title: One-step synthesis of a novel N-doped microporous biochar derived from crop straws with high dye adsorption capacity.
abstract: N-doping is one of the most promising strategies to improve the adsorption capacity and selectivity of carbon adsorbents. Herein, synthesis, characterization and dye adsorption of a novel N-doped microporous biochar derived from direct annealing of crop straws under NH3 is presented. The resultant products exhibit high microporosity (71.5%), atomic percentage of nitrogen (8.81%), and adsorption capacity to dyes, which is about 15-20 times higher than that of original biochar. Specifically, for the sample NBC800-3 pyrolyzed at 800°C in NH3 for 3 h, its adsorption for acid orange 7 (AO7, anionic) and methyl blue (MB, cationic) is up to 292 mg g(-1) and 436 mg g(-1), respectively, which is among the highest ever reported for carbonaceous adsorbents. The influences of N-doping and porous structure on dye adsorption of the synthesized carbons are also discussed, where electrostatic attraction, π-π electron donor-accepter interaction, and Lewis acid-base interaction mainly contribute to AO7 adsorption, and surface area (especially pore-filling) dominates MB adsorption. The N-doped biochar can be effectively regenerated and reused through direct combustion and desorption approaches.
authors.affiliation: Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA. Electronic address: lianfei@caas.cn.
authors.forename: Fei
authors.initials: F
authors.lastname: Lian
authors.affiliation: Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China; College of Life Science, Tianjin Normal University, Tianjin 300387, China.
authors.forename: Guannan
authors.initials: G
authors.lastname: Cui
authors.affiliation: Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China.
authors.forename: Zhongqi
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Life Science, Tianjin Normal University, Tianjin 300387, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Duo
authors.affiliation: Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, China.
authors.forename: Guilong
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
mesh_terms: D000327:Adsorption; D000641:Ammonia / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry; D002606:Charcoal / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D005240:Feasibility Studies; D009584:Nitrogen / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry; D016062:Porosity
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; C540010:biochar; D002606:Charcoal; D000641:Ammonia; C414357:Methyl Blue; D009584:Nitrogen; C014722:2-naphthol orange
keywords: Crop straw; Dye adsorption; N-doped biochar; Physicochemical property; Recyclability