Efficiency of low concentration hypochlorite on characteristics of paper derived from Sesbania grandiflora

In recent years, pulp and paper mill has faced environmental pressure and has been known as one of the major contributors to adverse effects on environment. Up till now, the environmental impact shows that significant results or pollutants are produced from the bleaching process. Large amount of lignin will be eliminated and discharged from the bleaching process which will lead to water pollution. Bleaching is the removal or alteration of coloured substances from chemical pulp to improve the whiteness and brightness of paper, without disturbing the physical and chemical properties of the pulps. By using sodium hypochlorite, it is expected that little or no lignin will be produced as effluents as hypochlorite aims to attack and alter the structure of lignin. This paper will investigate on low concentration of hypochlorite in pulp bleaching towards paper properties produced. Sesbania grandiflora was selected due to its potential and fast growing properties. Kraft pulp derived from Sesbania grandiflora was bleached with 2.5% sodium hypochlorite at 15% consistency for 0 minute, 20 minutes, 40 minutes and 60 minutes in 50°C water bath. The handsheets produced at 0 minute will serve as a control. The physical and mechanical properties of handsheets produced were evaluated followed TAPPI standard. In short, sodium hypochlorite is capable to improve the brightness of handsheets and increase the mechanical properties of handsheets to certain degree. However, temperature exceeds 60°C will bring adverse effect to the mechanical properties of handsheets produced.