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

Nara Han,Wooree Jang,Byung Kwon Kaang,Hye Young Koo,Sol Park,Won San Choi

doi:10.3390/ma12203389

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.

Highlights

Hazardous materials, including strong acids/bases, oils, and solvents, are widely used in manufacturing industries in general [1,2,3,4]
As the number of IO layers increased [MF/IO(2–5)], the bumpy structure on the particles gradually changed into a jagged surface morphology, and the overall size of the IO particles increased to 1 μm because of the growth of needlelike particles (Figure 1c–f)
melamine formaldehyde sponge (MFS)/IO(4) and MFS/IO(5) still exhibited their original color after the 1st use and continued to absorb the base solution in the 2nd and 3rd cycles (Figure 3g4–5,h4–5,i4–5). These results suggest that the absorption capability of MFS/IO for a strong base solution is related to the dissolution of IO in MFS/IO

Summary

Introduction

Hazardous materials, including strong acids/bases, oils, and solvents, are widely used in manufacturing industries in general [1,2,3,4]. Many approaches for hazardous material cleanup have been proposed, including neutralization, dilution, washing, bioremediation, solidification, or absorption [5,6,7,8,9,10]. Among these methods, the absorption of hazardous materials using absorbents is a convenient and efficient strategy for cleanup of hazardous materials, and there is significant interest in developing novel absorbents to remove hazardous materials. Most previous studies have focused on synthesizing hydrophobic absorbents to remove oils and organic solvents [11,12,13,14,15,16,17,18,19,20,21,22,23]

Methods

Results

Conclusion