Ammonia spectrophotometric method for evaluating activated carbon exhaustion in Cuban rum production

Abstract

In the Cuban rum industry, granular activated carbon used in aged spirits refining is declared "exhausted" by sensory criteria, leading to premature material disposal and economic losses. In this work, the ammonia spectrophotometry method (S-NH₃) was applied to determine the exhaustion profile of activated carbon in four Cuban rum factories, and a sigmoidal Boltzmann model was developed for quantitative analysis of the experimental data. Exhaustion profiles were fitted to the model with regression coefficients above 96%. Differential analysis of the curves allowed calculation of the unused bed length (LUB), fractional recovery coefficient (φ), and net management efficiency (eₙ). Recovery of the less exhausted layers increased carbon exploitation efficiency from 40-60 % to values above 70%, reaching 92% in the best-performing factory (Factory 1). The proposed method constitutes a quantitative, economical, and generalizable tool for efficient activated carbon management in Cuban rum production.