咖啡渣成型制备生物质炭及其CH_(4)/N_(2)分离性能  

Preparation of molded biomass carbon from coffee grounds and its CH_(4)/N_(2) separation performance

作　　者：高雨舟 徐爽[1] 王成通 张雪洁 刘汝帅 陆安慧[1] GAO Yu-zhou;Xu Shuang;WANG Cheng-tong;ZHANG Xue-jie;LIU Ru-shuai;LU An-Hui(School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学化工学院,精细化工国家重点实验室,辽宁省低碳资源高值化利用重点实验室,辽宁大连116024

出　　处：《新型炭材料（中英文）》2022年第6期1145-1153,共9页New Carbon Materials

基　　金：中石化大连院项目(HX20200500);辽宁省高等学校创新团队支持计划(LT2016001);中央高校基本科研业务费资助(DUT20GJ215)。

摘　　要：本文以咖啡渣为原料,硅酸钠为黏结剂和造孔剂,通过挤条成型技术制备柱状炭前驱体,经高温炭化活化和碱洗除硅,获得高强度柱状多孔炭吸附剂(CGCs),研究其CH_(4)/N_(2)的吸附分离性能。红外光谱分析结果显示9wt%硅酸钠溶液与原料质量比为1.5的样品CGC-1.5含有丰富的含氧官能团。CGCs的比表面积和孔容积随着前驱体中硅酸钠含量的增加而增大,其中CGC-1.5的比表面积为527 m^(2)·g^(−1),总孔容为0.33 cm3·g^(−1)。氮吸附等温线和CO_(2)吸附等温线分析结果表明CGCs含有丰富的微孔、介孔以及大孔(个别样品),微孔主要集中在0.48 nm左右。在298 K和0.1 MPa条件下CGC-1.5对CH_(4)的平衡吸附量为0.87 mmol·g^(−1),CH_(4)/N_(2)(3/7)的IAST分离选择性达到10.3,优于多数生物质基多孔炭固体吸附剂和晶态材料。双组份动态穿透测试结果证实该材料在常压和加压条件均具有优异的CH_(4)/N_(2)动态分离性能,298 K时0.11 MPa和0.5 MPa条件下的动态选择性分别达到10.4和17.9,经10次吸-脱附循环测试,吸附量保持不变。CGC-1.5的机械强度高达123 N·cm^(−1),具有潜在的工业应用前景。Coffee grounds are promising precursors for excellent porous carbon adsorbents.During the preparation of the porous carbons,sodium silicate was used as a binder and pore-forming agent,and extrusion molding technology was used to prepare them in a columnar form.After carbonization,steam activation and silica removal by alkaline washing,high-strength columnar porous carbon adsorbents(CGCs)were obtained.Their CH_(4)/N_(2)separation performance was studied by multicomponent breakthrough experiments.The Brunauer-Emmett-Teller(BET)surface area of CGC-1.5(where 1.5 is the mass ratio of a 9 wt%sodium silicate aqueous solution to the coffee grounds)is 527 m^(2)·g^(−1).Both the N_(2) and CO_(2)adsorption isotherms show that the CGCs are rich in micropores and mesopores,with the micropores mainly centered at about 0.48 nm.FT-IR results show that CGC-1.5 has abundant oxygen-containing functional groups.At 298 K and 1 bar,its equilibrium adsorption capacity for CH_(4) is 0.87 mmol·g^(−1),and the separation selectivity for a CH_(4)/N_(2)mixture(3/7,vol/vol)is 10.3,which is better than most biomass-based porous carbon adsorbents and crystalline materials.Dynamic breakthrough tests show that CGC-1.5 has an excellent CH_(4)/N_(2)separation performance at both high and atmospheric pressures.The dynamic selectivities at 298 K,1.1 bar and 5 bar are 10.4 and 17.9,respectively.The adsorption capacity is unchanged after 10 adsorption-desorption cycles.The mechanical strength of CGC-1.5 is as high as 123 N·cm^(−1),which meets the criteria of industrial applications.

关 键 词：咖啡渣 成型 多孔炭 CH_(4)/N_(2)分离 

分 类 号：TQ028.2[化学工程]