多孔二氧化锆纳米材料的制备与砷吸附性能表征

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	多孔二氧化锆纳米材料的制备与砷吸附性能表征
	崔航
学位类型	博士
导师	尚建库 ; 李琦
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	As(Iii)As(v) 砷吸附 Zro2• Xh2oam-zro2 水热方法 Zro2/fe2o3 As(Iii) As(v), Arsenic Removal, Zro2• Xh2o, Am-zro2, Hydrothermal Process
摘要	"简单和低成本的水热和热处理方法合成了晶化纳米ZrO2•xH2O。砷吸附试验研究发现，纳米ZrO2•xH2O对As(III)和 As(V)，不论是实验水还是自然水，都有较高的吸附性能。在pH为7的中性环境下，低平衡浓度砷溶液中纳米ZrO2•xH2O对As(III)和As(V)的吸附量分别为0.6mgg-1和3.6mgg-1，高平衡浓度砷溶液中对As(III)和As(V)的吸附量分别为47mgg-1和29mgg-1。简单和低成本的水热方法合成了无定形纳米am-ZrO2。砷吸附试验研究发现，纳米am-ZrO2对实验含砷水或自然含砷水中的As(III)和As(V)具有更加高效的移除效果。纳米am-ZrO2在pH7时低平衡浓度砷溶液中As(III)和As(V)吸附量分别为0.92mgg-1和5.2mgg-1；高平衡浓度砷溶液中As(III)和As(V) 吸附量分别为83.2mgg-1和32.5mgg-1。当吸附剂加载量非常低仅有0.1g-1L时，纳米am-ZrO2 就可以将80ppb的阳宗海自然水降到MCL饮用水标准。在溶液中存在超高浓度竞争离子时，ZrO2•xH2O和am-ZrO2也能吸附砷。通过改变NH3H2O条件及水热温度调控制备am-ZrO2的比表面积。研究发现，在较快的沉淀剂加入速度下、70ml氨水制备的纳米am-ZrO2结构较疏松、孔较多、且比表面积较大。最高的比表面积为488m2g-1。当氨水加入量为70ml时使溶液中存在高浓度的NH3H2O、OH-/NH4+/Cl-，从而在较宽的温度范围130 oC-170 oC条件下制备的ZrO2比表面积高达488m2g-1。并研究了其砷吸附效果。在较低平衡浓度0.01mgL-1 As(III)溶液、pH7条件下，纳米ZrO2对As(III)的吸附量为4.89mgg-1，是第四章制备的ZrO2的As(III)吸附量的5.3倍。在高平衡浓度下，As(III)吸附量也提高到133.4mgg-1。为了从水溶液中移除吸附剂并减少纳米材料扩散到环境中，本文还尝试将纳米ZrO2•xH2O和am-ZrO2负载到玻璃纤维布上，结果表明分散到玻璃纤维布上的ZrO2•xH2O和am-ZrO2具有更好的除砷效果。为了更好的从水溶液中移除吸附剂，本文制备了一种新的砷吸附剂-磁性纳米粒子ZrO2/Fe2O3，此复合材料不但降低了成本而且具有较强的磁性，可以实现处理砷后从水溶液中磁性分离。铁掺杂量为0.0035mol时，制备的材料比表面积高（450m2 g-1），且As(III)吸附量较高为22mg g-1。本文用新的方法制备了一种氧化锆球形颗粒，此材料是通过成本较低的琼脂材料（海藻中提取）为模板剂制备的。所制备的氧化锆球（平均直径0.6mm）为高比表面（98 m2/g）纳米多孔结构材料。并进行了固定床砷吸附实验与模拟。通过实验计算与模拟验证，得到孔扩散系数以及外部质量传输系数分别为Dp=3.8X10-6cm2s-1，Kf=3.5X10-3cm/s。并利用这些参数和PSDM模型进行预测三价和五价完整砷吸附效果。关键词：As(III)，As(V)，砷吸附，ZrO2•xH2O，am-ZrO2，水热方法，ZrO2/Fe2O3，PSDM模型"
其他摘要	"The crystalline hydrated zirconia，ZrO2•xH2O nanoparticles were synthesized by a simple and low-cost hydrothermal process followed with heat treatment. ZrO2•xH2O nanoparticles demonstrated an effective removal performance on both As(III) (arsenite) and As(V) (arsenate) in either lab-prepared or natural water samples. The adsorption capacities of these ZrO2•xH2O nanoparticles on As(III) and As(V) at pH7 are about 0.6mgg-1 for As(III) and 3.6mgg-1 for As(V) at the low arsenic equilibrium concentration of 0.01mgL-1, and greater than 47mgg-1 and 29mgg-1 at the high arsenic equilibrium concentration. The amorphous zirconia, am-ZrO2 nanoparticles were synthesized by a simple and low-cost hydrothermal process. Compared with crystalized ZrO2•xH2O nanoparticles, the am-ZrO2 nanoparticles demonstrated higher adsorption performance on both As(III) and As(V). At pH ~ 7, under low equilibrium arsenic concentrations (Ce at 0.01mgL-1, the maximum contaminant level (MCL) for arsenic in drinking water), the amount of arsenic adsorbed by am-ZrO2 nanoparticles is over 0.92mgg-1 for As(III) and over 5.2mgg-1 for As(V), respectively；under high equilibrium arsenic concentrations， the adsorption capacity is over 83 mg/g for As(III) and over 32.4mgg-1 for As(V), respectively. With only a relatively low material loading concentration (0.1gL-1), these am-ZrO2 nanoparticles successfully removed most of the arsenic contamination from natural water samples of Lake Yangzonghai to meet the MCL for drinking water. The adsorption process is also effective under high concentration competing ions. Specific surface area of ZrO2 nanoparticles were regulated by changing hydrothermal synthesized conditions of NH3H2O and hydrothermal temperature. It indicates that am-ZrO2 nanoparticles prepared by faster rate of precipitation with adding 70ml ammonia has looser structure, higher pore and higher specific surface area. The amorphous -zirconium oxide nanoparticles with highest specific surface area of 488m2g-1 were obtained by faster adding 70mL NH3H2O and at hydrothermal temperature of 150℃. For condition of the adding 70mL NH3H2O, due to the confinement of high concenration of NH3H2O/NH4+/Cl- confining the growth of the particles, am-ZrO2 nanoparticles obtained has the highest BET SSA of about 488m2 g-1 at a wide range of hydrothermal temperature 130 oC-170 oC. The highest BET SSA indicate that am-ZrO2 nanoparticles demonstrated an effective removal performance on As(III). The adsorption capacities of these ZrO2 nanoparticles on As(III) at pH7 are about 4.89mgg-1 at the low arsenic equilibrium concentration of 0.01mgL-1, 5.3 times of the adsorption capacity of ZrO2 nanoparticles synthesized under conditionof slowly droping 50mL NH3H2O and at hydrothermal temperature of 150℃, and more than 133.4 mg g-1 at the high arsenic equilibrium concentration of 76mgL-1. The ZrO2 nanoparticles were immobilized on glass fiber cloth to minimizethe dispersion of nanoparticles into treated water bodies. The composite cloth showed a higher arsenic adsorption capacity than that of ZrO2 nanoparticles. As an alternative, am-ZrO2/Fe2O3 magnetic nanoparticles synthesized by hydrothermal process. Due to doping Fe, am-ZrO2/Fe2O3 synthesized by lower cost has strong magnetismZrO2/Fe2O3 with 0.0035mol Fe has a BET SSA of 450m2g-1 and an As(III) adsorption capacity of 22mgg-1., and so could be separated from water with magnet fields after treatment of arsenic. The adsorbent am- Nanostructured zirconium oxide spheres for arsenic removal were fabricated on a low cost agar carrierThe zirconium oxide spheres with average diameter of 0.6mm and BET SSA of 98m2g-1 have highly porous structure (obtained from seaweed). （=0.79）. The continuous ﬂow experiments and PSDM were carried out, and the pore diffusion coefﬁcient (Dp=3.8X10-6cm2s-1) and the external mass transport coefﬁcient (Kf=3.5X10-3cms-1) were obtained. The Dp and Kf were used with PSDM to predict the arsenic breakthrough curve."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64445
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	崔航. 多孔二氧化锆纳米材料的制备与砷吸附性能表征[D]. 北京. 中国科学院金属研究所,2012.