- Preparation of KOH activated fish scale based biochar for the adsorptive removal of VOCs
- 摘要：以废弃生物质罗非鱼鳞为原料，用KOH一步炭化活化法制备了鱼鳞基多孔生物炭，借助XRD、SEM、FTIR及Boehm等方法对所制备生物炭的孔隙结构、形貌特征及表面化学性质进行表征。结果表明：650 ℃条件下制备的生物炭（FSBC-1）表面含有最多的含氧基团，其中酚羟基含量为0.3102 mmol·g-1，而850 ℃条件下制备的生物炭（FSBC-3）具备最高的比表面积（3370 m2·g-1）和孔容（1.91 cm3·g-1）。静态吸附实验表明，所制备生物炭对非极性分子甲苯的吸附过程符合Langmuir模型，而n-layer BET模型能更好地描述对极性分子丙酮的吸附。298 K条件下，FSBC-3对3 kPa甲苯的吸附量高达12.75 mmol·g-1，对20 kPa丙酮的吸附量达16.74 mmol·g-1。动态吸附实验和机理分析表明，对于低浓度VOCs，所制备生物炭对非极性分子甲苯的穿透吸附量主要受到材料比表面积及微孔孔容的影响，而极性分子丙酮的穿透吸附量与材料表面酚羟基数量呈显著正相关（R2 = 0.934）。本研究系统地研究了鱼鳞基生物炭的制备及其对两种典型VOC，甲苯和丙酮的吸附去除性能及机理，为高效VOCs吸附剂的制备提供参考。
- Abstract：Fish scale based biochars (FSBCs) were prepared from tilapia fish scale by one-step carbonization and KOH activation method. The pore structure, morphology and surface chemical properties of the FSBCs were analyzed using XRD, SEM, FTIR, Boehm method, etc. The results showed that the FSBC-1 prepared at 650 ℃ possessed the maximum amount of surface oxygen-containing groups, including 0.3102 mmol·g-1 of phenolic hydroxyl group, and the FSBC-3 prepared at 850 ℃ possessed the highest specific surface area (SSA) and pore volume, which were 3370 m2·g-1 and 1.91 cm3·g-1, respectively. Static adsorption experiments demonstrated the adsorption capacities of FSBC-3 for toluene and acetone were 12.75 mmol g-1 at 3 kPa and 16.74 mmol·g-1 at 20 kPa, respectively, at 298 K. Based on the data of dynamic adsorption experiments, the adsorption mechanism was analyzed. For low concentration of toluene (non-polar molecule), the adsorption capacity was mainly affected by SAA and micropore volume of FSBCs, while for low concentration of acetone (polar molecule), the adsorption capacity was highly positively correlated with the amount of phenolic hydroxyl groups on the surface of FSBCs (R2 = 0.934). This study systematically investigated the preparation of FSBC, and the adsorption performance and mechanism of FSBCs for two typical volatile organic compounds (VOCs), toluene and acetone. It may provide guidance on the preparation of high-efficient VOCs adsorbents.