铁基污泥炭活化过硫酸盐调理污泥脱水

Preparation of iron-based sludge biochar and its application in sludge dewatering as a activator for persulfate

利用给水厂含铁污泥和污水厂污泥混合热解制备铁基污泥炭(Iron-SBC),作为过硫酸盐活化剂,用于调理污泥脱水。研究了Iron-SBC的最佳制备条件及其活化PDS调理污泥脱水的效果,并探究其活化机制。结果表明,Iron-SBC最佳制备条件为给水厂含铁污泥和污水厂污泥比例3∶1、热解温度800℃、热解时间1 h。XRD、FT-IR及BET分析结果表明,与原混合污泥相比,Iron-SBC比表面积和孔容增大,表面负载了Fe^(0)和FeO、Fe^(2)O^(3)、Fe^(3)O^(4)等铁的氧化物,并含有大量官能团。在活化PDS过程中,Iron-SBC表面的Fe^(0)、铁的氧化物及官能团等均能有效活化PDS,产生SO^(4)^(-)·和·OH自由基。XPS分析结果表明,Iron-SBC表面部分Fe^(2+)被氧化为Fe^(3+),官能团C-C、C-OH和C=O等被氧化,并有Fe-O键生成。经Iron-SBC/PDS调理污泥后,CST、SRF和W^(c)分别由原泥的19.1 s、14.9×10^(12)m·kg^(-1)和85.06%下降到8.4 s、5.4×10^(12)m·kg^(-1)和73.48%。本研究结果可为含铁污泥和剩余污泥资源化及污泥深度脱水提供参考。

Iron-based sludge biochar(Iron-SBC)was prepared by pyrolysis using mixed iron-contained sludge from water supply plant and waste activated sludge from sewage treatment plant.It was used as a activator for persulfate to condition sludge for dewatering.The optimal preparation conditions of Iron-SBC,and the effect and mechanism of PDS/Iron-SBC on sludge dewatering were studied.The results showed that the optimum preparation conditions of Iron-SBC were as follows:the ratio of iron-contained sludge to waste activated sludge was 3:1,pyrolysis temperature was 800℃,and the pyrolysis time was 1 hour.XRD,FT-IR and BET analysis showed that compared with the original mixed sludge,the specific surface area and pore volume of Iron-SBC increased,and its surface was loaded with iron oxides,as Fe^(0),FeO,Fe^(2)O^(3)and Fe^(3)O^(4),and contained a large number of functional groups.During the process of activating PDS,Fe^(0),iron oxides and functional groups on the surface of Iron-SBC all could effectively activate PDS and generate SO^(4)^(-)·and·OH free radicals.XPS analysis showed that Fe^(2+)on the surface of Iron-SBC was oxidized to Fe^(3+),and functional groups as C-C,C-OH and C=O were also oxidized,and Fe-O bonds were formed.After the sludge treatment by Iron-SBC/PDS,CST,SRF and W^(c)were reduced from 19.1 s,14.9×10^(12)m·kg^(-1)and 85.06%of the raw sludge to 8.4 s,5.4×10^(12)m·kg^(-1)and 73.48%,respectively.The results of this study can provide a technical reference for the utilization of ironcontained sludge and waste activated sludge,and also for the sludge deep dewatering.