氧化-热活化氮掺杂改性活性炭吸附金-硫代硫酸根络离子  

Nitrogen-doped activated carbon modified by oxidation-thermal activation to adsorption of gold thiosulfate complex

作　　者：张汉泉[1] 谢蕾 张鹏飞 邢张溪 胡敏[1] 余洪[1] ZHANG Han-quan;XIE Lei;ZHANG Peng-fei;XING Zhang-xi;HU Min;YU Hong(School of Resources & Safety Engineering,Wuhan Institute of Technology,Wuhan 430073,China)

机构地区：[1]武汉工程大学资源与安全工程学院,湖北武汉430073

出　　处：《应用化工》2021年第4期985-990,996,共7页Applied Chemical Industry

基　　金：湖北省教育厅科学技术研究项目资助(B2017055);武汉工程大学校长基金(XZJJ2020158)。

摘　　要：硫代硫酸盐法是最有可能取代氰化法的浸金方法,但活性炭不能有效吸附Au(S_(2)O_(3))^(2-)_(2),使得硫代硫酸盐浸金法难以得到工业应用。为提高活性炭对Au(S_(2)O_(3))^(2-)_(2)的吸附效果,采用氧化-热活化氮掺杂法对活性炭改性,H_(2)O_(2)为氧化剂,三聚氰胺与氨水为氮源,热活化制备出不同的氮掺杂活性炭。采用Boehm滴定法和X射线光电子能谱(XPS)分析了活性炭表面含氧酸官能团含量、元素含量及官能团种类。结果表明,氧化活性炭过程中,在H_(2)O_(2)的浓度为4 mol/L,温度为55℃下改性1 h,活性炭表面酸性官能团含量为0.70574 mmol/g。在热活化氮掺杂过程中,三聚氰胺的掺杂效果高于氨水,三聚氰胺用量为0.016 mol/L,室温掺杂4 h,且在900℃下热活化2 h所得的活性炭对Au(S_(2)O_(3))^(2-)_(2)的最大吸附量为547.12μg/g,热活化氮掺杂活性炭表面负载吡咯氮显著提升了其对Au(S_(2)O_(3))^(2-)_(2)的负载量。The thiosulfate method is the most likely to replace the cyanidation method for gold leaching,but activated carbon cannot effectively adsorb Au(S_(2)O_(3))^(2-)_(2),making the thiosulfate gold leaching method difficult to obtain industrial applications.In order to improve the adsorption effect of activated carbon on Au(S_(2)O_(3))^(2-)_(2),this article adopts oxidation-thermal activated nitrogen doping method to modify activated carbon,H_(2)O_(2)is the oxidant,melamine and ammonia are the nitrogen source.The thermal activation reaction is carried out in a vacuum atmosphere furnace to prepare different nitrogen-doped activated carbons.Boehm titration and X-ray photoelectron spectroscopy(XPS)were used to analyze the content of oxyacid functional group,element content and functional group types on the surface of activated carbon.The results showed that during the oxidation of activated carbon,the concentration of H_(2)O_(2)was 4 mol/L and the temperature was 55℃for 1 h.The content of acidic functional groups on the surface of activated carbon was 0.70574 mmol/g.In the process of thermally activated nitrogen doping,the doping effect of melamine is higher than that of ammonia.The amount of melamine is 0.016 mol/L,the room temperature is doped for 4 h,and the activated carbon is thermally activated at 900℃for 2 h.The maximum adsorption capacity of 547.12μg/g,the surface loading of pyrrole nitrogen on heat activated nitrogen-doped activated carbon significantly improves its resistance to Au(S_(2)O_(3))^(2-)_(2)of the load.

关 键 词：活性炭 改性 氧化 热活化-氮掺杂 吸附 金-硫代硫酸根络离子 

分 类 号：TQ131.23[化学工程—无机化工] TD982[矿业工程—选矿]