Ice- and MOF-templated porous carbonaceous monoliths for adsorptive removal of dyes in water with easy recycling

• Published in: Environmental research 2020-07, Vol.186, p.109608-109608, Article 109608
• Main Authors: Fu, Qingshan, Zhang, Lei, Zhang, Haifei, Chen, Xuedan, Li, Mingtian, Gong, Min
• Format: Article
• Language: English
• Subjects: Carbon monolith; Dye adsorption; Ice-templating; Metal-organic frame; Water treatment
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2020.109608

Various nanoporous particles, nanofibers have been employed for adsorptive removal of dyes from wastewater. However, these nanomaterials are difficult in separation from solution, generally by centrifugation or filtration. These processes are tedious and will limit the upscale applications. Herein, a hierarchically porous carbon monolith has been fabricated on grounds of ice and metal organic framework (MOF) templating method. The prepared carbonaceous monolith exhibited abundant ice-templated macropores, MOF-templated micropores and mesopores, and a high BET (Brunauer-Emmett-Teller) special surface area (530 m2 g−1). The monolith achieved an MB (methylene blue) adsorption capacity of 95.82 mg g−1 (10 mg adsorbent/5 mL aqueous dye solution) and a theoretic maximum value of 179.86 mg g−1 by the Langmuir model. Compared with MB, the adsorption capacity for MO (methyl orange) was lower. Several adsorption kinetics and isotherms models were used for analysis of adsorptive data, and the results demonstrated the adsorption of MB and MO on the porous carbon monolith is a spontaneous endothermic physisorption process, which was mainly controlled by electrostatic reaction. Importantly, the monolith could be easily picked up using tweezers and used for recycling tests. After four cycles, the 94% of the initial adsorption capacity for MB can be retained. •Combination of Ice and MOF templates for preparation of porous carbon monolith.•Hierarchical pores were achieved in the carbon monolith.•The monolith exhibited high-performance removal of MB from aqueous solutions.•The carbonaceous monolith can be separated from solution easily.•The monolith can be reused several times without obvious capacity attenuation.