Bleaching of Bamboo (Phyllostachys bambusoides) Kraft-AQ Pulp with Sodium Perborate Tetrahydrate (SPBTH) after Oxygen Delignification

Abstract

The most prominent environmental problems facing the paper industry are those due to bleaching processes that use chlorine compounds. In this study, totally chlorine free (TCF) bleaching sequences were applied to Phyllostachys bambusoides bamboo unbleached kraft anthraquinone (AQ) pulp, using different conditions with Oxygen (O) delignification and Sodium Perborate Tetrahydrate (SPBTH) stages. The effects of oxygen pressure, SPBTH ratio, and bleaching time were studied to maximize the brightness gain at the lowest viscosity loss. Unbleached kraft-AQ bamboo pulp was applied to first stage oxygen delignification for bleaching with under 5 bar, 3% NaOH, and 12% concentration conditions. Following the chelated bleaching, Sodium Perborate Tetrahydrate (SPBTH) bleaching was carried out as the final stage. The optimum bamboo kraft pulp bleaching conditions were SPBTH level: 4%, MgSO 4 : 0.5%, Na 2 SiO 3 : 3%, bleaching time: 80 min., reaction temperature: 70°C, and concentration: 12%. An overall increase in the physical properties of paper was evident up to an SPBTH level of 4%. When the SPBTH level and bleaching time increased, the kappa number, viscosity, opacity, and yellowness were decreased, but the brightness was increased. Oxygen delignification with chelatation and SPBTH as a bleaching sequence was shown to be a promising alternative to produce high-quality pulp from bamboo for cleaner paper.

Application of Artificial Neural Networks for predicting tensile index and brightness in bleaching pulp

“…The brightness values of bamboo pulp were lower than poplar pulp in this study, probably due to the different lignin content in bamboo and poplar samples. Bamboo has been reported to have generally higher lignin content than poplar (Akgül et al 2002, Okan et al 2013. Examination of the effect of SPBTH ratio on tensile index of bleached bamboo and poplar handsheet revealed an increase in the SPBTH charge to above 2%, showing a generally positive effect for bamboo pulp but a negative effect on tensile index for poplar.…”

“…The main problems facing the pulp and paper industry are inadequate supplies of raw materials and the effect of contamination by bleaching chemical reagent in recent decades (Okan et al 2013). In order to resolve the problem of inadequate raw materials, there is growing emphasis on the use of alternative raw materials, particularly non-wood waste and fast-growing plants (Ferrer et al 2011).…”

“…These problems have led the pulp industry to develop new technologies which do not cause environmental problems in the production of bleached paper. Environmentally friendly bleaching procedures have thus replaced the classical steps based on chlorine and or chlorinated compounds with others that use alternative reagents such as hydrogen peroxide, oxygen and ozone (Jimenez et al 1999, Atik et al 2006, Moldes et al 2008, Okan et al 2013.…”

Comparison of pulping and bleaching behaviors of some agricultural residues

“…Another reason that renders the use of agricultural residues in the cellulose industry attractive is the limited forest resources of certain countries (Jimenez, 1999). When considering countries with an agriculture-dependent economy and limited forest sources, the use of agricultural residues and cultured or uncultured annual stalks for pulp manufacturing offer a significant solution to the raw materials problem (Okan et al, 2013). Being an agriculture-dependent country with limited forest resources, Turkey is still far from utilizing the current potential of agricultural residues in the cellulose industry.…”

“…After it was discovered that chlorine-containing components (for bleaching pulp with conventional methods) exist in the waste water of the bleaching process, and that these components react with lignin (a residue in the pulp) and are converted into environmentally hazardous chlorinated phenolic compounds and poisonous carcinogenic compounds (such as dioxin and furan groups), social pressures were exerted to limit the use of compounds containing chlorine, such as chlorine, chlorine dioxide, hypochloride, and chloride. All these facts led the pulp industry to develop new technologies that do not cause environmental problems in the production of bleached paper (Okan et al, 2013). However, the bleaching process of pulps (which are derived from annual plants) is difficult due to anatomic and chemical characteristics; therefore, modern totally chlorine-free bleaching procedures are not adequate to reach a high brightness level in this type of pulp (Camamero et al, 2004).…”