Fe_(2)O_(3)/PC功能化复合多孔炭材料的制备及除磷机理  

Fabrication of Fe_(2)O_(3)/PC functionalized biochar composites for phosphate removal from wastewater: Adsorption properties and mechanism

作　　者：曾凤美 孙丰文 孙恩惠[2,3,4] 杜静 黄红英[2,3,4] 曲萍 雍宬[2,3,4] 徐跃定 ZENG Fengmei;SUN Fengwen;SUN Enhui;DU Jing;HUANG Hongying;QU Ping;YONG Cheng;XU Yueding(College of Meterials Science and Engineering,Nanjing Forestry University,Nanjing 210037;Institute of Agricultural Resources and Environment,Jiangsu Academy of Agricultural Sciences,Nanjing 210014;Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs,Nanjing 210014;Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization,Nanjing 210014)

机构地区：[1]南京林业大学材料科学与工程学院,南京210037 [2]江苏省农业科学院农业资源与环境研究所,南京210014 [3]农业农村部种养结合重点实验室,南京210014 [4]江苏省有机固体废弃物资源化协同创新中心,南京210014

出　　处：《环境科学学报》2021年第9期3487-3496,共10页Acta Scientiae Circumstantiae

基　　金：国家重点研发计划(No.2018YFC1903204-02);国家自然科学基金项目(No.41807132,22078136)。

摘　　要：采用热活化法辅以加压超声浸渍技术将硅酸盐水泥颗粒(PC)和Fe_(2)O_(3)负载于稻壳生物炭(RHC)的表面,得到了具有优异除磷效能和高选择性吸附性能的Fe_(2)O_(3)/PC功能化复合多孔炭材料(Fe-PC/RHC).基于磷吸附容量和磷去除率,对PC和Fe^(3+)负载进行量的优化;选取优化炭进行比表面积、孔径分布、物相结构、表面结构、微观形貌和零电位点表征测定.结果表明:复合炭材料表面均匀分散着硅酸钙盐、硅酸铁盐和Fe_(2)O_(3)等矿物活性颗粒,对其比表面积、孔结构和吸附性能具有增强作用;当RHC∶PC=0.8∶1(质量比),Fe^(3+)∶RHC=2∶1(2 mmol·g^(-1))时制备的炭材料Fe2-PC/RHC,投加0.2 g,处理100 mg·L^(-1)的磷酸盐溶液,在pH=6~8的条件下表现出了优异的吸附性能;铁盐的掺杂能有效调控介质pH值从11.09降低至7.71,zeta电位从2.82提高到7.57;准二级动力学模型和Langmiur模型更适用于描述Fe2-PC/RHC吸附磷酸盐的过程,吸附4 h后逐渐趋于平衡,饱和吸附量为69.92 mg·g^(-1);在几种常见阴离子和阳离子共存的情况下,Fe2-PC/RHC对磷酸盐仍然表现出了优异的选择性吸附;结合吸附前后材料的表征结果,化学吸附是主要的除磷机理,此外还可能存在配体交换和静电吸引.The functionalized biochar composite materials(Fe-PC/RHC) were successfully prepared by loading Portland cement(PC) particles and iron oxide onto rice husk biochar(RHC) through thermal activation assisted by ultrasonic impregnation techniques. The as-prepared biochar-based porous adsorbents exhibited an excellent phosphorus removal efficiency and a remarkable selective adsorption performance. The effects of PC and Fe^(3+) on the phosphorus adsorption capacity and phosphorus removal of RHC were investigated and the optimal amount of PC and Fe^(3+) were determined. The optimized carbon was selected to determine its characterizations of the specific surface area, pore size distribution, phase structure, surface structure, microscopic morphology and zero-potential point of optimized composite material. The results indicated that Fe_(2)O_(3), calcium silicate and ferric silicate were uniformly dispersed on the surface of Fe-PC/RHC, which is conductive to improve the specific surface area, the pore structure and adsorption performance of modified composite materials. The highest adsorption capacity occurred at the mass ratio of RHC∶PC at 0.8∶1, Fe^(3+)∶ RHC at 2∶1 with the dosage of 0.2 g, when the initial phosphate concentration was 100 mg·L^(-1) over a pH range from 6 to 8. The doping of ferric chloride can not only significantly increase the adsorption sites of the modified biochar, but also effectively reduce the pH value from 11.09 to 7.11 and increase the zeta potential of the composite material from 2.82 to 7.57. The pseudo-second-order model and Langmuir model can better describe the adsorption kinetic of phosphate on Fe2-PC/RHC where the adsorption gradually reaches equilibrium after 4 h and the saturated adsorption capacity is 69.92 mg·g^(-1). Furthermore, Fe2-PC/RHC showed a remarkably selective adsorption for phosphate and the effect of common coexisting cations and anions was insignificant. With combination of characterization results of composite material before and after adsorption, it is revea

关 键 词：生物炭 Fe_(2)O_(3) 硅酸盐水泥 吸附 

分 类 号：TB34[一般工业技术—材料科学与工程]