Fe_(3)O_(4)/MoS_(2)改性生物炭活化过硫酸盐协同单宁酸调理污泥

Tannic Acid Coupled with Fe_(3)O_(4)/MoS_(2)Modified Biochar to Activate Permonosulfate for Improving Sludge Dewaterability

针对市政剩余污泥脱水难度大的问题,采用高铁酸钾活化法和水热法制备了Fe_(3)O_(4)/MoS_(2)改性生物炭(FeMo-BC),将其用于活化过硫酸盐(PMS)联合单宁酸(TA)调理污泥。以污泥比阻(SRF)和泥饼含水率(Wc)为测试指标,研究了改性生物炭结构特征及用量、pH、调理时间、PMS投加量和TA用量对市政污泥脱水的影响。结果表明,热解温度550℃,水热法中载铁生物炭(Fe-BC)与钼酸钠质量比为1∶1时制备的FeMo-BC活化PMS的效率最高。在FeMo-BC投加量为100 mg/g(以TS计)、pH为4、PMS和TA用量均为40 mg/g时,搅拌调理30 min,毛细吸水时间由29.3 s降为17 s,SRF由9.77×10^(11)m/kg下降为2.59×10^(11)m/kg,Wc由85.68%降为70.64%。通过活性自由基捕获实验以及分析污泥调理后胞外聚合物(EPS)中蛋白质和多糖含量的变化,表明FeMo-BC活化PMS生成的高氧化性SO_(4)^(-)·与^(1)O_(2)可以有效破解污泥中胞外聚合物,降低了紧密结合型EPS(TB-EPS)的含量,TA可以进一步络合沉淀EPS中的蛋白质,降低蛋白质含量;SEM分析结果显示,经过调理的污泥絮体呈明显的破碎状,有利于提高污泥脱水性能。

In order to improve the dewatering performance of municipal residual sludge,Fe_(3)O_(4)/MoS_(2)modified biochar(FeMo-BC)was prepared by using potassium ferrate activation method and followed hydrothermal treatment,and the FeMo-BC was used to active permonosulfate(PMS)combined with tannic acid(TA)to condition sludge.The sludge specific resis⁃tance(SRF)and water content(Wc)of sludge cake were used as evaluation index,the effects of structural characteristics and dosage of FeMo-BC,pH,conditioning time,PMS dosage and TA dosage on sludge dewatering performance were studied.The results showed that the highest efficiency of FeMo-BC in activating PMS was achieved when the pyrolysis temperature was 550℃,and the mass ratio of iron-loaded biochar(Fe-BC)to sodium molybdate in the hydrothermal process was 1∶1.When the dosage of FeMo-BC was 100 mg/g(calculated based on total solid,TS),the pH was 4,the dosages of PMS and TA were both 40 mg/g,and the sludge was stirred and conditioned for 30 minutes,the capillary suction time was decreased from 29.3 s to 17 s,SRF was decreased from 9.77×10^(11)m/kg to 2.59×10^(11)m/kg,and the Wc was decreased from 85.68%to 70.64%.Through active radical capture experiments,also analyzing the concentration changes of the protein and polysaccharide in extracellular polymeric substances(EPS)before and after sludge conditioning,it was found that the highly oxidative SO_(4)^(-)·and^(1)O_(2)derived from PMS which activated by FeMo-BC could effectively destroy EPS in the sludge,so as to reduce the con⁃tent of tightly bound EPS(TB-EPS).The addition of TA further complexed and precipitated proteins in EPS,and it could reduce protein content.SEM observation showed that the floccules of the conditioned sludge were fragmented,which was favorable for sludge dewatering.