The present work focuses on the utilization of biowaste material for a sustainable environment. In order to support the concept of ‘value-added product from waste’, Eggshell waste, which is a rich source of calcium is considered as a sustainable and renewable precursor for the synthesis of porous hydroxyapatite. This study introduces a novel, green and facile method for the synthesis of highly porous nano hydroxyapatite (nHA) and its magnetic composite aerogels (SPIONS@nHA) by freeze-drying technology. The synthesized materials have undergone through characterization. Perchlorate removal efficiency of the materials was investigated for the first time and the factors that influence the perchlorate adsorption capacity were explored and optimized. The magnetic composite of nHA showed an excellent separation in the presence of an external magnetic field from contaminated water after adsorption. XPS analysis and zeta potential measurements showed that the main driving force behind the adsorption of perchlorate is ion exchange and ion-pair formation/electrostatic interaction. Very fast removal kinetics was observed and the experimental maximum adsorption capacity for nHA and SPIONS@nHA were 148.4 and 305.8 mgg⁻¹ respectively. It is commendable that other commonly existing ions exhibited no remarkable effect on the adsorption performance, indicating SPIONS@nHA has an immense application potential. The adsorption process was found to follow by pseudo-second-order and intra-particle diffusion kinetic models. A novel method for the regeneration of perchlorate loaded adsorbent using phosphate buffer was also studied in this paper. The regeneration performance of spent magnetic adsorbent showed greater than 90% recovery on the adsorption capacity even after fifth cycle, revealing the stability, reusability and economic efficiency of the adsorbent. Thus, magnetic nanocomposite of the biogenic hydroxyapaptite can be exploited as a sustainable and efficacious material for the abolishment of perchlorate from aqueous media at near neutral pH.

目前的工作重点是利用生物废料来实现可持续的环境。为了支持“废物增值产品”的概念，富含钙的蛋壳废物被认为是合成多孔羟基磷灰石的可持续和可再生前体。本研究介绍了一种通过冷冻干燥技术合成高多孔纳米羟基磷灰石（nHA）及其磁性复合气凝胶（SPIONS@nHA）的新型、绿色、简便的方法。合成的材料已经过表征。首次研究了材料的高氯酸盐去除率，探索并优化了影响高氯酸盐吸附能力的因素。nHA 的磁性复合材料在存在外部磁场的情况下与吸附后的污染水表现出良好的分离效果。XPS 分析和 zeta 电位测量表明，高氯酸盐吸附背后的主要驱动力是离子交换和离子对形成/静电相互作用。观察到非常快的去除动力学，nHA 和 SPIONS@nHA 的实验最大吸附容量分别为 148.4 和 305.8 mgg⁻¹分别。值得称赞的是，其他普遍存在的离子对吸附性能没有显着影响，表明 SPIONS@nHA 具有巨大的应用潜力。发现吸附过程遵循伪二级和颗粒内扩散动力学模型。本文还研究了一种使用磷酸盐缓冲液再生高氯酸盐吸附剂的新方法。废磁性吸附剂的再生性能表明，即使经过第五次循环，吸附容量的回收率仍超过 90%，表明该吸附剂的稳定性、可重复使用性和经济性。因此，生物羟基磷灰石的磁性纳米复合材料可用作可持续且有效的材料，用于在接近中性 pH 值的水介质中去除高氯酸盐。