Electron beam assisted recycling of polyurethane (PU) sponge: Turning it into a superabsorbent for wastewater treatment

Abstract

Polyurethane (PU) sponge is being used on a large scale now‐a‐days, but that generates environmental pollution as it is not bio‐degradable. Moreover, the PU recycling existing techniques face several problems, which are being addressed sincerely throughout the world. Here, we report an easy, scalable, environment‐friendly, economic, and high throughput technique for converting scrap PU sponge into a superabsorbent for wastewater treatment. This is a new strategy for recycling scrap PU foam. This conversion follows the modification of surface energy of the PU sponge and generation of tiny‐scale roughness by a single‐step electron beam (EB) radiation‐assisted covalent attachment of dodecyl methacrylate (DMA) onto the waste PU sponge. The effect of degree of modification on the surface wettability is studied. Important process parameters namely, total dose, DMA concentration, solvent composition, and so forth are systematically varied and optimized to achieve the required extent of modification (~30 wt%). This desired degree of modification is achieved at 30 kGy total dose and in 15 vol% DMA concentration and 15 vol% water content in the reaction mixture. Grafting yield is measured gravimetrically and successful grafting is further confirmed by Fourier‐transform infrared spectroscopy, surface wettability, and surface morphology. The recycled PU shows superhydrophobicity with very high water contact angle (152°). Now, the recycled sponge can remove major liquid components of wastewater, namely, toxic organic solvents, oily liquids, nonpolar solvent soluble dyes from water media with high absorption capacity (25–30 g/g) successfully.

Biofouling reduction of EPDM by radiation‐assisted modification for water environment applications

“…Another possibility of deposition is the oligomer formation that may also generate roughness on the surface of EPDM. The formed topography is fixed through radiation‐assisted covalent bond formation facilitated by the radiation‐active acrylate group 38,44 . This results in a rough surface morphology for IDM and LMA‐grafted EPDM surfaces.…”

“…The formed topography is fixed through radiation-assisted covalent bond formation facilitated by the radiation-active acrylate group. 38,44 This results in a rough surface morphology for IDM and LMAgrafted EPDM surfaces. A similar process occurs for MAA grafting.…”

Radiation assisted hydrophobization of jute fiber

“…20,21 Therefore, an easy, low-cost, durable, environment friendly technology involving less number of steps for hydrophobization of jute fiber without hampering its basic properties is necessary. 17,18 Recently tuning of surface property of polyurethane sponge, 22,23 polyolefins, [24][25][26] flax fiber, 27 and so on, by gamma radiation as well as electron beam radiationassisted modification have been reported. Improvement of properties of linear low density polyethylene (LLDPE)/flax fiber composite, by hydrophobically modifying flax fiber has been reported.…”

“…Recently tuning of surface property of polyurethane sponge, 22,23 polyolefins, 24–26 flax fiber, 27 and so on, by gamma radiation as well as electron beam radiation‐assisted modification have been reported. Improvement of properties of linear low density polyethylene (LLDPE)/flax fiber composite, by hydrophobically modifying flax fiber has been reported 27 .…”

Construction of double cross‐linked networks in calcium alginate/poly‐N‐isopropylacrylamide hydrogel with photothermal responsiveness for absorbing heavy metal ions

“…Recently, numerous reports regarding wastewater treatment have been published 12–15 . Heavy metal ions can be removed in the following ways, such as chemical precipitation, 16 electrolytic method, 17 membrane separation technique, 18 ion exchange, 19 and adsorption 20,21 .…”