载钠硅碳羟基磷灰石的制备及其对水中As(Ⅴ)的吸附特性  

Adsorption of As(Ⅴ) from Aqueous Solution by Sodium and Silicate-Modified Carbonate Hydroxyapatite Composite

作　　者：曾荣英[1,2,3] 唐文清 康卓 陈静 刘兴 龚道新 ZENG Rongying;TANG Wenqing;KANG Zhuo;CHEN Jing;LIU Xing;GONG Daoxing(College of Resources&Environment,Hunan Agricultural University,Changsha 410128,China;Department of Chemistry and Materials Science,Hengyang Normal University,Hengyang 421008,China;Key Laboratory of Functional Organometallic Materials of Hunan Province College,Hengyang Normal University,Hengyang 421008,China)

机构地区：[1]湖南农业大学资源环境学院,湖南长沙410128 [2]衡阳师范学院化学与材料科学学院,湖南衡阳421008 [3]功能金属有机材料湖南省普通高等学校重点实验室,湖南衡阳421008

出　　处：《环境科学研究》2018年第11期1925-1932,共8页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.21603065);湖南省普通高校哲学社会科学重点研究基地"环境教育研究中心"项目(No.HJ15K01);"功能金属有机材料"湖南省普通高等学校重点实验室开放基金项目(No.GN18K02)~~

摘　　要：由于自然和人为活动导致自然水体和土壤被As(砷)污染,严重危及生态环境并已受到广泛关注.为实现更大程度地去除含As废水的新型吸附材料,以废弃蛋壳为原材料,采用超声波法制备多孔状且较大比表面积的Na-Si-CHAP[Ca10-xNax(PO4)6-y-z(Si O4)z(CO3)y(OH)2-α,载钠硅碳羟基磷灰石],深入分析去除含As(Ⅴ)废水的吸附特性.通过BET比表面积、扫描电镜(SEM)、EDX(能量色散X射线光谱)、X-射线衍射(XRD)等手段对样品进行表征,并进一步探讨了pH、吸附时间、初始ρ[As(Ⅴ)]以及反应温度等因素对吸附效果的影响.结果表明:在pH为6. 0、作用时间为60 min、反应温度为313 K等优化条件下,0. 2 g Na-Si-CHAP对100 mL 30 mg/L含As(Ⅴ)废水的去除率和平衡吸附容量分别为96. 53%和14. 48 mg/g. Langmuir等温吸附模型较好地拟合了吸附试验数据,313 K下相关系数(r2)高达0. 998 0,饱和吸附容量达46. 73 mg/g,明显高于其他同类材料;准二级动力学模型可较好地描述该吸附行为,相关系数高达0. 999 9;热力学参数ΔG(吉布斯自由能变)、ΔH(焓变)和ΔS(熵变)的计算值显示,该吸附过程为自发吸热过程.研究显示,Na-Si-CHAP作为一种吸附剂,对含As(Ⅴ)的去除效果明显优于同类材料.Arsenic contamination in water and soil due to natural and anthropogenic activities has been documented as a serious problem worldwide,posing a major threat to the environment.The present study focuses on the synthesis of sodium-and silicate-modified carbonate hydroxyapatite composites(Na-Si-CHAP)with relatively high specific area and pore volume,as a novel adsorbent for arsenic removal.The crystallized adsorbent was prepared by an ultrasonic method using waste egg shells and employed for enhancing the adsorption of As(Ⅴ)from aqueous solutions.The structures of the Na-Si-CHAP samples were characterized by Brunauer-Emmett-Teller(BET)analysis,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and powder X-ray diffraction(XRD).The effects of initial pH,contact time,initial concentration of As(Ⅴ)and temperature were studied.The optimum adsorption conditions were initial As(Ⅴ)concentration of 30 mg L,pH=6.0,m=0.2 g,adsorption time 60 min and temperature 313 K.Under the optimized conditions,the removal efficiency and adsorption capacity of As(Ⅴ)from solution by Na-Si-CHAP could reach to 96.53%and 14.48 mg g,respectively.The equilibrium data agreed well with the Langmuir isotherm(r 2>0.9980),and based on this model the saturated adsorption capacity of Na-Si-CHAP for As(Ⅴ)was found to be 46.73 mg g,which clearly exceeded the capacities of other similar adsorbents.The pseudo-second order kinetic model was proposed to fit the experimental data(r 2>0.9999).The thermodynamic parameters such as Gibb′s free energy(ΔG),enthalpy(ΔH)and entropy(ΔS)were calculated.The results reveal that As(Ⅴ)adsorption onto Na-Si-CHAP is spontaneous and endothermic in nature.The new adsorbent holds promise for application in the treatment of the heavy metal wastewater and restoration of heavy metal-polluted water bodies,because the properties of Na-Si-CHAP as an adsorbent for As(Ⅴ)are superior to those similar materials.

关 键 词：Na-Si-CHAP As(Ⅴ) 吸附因子 优化 吸附机理 

分 类 号：X703.1[环境科学与工程—环境工程]