Multiphysics CFD analysis of packed bed adsorption of Ni(II) using MnO2-modified Hypericum rhizome-derived biochar: Batch and column approaches - Sheng Qian; Xiang Ao; Wei Zhang; Chenhao Song; Kaihong Wen; Dona Souliyathai; Xingyong Li; Na Liu; Liping Ma; Longlong Ma; Shijie Liu; Yubao Chen (Biomass and Bioenergy, 2026)