硅藻土负载羟基氧化铁的制备及除磷性能研究

Preparation and phosphorous removal performance of FeOOH coated diatomite

采用铁盐法在硅藻原土上负载羟基氧化铁(FCD)颗粒,制备出一种新型的除磷吸附剂,利用SEM、EDAX、XRD以及物理吸附等手段对FCD样品进行表征检测。结果表明:经过改性后的硅藻土表面负载了颗粒状的羟基氧化铁,其微孔和表面粗糙度发生明显变化,比表面积比硅藻原土增大了10倍。还利用摇床实验模拟自然环境,探讨FCD的投加量、吸附扰动时间、pH以及温度等因素对FCD除磷效果的影响。研究结果表明:在常温和酸性条件下,扰动3 h时,该吸附剂能达到较好的吸附效果,在25℃、pH=3时除磷率达到92%,吸附容量为3.68 mg/g,比较适合应用于呈酸性的珠江水水样;Langmuir和Freundlich等温吸附方程都能较好地描述硅藻土对磷的等温吸附特征,为有效控制水体富营养化提供了理论依据。

A new phosphorous sorbent was prepared by ferric salt technology in which ferric oxyhydroxide（FeOOH） particles were immobilized on diatomite to produce FeOOH coated diatomite（FCD）.Prepared FCD samples were characterized by means of SEM,EDAX,XRD,and physical adsorption etc..From the results of characterization,conclusions were generalized as follows：FeOOH particles were immobilized on the surface of diatomite,causing its micropore and surface roughness changed evidently,and specific surface area became 10 times of unmodified diatomite.In addition,using shaking-bottle-incubating test to simulate natural environment,influences of the factors including FCD dosage,oscillating adsorption time,pH,and temperature on adsorption effect were studied and discussed.According to study results,best adsorption effect was reached at ambient temperature and acidic condition,after oscillating for 3 h.At 25 ℃,pH=3,phosphorous removal rate of 92% was reached,the adsorption capacity was 3.68 mg/g,thus FCD was suitable for phosphorus removal of the Pearl River of which water sample is acidic.Langmuir and Freundlich adsorption isotherm equations can well describe isothermal adsorption characteristics of diatomite to phosphorus,which provide theoretical basis for effectively controlling water eutrophication.