The Use of Mg(OH)2 in the Final Peroxide Bleaching Stage of Wheat Straw Pulp

Liu, Yanlan; Chen, Kefu; Lin, Benping

doi:10.15376/biores.9.1.161-170

Cited by 4 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dissociation of hydrogen peroxide in alkaline media generates the peroxide anion (HHO -), which is mainly responsible for the reduction in the concentration of chromophores (Liu et al 2014), leading to brighter bleached fibers. Bleaching effectiveness was also attested by the O/C ratio (Table 2).…”

Section: Resultsmentioning

confidence: 99%

How the chemical nature of Brazilian hardwoods affects nanofibrillation of cellulose fibers and film optical quality

et al. 2015

View full text Add to dashboard Cite

A wide range of alternative cellulose fibers for the development of new green nanomaterials can be obtained from Brazil's natural resources. The objective of the work is to evaluate the influence of the chemical composition of hardwoods on the nanofibrillation process and optical quality of nanofiber films. Wood wastes were selected from three native Amazonian species and from exotic planted Eucalyptus grandis species. Wood sawdust was submitted to chemical alkali and bleaching pretreatments. Nanofibers were produced from the bleached fibers after 10, 20, 30 and 40 passes through a Super Mass Colloider grinder, and films were produced by the casting method. Raw sawdust, alkali-treated fibers and bleached fibers were evaluated by the major chemical components, syringyl/guaiacyl ratio, Fourier transformed infrared spectroscopy, oxygen/carbon ratio and scanning electron microscopy. Morphological characteristics of nanofibers and films were analyzed by transmission and scanning electron microscopies. Optical parameters studied for the films were the opacity, total color difference and b value. The main challenge to delignification was attributed to the low syringyl/guaiacyl ratio. The different chemical natures of Amazonian and eucalyptus hardwoods greatly affected pretreatments and, consequently, the nanofibrillation and optical quality of the films. Consequences observed for highly purified cellulose starting fibers are: (1) lower diameters for individual nanofiber elements; (2) fewer opaque and colored films produced from nanofibers; (3) a tendency to stabilization of the nanofibrillation process after 20 passes through the grinder. For species whose chemical nature hindered cellulose purification, the increased number L. Bufalino (of passes through the grinder continuously decreased the opacity.

show abstract

Section: Resultsmentioning

confidence: 99%

How the chemical nature of Brazilian hardwoods affects nanofibrillation of cellulose fibers and film optical quality

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Mg(OH) 2 has been reported to be an attractive alkali source in peroxide bleaching because it is a solid and can be released slowly into the system, thus acting as a buffer to prevent rapid changes in pH (Johnson et al 2002). Previous studies have shown the environmental benefits of using magnesium hydroxide on wood mechanical or chemimechanical pulp (e.g., pressurized groundwood, thermomechanical pulp, and chemithermomechanical pulp) in peroxide bleaching (Hietanen et al 2013;Leduc et al 2010;Kong et al 2009) and wood chemical pulp (e.g., kraft pulp) in extraction stages (Gibson and Wajer 2003), as well as non-wood chemical pulp (e.g., wheat straw soda-AQ pulp) in peroxide bleaching (Liu et al 2010). However, the application of Mg(OH) 2 for peroxide bleaching of deinked pulp has not been welldocumented in the literature (Leduc et al 2010;Burnet et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Mg(OH)2-Based Hydrogen Peroxide Bleaching of Deinked Pulp

Yun¹,

He²

2013

BioResources

View full text Add to dashboard Cite

Sodium hydroxide (NaOH) has been used as an alkali source in conventional hydrogen peroxide bleaching. In the present work, partial and total replacement of NaOH with magnesium hydroxide (Mg(OH) 2 ) as the alkali source for hydrogen peroxide bleaching of deinked pulp was studied. The bleached pulp was studied with respect to brightness, post color (P.C.) number, and mechanical properties (i.e., the tensile, tear, and burst indices). The bleaching effluent was measured for residual peroxide, pH value, and chemical oxygen demand (COD). The main results from this work were that the brightness and mechanical properties of bleached pulp increased while the P.C. number declined when NaOH was partially replaced with Mg(OH) 2 . However, the total substitution of NaOH with Mg(OH) 2 resulted in a slight decrease in the brightness and mechanical properties in comparison with NaOH as the sole alkali source. Additionally, the residual peroxide of the bleaching filtrate increased from 3% to 61% and the COD load of the bleaching effluent decreased from 20% to 25% when NaOH was replaced with Mg(OH) 2 at various replacement ratios.

show abstract

“…Fiber strength properties and the structure and bonding of pulp in handsheets depend on individual fiber characteristics, such as fibrillation and density (Fiserova et al 2016). The bonding strength between fibers results from the physical contact with hydrogen bonding between hydroxyl groups on the fiber's surface (Liu et al 2013). The tensile indices of pulp 1 after DES treatments were considerably lower than that of the untreated pulp 1 sample.…”

Section: Resultsmentioning

confidence: 99%

“…The burst index is closely related to the degree of hydrogen bonding between fibers. More hydrogen bonding between fibers will increase the burst index because more force is needed to break the surface of the sample (Liu et al 2013). After DES application, there was a slight decrease in burst index and therefore less hydrogen bonding.…”

Section: Resultsmentioning

confidence: 99%

Mechanical properties of pulp delignified by deep eutectic solvents

Škulcová¹,

Majová²,

Šíma

et al. 2017

BioRes

View full text Add to dashboard Cite

Mechanical properties were evaluated for pulp delignified by four deep eutectic solvents (DES). The DES systems were based on choline chloride and lactic acid (1:9), oxalic acid:dihydrate (1:1), malic acid (1:1), and the system alanine:lactic acid (1:9). The results indicated that the type of DES system used influenced the delignified pulp’s mechanical properties including tensile, burst and tear indexes, tensile length, and stiffness. The most suitable DES systems were choline chloride:malic acid (1:1) and alanine:lactic acid (1:9), which achieved the best aforementioned mechanical properties compared to the other DES systems. The weakest performance in the process of pulp delignification was the system with choline chloride and oxalic acid dihydrate (1:1).

show abstract

The Use of Mg(OH)2 in the Final Peroxide Bleaching Stage of Wheat Straw Pulp

Cited by 4 publications

References 4 publications

How the chemical nature of Brazilian hardwoods affects nanofibrillation of cellulose fibers and film optical quality

How the chemical nature of Brazilian hardwoods affects nanofibrillation of cellulose fibers and film optical quality

Mg(OH)2-Based Hydrogen Peroxide Bleaching of Deinked Pulp

Mechanical properties of pulp delignified by deep eutectic solvents

Contact Info

Product

Resources

About