Resources Recycling Department, University of Science and Technology (UST), 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, South Korea; Center for Carbon Mineralization, Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, South Korea.
Department of Chemistry, Aligarh Muslim University, Aligarh, 202002, India.
J Environ Manage. 2021 Feb 15;280:111652. doi: 10.1016/j.jenvman.2020.111652. Epub 2020 Nov 20.
Phosphorus (P) concentration beyond threshold limit can trigger eutrophication in stagnant water bodies nevertheless it is an indispensable macronutrient for aquatic life. Even in low P concentration (≤1 mg L), P can be detrimental for ecosystem's health, but this aspect has not been thoroughly investigated. The elimination of low P content is rather expensive or complex. Therefore, a unique and sustainable approach has been proposed in which valorized bivalve seashells can be used for the removal of low P content. Initially, acicular shaped aragonite particles (21 μm) with an aspect ratio of around 21 have been synthesized through the wet carbonation process and used to treat aqueous solutions containing P in low concentration (P ≤ 1 mg L). Response surface methodology based Box-Behnken design has been employed for optimization study which revealed that with aragonite dosage (140 mg), equilibrium pH (10.15), and temperature (45 °C), a phosphorus removal efficiency of ~97% can be obtained in 10 h. The kinetics and isotherm studies have also been carried out (within the range P ≤ 1 mg L) to investigate a probable removal mechanism. Also, aragonite demonstrates higher selectivity (>70%) towards phosphate with coexisting anions such as nitrate, chloride, sulfate, and carbonate. Through experimental data, elemental mapping, and molecular dynamic simulation, it has been observed that the removal mechanism involved a combination of electrostatic adsorption of Ca ions on aragonite surface and chemical interaction between the calcium and phosphate ions. The present work demonstrates a sustainable and propitious potential of seashell derived aragonite for the removal of low P content in aqueous solution along with its unconventional mechanistic approach.
磷（P）浓度超过阈值会引发静止水体富营养化，但它是水生生物不可或缺的大量营养素。即使在低磷浓度（≤1mg/L）下，P 也可能对生态系统的健康有害，但这方面尚未得到彻底研究。消除低磷含量既昂贵又复杂。因此，提出了一种独特且可持续的方法，即利用有价值的双壳贝类贝壳来去除低磷含量。最初，通过湿碳酸化工艺合成了具有约 21 的纵横比的针状方解石颗粒（21μm），并将其用于处理含有低浓度 P（P≤1mg/L）的水溶液。基于响应面法的 Box-Behnken 设计已用于优化研究，结果表明，在方解石用量（140mg）、平衡 pH（10.15）和温度（45°C）的条件下，在 10h 内可获得约 97%的磷去除效率。还进行了动力学和等温线研究（在 P≤1mg/L 的范围内），以研究可能的去除机制。此外，方解石对磷酸盐具有较高的选择性（>70%），对共存的阴离子如硝酸盐、氯化物、硫酸盐和碳酸盐也是如此。通过实验数据、元素映射和分子动力学模拟，观察到去除机制涉及 Ca 离子在方解石表面的静电吸附和钙与磷酸盐离子之间的化学相互作用的结合。本工作证明了贝壳衍生的方解石具有可持续和有利的潜力，可用于去除水溶液中的低磷含量，以及其非常规的机制方法。
