Insights into the Influence of Aging Processes on Zero-Valent Iron Modified Biochar in Cu(Ii) Immobilization: From Batch Solution to Pilot-Scale Investigation

The zero-valent iron modified biochar (ZVI/BC) is widely employed for heavy metals immobilization. However, these materials would be inevitably aged by natural forces after entering into environment, while there are seldom studies reported the aging effects on ZVI/BC. In this work, HCl and H 2 O 2 solution were applied to simulate aging conditions of ZVI/BC. According to the results, the adsorption capacity of Cu(II) contaminants on BC, ZVI/BC-1, and ZVI/BC-2 after aging was decreased by 24.07%, 22.65%, and 23.26%, respectively. The surface interactions were assigned with chemisorption occurred on multi-molecular layers, which were proved by pseudo-second-order and Langmuir models. After aging, the decreasing of capacity could be mainly attributed to the inhibition of ion-exchange and ZVI oxidation. Moreover, the plant growth and soil leaching experiments also proved the effects of aging treatment. All these results bridged the gaps between bio-adsorbents customization and their environmental behaviors during practical agro-industrial application.