2D magnetic scallion sheathing-based biochar composites design and application for effective removal of arsenite in aqueous solutions

• Published in: Chemical engineering research & design 2019-12, Vol.152, p.384-392
• Main Authors: Song, Xiaoli, Zhang, Yun, Luo, Xiadan, Chen, Pei, Liu, Junliang
• Format: Article
• Language: English
• Subjects: Adsorption; Aqueous solutions; Arsenic; Composite materials; Iron oxides; Liquefaction; Magnetic biochar composites; Magnetic fields; Organic chemistry; Oxygen content; Pretreatment; Reaction kinetics; Sheathing; Sodium hydroxide; Two dimensional composites; Water purification
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2019.10.007

[Display omitted] •As(III) can be effectively removed from solutions by magnetic scallion sheathing-based biochar composites.•Surface groups played a significant role in As(III) removal of the composites.•Langmuir model well delineated the sorption affinity for As(III), especially Fe3O4/SS-BC.•Magnetic biochar composites have good reusability for As(III) removal. In this study, 2D magnetic composites based on Fe3O4 and scallion sheathings biochar were designed and prepared via simple hydrothermal method for removal of As(III) in aqueous solutions. The effects of acid/base pretreatment of biochar on the physicochemical properties and As(III) adsorption performance of the composites were investigated. The mechanism was discussed by XPS study and sorption isotherm models. The results revealed that oxygen content on the surface of the acid/base pretreated biochar decreased, which directly reduced the Fe3O4 content loaded on the biochar. The removal efficiency of As(III) by the composites based on original biochar, HCl-pretreated biochar and NaOH-pretreated biochar could reach 93.19%, 92.84% and 79.61%, respectively. XPS, adsorption kinetics, and isothermal adsorption model studies have shown that As(III) adsorption by these three composites is a chemical process with the maximum adsorption capacity of 39.47, 31.37 and 28.54 mg/g, respectively. In addition, the magnetic biochar composites still showed good reusability after 5 times of reuse. This study shows that the magnetic biochar composites possessed excellent performance to remove As(III) from solutions, especially the composites based on original biochar, indicating it is a promising adsorbent for arsenic removal from contaminated water.