Water Down Acid Pretreatment of Wheat Stubble Agro-residues to Eliminate Non-process Components Meant for Papermaking and Its Impact on Mechanical Strength Properties of Paper Products

Wheat stubble agro-residues material contains lingo-cellulose with high level of extractives and metal ions, which may be able to instigate some harmful impacts on the papermaking process. Pretreatment of stubble on the removal of metal ions and extractive and its impact on the content of chemical constituents like holocelluose, lignin, silica, the pulping yield as well as the mechanical properties of paper were examined in the laboratory. Acid pretreatment significantly reduced the content of the metal ions with about more than 50%. The conditions for acid pretreatment of the material were optimized to pH-2 at 5% consistency for 1 hour retention time with more benefits in extractives and metal ions removal and less impact on cellulose degradation. The demand for active alkali charge during pulpmaking was observed to be about 3% lower for the pretreated material as compared to the untreated one. Along with the chemical conservation, a higher pulping yield of about 6 – 7 % was also observed for acid pretreated materials. Improved thickness, more crystalline and a high degree of polymerization of cellulose fibre were noticed due to acid pretreatment and the pulp obtained from acid pretreated material showed improved mechanical strength properties (tensile, tear, burst strength etc.). The study revealed that pretreatment of agro-residue material with dilute acid (optimized conditions) could be used to remove the non-process component and make it suitable for utilization in papermaking process with improved mechanical properties in the paper products.