污水处理用多孔载体超临界流体技术制备实验研究

Preparation of porous carriers for wastewater treatment based on supercritical fluid process

生物膜载体是生物膜法污水处理的关键核心部分,载体性能的优良与否直接影响着生物膜法处理污水的效果。采用超临界流体诱导相分离-循环干燥工艺,以聚甲基丙烯酸甲酯(PMMA)为溶质,丙酮为溶剂,超临界CO_2为非溶剂,制备了PMMA污水处理多孔载体,采用扫描电镜对载体内部结构进行表征,考察了PMMA初始浓度、CO_2压力、CO_2温度、保压时间t_1、干燥时间t_2、卸压时间t_3等操作条件对多孔载体内部结构的影响。结果表明,利用该工艺可成功制备污水处理用PMMA多孔载体,且载体孔径分布均匀、孔间连通性好、孔隙率高。实验最优操作条件为PMMA初始溶液浓度20%(质量分数),CO_2压力10MPa、温度45℃,t_1 90min,t_2 90min,t_3 90min。

Biofilm carrier is a key part of the biological membrane method for wastewater treatment.The performance of the carrier has a direct impact on the wastewater treatment by biological membrane method.PMMA porous carrier was prepared by supercritical fluid induced phase separation-cyclic drying process,with PMMA as model material,acetone as solvent and supercritical CO_2 as non-solvent.Carrier interior structure was characterized by scanning electron microscope.The influence of operating conditions,such as PMMA concentration,CO_2 pressure,CO_2 temperature,pressure holding time t_1,drying time t_2 and pressure relief time t_3,on carrier interior structure was studied.The results show that the PMMA wastewater treatment porous carrier with uniform pore size distribution,excellent connectivity and high porosity can be prepared successfully by the process.The optimal preparation conditions of this process in this work are PMMA concentration of 20wt%,CO_2 pressure of 10 MPa,CO_2 temperature of 45℃,pressure holding time t_1 of 90min,drying time t_2 of 90min and pressure relief time t_3 of 90min.