A review of biochar as a low-cost adsorbent for aqueous heavy metal removal

• Published in: Critical reviews in environmental science and technology Vol. 46; no. 4; pp. 406 - 433
• Main Authors: Inyang, Mandu I., Gao, Bin, Yao, Ying, Xue, Yingwen, Zimmerman, Andrew, Mosa, Ahmed, Pullammanappallil, Pratap, Ok, Yong Sik, Cao, Xinde
• Format: Journal Article
• Language: English
• Published: Boca Raton Taylor & Francis 16.02.2016; Taylor & Francis Ltd
• Subjects: Activated carbon; Adsorbents; aqueous solutions; biochar; Black carbon; Charcoal; Complexation; Computational efficiency; electrostatic interactions; Electrostatic properties; feedstocks; Heavy metals; Literature reviews; Low cost; Mathematical models; Metals; pyrogenic carbon; Sorption; trace element; wastewater; Wastewater treatment; Water treatment
• ISSN: 1064-3389; 1547-6537; 1547-6537
• DOI: 10.1080/10643389.2015.1096880

As a low-cost adsorbent, biochar can be used as a low-cost adsorbent for wastewater treatment, particularly with respect to treating heavy metals in wastewater. A number of studies have demonstrated effective removal of heavy metals from aqueous solutions by biochar and, in some cases, proven the superiority of biochars to activated carbons. Among several factors affecting the sorption ability of biochars, feedstock materials play a significant role. This review incorporates existing literature to understand the overall sorption behavior of heavy metals on biochar adsorbents. Depending on the biochar type, heavy metal can be removed by different mechanisms such as complexation, physical sorption, precipitation and electrostatic interactions. Mathematical sorption models can be used to understand the efficiency of biochar at removing heavy metals, and promote the application of biochar technology in water treatment.