posted on 2024-02-19, 05:43authored byZhiyang Zhang, Guangzhou Dai, Hongye Hui, Jin-biao Bao, Chuanzhuang Zhao, Li Zhang
In
the field of emulsion separation, the application of porous
hydrophilic sponge materials is of paramount importance; however,
the conventional preparation process of hydrophilic poly(vinyl formal)
(PVF) restricts the simultaneous enhancement of separation efficiency
and water flux. In this work, by introducing two poly(vinyl alcohol)
(PVA) and aldehyde feedstocks with different molecular weights and
functional group contents into the reaction system, the differences
in the mobility and reactivity of the feedstocks were exploited to
successfully achieve tailoring of the pore size and hydrophilicity.
The PVF sponge prepared by using this method exhibited high separation
efficiency and water flux in emulsion separation. This preparation
method not only avoided the requirement for pore-forming agents in
traditional preparations but also significantly reduced the amount
of formaldehyde by adding trace amounts of glutaraldehyde, ensuring
the hydrophilicity of the sponge and markedly reducing the pore size.
The experimental results showed that the addition of 1.5 × 10–3 mol/L glutaraldehyde could effectively reduce the
average pore size of the PVF sponge from 26.5 to 7.2 μm while
maintaining excellent hydrophilicity. The preparation mechanism of
PVF sponges was thoroughly explored, and the effects of different
concentrations of formaldehyde and glutaraldehyde on the sponge properties
were extensively investigated. Experimental results demonstrated that
the prepared PVF sponge achieved a separation efficiency of up to
98.5% for the OP-10-stabilized oil-in-water emulsion and exhibited
outstanding recyclability. This cost-effective and easily scalable
method for PVF sponge preparation could be employed to produce a range
of highly efficient filtration materials, effectively separating target
oil-in-water emulsions.