Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
Department of Biotechnology, M.S.Ramaiah Institute of Technology, Bengaluru, 560054, Karnataka, India.
Environ Res. 2022 Sep;212(Pt B):113274. doi: 10.1016/j.envres.2022.113274. Epub 2022 Apr 21.
The present work reports the synthesis of hydroxyapatite (HAp) via the green chemistry approach by using the leaf extract of copper pod tree and its adsorptive potential to remove Acid blue 113 (AB113) dye. FESEM-EDS characterization of the synthesized HAp confirmed rod-shaped HAp with prominent Ca and P elements. The crystallinity of HAp was ascertained by XRD and thermal stability was analyzed by TGA. The colloidal suspension stability was determined as - 17.7 mV by Zeta potential analyzer. The mesoporous structure was affirmed via BET studies with a high magnitude of specific surface area. TEM studies substantiated the rod-shaped HAp as observed in FESEM. The signals specific to HAp were observed in XPS studies. Adsorption of AB113 on the synthesized HAp was examined by varying the process parameters. Batch experiments resulted in an optimum dye removal of 92.72% at a pH of 8, 1 g/L of CP-HAp nps dosage, 20 ppm AB113 concentration, 120 min contact time, 150 rpm agitation speed and at room temperature. The maximum adsorption capacity reached 120.48 mg/g. Multifarious isotherms characterized the adsorption with Freundlich isotherm (R > 0.968) dominating Langmuir indicating multilayer adsorption. The experimental data reasonably matched pseudo-second-order kinetics with R exceeding 0.99. Thermodynamic investigations underlined the spontaneity and exothermicity of the processes. Results showed the suitability of the HAp nanoadsorbent to remove AB113 from wastestreams.
本工作通过利用铜荚树的叶提取物，采用绿色化学方法合成了羟基磷灰石（HAp），并研究了其对酸性蓝 113（AB113）染料的吸附去除性能。合成的 HAp 的 FESEM-EDS 特征表明其为棒状结构，具有明显的 Ca 和 P 元素。通过 XRD 确定了 HAp 的结晶度，通过 TGA 分析了热稳定性。通过 Zeta 电位分析仪确定胶体悬浮液的稳定性为-17.7 mV。通过 BET 研究证实了具有高比表面积的介孔结构。TEM 研究证实了 FESEM 观察到的棒状 HAp。XPS 研究观察到了特定于 HAp 的信号。通过改变工艺参数研究了 AB113 在合成 HAp 上的吸附。批量实验结果表明，在 pH 值为 8、CP-HAp nps 剂量为 1 g/L、AB113 浓度为 20 ppm、接触时间为 120 min、搅拌速度为 150 rpm 和室温条件下，最佳染料去除率为 92.72%。最大吸附容量达到 120.48 mg/g。多种等温线表明吸附过程以 Freundlich 等温线（R>0.968）为主，Langmuir 表明多层吸附。实验数据与准二级动力学模型拟合良好，R 值超过 0.99。热力学研究强调了过程的自发性和放热性。结果表明，HAp 纳米吸附剂适用于从废水中去除 AB113。
