摘要
通过在合成功能材料层状双金属氢氧化物(layered double hydroxides,LDHs)过程中加入一定比例的清淤污泥制得改性污泥;并将其作为原料之一,制备4种不同质量掺混比的海绵城市用可净水透水砖。利用场发射扫描电子显微镜(SEM)、能谱分析仪(EDS)和X射线衍射仪(XRD),对掺混改性污泥前后透水砖的表面形态、化学成分与晶体结构进行表征;通过抗压性和透水性检测,结合吸附预试验结果,确定最佳改性质量掺混比;开展等温吸附、吸附动力学和热力学试验,探究掺混改性污泥前后透水砖对磷酸盐的吸附特性和作用机制。结果表明:1)掺混比为1∶1的改性清淤污泥透水砖,相较于其他几种掺混比更具实用性,在初始浓度32 mg/L,透水砖投加量1.2 g,吸附时间360 min时,对磷酸盐的吸附容量达到2.08 mg/g;2)掺混改性污泥前后透水砖对磷酸盐的吸附过程均符合Langmuir等温吸附模型和准二级动力学模型,且掺混后透水砖对磷酸盐的最大饱和吸附容量提升了25%;3)改性污泥的掺混,使得透水砖吸附磷酸盐所需能量减少,自发性增强,有助于透水砖在实际应用中对雨水的净化。
In this work,modified sludge was prepared by adding a certain proportion of dredging sludge in the process of synthesizing functional material layered double hydroxides(LDHs).It was used as one of the raw materials to prepare four kinds of water permeable bricks for sponge city construction with different mass mixing ratios.The surface morphology,chemical composition,and crystal structure of permeable bricks before and after mixing modified sludge were characterized by a field emission scanning electron microscope(SEM),energy dispersive spectrometer(EDS),and X-ray diffractometer(XRD).Through the detection of compressive strength and water permeability,combined with the results of purification experiments,the optimum blending ratio of modified quality was determined.Isothermal adsorption,adsorption kinetics,and thermodynamics experiments were carried out to explore the adsorption performance and mechanism of phosphate on permeable bricks before and after mixing modified sludge.The results showed that:1)the modified dredged sludge permeable brick with a blending ratio of 1∶1 was more practical than several other mass blending ratios.When the initial phosphate concentration was 32 mg/L,the dosage of water permeable brick was 1.2 g,and the adsorption time was 360 min,then the adsorption capacity of phosphate reached 2.08 mg/g;2)the adsorption process of phosphate by permeable brick before and after mixing modified sludge conformed to Langmuir isothermal adsorption model and pseudo-second-order kinetic model,and the maximum saturated adsorption capacity of phosphate by permeable brick increased by 25%after mixing modified sludge;3)the addition of modified sludge reduced the energy required for the permeable brick to adsorb phosphate,and enhanced the spontaneity,which helps the permeable brick to purify rainwater in practical applications.
作者
秦耀君
张翔凌
李栩灏
蔡纪贤
李雅婷
雷晓芸
李伊凡
QIN Yaojun;ZHANG Xiangling;LI Xuhao;CAI Jixian;LI Yating;LEI Xiaoyun;LI Yifan(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)
出处
《环境工程》
CAS
CSCD
2024年第3期73-81,共9页
Environmental Engineering
基金
国家自然科学基金项目(31670541)。
