Superior Mesoporosity of Lipid‐Free Spent Coffee Ground Residues

Abstract

As part of the biorefinery concept for spent coffee grounds (SCG), production of activated carbon (AC) was investigated from the degreased coffee grounds (DCG) left behind after oil extraction (primarily for biodiesel). The oils were extracted through conventional solvent extraction with GC/GC–MS confirming the oil was comparable to oils produced industrially. More significantly, analysis showed the DCG AC to have a four‐fold increase in mesoporosity compared with the SCG AC with mesopore volumes of 0.6 and 0.15 cm3 g−1, respectively. Adsorption trials showed a ten‐fold increase in capacity for AuIII from 8.7 to 88.6 mg g−1 with subsequent experiments confirming that DCG AC displayed standard behavior for mesoporous materials of increasing adsorption capacity with decreasing pH. This raises the potential for valorization of SCG into a functional material for water remediation without the need for templating agents or expansion pretreatments with the added bonus of an additional material being produced simultaneously.

Comprehensive Two-Dimensional Gas Chromatography Advances in Technology and Applications: Biennial Update

“…With the increasing interest to find alternatives to fossil fuels, scientists are exploring a diverse range of replacements, and so, it is not surprising that applications of GC×GC in this field are growing. Recent work has explored the composition of bio-oils obtained from vegetable sources and waste products, such as algae, safflower, coffee waste, − rice husk, sugar cane residues, , and coconut fibers for fuel applications. Caramão and co-workers − , optimized the biomass pyrolysis procedure to obtain bio-oils from the last four sources cited above, using GC×GC to obtain their chemical profiles.…”

Mesoporous-rich calcium and potassium-activated carbons prepared from degreased spent coffee grounds for efficient removal of MnO42− in aqueous media

“…As an example of this, in the coffee industry approximately 6 billion kg of spent coffee grounds (SCGs) are produced annually as UFSCW. 10 The common mode of waste management for UFSCW is either biomass burning which, in the case of SCGs, has negative connotations associated with NOx emissions, or aerobic digestion where water soluble ammonia generated from decomposition of SCGs can raise the pH, killing or inhibiting the methanogens that generate methane for renewable fuel. Hence a waste valorisation route for the management of UFSCW spent coffee grounds (SCGs) is highly desirable.…”

“…Previously, we reported the production of mesoporous activated carbon (AC) via zinc chloride activation derived from degreased spent coffee grounds (DCGs) in adsorbing gold and chromium from aqueous solutions. 10 However, with zinc being a ‘Critical element’, coupled with the health/environmental risks associated with it, it is essential to look for alternative, more benign and sustainable activating agent such as metal chlorides ( e.g. Ca, Na).…”

Byproduct Valorization: From Spent Coffee Grounds to Fatty Acid Ethyl Esters

“…The chemicals for all steps of the reaction were specifically chosen so that they reflect the green nature of the process itself, creating an alternative to crude oil. , Traditional methods for the production of biodiesel analogues from SCG use chemicals, such as heptane, methanol, and potassium hydroxide, that have higher amounts of associated hazards both to human health and to the environment. , Therefore, to minimize hazards and the variety of chemicals used in this experiment, ethyl acetate was used for the initial lipid extraction and the workup. Sodium hydroxide dissolved in ethanol was used for the transesterification; this differs from traditional methods using potassium hydroxide dissolved in methanol given the reduced hazards.…”