The Influence of Pretreatment Techniques on Ash Content of Cassava Residues

Abstract

Cassava residues (cassava stalk and cassava rhizome) were subjected to pretreatment techniques with an aim to reduce their ash content. The effects of biomass size reduction, water washing, water-washing temperature, and acid washing on the ash content of the residues were investigated. The results showed that although most simple method, ash could be removed by biomass size reduction and selection. In washing biomass with water, it was found that both washing time and temperature were major variables affecting the ash content. The ash content decreased with washing time. Increasing the washing temperature to 80°C did not significantly reduce further ash until the washing time was 24 h. In addition, the acid washing was concluded to be the most effective technique for ash removal. The ash contents of the cassava stalk and rhizome were decreased from 5.04% to 1.94% and 4.99% to 2.26%, respectively, after washing with dilute HCl solution for 3 h.