摘要
低浓度的磷在污水处理中较难去除,排放至水体会造成水体富营养化。采用溶胶-凝胶法,以壳聚糖和FeCl_3·6H_2O为原料,通过原位水解-浸渍法制备出壳聚糖载纳米羟基氧化铁(CNFeOOH),对其进行了场发射透射电镜(HRTEM)、比表面积和孔径、X射线衍射仪(XRD)分析的表征。结果表明,CNFeOOH中含有类似正方针铁矿(β-FeOOH)的晶体结构,呈纳米棒状分布,长约10 nm,宽约2~3 nm,比表面积为76.240 m^2·g^(-1)。磷吸附实验结果表明:Freundlich吸附等温式能更好地描述CNFeOOH对磷的吸附特征,其实际最大吸附量为24.50 mg·g^(-1)(pH=6,T=(20±1)?C);动力学吸附平衡时间约为24 h,其吸附过程符合准二级动力学模式和颗粒内扩散模式,证明吸附过程中同时发生了物理吸附和化学吸附;溶液的p H对CNFeOOH吸附磷的影响较为明显,随pH升高,吸附量降低;离子强度(0.01~0.5 mol·L^(-1))则影响不大;共存阴离子(SO_4^(2-)、NO_3^-、HCO_3^-)对磷的吸附影响较小。因此,推断CNFeOOH对磷的吸附机理是以静电引力和配位作用为主的特性吸附。
Low-concentration phosphate is difficult to be removed during wastewater treatment process, whose excessive discharge into surface water could cause eutrophication. A novel sorbent of rod-like nano akaganeite impregnated chitosan（CNFeOOH） was fabricated via in-situ hydrolysis and impregnation technique using FeCl3·6H2O and chitosan in this study. The sorbent was characterized using multiple techniques and its performance for phosphate（PO4^3-） removal from aqueous solution was investigated. Analyses including high resolution transmission electron microscopy（HRTEM）, Brunauer-Emmett-Teller（BET） surface area and pore size distribution, X-ray diffraction（XRD） confirmed the structural characteristics of the sorbent. Above results indicated that the iron oxide particles in CNFeOOH is nano akaganeite（β-FeOOH）, whose shape was rod-like with a length of about 10 nm and a width of about 2 to 3 nm.The specific surface area of CNFeOOH was about 76.240 m^2·g^（-1）. The data obtained from batch experiments could be well described using Freundlich isotherm model. Meanwhile, the maximum adsorption capacity was 24.50 mg·g^（-1） when the solution p H was 6 at room temperature. CNFeOOH had a high adsorption rate towards phosphate, which was fitted better with the pseudo-second-order kinetics model. The sorption of phosphate on CNFeOOH was strongly dependent on p H, whereas its sorption was weakly dependent on ionic strength and coexisting SO4^2-, NO3^- and HCO3^-. It can be inferred from above analyses that phosphate adsorption mechanism on the CNFeOOH surface was dominated by electrostatic attraction and ligand exchange.
作者
杨金梅
吕建波
李莞璐
孙力平
王少坡
程方
YANG Jinmei;LYU Jianbo;LI Wanlu;SUN Liping;WANG Shaopo;CHENG Fang(Sehool of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, China;Tianjin Key Laboratory of Water Quality Science and Technology, Tianjin 300384, China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2018年第5期1286-1294,共9页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(51478292)
天津市自然科学基金资助项目(12JCYBJC14800)
天津市水质科学与技术重点实验室开放基金资助项目(TJKLAST-PT-2016-05)
国家水体污染控制与治理科技重大专项(2017ZX07107-002-4)
关键词
低浓度的磷
壳聚糖载纳米羟基氧化铁
棒状
吸附
low-concentration phosphate
nano akaganeite impregnated in chitosan
rod
adsorption
