A facile and high-efficiency strategy towards instantaneous clean-up of positively-charged microcontaminants by regenerative carboxylated sponge

Abstract

Developing high-efficiency adsorbents by facile approaches for sewage treatment is high demand but challenging, numerous scientists have made great efforts to fabricate such adsorbents by controlling the structures and functional groups. However, simultaneously improving the adsorption amounts and rates for the microcontaminants seems to be incompatible, which has been puzzling researchers for a long time. To face this challenge, herein, we provided a solution from a strategic perspective instead of only developing a material. We conceived that the key to realize this target was achieving instantaneous diffusion of microcontaminants, and then used regenerative carboxylated sponge (RCS) to verify our supposition. As a result, just by simply swelling and squeezing, the sponge could instantaneously clean the positively-charged microcontaminants at a high concentration (1000 μmol/L) and high clearance ratios (the ratios for methylene blue, methyl violet, Cu2+, Cr3+ and Co2+ were 99.2%, 99.1%, 92.1%, 68.4% and 60.2%, respectively), what’s more, only in one second. Additionally, the sponge could also fulfill large-scaled water purification via suction filtration, and a fast flux of up to 45,000 L/m3·h with ultrahigh clearance ratios (as for positively-charged dyes, the clearance ratios were more than 99%; as for heavy metal ions, the clearance ratios were more than 90%) could be achieved. Additionally, with the advantages of the high adsorption capacity and excellent recyclability, the sponge exhibited long-term purification ability, which might be promising for both small and large-scaled sewage treatment. More importantly, we believed that this strategy might not only be applied in the field of sewage treatment, but also be referenced in the field of bacterial eradication and blood purification, etc.