Superhydrophobic conjugated microporous polymer-coated sponges: Synthesis and application for highly efficient oil/water separation and the recovery of palladium ions

Abstract

Superhydrophobic conjugated microporous polymer-coated sponges (CMP@sponges) have been synthesized by the in-situ Sonogashira polymerization of monomers with multiple carboxyl or hydroxy functional groups in the presence of melamine sponges in a one-pot synthesis. The water contact angles of CMP@sponges are 150.38 and 153.92°, respectively. Unsupported CMP nanowires with diameters of 50–150 nm are synthesized successfully. CMP@sponges show excellent separation efficiency not only for oil/water mixtures including low-density oils that float and high-density oils that sink (such as gasoline, diesel and common organic solvents) but also for emulsified oils, which are much more difficult to separate with high efficiency (up to 99.81% for a toluene-water emulsion). The absorption capacities of CMP@sponges for oils are exceptionally high (55–122 and 38–94 g/g) and stable after 10 cycles. Judging from the excellent performance of CMP@sponges on oil/water separation, an ultrafast oil-removal setup has been designed that can be used to continuously collect floating oil at high speed and with a high separation efficiency (up to 10.2–16.3 mL/s). In addition, the recovery of palladium ions (Pd(II)) from organic palladium waste solutions by using CMP@sponges has been achieved, and 297 mg/g Pd(II) ions can be adsorbed. This is the first example of a CMP@sponges setup, which can continuously recover oils from oil/water mixtures with high efficiency and can also be used for recovering Pd(II) from organic solvents. The novel CMP@sponges show great application prospects for treatingoil spills and heavy metal pollution.