Fabrication and evaluation of molecularly imprinted multi-hollow microspheres adsorbents with tunable inner pore structures derived from templating Pickering double emulsions

In this work, lignin was simply tailored by chemical modification with oleic acid, and then surfactant-free water-in-oil-in-water (W1/O/W2) Pickering double emulsions were formed by stabilizing two types of lignins (original and modified) at both interfaces. Based on as-prepared W1/O/W2 emulsions, three kinds of molecularly imprinted multi-hollow microspheres (denoted as MIMMs1, MIMMs2 and MIMMs3) were fabricated and evaluated as adsorbents to selective removal of lambda-cyhalothrin (LC). MIMMs exhibited tunable pore structures (size and number of inner pores) by adjusting the volume ratio of internal water phase to the medium oil phase (W1O), and MIMMs2 showed the larger adsorption capacity than those of MIMMs2 and MIMMs3, resulting from the common action mechanism of more and larger inner pores. Static adsorption experiments showed that equilibrium time was about 3.0 h, and the equilibrium adsorption amount was 24.79 mg g−1 for MIMMs2. The selective recognition experiments exhibited the obviously selective adsorption effect of the MIMMs2 for target LC, and MIMMs2 could be effectively regenerated and recycled at less seven times without significant loss of adsorption capacity. Overall, batch mode data suggested that MIMMs2 may be useful for the selective removal of LC from aqueous media.