Assessment of Growth Performance and Biomass Processing of Odontarrhena inflata for Nickel Agromining in Serpentine Soils

This study evaluated the efficiency of the native hyperaccumulator Odontarrhena inflata in extracting nickel (Ni) from ultramafic soils in the Robat-Sefid region of northeastern Iran and assessed the feasibility of applying agromining under controlled conditions. A six-month greenhouse experiment was conducted using homogenized serpentine soil with a total Ni concentration of ۱,۴۶۰ mg/kg. By the end of the cultivation period, the aerial parts of the plant yielded ۱۲۲ g of dry biomass containing ۲,۱۹۵ mg/kg of Ni. The calculated bioconcentration factor (BCF = ۱.۵) and translocation factor (TF = ۳.۵۳) confirmed effective Ni uptake and translocation from roots to shoots. The biomass was pyrolyzed at ۵۵۰ °C to produce ash, which underwent cross-washing and sulfuric acid (H₂SO₄) leaching. This leaching process achieved a Ni extraction efficiency of ۷۸.۹%, and the overall Ni recovery from soil to biomass ash was estimated at ۳.۵۳%. Elemental analyses showed substantial reduction of Magnesium (Mg) and Iron (Fe) in the final crystalline product; however, Calcium (Ca) and Sodium (Na) remained at appreciable levels, indicating that further recrystallization or purification steps are necessary to achieve industrial-grade ANSH (ammonium nickel sulfate hexahydrate). Compared with other Ni hyperaccumulators, O. inflata exhibited lower shoot Ni levels than Odontarrhena chalcidica and Alyssum murale, but the combination of its strong ecological adaptability, elevated TF, and native occurrence collectively designates it as a sustainable and promising candidate for agromining applications in nickel-rich soils of Iran.

کلیدواژه ها:

Agromining ، Odontarrhena inflata ، ANSH ، Serpentine soil ، Robat-Sefid