Praipipat Pornsawai, Ngamsurach Pimploy, Prasongdee Vatcharaporn
Department of Environmental Science, Khon Kaen University, Khon Kaen40002, Thailand.
Environmental Applications of Recycled and Natural Materials (EARN) Laboratory, Khon Kaen University, Khon Kaen40002, Thailand.
ACS Omega. 2022 Nov 1;7(45):41744-41758. doi: 10.1021/acsomega.2c05956. eCollection 2022 Nov 15.
The increasing concern of dye contamination in wastewater results in the toxicity of aquatic life and water quality, so wastewater treatment is required to treat the low water quality standard for safety purposes. Lemon peel beads-doped iron(III) oxide-hydroxide (LBF) and lemon peel beads-doped zinc oxide (LBZ) were synthesized and characterized to investigate their crystalline structure, surface morphology, chemical compositions, chemical functional groups, and ζ potentials by X-ray diffraction, field emission scanning electron microscopy and focused ion beam, energy dispersive X-ray spectroscopy, Fourier transform infrared, and zetasizer techniques. Their effects of dose, contact time, temperature, pH, and concentration for reactive blue 4 (RB4) dye removal efficiencies were investigated by batch experiments, and their adsorption isotherms, kinetics, and desorption experiments were also studied. LBF and LBZ demonstrated semicrystalline structures, and their surface morphologies had a spherical shape with coarse surfaces. Five main elements of carbon (C), oxygen (O), calcium (Ca), chlorine (Cl), and sodium (Na) and six main function groups of O-H, C≡N, C=C, C-OH, C-O-C, and C-H were detected in both materials. The results of ζ potential demonstrated that both LBF and LBZ had negative charges on the surface at all pH values, and their surfaces increased more of the negative charge with the addition of the pH value from 2-12. For batch tests, the RB4 dye removal efficiencies of LBF and LBZ were 83.55 and 66.64%, respectively, so LBF demonstrated a higher RB4 dye removal efficiency than LBZ. As a result, the addition of iron(III) oxide-hydroxide helped in improving the material efficiency more than zinc oxide. In addition, both LBF and LBZ could be reused in more than five cycles for RB4 dye removal of more than 41%. The Freundlich model was a good explanation for their adsorption patterns relating to physiochemical adsorption, and a pseudo-second-order kinetic model was a well-fitted model for explaining their adsorption mechanism correlating to the chemisorption process with heterogeneous adsorption. Therefore, LBF was a potential adsorbent to further apply for RB4 dye removal in industrial applications.
废水中染料污染问题日益受到关注，这会导致水生生物毒性和水质下降，因此出于安全考虑，需要对低水质标准的废水进行处理。合成并表征了柠檬皮珠掺杂氢氧化铁（III）（LBF）和柠檬皮珠掺杂氧化锌（LBZ），通过X射线衍射、场发射扫描电子显微镜和聚焦离子束、能量色散X射线光谱、傅里叶变换红外光谱和zeta电位仪技术研究它们的晶体结构、表面形态、化学成分、化学官能团和ζ电位。通过批量实验研究了它们的剂量、接触时间、温度、pH值和浓度对活性蓝4（RB4）染料去除效率的影响，并研究了它们的吸附等温线、动力学和解吸实验。LBF和LBZ呈现半结晶结构，其表面形态为球形且表面粗糙。在两种材料中均检测到碳（C）、氧（O）、钙（Ca）、氯（Cl）和钠（Na）这五种主要元素以及O-H、C≡N、C=C、C-OH、C-O-C和C-H这六种主要官能团。ζ电位结果表明，LBF和LBZ在所有pH值下表面均带负电荷，且随着pH值从2增加到12，其表面负电荷增加更多。对于批量测试，LBF和LBZ对RB4染料的去除效率分别为83.55%和66.64%，因此LBF对RB4染料的去除效率高于LBZ。结果表明，添加氢氧化铁（III）比氧化锌更有助于提高材料效率。此外，LBF和LBZ均可重复使用超过五个循环，对RB4染料的去除率超过41%。Freundlich模型很好地解释了它们与物理化学吸附相关的吸附模式，伪二级动力学模型是解释其与非均相吸附化学吸附过程相关的吸附机制的良好拟合模型。因此，LBF是一种有潜力的吸附剂，可进一步应用于工业应用中去除RB4染料。
