Aminated polystyrene-polymaleic(anhydride) hollow microsphere membrane for fast and efficient dyes and oils filtration from water

Abstract

The development of advanced adsorbents with high capacity, fast rate, and easy regeneration has great practical application value. In this paper, polystyrene-polymaleic(anhydride) (PSMM-NH₂) hollow microspheres with a high density of amino groups are prepared and used for the efficient adsorption of anionic dyes with the maximum adsorption amount for acid red as high as 951.1 mg g⁻¹. More importantly, at low dye equilibrium concentration (10 mg L⁻¹), the adsorption capacity still exceeds 850 mg g⁻¹. Due to the full exposure of adsorption sites on the surface of PSMM-NH₂, anionic dyes can be removed from water within 10 minutes and the adsorption rate is 4.76 × 10⁻³ g mg⁻¹ min⁻¹, which is tens of times higher than that of most reported adsorbents. Protonation and deprotonation of amino groups under different pH conditions can change the surface potential of PSMM-NH₂, thereby realizing the adsorption–desorption of anionic pollutants. After five cycles of adsorption, the removal rate of acid red still exceeds 99%. For easy recovery from water, PSMM-NH₂ is loaded onto glass fibers to form membranes and used for efficient filtration of acid red from water by only gravity. After 4000 L m⁻² filtration, the removal of acid red is still higher than 99% and the average flux is over 3000 L m⁻² h⁻¹. In addition, the PSMM-NH₂ membrane can also be used to separate various oil–water mixtures. We believe that this advanced adsorbent has great application potential in the remediation of industrial dye wastewater and oily wastewater.