Integrated Science and Technology Research Center, Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket, 83120, Thailand.
Department of Chemistry, Faculty of Sciences, Shahrekord University, P.O. Box 115, Shahrekord, Iran.
Environ Res. 2024 Dec 15;263(Pt 3):120229. doi: 10.1016/j.envres.2024.120229. Epub 2024 Oct 23.
The removal of phosphate from water is necessary to avoid eutrophication. In this work, a novel composite film of calcium silicate hydrate (CSH) immobilized within calcium cross-linked polyvinyl alcohol (CSH-PVA) was developed for efficient phosphate removal from water using a simple and environmentally friendly preparation method. The characterization showed that flake crystal-like CSH nanoparticles were immobilized on a PVA film (86-106 μm). Amorphous calcium phosphate and hydroxyapatite were observed after phosphate adsorption. The adsorption efficiency and capability of phosphate were examined under various conditions using batch experiments. The phosphate removal data fitted well to the pseudo-second-order kinetic model (R = 0.9903-0.9999) and the Langmuir isotherm model (R = 0.9958), which estimated a maximum removal capacity (99.01 mg g). Phosphate adsorption was found to be endothermic with spontaneous adsorption via chemisorption with strong affinity (ΔG° = -3.96 to -8.62 kJ mol, ΔH° = 65.4 kJ mol, and ΔS° = 232.94 J mol K). Additionally, significant amounts of fluoride and carbonate ions affected phosphate adsorption at levels exceeding 5-fold and 20-fold that of phosphate, respectively. An excellent removal efficiency was achieved in the range of 72.06%-97.87% using phosphate-containing real samples. Therefore, the proposed CSH-PVA film showed great potential for effective phosphate removal from water, with potential for further use as a fertilizer.
从水中去除磷酸盐是避免富营养化所必需的。在这项工作中，开发了一种新型的硅酸钙水合物（CSH）固定在交联聚乙烯醇（CSH-PVA）内的复合膜，通过简单且环保的制备方法从水中高效去除磷酸盐。表征表明，片状晶体状的 CSH 纳米颗粒固定在 PVA 膜上（86-106μm）。吸附磷酸盐后观察到无定形磷酸钙和羟基磷灰石。通过批处理实验在各种条件下检查了磷酸盐的去除效率和能力。磷酸盐去除数据很好地符合准二级动力学模型（R=0.9903-0.9999）和 Langmuir 等温模型（R=0.9958），估计最大去除容量为 99.01mg g。发现磷酸盐吸附是吸热的，通过化学吸附具有强亲和力的自发吸附（ΔG°=-3.96 至-8.62kJ mol，ΔH°=65.4kJ mol，ΔS°=232.94J mol K）。此外，当氟离子和碳酸根离子的浓度分别超过磷酸盐浓度的 5 倍和 20 倍时，它们会显著影响磷酸盐的吸附。在含有磷酸盐的实际样品中，去除效率在 72.06%-97.87%的范围内非常高。因此，所提出的 CSH-PVA 膜在从水中有效去除磷酸盐方面显示出巨大的潜力，具有作为肥料进一步使用的潜力。
