Valorization of spent coffee grounds through pyrolysis as adsorbent for the removal of Vivizole Red 3BS dye from aqueous solution. Issue 5 (18th April 2022)

• Record Type: Journal Article
• Authors: Adamu, Admasu; Zewge, Feleke; Chebude, Yonas
• Is Part Of: Water practice and technology. Volume 17:Issue 5(2022)
• Page Start: 1019
• Page End: 1034
• Publication Date: 2022-04-18
• Subjects: adsorption -- biochar -- pyrolysis -- spent coffee ground -- textile dye -- valorization; Sewerage; Sewerage -- Management; Water-supply; Water-supply engineering; Periodicals; 628.205
• DOI: 10.2166/wpt.2022.036
• Languages: English
• ISSNs: 1751-231X

Abstract

Abstract: Ever-increasing coffee consumption results in the generation of a significant amount of solid residue in the form of spent coffee grounds (SCG) and their subsequent disposal causes environmental pollution. Valorization of SCG through pyrolysis could be one of the solutions to this challenge. Pristine biochar of SCG shows less efficiency to remove dyes from aqueous solutions. Herein, iron(III) salt was used as a catalyst during the carbonization of SCG and has a good graphitization efficiency and thus enhanced the formation of aromatic structures, which provide adsorption sites for the dye. The physical characteristics of the prepared biochar were analyzed by FTIR, XRD, and BET. A predictive model for the removal of the dye was investigated with the Design Expert 11.0 software through the central composite design (CCD) - response surface methodology (RSM) by conducting a batch adsorption study, and the suggested optimum values of the CCD were 10 ppm initial dye concentration, 1 g per 100 ml adsorbent dose, and contact time of 101 min with optimum predicted dye removal of 99%. The Langmuir model was the best fitted isotherm model with an adsorption capacity of 2.07 mg/g, and the adsorption kinetic equilibrium data was better described by the pseudo-second-order model and from the thermodynamic study, it has been suggested that the adsorption process was spontaneous, favorable, endothermic, and a physicochemisorption in nature. The possible adsorption mechanisms governing the adsorption process of the dye with biochar are π – π electron donor-acceptor interactions and hydrogen bonding. HIGHLIGHTS: Valorization of SCG waste through pyrolysis results in composite biochar. Iron(III) salt was used to catalyze the graphitization of biochar. Composite biochar helps to remove Vivizole Red 3BS dye from aqueous solution. Use of composite biochar as adsorbent offers an opportunity to manage the environmental impacts of SCG waste. The exhausted composite biochar is easily separated by an external magnet. Graphical Abstract