Nature Sunflower Stalk Pith with Zwitterionic Hydrogel Coating for Highly Efficient and Sustainable Solar Evaporation

Abstract

Solar-driven water evaporation is considered to be an appealing way to solve water scarcity issues globally. Various natural creatures possess unique structural features and exhibit an excellent pumping ability in arid environments. Motivated by sunflower stalk pith, here, the biomass porous foam modified with zwitterionic hydrogel coating for solar desalination devices is introduced. It is demonstrated that the multi-curvature and gradient honeycomb architecture offers a remarkable solar desalination system, which combines critical aspects of solar evaporation including high light absorption, localizing converted heat, rapid water transport, water activation, and multi-channel release of steam via its ubiquitous structure, and substantially outperforms other natural biomass materials. The device exhibits long-term stability in actual seawater, as well as high performance for soybean oil emulsion and oily brines (crude oil, salts). Furthermore, the long-term use of excellent storability to prevent putrefying is shown, which is attributed to the outstanding antifouling property of zwitterionic hydrogel. It is envisioned that the nature material with the advantage of being inexpensive, environmentally friendly, and portable, may be a new candidate for water purification and desalination.

Liquid Transport and Real-Time Dye Purification via Lotus Petiole-Inspired Long-Range-Ordered Anisotropic Cellulose Nanofibril Aerogels

“…Ethanol exhibited the longest transmission distance and the fastest transmission rate, reaching a height of 40 mm at 50 s (Figure S8b), which was superior to other reports (Table S3). ,,− The rate at this time was still 0.8 mm/s, which exceeded that of the water. Such a phenomenon might be because although the ethanol had lower surface tension than water, the lower density made it easier to transport from bottom to top inside the aerogel than water.…”

Enhanced Solar Evaporation Using a Scalable MoS2‐Based Hydrogel for Highly Efficient Solar Desalination

“…However, as the thickness increased further to 3.0 cm, the evaporation rate slightly decreased to 2.873 kg m −2 h −1 . The decreased evaporation rate might be caused by the decrease of water transfer efficiency due to the overlong water path from the water surface to the surface of the SMoS 2 ‐PH [36] . In addition, we tested the optical absorption properties of SMoS 2 ‐PH with different thicknesses over the full spectral range.…”

A Comparative Investigation on Structural and Chemical Differences between the Pith and Rind of Sunflower Stalk and Their Influences on Nanofibrillation Efficiency

“…The diameter of lumina was around 119 μm and cell wall thickness was around 0.87 μm. Such unique porous structure with huge lumina has been reported to endow the stalk pith with highly efficient water transportation when used as solar evaporators [ 17 ]. Presence of cavities in cell corners were observed in pith (arrow in Figure 3 b), and similar phenomenon were also observed in bamboo [ 19 ].…”

“…In general, the pith is considered a waste and removed before stalk utilization [ 12 ]. Very recently, stalk pith has been receiving increasing attentions in solar evaporators [ 16 , 17 ], and feedstock for the coproduction of pectin and glucose [ 18 ]. Currently, unlike stalk rind, whose anatomy and cell wall ultrastructure has been investigated thoroughly [ 11 ], information regarding stalk pith and its effects on bioconversion and utilization has not been reported.…”