Eltaweil Abdelazeem S, Abd El-Monaem Eman M, Elshishini Hala M, El-Aqapa Hisham G, Hosny Mohamed, Abdelfatah Ahmed M, Ahmed Maha S, Hammad Eman Nasr, El-Subruiti Gehan M, Fawzy Manal, Omer Ahmed M
Chemistry Department, Faculty of Science, Alexandria University Alexandria Egypt
Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University 163, Horrya Avenue Alexandria Egypt.
RSC Adv. 2022 Mar 15;12(13):8228-8248. doi: 10.1039/d1ra09193j. eCollection 2022 Mar 8.
The huge development of the industrial sector has resulted in the release of large quantities of phosphate anions which adversely affect the environment, human health, and aquatic ecosystems. Naturally occurring biopolymers have attracted considerable attention as efficient adsorbents for phosphate anions due to their biocompatibility, biodegradability, environmentally-friendly nature, low-cost production, availability in nature, and ease of modification. Amongst them, alginate-based adsorbents are considered one of the most effective adsorbents for removing various types of pollutants from industrial wastewater. The presence of active COOH and OH groups along the alginate backbone facilitate its physical and chemical modifications and participate in various possible adsorption mechanisms of phosphate anions. Herein, we focus our attention on presenting a comprehensive overview of recent advances in phosphate removal by alginate-based adsorbents. Modification of alginate by various materials, including clays, magnetic materials, layered double hydroxides, carbon materials, and multivalent metals, is addressed. The adsorption potentials of these modified forms for removing phosphate anions, in addition to their adsorption mechanisms are clearly discussed. It is concluded that ion exchange, complexation, precipitation, Lewis acid-base interaction and electrostatic interaction are the most common adsorption mechanisms of phosphate removal by alginate-based adsorbents. Pseudo-2 order and Freundlich isotherms were figured out to be the major kinetic and isotherm models for the removal process of phosphate. The research findings revealed that some issues, including the high cost of production, leaching, and low efficiency of recyclability of alginate-based adsorbents still need to be resolved. Future trends that could inspire further studies to find the best solutions for removing phosphate anions from aquatic systems are also elaborated, such as the synthesis of magnetic-based alginate and various-shaped alginate nanocomposites that are capable of preventing the leaching of the active materials.
工业部门的巨大发展导致大量磷酸根阴离子的释放，这对环境、人类健康和水生生态系统产生了不利影响。天然存在的生物聚合物因其生物相容性、可生物降解性、环境友好性、低成本生产、自然界中的可获得性以及易于改性等特点，作为磷酸根阴离子的高效吸附剂受到了广泛关注。其中，基于海藻酸盐的吸附剂被认为是从工业废水中去除各类污染物最有效的吸附剂之一。海藻酸盐主链上存在的活性羧基（COOH）和羟基（OH）基团有利于其物理和化学改性，并参与磷酸根阴离子的各种可能吸附机制。在此，我们重点全面概述基于海藻酸盐的吸附剂在除磷方面的最新进展。讨论了用包括粘土、磁性材料、层状双氢氧化物、碳材料和多价金属等各种材料对海藻酸盐进行改性的情况。除了吸附机制外，还清楚地讨论了这些改性形式去除磷酸根阴离子的吸附潜力。得出的结论是，离子交换、络合、沉淀、路易斯酸碱相互作用和静电相互作用是基于海藻酸盐的吸附剂除磷最常见的吸附机制。拟二级动力学模型和弗伦德利希等温线被确定为磷酸根去除过程的主要动力学和等温线模型。研究结果表明，基于海藻酸盐的吸附剂仍存在一些问题需要解决，包括生产成本高、浸出以及回收效率低等。还阐述了未来的发展趋势，这些趋势可能会激发进一步的研究，以找到从水生系统中去除磷酸根阴离子的最佳解决方案，例如合成能够防止活性材料浸出的磁性海藻酸盐和各种形状的海藻酸盐纳米复合材料。
