A Statistical Approach to Acid Red 18 Dye Removal From Water Using Capsicum Annum Membrane: Optimization and Batch Studies Using BBD and CCD Designs

Capsicum annum outer membrane (CAM) powder was applied for the first time as a natural adsorbent for the removal of AR-18 (acid red 18) dye from water. In a series of batch studies, Langmuir was found to be the best-fitted isotherm model for mono-layer adsorption of AR-18 dye with Q_max of 90.09 mg/g. Both BBD and CCD statistical tools were used to get the optimal conditions for the adsorption of AR-18 to cut down on chemical use and time and to conserve the environment in sustainable ways. In the BBD matrix, the value of F was much higher (201.32) than that of CCD (34.27), indicating the greater significance of the BBD model. Moreover, the BBD model had high R² (BBD=0.995) compared to the CCD model (CCD=0.969), indicating it was the best-fitting model. Percentage removal of AR-18 dye (96.74%) on CAM was obtained at an initial AR-18 concentration of 53.32 mg/L, pH 6.27, contact time 84.40 minutes and dose of 2.0 g/L using the BBD model. Whereas 96.14% removal on CAM was obtained at an initial dye concentration of 40.57 mg/L, pH 5.24, contact time 64.94 min and dose of 1.86 g/L using the CCD model. The results indicated that BBD was the best model for optimization of the experimental results to yield the optimal conditions for AR-18 dye adsorption.