An Active Absorbent for Cleanup of High-Concentration Strong Acid and Base Solutions

Abstract

There is significant interest in developing novel absorbents for hazardous material cleanup. Iron oxide-coated melamine formaldehyde sponge (MFS/IO) absorbents with various IO layer thicknesses were synthesized. Various other absorbents were also synthesized and compared to evaluate the absorption capability of the MFS/IO absorbents for strong acid (15%, v/v) and base (50%, m/m) solutions. Specifically, absorbent and solution drop tests, dust tests, and droplet fragment tests were performed. Among the various absorbents, MFS/IO absorbents possessing a needlelike surface morphology showed several unique characteristics not observed in other absorbents. The MFS/IO absorbents naturally absorbed a strong base solution (absorption time: 0.71–0.5 s, absorption capacity: 10,000–34,000%) without an additional external force and immediately absorbed a strong acid solution (0.31–0.43 s, 9830–10,810%) without absorption delay/overflow during absorbent and solution drop tests, respectively. The MFS/IO absorbents were also demonstrated to be ideal absorbents that generated fewer dust particles (semiclass 1 (ISO 3) level of 280 piece/L) than the level of a clean room (class 100). Furthermore, the MFS/IO absorbents were able to prevent the formation of droplet fragments and solution overflow during the solution drop test due to their unique surface morphology and extremely high absorption speed/capacity, respectively.

An Efficient Photocatalytic Oxygen Evolution System with the Coupling of Polyoxometalates with Bismuth Vanadate

“…However, the catalyst was fabricated under harsh condition with the involvement of strong acid at pH 0 in contrast to the mild synthesis condition presented in this study. Indeed, harsh reaction condition is not favourable due to the experimental hazard [42,43]. The utilization of weak base instead of strong base in BiVO 4 synthesis was illustrated in a work conducted by Usai et al [44] with as-synthesized material showed prominent water oxidation reaction with the evolution of 53.0 µmol oxygen within the first hour of reaction.…”

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.…”

“…No attention has been paid to hydrophilic absorbents that can eliminate strong acid and base solutions. Choi et al report a novel absorbent for the removal of strong acid and base solutions [ 5 ]. Needlelike iron oxide-coated sponge (NIOS) absorbents with various IO layer thicknesses were prepared.…”