Enhancement of Pulp Brightness and Yield in ECF Bleaching Using Xylanase Treatment: A Comparative Study on Different Wood Species
Bibliographic record
Abstract
Bleaching is a process used to remove lignin from wood fibers, which contributes to their light brown-yellowing color.The brightness reversion of chemical pulp comes from the residual lignin left in the pulp.Pulp, a wood fiber, contains lignocellulose, extractive, and ash.In conventional ECF (Elementally Chlorine Free) bleaching, lignin degraded in cooking is removed before bleaching.Xylanase treatment is performed before O2 delignification and ECF bleaching to allow oxygen and bleach chemicals to penetrate the lignocellulose structure and peel off the lignin intact.This process must be done in the lignocellulose structure rather than the cellulose molecule to avoid cellulose degradation impacting product yield and fiber properties.This experiment involved 250 g of ovendry, unbleached pulp.It involved ECF bleaching O-D-E-D stages, including oxygen delignification, Chlorine dioxide bleaching, and extraction with dilute NaOH solution in pressurized oxygen.The pulp was centrifuged between each step to remove liquor and displaced with water with a dilution factor of 3 kg.The standard method used was the SCAN method.The research results showed that higher brightness led to fewer yield losses.This phenomenon occurs due to the more significant amount of lignin removal.After bleaching, Eucalyptus Camaldulensis maintained a yield value of 80.22%, the highest result among the three samples tested.The soft matrix in Eucalyptus Camaldulensis can cover the S2 layer and protect the boundary pith, making it more readily dissolved by xylanase treatment than Acacia Mangium and Mixed Tropical Hardwood.Additionally, Eucalyptus Camaldulensis has larger pore sizes, vessels, and lumens, which enhance accessibility for xylanase enzymes and bleaching chemicals to reach the Lignin-Cellulose-Hemicellulose matrix compared to Acacia Mangium and Mixed Tropical Hardwood.Thus, Eucalyptus Camaldulensis demonstrates better performance in the bleaching process regarding lignin removal and the efficiency of enzyme and chemical usage.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".