Copper/Nickel-Decorated Olive Pit Biochar: One Pot Solid State Synthesis for Environmental Remediation

Abstract

Developing micro- and nanomaterials for environmental pollution remediation is currently a pertinent topic. Among the plethora of strategies, designing supported nanocatalysts for the degradation of pollutants has achieved prominence. In this context, we are addressing one of the UN Sustainable Development Goals by valorizing agrowaste as a source of biochar, which serves as a support for bimetallic nanocatalysts. Herein, olive pit powder particles were impregnated with copper and nickel nitrates and pyrolyzed at 400 °C. The resulting material consists of bimetallic CuNi-decorated biochar. CuNi nanocatalysts were found to be as small as 10 nm and very well dispersed over biochar with zero valent copper and nickel and the formation of copper–nickel solid solutions. The biochar@CuNi (B@CuNi) exhibited typical soft ferromagnet hysteresis loops with zero remanence and zero coercivity. The biochar@CuNi was found to be an efficient catalyst of the reduction in methyl orange (MO) dye, taken as a model pollutant. In sum, the one-pot method devised in this work provides unique CuNi-decorated biochar and broadens the horizons of the emerging topic of biochar-supported nanocatalysts.

Biochar-Based Adsorbents for Pesticides, Drugs, Phosphorus, and Heavy Metal Removal from Polluted Water

“…CuNi-decorated biochar was found to be an efficient catalyst for the reduction in methyl orange dye. Their results open new horizons for the emerging topic of biochar-supported nanocatalysts [26].…”

“…Khalil and co-authors, in 2021, after a literature search, presented a graph of the growing interest of the scientific community in the use of biochar: 2 papers in 2001, 221 in 2011, 1408 in 2016, 4225 in 2020, and 1289 in 2021 (until April 2021) [26]. They also presented the results of a bimetallic biochar, a CuNi-decorated biochar, which was prepared in the one pot method (olive pit powder particles were impregnated with copper and nickel nitrates and pyrolyzed together at 400 • C) that presented soft ferromagnetic hysteresis loops with zero remanence and zero coercivity and small sizes (up to 10 nm).…”

Biochars Derived from Olive Mill Byproducts: Typology, Characterization, and Eco-Efficient Application in Agriculture—A Systematic Review

“…Slow pyrolysis conducted at elevated temperatures is observed to yield optimal results for activating and functionalizing the olive mill byproducts. It is the preferred method to produce activated carbons (ACs), although pyrolysis is still carried out [53,56,71].…”

“…This flexibility allows for a comprehensive and customizable approach to meet specific application requirements. The mentioned functionalizations generally involve metallic oxides (e.g., Co 3 O 4 ) [56], acids (e.g., HNO 3 , H 2 SO 4 , H 3 PO 4 ) [41,59,66], and metallic salts (e.g., Ni(NO 3 ) 2 •6H 2 O, Cu(NO 3 ) 2 •3H 2 O), or a mixture of chemical compounds, water vapor, and gases [71,77,84].…”

Surface Treatment of Biochar—Methods, Surface Analysis and Potential Applications: A Comprehensive Review

“…-Method (i) consists in impregnating the initial biomass with catalyst precursor prior to pyrolysis. This process yields biochar powder impregnated with nanoparticles [37,[123][124][125]. -Method (ii) concerns the deposition of catalyst precursor onto prefabricated biochar, followed by in situ reductive process to obtain biochar-immobilized nanocatalysts [8,88,126].…”