微米级蜂窝状软木多孔炭的制备及吸附四环素的性能

Honeycomb-like hierarchically porous carbon derived from waste biomass cork for efficient tetracycline removal

以工业废弃软木颗粒为原料,KHC_(2)O_(4)为活化剂,采用一步法慢速热解、活化得到具有蜂窝状结构的分级多孔活性炭KHBC,并将其应用于吸附水体中的盐酸四环素(TC)。通过拟合孔隙结构参数与四环素吸附量分析活性炭孔隙与吸附性能的关系,通过静态吸附实验探究初始pH、温度、初始质量浓度、离子强度等因素对吸附性能的影响,利用SEM、FT-IR等技术对KHBC吸附前后的物理化学结构进行表征,建立活化工艺-软木活性炭孔隙结构-吸附性能间的相关关系。结果表明,活化温度和KHC_(2)O_(4)添加比例的提高对比表面积和总孔体积有积极影响,并促进2~5 nm介孔的形成。比表面积和总孔体积与吸附TC容量间呈较强的线性关系,R^(2)分别为0.9852、0.958,2~5 nm介孔容积与TC吸附容量的R2为0.8388。当活化温度为900℃、活化剂添加比例为5∶1时,得到的KHBC5-900比表面积高达2447 m^(2)/g,2~5 nm的介孔明显增多,对水体中TC的吸附效果最好,其呈现微孔-介孔的孔径结构,在45℃时吸附量高达1113.45 mg/g,25℃时吸附量高达961.54 mg/g,5 min即可达吸附总量的85%,1 h可达吸附平衡,是未活化BC-900吸附量(21.25 mg/g)的46倍。且吸附能力几乎不受环境pH和离子强度的影响。KHBC5-900对TC的吸附符合准二级动力学方程和Langmuir等温吸附模型,吸附过程是自发和吸热的,吸附机理表明,孔隙填充是主要的吸附机制,同时存在π-π相互作用和氢键相互作用。

Hierarchical porous activated carbon(KHBC)with honeycomb structure was obtained by one-step slow pyrolysis using industrial waste cork particles as raw materials and KHC_(2)O_(4) as activator,and it was applied to adsorb tetracycline hydrochloride(TC)in water.The relationship between activated carbon pore structure and adsorption performance was analyzed by fitting pore structure parameters with tetracycline adsorption capacity.Static adsorption experiments were conducted to investigate the effects of initial pH,temperature,initial concentration,and ionic strength on adsorption performance.The physicochemical structures of KHBC before and after adsorption were characterized using SEM and FT-IR techniques,establishing the correlation between the activation process,cork activated carbon pore structure,and adsorption performance.The results show that increasing the activation temperature and KHC_(2)O_(4) addition ratio positively affects the specific surface area and total pore volume,promoting the formation of 2-5 nm mesopores.The specific surface area and total pore volume exhibit a strong linear relationship with TC adsorption capacity,with R^(2) values of 0.9852 and 0.958,respectively,and R2 of 0.8388 between 2-5 nm mesopore volume and TC adsorption capacity.At an activation temperature of 900℃ and an addition ratio of 5∶1,the resulting KHBC5-900 exhibits a specific surface area of 2447 m^(2)/g,with a significant increase in 2-5 nm mesopores,showing the best adsorption effect on TC in water.It presents a microporemesopore pore size structure,with adsorption capacities of 1113.45 mg/g at 45℃ and 961.54 mg/g at 25℃,reaching 85%of the total adsorption in 5 minutes and equilibrium in 1 hour,which is 46 times that of un-activated BC-900(21.25 mg/g).Also,the adsorption capacity is almost unaffected by environmental pH and ionic strength.The adsorption of TC by KHBC5-900 fits the quasi-second-order kinetic equation and Langmuir isotherm adsorption model,and the adsorption process is spontaneous and endothermic.The adsorption mechanism indicates that pore filling is the main adsorption mechanism,with the coexistence ofπ-πinteractions and hydrogen bond interactions.