不同活化剂制备秸秆-污泥复配活性炭的机理及性能

Mechanism and Performance of Preparation of Compositional Straw-Sludge Based Activated Carbon with Different Chemical Activators

以污水处理厂剩余污泥和芦苇秸秆为基料,分别采用KOH、H3PO4和ZnCl2为活化剂,通过化学活化和高温热解的方法制备了秸秆-污泥复配活性炭,研究了焙烧温度、各活化剂浓度及酸洗条件等对制备的复配活性炭吸附碘值、得率等的影响。结果表明经KOH、H3PO4及ZnCl2活化制备复配活性炭,其在本试验中的最佳活化剂浓度和焙烧温度分别为0.8、0.2和0.8 mol/L以及800、400和800℃,在该条件下制得的样品经酸洗后其吸附碘值和得率分别为661.7、646.4和603.3 mg/g以及51.3%、63.5%和58.1%。N2吸附脱附曲线表明三种活化剂活化后制得的活性炭均以微孔为主,其中经KOH活化的样品其在较高相对压力(P/P0≥0.5)时,吸附容量明显高于其他样品,表明在其活化热解过程中伴随有一定量的中孔生成。热分析发现经三种活化剂活化后的样品热解过程均伴随多段失重现象,显示出不同的活化机理。

A straw-sludge based on activated carbon was prepared by a physicochemical activation and pyrolysis process using KOH, H3PO4 and ZnCl2 as chemical activators, respectively. Effect of pyrolysis temperature, chemical concentration and washing con- ditions on carbon＇s iodine value and yield were investigated. The results show that the optimal concentration of activators and thermal treatment temperatures are 0.8, 0.2, 0.8 mol/L and 800, 400, 800 ℃ under conditions of which the iodine value and carbon yield of the prepared products are 661.7, 646.4, 603.3 mg/g and 51.3 %, 63.5 %, 58.1%, respectively. Nz adsorption isotherms indicate a large amount of micro porous in chemicals activated carbon and an obvious meso porous structure can be observed when using KOH as activator. Thermo analysis suggests a staged carbonization process of all chemicals activated precursors, indicating a quiet different activation mechanism during the thermal process.