木质素活性炭的制备及其对硝基苯的吸附

利用工业碱木质素分别经KOH及H3PO4活化制备两种木质素活性炭（KAC和PAC），并用于模拟硝基苯废水的处理。采用SEM和IR等手段对木质素活性炭进行了表征。考察了木质素活性炭加入量、废水pH、吸附时间等因素对硝基苯吸附量的影响。表征结果显示，KAC具有丰富的孔结构，PAC表面含有多种功能基团。实验结果表明： 在吸附温度298 K、初始硝基苯质量浓度250 mg/L、木质素活性炭加入量1.0 g/L、废水pH 3、吸附时间24 h的条件下，KAC及PAC对硝基苯的吸附量分别为237.8 mg/g和211.9 mg/g，去除率分别达到91%和84%; KAC及PAC对硝基苯的吸附过程符合拟二级动力学方程，吸附等温线满足Langmuir等温吸附方程;当解吸剂的V（乙醇）∶V（去离子水）=9时，在PAC和KAC上吸附的硝基苯的解吸率分别达到99%和93%;木质素活性炭重复使用5次后，KAC和PAC对硝基苯的吸附量分别为115.4 mg/g和130.7 mg/g。

Preparation of Lignin-based Activated Carbons and Adsorption of Nitrobenzene

Two kinds of lignin-based activated carbons (KAC and PAC) were prepared from industrial alkali lignin by chemical activation with KOH and H3PO4 respectively，and used to treat the simulated nitrobenzene(NB) wastewater. They were characterized by SEM and IR. The factors affecting the nitrobenzene adsorption were studied. The characterization results show that KAC has a fully-porous structure，while PAC surface has many functional groups. The experimental results show that：Under the conditions of adsorption temperature 298 K，initial NB mass concentration 250 mg/L，lignin-based activated carbon dosage 1.0 g/L，wastewater pH 3 and adsorption time 24 h，the adsorption capacities of KAC and PAC to NB are 237.8 mg/g and 211.9 mg/g with 91% and 84% of removal rate respectively;The adsorption of NB on KAC and PAC can be represented by the pseudo-second-order kinetic model，and their adsorption isotherms fit well with the Langmuir equation;When the mixed liquid of ethanol and deionized water with V(ethanol)∶V(deionized water)=9 is used as desorption agent，the desorption rates of NB from PAC and KAC are 99% and 93% respectively;After reused by 5 times，the adsorption capacity of KAC and PAC to NB remain 115.4 mg/g and 130.7 mg/g respectively.