Different Plant Biomass Characterizations for Biochar Production

Abstract

ABSTRACT:The use of biomass for biochar production is already a reality. However, little is known about its structure and composition, mainly due to the changes occurred during the heat treatment. This information is crucial since it will have an immediate impact on the quality and applicability of the material produced. Therefore, this study aimed to analyze different biomasses, characterizing their potential for biochar production. Woods from Eucalyptus urophylla and Corymbia citriodora and coffee husk were assessed. The biomass was ground and sieved, and then stored under controlled conditions of temperature and humidity. Subsequently, the material characterizations were performed through proximate analysis, elemental analysis, thermogravimetric analysis and Fourier transform infrared spectroscopy (FTIR). In general, all biomasses presented potential to be used in the production of biochar, where low H/C and O/C ratios were found. The coffee husk has higher lignin, extractives, ash and fixed carbon contents, which certainly contributed to its greater thermal stability. The FTIR analysis showed the presence of bands related to recalcitrant chemical groups such as carboxylics and phenolics in the spectra of all biomasses. The thermogram profiles of the C. citriodora and E. urophylla wood were similar to each other, and different from that of the coffee husk, which showed higher thermal stability. CARACTERIZAÇÃO DE DIFERENTES BIOMASSAS VEGETAIS PARA PRODUÇÃO DE BIOCARVÕESRESUMO: A utilização da biomassa para produção de biocarvões já é uma realidade. Porém, pouco se sabe sobre a sua estrutura e composição, principalmente, mediante as transformações ocorridas durante o tratamento térmico. Estas informações são fundamentais, uma vez que terão impacto imediato na qualidade e aplicabilidade do material produzido. Portanto este trabalho objetivou analisar diferentes biomassas, caracterizando-as como potenciais para produção de biocarvões. Foram utilizadas madeiras de Eucalyptus urophylla e Corymbia citriodora e cascas de café. As biomassas foram moídas e peneiradas e, em seguida, armazenadas sob condições de temperatura e umidade controlada. Posteriormente realizou-se a caracterização dos materiais, por meio de análise química, química imediata, elementar (CHNS-O), térmica (TGA e DTA) e de espectroscopia vibracional na região do infravermelho (FTIR). De forma geral, todas as biomassas apresentaram potencial para serem utilizadas na produção de biocarvão, no entanto, a casca de café apresentou maiores teores de lignina, extrativos, cinzas e carbono fixo, o que, certamente, contribuiu para que a mesma apresentasse maior potencial de utilização como condicionador de solos. Com relação à análise de FTIR, observou-se a presença de bandas referentes aos grupos químicos recalcitrantes, como os carboxílicos e fenólicos nos espectros de todas as biomassas. O perfil dos termogramas de C. citriodora e de E. urophylla foram semelhantes entre si e diferentes da casca de café, que apresentou maior estabilidade térmica.

Enhancing Cation Exchange Capacity of Weathered Soils Using Biochar: Feedstock, Pyrolysis Conditions and Addition Rate

“…The high CEC observed for CH biochar is possibly due to the high K content in the feedstock, which during pyrolysis can intercalate and cause the separation of carbonaceous lamellae by the oxidation of cross-linking C atoms [29]. According to Veiga et al [53], compared to wood biomasses, coffee husk has greater lignin, ash and fixed C contents, which contribute to its higher thermal stability evidenced by thermal gravimetric analysis. The presence of K in the feedstock alters C degradation due to a greater thermal stability of organic compounds formed during pyrolysis [54].…”

Process optimisation of methylene blue sequestration onto physical and chemical treated coffee husk based adsorbent

“…The peaks located at 1746 and 1628 cm −1 are attributed to stretching vibrations of aldehydes and ketones, and peak at 1429 cm −1 can be assigned to carboxyl group C-O bond stretching vibration. Peaks at 1248 and 1437 cm −1 correspond to C-N stretching vibration of the amine group and O-H bending vibration of the carboxylic group, respectively [43][44][45][46][47][48].…”

Carbon stability and biochar aging process after soil application

“…The biochar proved to be very concentrated in carbon, overcoming 70% in mass; which is superior to values close to 50% of C in eucalyptus wood. 33,34 It has been known that during pyrolysis there is an increasing of aromaticity through the establishment of carboncarbon bond and loss of O and H, 34 which resulted in O/C ratio values of 0,22 and H/C of 0,46 less than eucalyptus wood values, equals to 0,67 and 1,45, respectively. 35 After comparing band and functional groups of Table 3 with other results from literature, 36,37 one seen that biochar still presents original peaks of biomass, such as OH band and cellulose and lignin signs.…”