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Control of malodorous gases emission from wet-end white water with hydrogen peroxide, TAPPI Journal October 2021
ABSTRACT: White water is highly recycled in the papermaking process so that its quality is easily deteriorated, thus producing lots of malodorous gases that are extremely harmful to human health and the environment. In this paper, the effect of hydrogen peroxide (H2O2) on the control of malodorous gases released from white water was investigated. The results showed that the released amount of total volatile organic compounds (TVOC) decreased gradually with the increase of H2O2 dosage. Specifically, the TVOC emission reached the minimum as the H2O2 dosage was 1.5 mmol/L, and meanwhile, the hydrogen sulfide (H2S) and ammonia (NH3) were almost completely removed. It was also found that pH had little effect on the release of TVOC as H2O2 was added, but it evidently affect-ed the release of H2S and NH3. When the pH value of the white water was changed to 4.0 or 9.0, the emission of TVOC decreased slightly, while both H2S and NH3 were completely removed in both cases. The ferrous ions (Fe2+) and the copper ions (Cu2+) were found to promote the generation of hydroxyl radicals (HOœ) out of H2O2, enhancing its inhibition on the release of malodorous gases from white water. The Fe2+/H2O2 system and Cu2+/H2O2 system exhibited similar efficiency in inhibiting the TVOC releasing, whereas the Cu2+/H2O2 system showed better perfor-mance in removing H2S and NH3.
Journal articles
Magazine articles
Evaluation of rice straw for purification of lovastatin, TAPPI Journal November 2021
ABSTRACT: Cholesterol synthesis in the human body can be catalyzed by the coenzyme HMG-CoA reductase, and lovastatin, a key enzyme inhibitor, can reduce hypercholesterolemia. Lovastatin can be obtained as a secondary metabolite of Aspergillus terreus ATCC 20542. In this study, rice straw of lignocellulose was used in aeration and agitation bath fermentation in a 1-L flask, and a maximal crude extraction rate of 473 mg/L lovastatin was obtained. The crude extract was treated with silica gel (230•400 mesh) column chromatography. Ethyl acetate/ethanol (95%) was used as the mobile phase, and isolation was performed through elution with various ethyl acetate/ethanol ratios. The highest production rate of 153 mg/L was achieved with ethyl acetate/ethanol in a ratio of 8:2. The lovastatin gained from the crude extract was added to 12 fractions treated with 0.001 N alkali, and acetone was then added. After 24 h of recrystallization at 4°C, the extract underwent high-performance liquid chromatography. The purity had increased from 25% to 84.6%, and the recovery rate was 65.2%.
Journal articles
Magazine articles
Probing the molecular weights of sweetgum and pine kraft lignin fractions, TAPPI Journal June 2021
ABSTRACT: The present investigation undertook a systematic investigation of the molecular weight (MW) of kraft lignins throughout the pulping process to establish a correlation between MW and lignin recovery at different extents of the kraft pulping process. The evaluation of MW is crucial for lignin characterization and utilization, since it is known to influence the kinetics of lignin reactivity and its resultant physico-chemical properties. Sweetgum and pine lignins precipitated from black liquor at different pHs (9.5 and 2.5) and different extents of kraft pulping (30•150 min) were the subject of this effort. Gel permeation chromatography (GPC) was used to determine the number average molecular weight (Mn), mass average molecular weight (Mw), and polydispersity of the lignin samples. It was shown that the MW of lignins from both feedstocks follow gel degradation theory; that is, at the onset of the kraft pulping process low molecular weight-lignins were obtained, and as pulping progressed, the molecular weight peaked and subsequently decreased. An important finding was that acetobromination was shown to be a more effective derivatization technique for carbohydrates containing lignins than acetylation, the technique typically used for derivatization of lignin.
Journal articles
Clonal forestry and genetic engineering: where we stand, future prospects, and potential impacts on mill operations, TAPPI JOURNAL, February 1998, Vol. 81(2)
Clonal forestry and genetic engineering: where we stand, future prospects, and potential impacts on mill operations, TAPPI JOURNAL, February 1998, Vol. 81(2)
Journal articles
Champion international's long log pine chip mill: a nontraditional approach, TAPPI JOURNAL, February 1998, Vol. 81(2)
Champion international's long log pine chip mill: a nontraditional approach, TAPPI JOURNAL, February 1998, Vol. 81(2)
Journal articles
A man of ideas: 1998 Gunnar Nicholson Gold Medalist Douglas Wahren, TAPPI JOURNAL, February 1998, Vol. 81(2)
A man of ideas: 1998 gunnar nicholson gold medalist douglas wahren, TAPPI JOURNAL, February 1998, Vol. 81(2)
Journal articles
Biocides-bug killers that enhance pulpmaking and papermaking processes, TAPPI JOURNAL, July 1996, Vol. 79(7)
Biocides-bug killers that enhance pulpmaking and papermaking processes, TAPPI JOURNAL, July 1996, Vol. 79(7)
Journal articles
Public perceptions of the pulp and paper industry, TAPPI JOURNAL, October 1996, Vol. 79(10)
Public perceptions of the pulp and paper industry, TAPPI JOURNAL, October 1996, Vol. 79(10)
Journal articles
It's a dirty job, TAPPI JOURNAL, August 1996, Vol.79(8)
It's a dirty job, TAPPI JOURNAL, August 1996, Vol.79(8)
Journal articles
Development of Predictive Oxygen Delignification Models Usin
Development of Predictive Oxygen Delignification Models Using Kinetic Expressions and Neural Networks, TAPPI JOURNAL, May 2006, Vol. 5(5) (151 KB)
