Controlled pesticide release of a novel superabsorbent by grafting citric acid onto water hyacinth powders with the assistance of dopamine

With the purpose of treating the presence of abundant water hyacinth, increasing biodegradability and reducing costs of water-absorbing material, ecofriendly composite CA–PD@WH was fabricated by chemical modification of dopamine-coated water hyacinth with citric acid. FTIR and SEM revealed that dopamine was first deposited on the surface of water hyacinth and then reacted with citric acid. The product exhibited good water absorption (12.0 g g−1 in distilled water) that is much stronger than that of raw WH (1.3 g g−1) and can be thoroughly degraded. Moreover, the resultant composite shows a pH-responsive controlled avermectin-release property and has a high loading capacity for avermectin (about 98.1 mg g−1). This simple and intriguing approach not only extends any future utilization of water hyacinth but also supplies a potential method to control pesticide release and mitigate negative effects on the environment.