Rusmin Ruhaida, Sarkar Binoy, Tsuzuki Takuya, Kawashima Nobuyuki, Naidu Ravi
Future Industries Institute, University of South Australia, Building X, Mawson Lakes, SA 5095, Australia; Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor, Malaysia.
Future Industries Institute, University of South Australia, Building X, Mawson Lakes, SA 5095, Australia.
Chemosphere. 2017 Nov;186:1006-1015. doi: 10.1016/j.chemosphere.2017.08.036. Epub 2017 Aug 13.
A palygorskite-iron oxide nanocomposite (Pal-IO) was synthesized in situ by embedding magnetite into the palygorskite structure through co-precipitation method. The physico-chemical characteristics of Pal-IO and their pristine components were examined through various spectroscopic and micro-analytical techniques. Batch adsorption experiments were conducted to evaluate the performance of Pal-IO in removing Pb(II) from aqueous solution. The surface morphology, magnetic recyclability and adsorption efficiency of regenerated Pal-IO using desorbing agents HCl (Pal-IO-HCl) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na) (Pal-IO-EDTA) were compared. The nanocomposite showed a superparamagnetic property (magnetic susceptibility: 20.2 emu g) with higher specific surface area (99.8 m g) than the pristine palygorskite (49.4 m g) and iron oxide (72.6 m g). Pal-IO showed a maximum Pb(II) adsorption capacity of 26.6 mg g (experimental condition: 5 g L adsorbent loading, 150 agitations min, initial Pb(II) concentration from 20 to 500 mg L, at 25 °C) with easy separation of the spent adsorbent. The adsorption data best fitted to the Langmuir isotherm model (R = 0.9995) and pseudo-second order kinetic model (R = 0.9945). Pb(II) desorption using EDTA as the complexing agent produced no disaggregation of Pal-IO crystal bundles, and was able to preserve the composite's magnetic recyclability. Pal-IO-EDTA exhibited almost 64% removal capacity after three cycles of regeneration and preserved the nanocomposite's structural integrity and magnetic properties (15.6 emu g). The nanocomposite holds advantages as a sustainable material (easily separable and recyclable) for potential application in purifying heavy metal contaminated wastewaters.
通过共沉淀法将磁铁矿嵌入坡缕石结构原位合成了坡缕石-氧化铁纳米复合材料（Pal-IO）。通过各种光谱和微观分析技术研究了Pal-IO及其原始组分的物理化学特性。进行了批量吸附实验，以评估Pal-IO从水溶液中去除Pb(II)的性能。比较了使用脱附剂HCl（Pal-IO-HCl）和乙二胺四乙酸二钠盐（EDTA-Na）（Pal-IO-EDTA）再生的Pal-IO的表面形态、磁回收性和吸附效率。该纳米复合材料表现出超顺磁性（磁化率：20.2 emu g），比原始坡缕石（49.4 m² g）和氧化铁（72.6 m² g）具有更高的比表面积（99.8 m² g）。Pal-IO在25°C下表现出最大Pb(II)吸附容量为26.6 mg g（实验条件：吸附剂负载量5 g L，搅拌速度150次/分钟，初始Pb(II)浓度20至500 mg L），且废吸附剂易于分离。吸附数据最符合朗缪尔等温线模型（R² = 0.9995）和准二级动力学模型（R² = 0.9945）。使用EDTA作为络合剂进行Pb(II)脱附不会导致Pal-IO晶体束解聚，并且能够保持复合材料的磁回收性。Pal-IO-EDTA在三个再生循环后表现出近64%的去除能力，并保持了纳米复合材料的结构完整性和磁性（15.6 emu g）。该纳米复合材料作为一种可持续材料（易于分离和回收）在净化重金属污染废水方面具有潜在应用优势。
