterogeneous adsorption; Indicator Dilution Techniques; Nitrogen - chemistry; Slow-release fertilizer; Solutions - chemistry; Surface complexation; Surface precipitation; Water - chemistry; Surface precipitation; Heterogeneous adsorption; Ammonium; Slow-release fertilizer; Biochar; Surface complexation
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2018.10.064

[Display omitted] •Bamboo biochar effectively adsorbs ammonium from dilute aqueous solutions.•pH, ionic strength, particle size, and temperature affect ammonium adsorption.•Surface hydroxyl groups development on hydrous biochar surface.•FTIR results show changes of surface chemical groups upon ammonium adsorption.•Surface complexation and precipitation are major ammonium adsorption reactions. This research aims at studying the characteristics of ammonium adsorption onto hydrous bamboo biochar. Results showed that pH played the most important role in ammonium adsorption. High ionic strength enhanced the ammonium adsorption capacity of bamboo biochar. Ammonium adsorption was exothermic and spontaneous. FTIR results showed shift, disappearance, or appearance of specific functional groups on the bamboo biochar surface. Surface precipitation and complex formation contributed to the adsorption of ammonium onto hydrous bamboo biochar. Biochar can be an effective adsorbate for ammonium removal from water. Additionally, the formation of nitrogen containing precipitates on the biochar surface, potentially, leads to the in-situ synthesis of slow-release fertilizer.