Orange peel (OP) was used as raw material for cellulose extraction. Two different pulping reagents were
used, sodium sulfite and sodium metabisulfite. The effect of the main process parameters, sulfite agent
dosage and reaction duration, on cellulose yield was investigated. A central composite rotatable design
involving two variables at five levels and response surface methodology were used for the optimization
of cellulose recovery. Other two invariable parameters were reaction temperature and hydromodulus.
The optimum yields, referred to the weight of double extracted OP, were 40.4% and 45.2% for sodium sulfite
and sodium metabisulfite digestions, respectively. The crude celluloses were bleached with hypochlorite
and oxygen. The physicochemical characterization data of these cellulose materials indicate
good levels of purity, low crystallinities, good whitenesses, good water retention and moderate molecular
weights. According to these specific properties the recovered celluloses could be used as fillers, water
absorbents, or as raw materials for cellulose derivatives.