Bosso S T, Enzweiler J
Instituto de Geociências, UNICAMP, Campinas, SP, Brazil.
Water Res. 2002 Nov;36(19):4795-800. doi: 10.1016/s0043-1354(02)00208-7.
Scolecite is a zeolite associated to basalts of the Parana Continental Igneous Province (PCIP South America). The potential of scolecite as a new material for heavy metal removal (Pb2+ Cu2+, Zn2+, Ni2+, Co2+ and Cd2+) from aqueous solutions is evaluated. The experiments were carried out by immersion of 0.5 g of sample in solutions containing the metal ions, and kept under constant agitation for 24h, at ambient temperature. The meq of cations retained per mass of scolecite was evaluated as a function of: initial concentration (5-60 mg L(-1)), pH (4-6), liquid/solid ratio (200, 1000 and 2000) and particle size. The results indicated a great affinity of scolecite for Cu2+ with a retention value of 130 microeq g(-1) at pH 6, Ci = 30 mg L(-1) and liquid/solid ratio of 200. In the same conditions, the maximum retention measured for the other ions were 64 microeq g(-1) (Zn2+), 56 microeq g(-1) (Pb2+), 31 microeq g(-1) (Ni2+), 7.8 microeq g(-1) (Co2+) and 3.2 microeq g(-1) (Cd2+). These values increase substantially when the L/S ratio is increased. The affinity of copper and lead for scolecite is discussed based on their free ionic forms (i.e., their hydrated bivalent ions) and their hydrolysis products. The remaining ions are retained as free ions.
钙沸石是一种与巴拉那大陆火成岩省（南美洲）玄武岩相关的沸石。评估了钙沸石作为从水溶液中去除重金属（Pb2+、Cu2+、Zn2+、Ni2+、Co2+和Cd2+）的新材料的潜力。实验通过将0.5克样品浸入含有金属离子的溶液中进行，并在室温下持续搅拌24小时。评估了每质量钙沸石保留的阳离子毫当量与以下因素的函数关系：初始浓度（5 - 60毫克/升）、pH值（4 - 6）、液固比（200、1000和2000）以及粒径。结果表明，在pH值为6、Ci = 30毫克/升和液固比为200的条件下，钙沸石对Cu2+具有很强的亲和力，保留值为130微当量/克。在相同条件下，其他离子的最大保留量分别为64微当量/克（Zn2+）、56微当量/克（Pb2+）、31微当量/克（Ni2+）、7.8微当量/克（Co2+）和3.2微当量/克（Cd2+）。当液固比增加时，这些值会大幅增加。基于铜和铅的自由离子形式（即它们的水合二价离子）及其水解产物，讨论了它们对钙沸石的亲和力。其余离子以自由离子形式被保留。
