The application of water bamboo (Zizania latifolia) husk-derived biochar for copper-contaminated irrigation water treatment and soil amendment

Abstract

In Taiwan, farmlands are polluted with metals mainly caused by irrigation water and sediments in irrigation channels. Copper (Cu) presents a major challenge in Taiwan's agricultural lands. This study investigates the potential of utilizing water bamboo (Zizania latifolia) husk-derived biochar (WBC) for the treatment of copper-contaminated irrigation water and soil amendment. BET-SSA for WBC that is produced at 600oC is 192 m2/g and pore volume is 0.174 cc/g. The FTIR spectrum of WBC exhibits several functional groups, such as phosphate, carboxylate (-COO), or aromatic (C=C) that can contribute to biochar alkalinity. The point of zero charge (pHPZC) of WBC is determined to be 2.7. The optimum adsorption of copper by WBC occurs at pH 5. Copper adsorption by WBC fits well with pseudo-second-order kinetics and Langmuir isotherm, which demonstrates that chemisorption and monolayer adsorption are the dominant mechanisms for copper removal. The maximum Cu2+ adsorption capacity of WBC is 144.9 mg/g, which is much higher than those of many existing reports. The addition of 1 to 5% (wt/wt) WBC neutralizes acidic soil pH effectively, making it suitable for water bamboo cultivation.