Superoleophilic-Hydrophobic Kapok Oil Sorbents via Energy Efficient Carbonization

ABSTRACT

High oil sorption, dynamic oil/water selectivity and oil retention are essential for advanced materials to remediate offshore oil spills. In this context, superoleophilic-hydrophobic kapok bundles, synthesized via a simple, one-step and energy efficient carbonization (300°C), were investigated as effective oil sorbents. It was shown that the surface roughness and intrinsic graphite phase of the kapok bundles were tunable by varying the carbonization temperature, thereby enhancing their oil sorption and retention. Lumen preservation enables the carbonaceous kapok bundles to exhibit tunable oil sorption capacities of 34.0 g/g – 95.5 g/g for various types of oil, unrivaled among other oil spill recovery methods. The origin of oil permeability into lumen is attributed to nanopores observed for the first time on the carbonaceous kapok fibers. The kapok bundles selectively absorbed oil slick under vigorous water vortex and demonstrated distinctly high oil retention of 100% under gravitation force. Multiple oil sorption-desorption and compression cycles (up to 15 times) demonstrate a considerable promise of the carbonaceous kapok bundles for high reusability with low environmental impact.

摘要

高吸油率, 动态油/水选择性和油保留率对于修复海上石油泄漏的先进材料至关重要. 在此背景下, 通过简单, 一步且节能的炭化 (300°C) 合成的超亲油疏水木棉束被研究为有效的吸油剂. 结果表明, 通过改变炭化温度, 木棉纤维束的表面粗糙度和固有石墨相是可调的, 从而提高了它们的吸油率和保留率. 管腔保护使含碳木棉束对各种类型的油具有34.0 g/g-95.5 g/g的可调吸油能力, 在其他漏油回收方法中是无与伦比的. 油进入内腔的渗透性起源于首次在碳质木棉纤维上观察到的纳米孔. 木棉束在剧烈的水流漩涡下选择性地吸收浮油, 在重力作用下表现出明显的100%高持油率. 多次吸油, 解吸和压缩循环 (最多15次) 表明, 碳质木棉束具有很高的可重复使用性和低环境影响.

KEYWORDS:

• Kapok fibers
• oil sorption
• nanoporous
• hydrophobic
• superoleophilic
• carbonization

关键词:

• 木棉纤维
• 吸油
• 纳米多孔
• 疏水性
• 超嗜性
• 碳化

Acknowledgments

Ministry of Education Malaysia funded this research through Fundamental Research Grant Scheme (Grant No.: FRGS/1/2018/STG07/UMT/02/7) and University of Siegen. Part of this work was performed at Micro- and Nanoanalytics Facility (MNaF) and Physical Chemistry I & Research Center of Micro and Nanochemistry and Engineering (Cμ), University of Siegen, Germany.

Author contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. O.J.L., N.Y. designed and organized this work. O.J.L. and N.Y., fabricated kapok bundles, characterized FTIR and carried out the oil sorbent’s functionality tests. M.S.M.G. and N.S.M.S performed CHNS measurement. B.B., N.Y. and M.H. performed and analyzed SEM and TEM. A.S., H.S. and D.W. carried out and analyzed X-ray photoelectron spectroscopy and additional AFM measurements. S.K.C. and K.B.T. carried out and analyzed TGA and proposed chemical conversion. Z.A.T. conducted water/oil contact angle measurement.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website

Additional information

Funding

Ministry of Education Malaysia - Fundamental Research Grant Scheme (FRGS/1/2018/STG07/UMT/02/7).