One-Step Synthesis of Environmentally Friendly Superhydrophilic and Superhydrophobic Sponges for Oil/Water Separation

Abstract

Environmentally friendly superhydrophilic and superhydrophobic sponges were synthesized using a one-step approach for oil/water separation. A superhydrophilic or superhydrophobic sponge (MFS/CC-DKGM or MFS/CC-PDMS) was synthesized by one-step coating of melamine formaldehyde sponge (MFS) with a mixture of calcium carbonate (CC) rods and deacetylized Konjac glucomannan (DKGM) [or polydimethylsiloxane (PDMS)]. The MFS/CC-PDMS showed excellent absorption capacity, which reached 52–76 g/g following immersion into various types of oil/water mixtures. Furthermore, the MFS/CC-DKGM and MFS/CC-PDMS exhibited excellent water- and oil-flux performances, which reached 4,702 L/m2 h and 19,591 L/m2 h, respectively, when they were used as filters. The MFS/CC-DKGM and MFS/CC-PDMS maintained their wettability characteristics relatively well after the chemical, thermal, and mechanical stability tests.

A Durable and Self-Cleaning Superhydrophobic Surface Prepared by Precipitating Flower-Like Crystals on a Glass-Ceramic Surface

“…Herein, the volume of each water droplet was~50 µL. Figure 11c presents the changes of WCA after the samples were immersed in H 2 SO 4 and NaOH solutions (pH = 1, 3,5,7,9,11,14) for 48 h, showing that the WCA remained above 165 • for the different pH of the water droplets. Furthermore, the durability of the superhydrophobic glass-ceramic surface was demonstrated by the tape peeling test.…”

“…A value of θ is greater than 150 • corresponds to superhydrophobicity [5,6]. Superhydrophobic surfaces have a wide range of application prospects for self-cleaning [7][8][9], anti-icing [10], anti-corrosion [9,10], oil-water separation [11,12], anti-fogging [13,14], and drag reduction [15,16].…”

“…13, x FOR PEER REVIEW 11 of (a,b) Digital photographs of water droplets with different pH on the superhydrophobic glass-ceramic surface and (c) changes of WCA after the samples were immersed in H2SO4 and NaOH solutions (pH = 1,3,5,7,9,11,14) for 48 h.…”

Special Issue: Smart Nanomaterials for Environmental Remediation

“…This Special Issue deals with the recent progresses in smart nanomaterials and related nanomaterials for environmental remediation. Our Special Issue is composed of five main topics, such as oil/water separators [ 1 , 2 ], adsorbents/absorbents [ 3 , 4 , 5 ], catalysts [ 6 , 7 ], and fundamental studies [ 8 , 9 ] for environmental remediation ( Figure 1 ). Herein, I summarize each topic discussed in our Special Issue.…”

“…To solve the abovementioned problems, Choi et al propose using environmentally friendly materials that are part of nature and nontoxic to nature for superhydrophobic and superhydrophilic oil/water separators [ 2 ]. Superhydrophobic (MFS/CC-PDMS) and superhydrophilic (MFS/CC-DKGM) sponges are prepared by a simple coating of pristine sponge (melamine formaldehyde sponge, MFS) with a mixture of calcium carbonate (CC) rods and deacetylized Konjac glucomannan (DKGM) (or polydimethylsiloxane (PDMS)).…”