ABSTRACT

Natural clinoptilolite (Clin) was modified with iron oxide using three different methods including precipitation, wet-impregnation and ion-exchange and then the modified adsorbent with highest As(V) removal efficiency was encapsulated into Alginate by a simple cross-linking method to obtain Fe-Clin granules. The surface morphology and chemical composition of the Fe-Clin sorbents were characterized by scanning electron microscope and X-ray diffraction analysis. The selected Fe-Clin powders and granules possessed enhanced affinity towards the highly toxic arsenic pollutant in a very short time. Batch adsorption experiments showed that the Fe-Clin adsorbent can be widely used within a wide range of pH (2-9). In addition, to reach a high removal percentage (over 90%) of As(V), the optimum dosage of powder and granule shaped adsorbents was obtained as 0.1 and 0.6 g L⁻¹, respectively. Both adsorbents could successfully remove As(V) in a very short amount of time as 20 and 30 min in the case of powders and granules, respectively. The maximum adsorption capacity of Fe-Clin granules evaluated by using Langmuir adsorption isotherm was found to be 11.17 mg g⁻¹. By testing the granules in a circulated fluidized column experiment, it was demonstrated that Fe-Clin granules could remove As(V) up to an acceptable level (93%) within 10 min. This study demonstrates that Fe-Clin granules, obtained by exploiting natural clinoptilolite, iron oxide and alginate, are efficient, sustainable and fairly cheap adsorbents for the removal of arsenate from the aquatic environment in a very short contact time.

摘要

采用沉淀法、湿法浸渍法和离子交换法三种不同方法对天然斜发沸石（Clin）进行改性，然后通过简单的交联法将去除As（V）效率最高的改性吸附剂包封在海藻酸盐中，得到Fe-Clin 颗粒。通过扫描电子显微镜和 X 射线衍射分析对 Fe-Clin 吸附剂的表面形貌和化学成分进行了表征。所选的 Fe-Clin 粉末和颗粒在很短的时间内对剧毒砷污染物具有增强的亲和力。批量吸附实验表明，Fe-Clin 吸附剂可在较宽的 pH 值（2-9）范围内广泛使用。此外，为了达到较高的 As(V) 去除率（超过 90%），^-1，分别。两种吸附剂都可以在很短的时间内成功去除 As(V)，粉末和颗粒的吸附时间分别为 20 分钟和 30 分钟。通过使用 Langmuir 吸附等温线评估的 Fe-Clin 颗粒的最大吸附容量为 11.17 mg g ^-1。通过在循环流化柱实验中测试颗粒，证明 Fe-Clin 颗粒可以在 10 分钟内将 As(V) 去除至可接受的水平 (93%)。这项研究表明，通过利用天然斜发沸石、氧化铁和海藻酸盐获得的 Fe-Clin 颗粒是一种高效、可持续且相当便宜的吸附剂，可在极短的接触时间内从水生环境中去除砷酸盐。