Min Bing-Kun, Li Kun-Quan
College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
Huan Jing Ke Xue. 2023 Mar 8;44(3):1528-1536. doi: 10.13227/j.hjkx.202205046.
High activity nitrogen and sulfur co-doping high specific surface-modified peanut shell carbon PBC-NS was prepared through one-step carbonization using thiourea and phosphoric acid as modifiers. The TC/Cu(Ⅱ) adsorption characteristics of peanut shell carbon in single and mixed-adsorption systems were discussed, and the enhancement effect and mechanism of modification on TC/Cu(Ⅱ) adsorption were studied. The results showed that the modified peanut shell carbon PBC-NS successfully introduced nitrogen-sulfur functional groups such as Pyridinic N, Graphitic N, C- S-C, and -SH, and the modified specific surface area was as high as 1437 m·g, which was 2.6 times higher than that before modification. The maximum adsorption capacities of modified peanut shell carbon PBC-NS for single-system TC and Cu(Ⅱ) were 585 mg·g and 21.2 mg·g, respectively, which were 2.6 times and 2.7 times higher than those before modification. The saturated adsorption capacities of TC and Cu(Ⅱ) in the system were increased by 13 mg·g and 6.8 mg·g compared with that in the single system. The adsorption capacity of PBC-NS for TC and Cu(Ⅱ) could still reach 66% and 70% of the initial adsorption capacity after four times of repeated use. Isotherm fitting and modern spectroscopic analysis indicated that the substantial increase in the adsorption capacity of TC/Cu(Ⅱ) on PBC-NS by modification was mainly attributed to the combined effect of chemical chelation of nitrogen-sulfur active functional sites and pore filling caused by high specific surface area. These results indicated that thiourea/phosphoric acid chemical modification could effectively improve the adsorption capacity of peanut shell carbon for TC/Cu(Ⅱ), which can provide a new idea for the structural regulation of mixed-pollution biochar with high adsorption capacity and adsorption treatment of TC/Cu(Ⅱ) water pollution.
以硫脲和磷酸为改性剂，通过一步碳化法制备了高活性氮硫共掺杂高比表面积改性花生壳炭PBC-NS。探讨了花生壳炭在单吸附体系和混合吸附体系中对TC/Cu(Ⅱ)的吸附特性，研究了改性对TC/Cu(Ⅱ)吸附的增强作用及机理。结果表明，改性花生壳炭PBC-NS成功引入了吡啶氮、石墨氮、C-S-C和-SH等氮硫官能团，改性后的比表面积高达1437 m·g，是改性前的2.6倍。改性花生壳炭PBC-NS对单体系TC和Cu(Ⅱ)的最大吸附量分别为585 mg·g和21.2 mg·g，分别是改性前的2.6倍和2.7倍。与单体系相比，该体系中TC和Cu(Ⅱ)的饱和吸附量分别提高了13 mg·g和6.8 mg·g。PBC-NS对TC和Cu(Ⅱ)的吸附量在重复使用4次后仍能达到初始吸附量的66%和70%。等温线拟合和现代光谱分析表明，改性后PBC-NS对TC/Cu(Ⅱ)吸附量的大幅提高主要归因于氮硫活性官能团的化学螯合作用和高比表面积引起的孔隙填充作用。这些结果表明，硫脲/磷酸化学改性能有效提高花生壳炭对TC/Cu(Ⅱ)的吸附能力，为高吸附容量混合污染生物炭的结构调控及TC/Cu(Ⅱ)水污染的吸附处理提供了新思路。
