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Evaluation of Hydrophobic Polyvinyl-Alcohol Formaldehyde Sponges As Absorbents for Oil Spill
journal contribution
posted on 2014-06-11, 00:00 authored by Yanxiong Pan, Kai Shi, Chao Peng, Weicai Wang, Zhi Liu, Xiangling JiMacroporous materials are a class
of absorbents used for oil spill cleanup. In this article, novel macroporous
and hydrophobic polyvinyl formaldehyde (PVF-H) sponges were prepared
by the reaction of stearoyl chloride with hydroxyl groups of hydrophilic
PVF sponge at different temperatures. Attenuated total reflectance-infrared
(ATR-IR) spectroscopy confirmed the successfully anchoring of hydrophobic
stearoyl groups on the PVF networks. Scanning electron microscopy
(SEM) images demonstrated that the as-prepared PVF-H had interconnected
open-cell structures, and mercury intrusion porosimetry indicated
that the average pore size ranged from 60 to 90 μm and porosity
was greater than 94.8%. Such PVF-H sponges can absorb oil products
effectively, such as toluene, n-hexane, kerosene,
soybean oil, hydraulic oil, and crude oil up to 13.7 g·g–1 to 56.6 g·g–1, and this level
of absorption was approximately 2–4 times higher than that
absorbed by commercial polypropylene nonwoven mat. In low-viscosity
oils, the samples can reach the saturated absorption amount only in
1 min, but in higher-viscosity oils, absorption equilibrium can be
reached in 10 min. In a simulated oil slick system, these macroporous
and hydrophobic sponges can still maintain high oil absorption capacities
within the range of 14.4 g·g–1 to 57.6 g·g–1, whereas a relatively low absorption rate (approximately
20 min) indicated high absorption performance and excellent selectivity
in the oil–water mixture. In addition, the absorbed oils were
collected effectively only through a simple squeeze. The PVF-H sponges
were subjected to 35 absorption–squeeze cycles and exhibited
good reusability and 90% recovery for oils. The samples prepared at
different temperatures differed in their absorption capacities to
some extent. However, this new kind of macroporous and PVF-H sponges
had excellent absorption performance on oil products.