Adsorption of UV254 in Kerian River water onto ZeliacTM: Analysis using linear and non-linear forms of isotherm models

The composite media, Zeliac^TM was developed with the initial aim to provide low cost adsorbent with promising adsorption capacity. This study was conducted to investigate the removal of UV absorbance at 254 nm (UV₂₅₄) in Kerian river water using Zeliac^TM as the media. Batch experiments study was carried out to determine the optimum removal of UV₂₅₄ by Zeliac^TM. The experimental data were fitted to Langmuir and Freundlich isotherms to investigate the adsorption mechanism. The results from batch study exhibit that Zeliac^TM is capable to remove 74.4% UV₂₅₄ at the dosage of 7g/100 ml. Linear isotherm analysis suggests that the best fitting linear line is Freundlich isotherm with R² values of 0.9294 indicating multilayer adsorption. Similarly, non-linear regression analysis reveals that the adsorption of UV₂₅₄ by Zeliac^TM is attributed by physisorption. The non-linear Freundlich isotherm gives a better fit to the adsorption of UV₂₅₄ than Langmuir isotherm with R² values of 0.9488. The results are supported with low values of X², ARE, HYBRID and MPSED from the error function analysis.  Additionally, it is noted that the linear analysis overestimates the constant parameters’ values for Freundlich isotherm, which cause larger errors as estimated by the error function analysis. Hence, non-linear analysis is more appropriate in explaining the batch experiment data.