Lignin-Based Microsphere: Preparation and Performance on Encapsulating the Pesticide Avermectin

Considering the superior ultraviolet (UV) absorptivity and environmental friendliness of lignin, a novel lignin-based microsphere was prepared. Through self-assembly, sodium lignosulfonate (SL) and cetyltrimethylammonium bromide (CTAB) aggregated into uniform colloidal spheres (SL-CTAB). SL-CTAB performed a reversible aggregation behavior and was used as the shell material to prepare microspheres to encapsulate avermectin (AVM), a kind of photosensitive pesticide. Moreover, the microsphere (AVM@SL-CTAB) exhibited an uniform spherical structure. To reveal the excellent embedding capability of AVM@SL-CTAB, the controlled release and antiphotolysis performance for AVM were systematically investigated in this work. As a result, the encapsulation efficiency value of AVM@SL-CTAB reached to 62.58 ± 0.06%. The release of AVM from AVM@SL-CTAB was still going on after 70 h, and its cumulative release amount at that time was 49.96 ± 1.13%. The release process of AVM@SL-CTAB could be controlled by adjusting the doped proportion of SL-CTAB. The half-life (DT50) of AVM in AVM@SL-CTAB under UV irradiation could be prolonged for 7.35 times that of uncoated AVM. The enhanced photoprotection and the controlled release of AVM implied that SL-CTAB possessed a great application prospect for efficient pesticide utilization.