Statistical optimization of Remazol Brilliant Blue R dye adsorption onto activated carbon prepared from pomegranate fruit peel

Abstract

This study explored the use of pomegranate-fruit-peel activated carbon (PFPAC) prepared using potassium hydroxide (KOH) activation and carbon dioxide (CO2) gasification methods for the adsorptive removal of Remazol Brilliant Blue R (RBBR) dye from synthetic wastewater. The adsorbent was characterized using BET, FTIR, SEM and proximate analysis respectively. Central composite design (CCD) in response surface methodology (RSM) was used for the optimization of RRBR dye adsorption onto PFPAC surface. Quadratic model and two-factor interaction models were developed for the percentage RBBR dye removal and PFPAC yield. Model suitability was judged using Analysis of Variance (ANOVA). BET surface area showed a significant improvement from 1.01 m2/g (raw PFP) to 845.96 m2/g (PFPAC), aside volatile matters (60.63% to 17.6%) which gave a sharp reduction, other proximate analyses parameters increased from PFP to PFPAC: fixed carbon contents (15.34% to 75.24%), carbon content in the precursor was found to increase from 30.44% (raw PFP) to 78.32% (PFPAC). The FTIR analysis showed the presence of stretching bands such as OH, CH, OCO, CC, CO, NO, CO and CCH:CH which are altered after activation and adsorption process, leading to additional CO stretching belonging to lactone, ketone, and carboxylic anhydride and CH bending vibrations after RBBR dye adsorption. The optimum removal conditions for RBBR dye adsorption were 350-watt, 4.50 min and 0.90 for radiation power, radiation time and IR respectively. This led to a maximum RBBR dye removal percentage of 81.35% and PFPAC's yield percentage of 31.2%. The error percentage between predicted and actual results for the preparation of PFPAC was 1.92%, indicating that the results of experimental studies were in perfect agreement with those suggested from model. Thus, the prediction by the model was in good conformity with actual outcome. PFPAC was found to be effective in trapping RBBR dye from aqueous solution.