高比表面硫脲改性花生壳炭的制备及对四环素和铜的吸附

Preparation of High Specific Surface Thiourea Modified Peanut Shell Carbon and Adsorption of Tetracycline and Copper

以硫脲和磷酸为改性剂,通过一步碳化制备了高活性氮硫共掺杂高比表面改性花生壳炭PBC-NS.探讨了改性花生壳炭PBC-NS吸附单一与混合体系中TC/Cu(Ⅱ)吸附特性,并研究了改性对TC/Cu(Ⅱ)吸附的增强作用及机制.结果表明,改性花生壳炭PBC-NS成功引入了砒啶氮、石墨氮、C—S—C和—SH等氮硫官能团,且改性后比表面积高达1437 m^(2)·g^(-1),比改性前提升了2.6倍.改性花生壳炭PBC-NS对单一体系TC和Cu(Ⅱ)的最大吸附量分别为585mg·g^(-1)和21.2mg·g^(-1),较改性前提升2.6倍和2.7倍;且PBC-NS对混合体系中的TC和Cu(Ⅱ)的饱和吸附量较单一体系提升13mg·g^(-1)和6.8mg·g^(-1).PBC-NS在4次重复使用后对TC和Cu(Ⅱ)的吸附容量仍能达到初始吸附量的66%和70%.等温拟合与现代光谱分析表明,改性使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位的化学络合和高比表面引起的孔填充共同作用.结果表明硫脲/磷酸化学改性能有效提升花生壳炭对TC/Cu(Ⅱ)的吸附性能,可为混合污染高吸附性能生物炭结构调控和TC/Cu(Ⅱ)水污染吸附处理提供新思路.

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~2·g^(-1),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^(-1)and 21.2 mg·g^(-1),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^(-1)and 6.8 mg·g^(-1)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.