Production and Physico-chemical Characterization of Biochar Obtained from Coffee Silver Skin

Biochar is a carbonaceous product derived from pyrolysis of agricultural waste biomass under oxygen free condition. Coffee silver skin is the waste biomass generated during the process of roasting the coffee beans. Published report on biochar production from coffee silver skin is very scarce and no report is available hitherto on mineral nutrient content of biochar derived from coffee silver skin. Therefore, the objective of the current study was to characterize the biochar obtained from coffee silver skin, produced under different pyrolytic temperature (400 o C, 500 o C and 600 o C). The biochar from coffee silver skin was produced using an electric biomass pyrolyzer and physico-chemical attributes and nutrient content of biochar were studied. The data indicated that pH, electrical conductivity, ash level and carbon proportion of CSS-biochar increased when pyrolytic temperature increased. While the biochar yield, moisture level, density and volatile matter declined with increasing pyrolytic temperature. Pyrolytic temperature appeared to have little effect on porosity. Regarding mineral nutrient content, excepting nitrogen and magnesium, all other nutrients increased when pyrolytic temperature increased. The results of the current investigation revealed that pyrolytic temperature has greater impact on the physico-chemical attributes of biochar and thus the physicochemical characterization of biochar is a pre-requisite for determining its significance for various applications. The results also showed that the CSS-biochar has potential for augmenting soil health considering its physicochemical properties.