Effects of treatment methods on relative reactivity of biomass extracts toward formaldehyde

Four biomass materials — rice (Oryza sativa L.) hull, sugarcane (Saccharum officimarum L.) bagasse, and Taiwan acacia (Acacia confusa Merr.) bark and foliage — were extracted with various concentrations of acid and base solutions at 95?C and an elevated temperature of either 135? or 175?C. These extracts were reacted with 44 percent formalin or paraformaldehyde for 3 hours at 60? and 80?C, respectively, to investigate their reactivity toward formaldehyde. The free formaldehyde in the reaction mixtures was quantitated by hydroxylamine hydrochloride titration to an end point of pH 4. Extraction temperature, reaction temperature, acid or base solution of treatment, and type of biomass material were found to considerably influence the reactivity of the extracts toward formaldehyde. With respect to acacia barks, rice hull, and sugarcane bagasse, the optimum alkaline extract condition for reaction with formaldehyde was extracted with a 15 percent sodium hydroxide solution at 95?C for 6 hours. For acacia foliage, the optimum results were achieved by extraction at 135?C for 3.5 hours. However, biomass materials pre-treated with an acid solution prior to alkaline extraction enhanced reactivity toward formaldehyde and reduced the amount of base required in extraction and digestion of biomass materials.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member