Jia Kun, Pan Bingcai, Lv Lu, Zhang Qingrui, Wang Xiaoshu, Pan Bingjun, Zhang Weiming
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
J Colloid Interface Sci. 2009 Mar 15;331(2):453-7. doi: 10.1016/j.jcis.2008.11.068. Epub 2008 Dec 6.
Titanium phosphate (TiP) exhibits preferable sorption toward lead ion in the presence of competing calcium ions at high levels, however, it is present as fine or ultrafine particles and cannot be directly employed in fixed-bed or any flow-through systems due to the excessive pressure drop and poor mechanical strength. In the present study a new hybrid sorbent TiP-001 was fabricated by impregnating titanium phosphate (TiP) nanoparticles onto a strongly acidic cation exchanger D-001 for enhanced lead removal from waters. D-001 was selected as a host material mainly because of the Donnan membrane effect resulting from the immobilized sulfonic acid groups bound on the exchanger matrix, which would enhance permeation of the target metal cation prior to effective sequestration. TiP-001 was characterized by transmission electron micrograph (TEM), X-ray diffraction (XRD), and pH-titration. Batch and column sorption onto TiP-001 was assayed to evaluate its performance as compared to the host exchanger D-001. Lead sorption onto TiP-001 is a pH-dependent process due to the ion-exchange nature, and its sorption kinetics follows the pseudo-second-order model well. Compared to D-001, TiP-001 displays highly selective lead sorption in the presence of competing calcium cations at concentration of several orders higher than the target metal. Fixed-bed sorption of a synthetic feeding solution indicates that lead retention by TiP-001 results in a conspicuous decrease of this toxic metal from 0.50 to below 0.010 mg/L (drinking water standard recommended by WHO). Moreover, its feasible regeneration by dilute HCl solution also favors TiP-001 to be a feasible sorbent for enhanced lead removal from water.
在存在高浓度竞争钙离子的情况下，磷酸钛（TiP）对铅离子表现出较好的吸附性能。然而，它以细颗粒或超细颗粒形式存在，由于压降过大和机械强度差，不能直接用于固定床或任何流通系统。在本研究中，通过将磷酸钛（TiP）纳米颗粒负载到强酸性阳离子交换剂D - 001上制备了一种新型混合吸附剂TiP - 001，以增强从水中去除铅的能力。选择D - 001作为主体材料主要是因为固定在交换剂基质上的磺酸基团产生的唐南膜效应，这将在有效螯合之前增强目标金属阳离子的渗透。通过透射电子显微镜（TEM）、X射线衍射（XRD）和pH滴定对TiP - 001进行了表征。测定了TiP - 001上的批量和柱吸附，以评估其与主体交换剂D - 001相比的性能。由于离子交换性质，铅在TiP - 001上的吸附是一个pH依赖过程，其吸附动力学很好地符合准二级模型。与D - 001相比，在竞争钙离子浓度比目标金属高几个数量级的情况下，TiP - 001表现出对铅的高度选择性吸附。对合成进料溶液的固定床吸附表明，TiP - 001对铅的保留导致这种有毒金属从0.50显著降低至低于0.010 mg/L（世界卫生组织推荐的饮用水标准）。此外，用稀盐酸溶液对其进行可行的再生也有利于TiP - 001成为从水中增强去除铅的可行吸附剂。
