Zhan Xin-Min, Zhao Xuan
Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
Water Res. 2003 Sep;37(16):3905-12. doi: 10.1016/S0043-1354(03)00312-9.
Adsorption is a method for removing lead from wastewater. The adsorption of lead on a new adsorbent synthesized from natural condensed tannin has been investigated using a series of batch adsorption experiments. The study on the adsorption mechanism indicates that the adsorbent performed in aqueous solutions as an ionic exchanger whose end group was sodium ion (Na(+)). One lead (II) ion (Pb(2+)) was adsorbed onto the adsorbent by taking the place of two Na(+) ions. The maximum exchangeable Na(+) present on the adsorbent was measured with the proton titration experiments and it was up to 1.0 mmol x Na(+)g(-1) dry adsorbent. To a significant extent, pH influenced the extraction of lead from aqueous solutions. The lead removal efficiency was up to 71%, 87% and 91% with initial solution pH at 3.0, 3.6 and 4.2, respectively. The Langmuir equation fitted the adsorption isotherm data well. The maximum adsorption capacity of lead calculated was 57.5, 76.9 and 114.9 mg lead g(-1) dry adsorbent at initial solution pH of 3.0, 3.6 and 4.2, respectively. Therefore, the adsorbent does offer favorable characteristics in lead removal from acidic wastewater.
吸附是一种从废水中去除铅的方法。通过一系列批量吸附实验，研究了铅在由天然缩合单宁合成的新型吸附剂上的吸附情况。对吸附机理的研究表明，该吸附剂在水溶液中作为一种离子交换剂发挥作用，其端基为钠离子（Na(+)）。一个铅（II）离子（Pb(2+)）通过取代两个Na(+)离子而被吸附到吸附剂上。通过质子滴定实验测定了吸附剂上存在的最大可交换Na(+)量，其高达1.0 mmol x Na(+)g(-1)干吸附剂。在很大程度上，pH值影响了从水溶液中提取铅的过程。当初始溶液pH值分别为3.0、3.6和4.2时，铅的去除效率分别高达71%、87%和91%。朗缪尔方程很好地拟合了吸附等温线数据。在初始溶液pH值为3.0、3.6和4.2时，计算得出的铅的最大吸附容量分别为57.5、
