TY  - JOUR
A1  - Figueroa Campos, Gustavo A.
A1  - Perez, Jeffrey Paulo H.
A1  - Block, Inga
A1  - Tchewonpi Sagu, Sorel
A1  - Saravia Celis, Pedro
A1  - Taubert, Andreas
A1  - Rawel, Harshadrai Manilal
T1  - Preparation of activated carbons from spent coffee and coffee parchment and assessment of their adsorbent efficiency
JF  - Processes
N2  - The valorization of coffee wastes through modification to activated carbon has been considered as a low-cost adsorbent with prospective to compete with commercial carbons. So far, very few studies have referred to the valorization of coffee parchment into activated carbon. Moreover, low-cost and efficient activation methods need to be more investigated. The aim of this work was to prepare activated carbon from spent coffee grounds and parchment, and to assess their adsorption performance. The co-calcination processing with calcium carbonate was used to prepare the activated carbons, and their adsorption capacity for organic acids, phenolic compounds and proteins was evaluated. Both spent coffee grounds and parchment showed yields after the calcination and washing treatments of around 9.0%. The adsorption of lactic acid was found to be optimal at pH 2. The maximum adsorption capacity of lactic acid with standard commercial granular activated carbon was 73.78 mg/g, while the values of 32.33 and 14.73 mg/g were registered for the parchment and spent coffee grounds activated carbons, respectively. The Langmuir isotherm showed that lactic acid was adsorbed as a monolayer and distributed homogeneously on the surface. Around 50% of total phenols and protein content from coffee wastewater were adsorbed after treatment with the prepared activated carbons, while 44, 43, and up to 84% of hydrophobic compounds were removed using parchment, spent coffee grounds and commercial activated carbon, respectively; the adsorption efficiencies of hydrophilic compounds ranged between 13 and 48%. Finally, these results illustrate the potential valorization of coffee by-products parchment and spent coffee grounds into activated carbon and their use as low-cost adsorbent for the removal of organic compounds from aqueous solutions.
KW  - coffee by-products
KW  - spent coffee grounds
KW  - parchment
KW  - valorization
KW  - calcination
KW  - activated carbon
KW  - organic compounds adsorption
Y1  - 2021
U6  - https://doi.org/10.3390/pr9081396
SN  - 2227-9717
VL  - 9
IS  - 8
PB  - MDPI
CY  - Basel
ER  -