Cost effective biochar gels with super capabilities for heavy metal removal

• Published in: RSC advances 2016-01, Vol.6 (79), p.7543-75439
• Main Authors: Chen, Pan-pan, Zhang, Hong-ping, Liu, Huan-de, Luo, Xue-gang, Lin, Xiao-yan, Lu, Xiong, Tang, Youhong
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Carbon; Chemisorption; Heavy metals; Lead (metal); Nanospheres; Surface chemistry
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c6ra10692g

A novel material, the biochar of a konjac-based material (KGMB), was prepared conveniently and economically with chemical activation of hydrothermally synthesized carbon nanospheres. Those carbon nanospheres have small sizes and high surface areas due to the high temperature sintering, which could be used for efficient adsorption of heavy metal ions such as Pb 2+ and Cd 2+ . Detailed adsorption behaviors of the optimized biochar including adsorption isotherms and adsorption kinetics were investigated. The results indicated that the adsorption process is spontaneous, exothermic and pseudo-second-order chemisorption. When the temperature was 298 K, the KGMB dose was 5 mg, the initial concentration of Pb 2+ and Cd 2+ was both 50 mg L −1 , the contact time was 24 h and pH of the ion solution was 5.5, the adsorption capacity reached up to 186.56 mg g −1 for Pb 2+ and 129.67 mg g −1 for Cd 2+ , respectively. What's more, the adsorption capacities of Pb 2+ and Cd 2+ were 69.34 and 71.06 mg g −1 , respectively, after adsorption-desorption process happened three times. Comparisons of the adsorption capacity of various adsorbents for Pb 2+ and Cd 2+ , showed that this biochar is superior to many other adsorbents in terms of adsorption capacity and it is a cheap, efficient and accessible biochar. Thus, KGMB is a promising candidate for wastewater treatment. A novel KGM based biochar with super heavy metal removal capacities can be prepared conveniently.