QUANTITATIVE DETERMINATION METHOD OF LIGNIN

摘要

PROBLEM TO BE SOLVED: To provide an analysis method capable of accurately determining the quantity of lignin in an active material of a negative electrode plate of a lead-acid battery.

SOLUTION: The active material of the negative electrode plate is crushed and dissolved by adding acetic acid and oxygenated water, sulfic acid is added to it and lead sulfate is precipitated by a centrigugal method. Sodium hydroxide aqueous solution and manganese dioxide are added to a supernatant solution with lead elements removed therefrom to decompose hydrogen peroxide, and a filtrate is made by filtering the solution. The absorbance of the made filtrate is measured at an absorption wavelength in the vicinity of 292 nm by using an ultraviolet-visible spectrophotometer and the quantity of lignin is determined by comparing the measurement value with an analytical curve.

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