Potassium enriched biochar production by thermal plasma processing of banana peduncle for soil application

•Thermal plasma processing of banana peduncle produced potassium enriched biochar.•Argon gas charging for 7 min produced maximum potassium enrichment in biochar.•Enriched available potassium in biochar was due to formation of Kalicinite mineral.

Banana peduncle biomass was processed in thermal plasma reactor to produce potassium (K) enriched biochar. The effect of different gases (argon and oxygen) and plasma processing time (3, 5, 7 and 9 min) on enrichment of K in biochar was evaluated. Potassium of banana peduncle enriched in biochar due to its residualization and mineralization during the plasma processing. Proximate, elemental, FT-IR, BET surface area and SEM analysis revealed the dominant effect of processing time on physico-chemical and surface characteristics of biochar. K enrichment was found to be relatively higher in case of Argon (Ar) gas and 7 min plasma processing time. The available K content of banana peduncle (66.3 g/kg) increased to 86.2, 163.5 and 258.5 g/kg in biochar produced by argon plasma processing for 3, 5 and 7 min respectively. XRD peaks confirmed the formation of K containing Kalicinite (KHCO3) mineral in biochar samples, which mainly contribute for water soluble K-fraction. The research findings highlight the scope of K-enriched biochar production through plasma processing of waste biomass for K replenishment in soil along with additional advantages of liming, conditioning and carbon sequestration.

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