Removal of pesticide acetamiprid using KOH activated biochar derived from crayfish shell: Behavior and mechanism

Over the past few decades, the excessive use of pesticides has resulted in serious environment pollution, and residual pesticides prompt significant concern regarding their potential harm to both the ecological security and human health. In this study, KOH activated crayfish shell biochar (KBC) was successfully prepared and used to effectively remove acetamiprid (ACE) and triadimefon (TDM) from aqueous solutions. Batch experiments results indicated that, the adsorption process of ACE was predominantly by chemical reaction and controlled by multiple mechanisms, and ACE adsorption was a thermodynamically spontaneous and exothermic reaction. The KBC exhibited exceptional adsorption performance in removing ACE with a maximum adsorption capacity of 40.41 mg g-1. A superior adsorption capacity toward both ACE and TDM over KBC could be achieved at lower concentration levels, and KBC exhibited good reuse for the removal of ACE and TDM. Different adsorption models and characterization results revealed the adsorption mechanism of ACE and TDM by KBC, including van der Waals forces, pore filling, hydrogen bonding, and π-π electron donor-acceptor interactions. These findings suggested that KBC was an excellent adsorbent for removing pesticide-contaminated water.