Department of Electrical and Computer and Environment Engineering, West Tehran Branch-Islamic Azad University, Tehran, Iran.
Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Sci Rep. 2022 Jun 10;12(1):9655. doi: 10.1038/s41598-022-13756-3.
Nowadays, the presence of excessive ions in water resources is of utmost concern and has attracted increasing attention; therefore, excessive amounts of these ions such as fluoride should be removed from drinking water. Conventional water treatment processes are shown to be incapable of the complete removal of redundant fluoride from aqueous water bodies, whereas adsorption is a promising, effective, cost-benefit, and simple method for this purpose. This study aimed to synthesize effective adsorbents from bivalve shells and evaluate the adsorption function of bivalve shells in removing fluoride from aqueous solutions. In this study, the oyster shell was collected from the Persian Gulf's seaside and were crushed by manual mortar and blender, and graded with standard sieves with 70 mesh size. The prepared bivalve shell was characterized by SEM and FTIR. To investigate and optimize various variables on fluoride removal percentage a response surface methodology based on central composite design (RSM-CCD) was used. Under optimal conditions (pH: 5.5, adsorbent dose: 0.3 g/L, contact time: 85 min and fluoride concentration: 3 mg/L) the maximum removal efficiency was 97.26%. Results showed that the adsorption equilibrium and kinetic data were matched with the isotherm Langmuir Model (R = 0.98) with q = 27.31 mg/g and pseudo-second-order reaction (R = 0.99). Also, a thermodynamic study exhibited that the adsorption process of fluoride into bivalve shells was an exothermic reaction and could not be a spontaneous adsorption process. Based on the results, the bivalve shell was found as an appropriate adsorbent to remove fluoride from aqueous solutions.
如今，水资源中过量离子的存在是一个极其关注的问题，引起了越来越多的关注；因此，应该从饮用水中去除过量的氟离子等这些离子。常规的水处理工艺被证明无法完全去除水中多余的氟化物，而吸附是一种有前途的、有效的、具有成本效益的和简单的方法。本研究旨在从双壳贝类中合成有效的吸附剂，并评估双壳贝类在去除水溶液中氟化物方面的吸附功能。在这项研究中，从波斯湾的海滨收集了牡蛎壳，并通过手动研钵和搅拌器将其粉碎，并使用标准 70 目筛进行分级。通过 SEM 和 FTIR 对制备的双壳贝类进行了表征。为了研究和优化各种变量对氟去除率的影响，采用基于中心复合设计（RSM-CCD）的响应面法。在最佳条件下（pH：5.5、吸附剂用量：0.3 g/L、接触时间：85 分钟和氟浓度：3 mg/L），最大去除效率为 97.26%。结果表明，吸附平衡和动力学数据与等温 Langmuir 模型（R=0.98）匹配，q=27.31mg/g，准二级反应（R=0.99）。此外，热力学研究表明，氟化物进入双壳贝类的吸附过程是一个放热反应，不可能是自发的吸附过程。根据结果，双壳贝类被发现是一种从水溶液中去除氟化物的合适吸附剂。
