Department of Environmental Science, Khon Kaen University, Khon Kaen, 40002, Thailand.
Environmental Applications of Recycled and Natural Materials (EARN) Laboratory, Khon Kaen University, Khon Kaen, 40002, Thailand.
Sci Rep. 2023 Jul 4;13(1):10772. doi: 10.1038/s41598-023-38035-7.
Lead contamination in wastewater causes toxicity to aquatic life, the environment, and water quality, and it causes many human dysfunctions and diseases. Thus, it is necessary to remove lead from wastewater before discharging it into the environment. Orange peel powder (OP) and orange peel powder doped iron (III) oxide-hydroxide (OPF) were synthesized, characterized, and investigated lead removal efficiencies by batch experiments, adsorption isotherms, kinetics, and desorption experiments. The specific surface area of OP and OPF were 0.431 and 0.896 m/g, and their pore sizes were 4.462 and 2.575 nm, respectively which OPF had a higher surface area than OP, whereas its pore size was smaller than OP. They were semi-crystalline structures that presented the specific cellulose peaks, and OPF also detected the specific iron (III) oxide-hydroxide peaks. The surface morphologies of OP and OPF were irregular and porous surfaces. Carbon (C), oxygen (O), calcium (Ca), O-H, C-H, C=C, C-O, C=O, and -COOH were observed in both materials. The pH of OP and OPF were 3.74 and 4.46. For batch experiments, OPF demonstrated a higher lead removal efficiency than OP because of spending less on material dosage than OP, and OPF demonstrated high lead removal by more than 95% while OP could remove lead at only 67%. Thus, the addition of iron (III) oxide-hydroxide helped to increase material efficiency for lead adsorption. Both materials corresponded to the Freundlich model relating to physiochemical adsorption, and they also corresponded to a pseudo-second-order kinetic model relating to a chemisorption process. Moreover, both materials could be reusable for more than 5 cycles for lead adsorption of more than 55%. Therefore, OPF was potential material to apply for lead removals in industrial applications.
废水中的铅污染会对水生生物、环境和水质造成毒性，还会导致许多人类功能障碍和疾病。因此，有必要在将废水排放到环境中之前将其进行除铅处理。本研究合成并表征了橙皮粉（OP）和橙皮粉掺杂三氧化二铁-氢氧化物（OPF），通过批量实验、吸附等温线、动力学和解吸实验研究了它们的除铅效率。OP 和 OPF 的比表面积分别为 0.431 和 0.896 m/g，孔径分别为 4.462 和 2.575 nm，OPF 的比表面积大于 OP，但其孔径小于 OP。它们均为半结晶结构，呈现出特定的纤维素峰，而 OPF 还检测到特定的三氧化二铁-氢氧化物峰。OP 和 OPF 的表面形貌均为不规则多孔表面。两种材料中均观察到碳（C）、氧（O）、钙（Ca）、O-H、C-H、C=C、C-O、C=O 和 -COOH。OP 和 OPF 的 pH 值分别为 3.74 和 4.46。在批量实验中，OPF 的除铅效率高于 OP，因为其材料用量比 OP 少，OPF 能去除 95%以上的铅，而 OP 只能去除 67%的铅。因此，添加三氧化二铁-氢氧化物有助于提高材料的除铅效率。两种材料均符合描述物理化学吸附的 Freundlich 模型，也符合描述化学吸附过程的准二级动力学模型。此外，两种材料在进行 5 次以上的循环实验中，均能用于铅吸附，且吸附率仍高于 55%。因此，OPF 是一种应用于工业除铅的潜在材料。
