ABSTRACT Implementing sustainable practices for using agricultural waste is urgent in the face of the challenges of climate change. This study aimed to investigate the application of carboxymethyl ...cellulose (CMC) derived from soybean hulls as a bioinput in the seed coat of beans. CMC was obtained after bleaching the pulp, alkalizing and etherifying it varying the chloroacetic acid concentration and the reaction time. The properties of CMC were compared to those of soybean hulls and bleached pulp. The CMC with the highest degree of substitution (DS) was chosen as bioinput. In addition to the control treatment, concentrations of 1%, 2%, and 3% CMC were used for coating, and the impact on the physiological quality of seeds was evaluated. CMC proved suitable as a coating agent for seeds, with a DS of 1.56 obtained with 1.2 g chloroacetic acid per gram of bleached pulp during 192 min at 63 °C. The 2% CMC solution proved to be effective, resulting in 93%, 94%, and 43.5% of germinated seeds at 5 days, 8 days, and after accelerated aging, respectively. Seedlings reached 34.2 cm in length and a dry mass of 0.05 g. Our results indicate that soybean hulls can be successfully used in the production of CMC as a coating material, improving the physiological quality of bean seeds and contributing to more sustainable agricultural practices.
RESUMO Este estudo aborda a necessidade de adoção de práticas sustentáveis de aproveitamento de resíduos agrícolas diante dos desafios das mudanças climáticas. O objetivo do presente estudo foi investigar a aplicação da carboximetilcelulose (CMC) obtida a partir da casca de soja como bioinsumo no revestimento de sementes de feijão. A CMC foi obtida após o branqueamento da polpa, alcalinização e eterificação, variando o ácido cloroacético e o tempo de reação. Compararam-se as propriedades da CMC com as da casca de soja e da polpa branqueada. A CMC com maior grau de substituição (GS) foi escolhida como bioinsumo. Além do tratamento controle, foram avaliadas as concentrações de 1%, 2% e 3% de CMC para o recobrimento, impactando na qualidade fisiológica das sementes. A CMC revelou-se adequada como agente de recobrimento para as sementes, com um GS de 1,56, obtido com 1,2 g de ácido cloroacético por grama de polpa branqueada, durante 192 minutos a 63 °C. A solução de 2% de CMC mostrou-se eficaz, resultando em mais de 94% de germinação aos 8 dias, 93% na primeira contagem de sementes germinadas (5° dia), 43,5% após o envelhecimento acelerado, e crescimento de plântulas de 34,2 cm de comprimento e massa seca de 0,05 g. Os resultados indicam que a casca de soja tem potencial para utilização na produção de CMC, que pode ser aplicada como recobrimento, melhorando a qualidade fisiológica das sementes de feijão e contribuindo para práticas agrícolas mais sustentáveis.
The shell surrounding fruits of the jatobá-do-cerrado tree, in its natural state, was modified by the addition of HNO
3
and NaOH and used as an adsorbent in the removal of Cu(II) and Ni(II) from ...aqueous solutions. The untreated (JIN) and chemically modified (JCT) fruit shell samples were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction. Their efficiency as adsorbents in the removal of Cu(II) and Ni(II) ions from aqueous solutions was studied under different conditions of pH (2-9) and it was observed that the optimal pH for Cu (II) adsorption was 5.5 and for Ni (II) it was 6.0. The adsorption isotherms were obtained at different temperatures (298, 308, 318 K) and the q
max
values ranged from 33.96 to 41.00 mg g
-1
. The adsorbents presented higher selectivity toward Cu ions (II). The thermodynamic analysis results suggest that the adsorption process studied is of a physical nature. Supported by quantum mechanical calculations, the interaction sites of the ion-cellulose and ion-lignin complexes were identified, evidencing the central role of water molecules in stabilization of the complexes. The experimental and theorical results indicate that JIN and JCT have good potential for the adsorption of Cu(II) and Ni(II) ions and are thus promising materials for the removal of other metal ions in aqueous systems.
This study aimed to elaborate a hydrogel constituted by carboxymethyl chitosan (CMC), hyaluronic acid (HA) and silver (Ag) and to evaluate its healing effect on partial-thickness burn wounds ...experimentally induced in rats.
CMC was obtained by chitosan reacting with monochloroacetic acid. The carboxymethylation was confirmed by Fourier-transform infrared spectroscopy and hydrogen nuclear magnetic resonance (NMR). Scanning electron microscopy was used to determine the morphologicalcharacteristics of chitosan and CMC. After the experimental burn wound induction, the animals (n = 126) were treated with different CMC formulations, had their occlusive dressings changed daily and were followed through 7, 14 and 30 days. Morphometric, macroscopic and microscopic aspects and collagen quantification were evaluated.
Significative wound contraction, granulation tissue formation, inflammatory infiltration and collagen fibers deposit throughout different phases of the healing process were observed in the CMC hydrogels treated groups.
The results showed that, in the initial phase of the healing process, the most adequate product was the CMC/HA/Ag association, while in the other phases the CMC/HA association was the best one to promote the healing of burn wounds.
In this paper, chitosan was reacted with monochloroacetic acid under alkaline conditions to prepare carboxymethyl chitosan. A 23 full-factorial central composite design was applied to evaluate the ...effect of molar ratio sodium hydroxide (NaOH)/Chitosan (Ch), time and molar ratio monochloroacetic acid (MCA)/Chitosan (Ch) on the reaction yield and on the characteristics of carboxymethyl chitosan such as average degree of substitution (DS¯) and solubility. An optimization strategy based on response surface methodology was used together with the desirability function approach to optimize this process. The occurrence of carboxymethylation was evidenced by FTIR and 1H NMR spectroscopy. The optimum conditions for carboxymethylation process were found to be 12.4, 10.6h and 5 for molar ratio sodium hydroxide (NaOH)/Chitosan (Ch), time and molar ratio monochloroacetic acid (MCA)/Chitosan (Ch), respectively. Under these optimal conditions, it was possible to obtain carboxymethyl chitosan with DS¯ of 1.86 and solubility of 99.6%. X-ray diffraction and thermogravimetry analysis showed that crystallinity and thermal stability of derivatives was lower than chitosan and decreased with increase of DS¯.
•CMCh did not show toxicity to A. salina (LC50>2400μgmL−1).•CMCh was not able to inhibit the growth of Gram-positive or Gram-negative bacteria.•Gram-negative biofilms were more susceptible to ...compounds than Gram-positive.•CMCh inhibited 80% of biofilm of B. cepacia, E. coli, S. aureus and K. rhizophila.
Investigation of the antimicrobial action of carboxymethyl chitosan (CMCh) is among the alternative approaches in the control of pathogenic microorganisms. This study aimed to screen the toxicity using the brine shrimp lethality assay and to investigate the inhibitory activity of carboxymethyl in isolation or in combination with silver nitrate, copper sulfate and zinc sulfate on biofilm formation by Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Kocuria rhizophila ATCC 9341, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25312, and Burkholderia cepacia ATCC 17759. The CMCh was obtained by reacting chitosan with monochloroacetic acid under alkaline conditions, and the occurrence of carboxymethylation was evidenced by FTIR and 1H NMR spectroscopy. The CMCh was combined with metallic salts (AgNO3, CuSO4·5H2O and ZnSO4) to perform the bioassays to screen the toxicity, to determine the minimum inhibitory concentration and the impact of sub-inhibitory concentrations against biofilm formation. Although CMCh did not show inhibitory activity against bacterial growth, it had an interesting level of inhibition of bacterial biofilm. The results suggest that sub-inhibitory concentrations of compounds were effective against biofilm formation.
•Isolation and characterization of cellulose from brewer's spent grain.•Conversion of cellulose to carboxymethyl cellulose in a fast microwave-assisted reaction.•Carboxymethyl cellulose with high ...degree of substitution was obtained.
Cellulose was extracted from brewer's spent grain (BSG) by alkaline and bleaching treatments. The extracted cellulose was used in the preparation of carboxymethyl cellulose (CMC) by reaction with monochloroacetic acid in alkaline medium with the use of a microwave reactor. A full-factorial 23 central composite design was applied in order to evaluate how parameters of carboxymethylation process such as reaction time, amount of monochloroacetic acid and reaction temperature affect the average degree of substitution (DS¯) of the cellulose derivative. An optimization strategy based on response surface methodology has been used for this process. The optimized conditions to yield CMC with the highest DS¯ of 1.46 follow: 5g of monochloroacetic acid per gram of cellulose, reaction time of 7.5min and temperature of 70°C. This work demonstrated the feasibility of a fast and efficient microwave-assisted method to synthesize carboxymethyl cellulose from cellulose isolated of brewer's spent grain.
Jatobá-do-cerrado fruit shells, archetypical of lignocellulosic-based biomass, were used as an adsorbent to remove crystal violet (CV) and methylene blue (MB) from water. The adsorbent was ...characterized using various techniques, and kinetic studies showed dye adsorption followed second-order kinetics. An experimental design investigated the effects of pH and temperature on removal efficiency, with a quadratic model fitting the data best. The results suggest pH influences MB's adsorption capacity more than temperature and at 25 °C and pH 8, MB had a desirability value of 0.89, with 95 % removal efficiency. For CV, temperature had a greater influence, with a desirability value of 0.874 at 25 °C and pH 10, and 95 % removal efficiency. Adsorption isotherm studies revealed maximum adsorption capacities of 123.0 mg·g−1 and 113.0 mg·g−1 for CV and MB, respectively. Experimental thermodynamic parameters indicated an endothermic and spontaneous process which it was supported by quantum chemistry calculations. The protocols developed confirmed the potential for adsorbing CV and MB dyes in water, achieving over 73.1 and 74.4 mg g−1 dyes removal.
The process employed for the pulping and bleaching of sorghum straw was optimized prior to the synthesis of cellulose acetate. A 22 factorial central composite design was carried out. The variables ...considered were cooking time (1.5 to 2.5 h) and dilute alkali concentration (0.75 to 1.25%) for the pulping and bleaching time (30 to 35 min) and bleach volume (20 to 25 mL) for the bleaching. The sorghum straw was comprised of 49.43% α-cellulose, 19.18% hemicellulose and 30.42% lignin. The optimum conditions that maximize these processes were 2.5 h and 1.25% (dilute alkali concentration) at 90 °C, and 35 min and 25 mL (bleach volume) at 80 °C, respectively, providing pulps with a low Kappa number (<3) and lignin content, and cellulose with a high degree of crystallinity. The 1H NMR, XRD, FTIR spectroscopy, SEM and thermal analysis demonstrated that it is possible to synthetize cellulose acetate (with 2.62 degrees of substitution) by acetylating bleached pulp for 16 h at 25 °C.
•Sorghum straw can be used as a raw material to produce pulps and cellulose derivatives.•Sorghum straw does not require sophisticated pretreatment to remove the lignin.•The bleaching process yields high-quality sorghum straw cellulose.•Cellulose acetate synthesis provides a high added-value product from sorghum straw.
Chitosan-N-lauroyl (CL) was synthesized from the reaction between chitosan and lauroyl chloride, in two proportions, obtaining the adsorbents CL1P (1:1) and CL2P (2:1). These were used for studies in ...aqueous Cu(II) and Pb(II) solutions on the metal ion adsorption capacity and the metal/adsorbent interaction. The pH, temperature, kinetics, selectivity and adsorption equilibrium were investigated. The feasibility of complexation between the ions and the adsorbent was verified theoretically through a density functional theory (DFT) approach. The theoretical maximum adsorption capacities (qmax) of CL1P and CL2P for Cu(II)/Pb(II) ions were 36.4/41.0 and 48.5/37.6 mg g−1, respectively. The experimental qmax values were lower than the theoretical values and ranged from 31.5–33.0 mg g−1. At the optimum pH value (5.5) the ion adsorption process was spontaneous, endothermic and associated with pseudo-second-order kinetics. Supported by quantum mechanical calculations, the site of ion-chitosan interaction was identified, evidencing the role of carbonyl, hydroxyl and amide groups in the stabilization of the complexes. Considering the scarcity of studies on apolar chitosan-based adsorbents for the removal of heavy metals, the promising results presented herein allow a better understanding of the relation between apolar groups and pH control, which could aid the design of polymeric adsorbents.
Soybean hulls, a co-product generated in high volumes, were used to obtain pulp and CMC. The pulping process was optimized with the aid of 1%, 2%, and 2.5% NaOH solutions at 90 °C for 2 h. A 22 ...central composite design was used in order to optimize the bleaching process and the CMC synthesis. Volumes of bleaching solution (VS) of between 55 and 65 mL/g at temperatures between 85 and 95 °C and VS of 70 and 75 mL/g at 95 °C were applied in the pulp bleaching process. The factors considered in the carboxymethylation were the chloroacetic acid mass (1.2–2.1 g/g) and the reaction time (192–228 min), at 63 °C. The soybean hulls contain 40.62% of cellulose and have a low lignin content. The pulping process was optimized when 1% NaOH was used at 90 °C/2 h and bleaching process applying VS = 75 mL at 95 °C/4 h. The pulps showed low lignin content (<6%) and the cellulose had a high degree of crystallinity. The SEM, 1H NMR, XRD, FTIR and TGA/DTG analysis results demonstrated that it is possible to synthesize CMC (DS = 1.45) by acetylating the bleached pulp with 2.1 g of chloroacetic acid for 192 min, at 63 °C.
•Soybean hulls can be used as a raw material to produce pulps and cellulose derivatives.•Soybean hulls does not require sophisticated pretreatment to remove the lignin.•The bleaching process yields high-quality soybean hulls cellulose.•Carboxymethyl cellulose synthesis provides a high added-value product from soybean hulls.
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