Kraft pulping and bleaching of Eichhornia crassipes (Mart.) Solms (water hyacinth)

Abstract

Eichhornia crassipes (water hyacinth) was pulped by means of a kraft pulping process with reagent loads of 10 and 20% on a dry matter basis to determine yield, rejects, kappa number, and ash. Fiber classification, brightness, opacity, and viscosity were measured in the brown pulp. Bleaching was performed by means of an O1O2D1(PO)D2HD3 sequence. Yield, kappa number, pH, ash, brightness, opacity, and viscosity were evaluated in the bleached pulp. Finally, a microanalysis of inorganic elements was carried out in both the bleached and unbleached pulp ash. The highest kraft pulp yield was 26.4%, with a 10% reagent load at 120 °C and 30 minutes cooking. It was determined that E. crassipes cellulosic pulp contains large amounts of fines. Results of the bleaching sequence indicate low brightness (58.0 %) and low viscosity (6.43 cP). The most abundant inorganic elements in the ash of both bleached and unbleached pulp were Ca, Mg, P, and Si. These results suggest that E. crassipes biomass might complement cellulosic fibers in pulping processes of low yield, such as the wood fibers used to produce handmade paper.

Cellulose Nanocrystals and Lignin Nanoparticles Extraction from Lemna minor L.: Acid Hydrolysis of Bleached and Ionic Liquid-Treated Biomass

“…Despite this, for aquatic species, over the last decade, few studies have paid attention to them, focusing on the isolation of nanocellulose (including nanocrystals and nanofibers) by acid hydrolysis, as in the case of water hyacinth [20][21][22], while no examples of extracted nanosized lignin can be found for these plants. It should also be underlined that chemical pretreatments of these species, particularly ones that use NaOH and NaClO 2 in acidic conditions (for bleaching or delignification), are some of the most common procedures that aim to isolate cellulose with, on the other hand, low in-process lignin residue generation [23]. Most available studies did not address this point, and lignin recovery was mainly not attempted.…”