Efficient methods and compositions for recovery of products from organic acid pretreatment of plant materials

A method of producing an alkalized cellulose, the method comprising the steps of:

• a) pretreating plant material with organic acids to produce a cellulose containing organic acids and then neutralizing the organic acids contained in the cellulose with sodium hydroxide liquor recycled from step d) of the process to form a neutralized cellulose mixture having a pH of pH 5 to pH 8, and
• b) separating neutralized cellulose and a first filtrate from the neutralized cellulose mixture with a press wherein the first filtrate is directly released to waste water treatment system, and
• c) alkalizing the neutralized cellulose by addition of a sodium hydroxide solution in a reactor to form an alkalized cellulose mixture, and
• d) separating alkalized cellulose from the alkalized cellulose mixture with a second press, wherein a sodium hydroxide liquor, obtained as a second filtrate of the alkalized cellulose mixture, comprises sodium hydroxide for reuse in step a) of the process.