Population growth
coupled with significant pressure for clean agricultural
practices puts a heavy burden on conventional crop treatments that
target high yields with minimal cropland expansion. Optimization of
fertilization systems is required as part of the solutions to current
megatrends. Herein, we present a sustainable strategy to achieve controlled
release formulations for nitrogen fertilization. Specifically, we
used interfacial engineering to design alginate-based matrices that
incorporated biogenic silica particles to achieve increased interfacial
area for dynamic entrapment and release of ammonium nitrate. The incorporation
of biogenic silica in the alginate matrix provided a porous architecture
spanning length scales from the micro- (within particles) to the macrosize
(within the polymeric matrix) levels, leading to tunable patterns
of nitrogen release. Alginate–biogenic silica granules approached
the European requirements of “slow-release” compositions.
At optimized silica content, 15% of the nitrogen was released within
24 h and 56% over 28 days. The complete nitrogen dissolution was achieved
after 60 days. The experimental results and kinetic models provided
insights on the mechanisms driving the nitrogen release from the alginate–silica
matrix as a function of the pore–polymer hybrid architectures.
Lignin is one of the most important and widespread carbon sources on Earth. Significant amounts of lignin are delivered to the market by pulp mills and biorefineries, and there have been many efforts to develop routes for its valorization. Over the years, lignin has been used to produce biobased chemicals, materials, and advanced biofuels on the basis of its variable functionalities and physicochemical properties. Today, lignin’s applications are still limited by its heterogeneity, variability, and low reactivity. Thus, modification technologies have been developed to allow lignin to be suitable for a wider range of attractive industrial applications. The most common modifications used for this purpose include amination, methylation, demethylation, phenolation, sulfomethylation, oxyalkylation, acylation or esterification, epoxidation, phosphorylation, nitration, and sulfonation. This article reviews the chemistry involved in these lignin modification technologies, discussing their effect on the finished product while presenting some market perspectives and future outlook to utilize lignin in sustainable biorefineries.
Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has been reported to possess a high quantity of caffeoylquinic acids that may be beneficial for other applications instead of its conventional use as a hot beverage. Therefore, we investigate the effect of blending yerba mate extract during and after defibrillation of Eucalyptus sp. bleached kraft paper by ultrafine grinding. Blending the extract during defibrillation increased the mechanical and thermal properties, besides being able to use the whole extract. Afterwards, this material was also investigated with high content loadings of starch and glycerine. The results present that yerba mate extract increases film resistance, and the defibrillated cellulose is able to protect the bioactive compounds from the extract. Additionally, the films present antibacterial activity against two known pathogens S. aureus and E. coli, with high antioxidant activity and increased cell proliferation. This was attributed to the bioactive compounds that presented faster in vitro wound healing, suggesting that microfibrillated cellulose (MFC) films containing extract of yerba mate can be a potential alternative as wound healing bandages.
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