磁性膨润土对养牛和养猪沼液的处理性能研究

采用微波共沉淀法合成磁性膨润土(M-Bent),并研究其对养牛和养猪沼液中化学需氧量COD和悬浮物SS的去除效果。M-Bent的XRD、VSM的表征结果表明:磁性Fe3O4纳米颗粒已负载到膨润土上,M-Bent的饱和磁化值为9.41 A·m2/kg,能够成功实现固液分离。吸附实验结果表明:随着M-Bent投加量的增加,对猪、牛沼液中COD和SS的去除率均增大,当投加量为1.0 g/L时,猪沼液中COD和SS的浓度即达到国家标准(GB 18596-2001)的排放要求;由于牛沼液中COD和SS的浓度较高,采用"混凝+吸附"的组合工艺处理牛沼液比单独使用M-Bent吸附的去除效果更佳,并且可达到GB 18596-2001的排放要求。

Treatment of Cattle and Pig Biogas Slurry by Magnetic Bentonite

Livestock biogas slurries in our country contain a large number of toxic and harmful pollutants including antibiotic and hormone, hence it is very important to control the emission concentrations of COD and SS in livestock biogas slurry. In this study, magnetic bentonite (M-Bent) was prepared by microwave precipitation oxidization method and applied for COD & SS removal from cattle and pig slurries. The characterization results of XRD and VSM showed that the magnetic Fe3O4 particles were coated on bentonite. The saturation magnetization value of M-Bent was 9.41 A?m2/Kg, which indicated that M-Bent can be separated from wastewater successfully. The adsorption experiments indicated that COD and SS removal from cattle and pig biogas slurry by M-Bent increased with the increase of adsorbent dosage. The concentrations of COD and SS in pig biogas slurry were up to the discharge standard of the national standards (GB 18596-2001) using 1.0 g/L M-Bent. Due to the higher concentration of COD and SS in cattle biogas slurry, the combined process of coagulation and adsorption was better than the single M-Bent adsorption for cattle biogas slurry and the emission concentrations of COD & SS can meet the GB 18596-2001 standard.