Response surface methodology and kinetic study for removal of colour and chemical oxygen demand from coffee wastewater by using spent coffee grounds

• Published in: Desalination and Water Treatment
• Main Author: Mohd Zainuddin N.A.; Azmi N.; Puasa S.W.; Mohd Yatim S.R.
• Format: Article
• Language: English
• Published: Desalination Publications 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134589936&doi=10.5004%2fdwt.2022.28396&partnerID=40&md5=9c32dcdefcc72ee07c74a198cea91de3

Removal of chemical oxygen demand (COD) and colour from coffee wastewater using waste from industry are required due to abundant source for wastewater treatment. This paper presents a treatment of COD and colour from coffee wastewater by using spent coffee grounds (SCG) biochar. The removal of COD and colour was performed using a standard jar test procedure for the effect of pH, adsorbent dosage, and contact time. The samples for phosphoric acid (H3 PO4) at the ratios of 1:2 (SCG: acid solution) was prepared for impregnation onto SCG. Afterwards, the samples were carbonized at 700°C in 1 h period. The results revealed that the optimum removal condition was obtained at the SCG biochar dosage of 20 g, pH 4 and in 60 min of contact times. The maximum colour and COD removal were approximately 99%. The isotherm model and adsorption kinetic model was conducted in the study. The selected data obtained were fitted using linear regression via Microsoft Excel. The regression analysis shows the adjusted R2 obtained is above 90%, which indicates the best fitting data. The analysis of variance analysis proved that the mathematical expression could be used to predict the removal of colour and COD from coffee wastewater. Besides, response surface methodology is used to analyse the optimum parameters in colour and COD adsorption using SCG biochar to increase the adsorption efficiency further. © 2022 Desalination Publications. All rights reserved.