Conventional and microwave-assisted acid pretreatment of tea waste powder: analysis of functional groups using FTIR.

Autor: Hamzah HT; Department of Chemical Engineering, AU College of Engineering (A), Andhra University, -530003, Visakhapatnam, India., Sridevi V; Department of Chemical Engineering, AU College of Engineering (A), Andhra University, -530003, Visakhapatnam, India. vellurusridevi@yahoo.co.in., Surya DV; Department of Chemical Engineering, Pandit Deendayal Energy University, -382426, Gandhinagar, India., Palla S; Department of Chemical Engineering, Indian Institute of Petroleum Energy, -530003, Visakhapatnam, India., Yadav A; Department of Chemical Engineering, Pandit Deendayal Energy University, -382426, Gandhinagar, India., Rao PV; Department of Chemical Engineering, AU College of Engineering (A), Andhra University, -530003, Visakhapatnam, India.
Jazyk: angličtina
Zdroj: Environmental science and pollution research international [Environ Sci Pollut Res Int] 2024 Oct; Vol. 31 (46), pp. 57523-57532. Date of Electronic Publication: 2023 Jun 27.
DOI: 10.1007/s11356-023-28272-8
Abstrakt: Tea waste powder (TWP) is one of the potential biomass waste to recover valuable chemicals and materials. The prime objective of this work is to investigate the role of acid pretreatment on TWP. Diluted acids (HCl, H 3 PO 4 , CH 3 COOH, and H 2 SO 4 ) were used to soak the TWP to understand the role of acids on bond cleavage and chemicals formation. One gram of TWP was soaked in 100 mL of diluted acids for 24 h. The soaked samples were further subjected to a hot air oven (temperature: 80 °C, duration: 6 h), orbital shaking (shaking speed: 80-100 rpm, duration: 6 h), and microwave irradiation (microwave power: 100 W, duration: 10 min) to understand the synergistic effects of acids and mode of exposure. The pretreated solid samples and liquid samples were analyzed using FTIR to understand the presence of functional groups. The mass loss of TWP after treatment significantly varied with the type of acid and exposure mode used. In the orbital shaker, the mass loss was varied in the following order: H 2 SO 4 (36%) > CH 3 COOH (32%) > H 3 PO 4 (22%) > HCl (15%). In hot air oven, high mass loss was observed compared to orbital shaking [HCl (48%) > CH 3 COOH (37%) > H 2 SO 4 (35%) > H 3 PO 4 (33%)]. The mass loss in microwave irradiation is lower (19 to 25%) with all acids compared to orbital shaking. In the solid samples, O-H stretching, C-H stretching, C=O stretching, C=C stretching, -C-O-, and -C-OH- functional groups were noticed. Similarly, C=O and C=C peaks and C-O and -C-OH peaks were noticed in liquid samples. Interestingly, microwave irradiation showed promising results in 10 min of pretreatment, whereas orbital shaking and hot air oven pretreatments require 6 h to achieve the same result.
(© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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