Gao Yurong, Fang Zheng, Lin Wenhui, Chen Hanbo, Bhatnagar Amit, Li Jianhong, Xie Yanhai, Bao Yanping, Chen Junfeng, Zhao Hongting, Meng Jun, Chen Wenfu, Wang Hailong
Agronomy College, Shenyang Agricultural University, Shenyang, 110866, China; Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong, 528000, China; Key Laboratory of Biochar and Soil Improvement, Ministry of Agriculture and Rural Affairs, China.
Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong, 528000, China.
Environ Pollut. 2023 Jan 15;317:120847. doi: 10.1016/j.envpol.2022.120847. Epub 2022 Dec 7.
The combined effects of graphene and biochar for enhanced adsorption of organic pollutants have not been demonstrated yet. Therefore, the mechanisms of graphene-modified biochar synthesis and its application to adsorption of contaminants remain unclear. In this study, the effect of flake-size graphene on biochar modification and its bisphenol S (BPS) adsorption performance was explored for the first time. Three sizes of graphene oxide were used as the precursor to prepare graphene/biochar composites using pyrolysis. It was found that the graphene with a small flake size was interspersed in the macropores of biochar, while the biochar was completely or mostly wrapped by the large-sized graphene sheet, which effectively prevented the agglomeration and pore blockage of biochar. Large-flake graphene oxide modified biochar (LGB) showed the highest adsorption capacity towards BPS, exhibiting 2.8 times higher adsorption than pristine biochar. Density functional theory (DFT) calculation suggested that the maximum diffusion barrier of O atoms in graphene coated cellulose (most frequently used biochar representative) could be reduced significantly (∼46%) at pyrolysis temperature of 873 K. Taking the advantage of small amount of graphene and enhanced adsorption performance, LGB could be a promising adsorbent for the removal of certain organic pollutants from wastewater and is conducive for the development of high-valued biochar modification.
石墨烯和生物炭对有机污染物吸附增强的联合效应尚未得到证实。因此，石墨烯改性生物炭的合成机制及其在污染物吸附中的应用仍不清楚。在本研究中，首次探索了片状尺寸石墨烯对生物炭改性及其对双酚S（BPS）吸附性能的影响。使用三种尺寸的氧化石墨烯作为前驱体，通过热解制备石墨烯/生物炭复合材料。结果发现，小片状尺寸的石墨烯散布在生物炭的大孔中，而生物炭则被大尺寸的石墨烯片完全或大部分包裹，这有效地防止了生物炭的团聚和孔堵塞。大尺寸氧化石墨烯改性生物炭（LGB）对BPS表现出最高的吸附容量，其吸附量比原始生物炭高2.8倍。密度泛函理论（DFT）计算表明，在873 K的热解温度下，石墨烯包覆纤维素（最常用的生物炭代表）中O原子的最大扩散势垒可显著降低（约46%）。利用少量石墨烯和增强的吸附性能，LGB可能是一种有前途的吸附剂，用于从废水中去除某些有机污染物，有利于高价值生物炭改性的发展。
