Laboratory of Environmental Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, PR China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, PR China; Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment, Suzhou, 215009, PR China.
Laboratory of Environmental Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, PR China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, PR China; Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment, Suzhou, 215009, PR China.
Chemosphere. 2022 Jun;296:133898. doi: 10.1016/j.chemosphere.2022.133898. Epub 2022 Feb 5.
Traditional biological processes combined with chemical precipitation methods can effectively reduce phosphate concentration in wastewater. However, discharge standards required additional advanced treatment technologies, and the removal of low phosphorus concentration is complicated and expensive. This study proposes application of a simple and recyclable adsorbent to remove low-concentration phosphorus from water. The removal efficiency of phosphorus from low-strength synthetic wastewater was investigated and the adsorption mechanism was analyzed. When the initial phosphorus concentration was 2.0 mg/L, the phosphorus adsorption capacity of Ca-GAT increased to 0.891 mg/g from 0.074 mg/g for GAT at 298 K and pH of 7. Phosphorus adsorption on Ca-GAT performs well when the solution pH is in the range of 5-10, and it is not conducive to the adsorption reaction when the solution pH exceeds 11. The competing anions (such as NO, SO, HCO and F) existed, Ca-GAT still performed better in removing phosphorus. Then, the saturated absorbents could be effectively regenerated with a 0.5 mos/L NaOH solution, while desorption efficiency was reduced from 97.11% to 33.06% after fifth regeneration cycle. Finally, Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the Ca content on the Ca-GAT surface played an important role in capturing phosphate ions from wastewater. Phosphorus was mainly removed via the formation of Ca-phosphorus precipitation. To some extent, ligand exchanges of CO and OH- with HPO and HPO were also beneficial for phosphorus removal. The present work shows that attapulgite has sustainable and beneficial potential in the removal of low-strength phosphorous in wastewater, and the phosphorus loaded adsorbent can be used in the agriculture as slow-release fertilizer.
传统的生物处理法结合化学沉淀法可以有效地降低废水中的磷浓度。然而，排放标准需要额外的先进处理技术，而去除低浓度磷则复杂且昂贵。本研究提出了一种简单且可回收的吸附剂，用于从水中去除低浓度磷。研究了该吸附剂从低浓度合成废水中去除磷的效率，并分析了吸附机制。当初始磷浓度为 2.0mg/L 时，GAT 的磷吸附容量从 298K 和 pH 值为 7 时的 0.074mg/g 增加到 0.891mg/g。当溶液 pH 值在 5-10 范围内时，Ca-GAT 对磷的吸附效果良好，当溶液 pH 值超过 11 时，不利于吸附反应。存在竞争阴离子（如 NO、SO、HCO 和 F）时，Ca-GAT 仍能更好地去除磷。然后，用 0.5mol/L 的 NaOH 溶液可有效再生饱和吸附剂，而经过五次再生循环后，解吸效率从 97.11%降低至 33.06%。最后，扫描电子显微镜-能谱仪（SEM-EDS）、傅里叶变换红外光谱（FTIR）和 X 射线光电子能谱（XPS）分析表明，Ca-GAT 表面的 Ca 含量在从废水中捕获磷酸根离子方面起着重要作用。磷主要通过形成 Ca-磷沉淀而被去除。在某种程度上，CO 和 OH-与 HPO 和 HPO 的配体交换也有利于磷的去除。本研究表明，凹凸棒石在去除废水中低浓度磷方面具有可持续和有益的潜力，负载磷的吸附剂可用作农业中的缓释肥料。
