Department of Chemical Engineering, Qatar University, P. O. Box 2713, Doha, Qatar.
Department of Chemical Engineering, Qatar University, P. O. Box 2713, Doha, Qatar.
Chemosphere. 2021 Feb;265:129054. doi: 10.1016/j.chemosphere.2020.129054. Epub 2020 Nov 25.
In this study, an innovative magnetic demulsifier (MD) was prepared by grafting a silica layer onto the surface of the FeO magnetic nanoparticles (MNPs) using the modified Stober process. The MD was characterized using various analytical techniques (XRD, FTIR, TGA, TEM, VSM, etc.) and employed to recover oil from O/W emulsion, which were then regenerated and recycled several times. The effects of magnetic demulsifier dosage (MD), the concentration of oil (C), pH, the concentration of the surfactant (C), and separation time (t) on the demulsification efficiency (%η), and the percentage of oil recovered (%R) were evaluated. An excellent %η ≥ 90% was achieved C in the range 50-2000 mg/L. Using an MD as low as 10 mg/L attained a %η in the range of 93%-94.3% for O/W mixtures with C < 2000 mg/L, which slightly decreased to ∼90% for higher concentrations. The reported %R (p-value <0.05) was >90 ± 0.1 for tests carried out with pH ≤ 7 and C ≤ 0.1 g/L and declined at higher pH and C to % 86.5 due to the increase in emulsion stability. The developed MD exhibited high recyclability at an effective and stable %R and %η of ∼90% and 86.4% after 9 cycles, respectively. Demulsification process best fits the combined Langmuir-Freundlich (L-F) isotherm with highest adsorption capacity (Q) of 186.0 ± 5 mg/g compared to 86.0 ± 5 mg/g for FeO, which is 1.1 folds greater than Q reported in the literature for other demulsifiers.
在这项研究中，通过使用改进的 Stober 工艺，将二氧化硅层嫁接到 FeO 磁性纳米粒子（MNPs）表面，制备了一种创新性的磁破乳剂（MD）。使用各种分析技术（XRD、FTIR、TGA、TEM、VSM 等）对 MD 进行了表征，并将其用于从 O/W 乳液中回收油，然后对其进行再生和多次循环使用。考察了磁破乳剂用量（MD）、油浓度（C）、pH 值、表面活性剂浓度（C）和分离时间（t）对破乳效率（%η）和油回收率（%R）的影响。在 50-2000mg/L 的范围内，C 达到了优异的%η≥90%。使用低至 10mg/L 的 MD，在 C < 2000mg/L 的情况下，对 O/W 混合物的%η 达到 93%-94.3%，而在更高浓度下则略微下降至约 90%。报告的%R（p 值<0.05）在 pH 值≤7 和 C 值≤0.1g/L 的测试中>90±0.1，而在更高的 pH 值和 C 值下，由于乳液稳定性的增加，降至 86.5%。所开发的 MD 在 9 次循环后分别具有约 90%和 86.4%的有效且稳定的%R 和%η，表现出较高的可循环性。破乳过程最佳拟合 Langmuir-Freundlich（L-F）等温线，吸附容量（Q）最高为 186.0±5mg/g，而 FeO 的 Q 值为 86.0±5mg/g，比文献中报道的其他破乳剂的 Q 值高 1.1 倍。
