Bisphenol A removal from aqueous solutions using novel UV/persulfate/H(2)O(2)/Cu system: optimization and modelling with central composite design and response surface methodology

BACKGROUND: Bisphenol A is a high production volume chemical widely used in manufacturing polycarbonate plastics and epoxy resins used in many industries. Due to its adverse effects on human health as an endocrine disruptor and many other effects on the various organs of the human body as well as aquatic organisms, it should be removed from the aquatic environments. This study aimed to mineralisation of BPA from aquatic environments by application of novel UV/SPS/H(2)O(2)/Cu system and optimization and modelling of its removal using central composite design (CCD) from response surface methodology (RSM). METHODS: CCD from RSM was used for modeling and optimization of operation parameters on the BPA degradation using UV/SPS/HP/Cu system. Effective operation parameters were initial persulfate, H(2)O(2), Cu(2+) and BPA concentration along with pH and reaction time, all in three levels were investigated. For analysis of obtained data ANOVA test was used. RESULTS: The results showed that a quadratic model is suitable to fit the experimental data (p < 0.0001). Analysis of response surface plots showed a considerable impact of all six selected variables which BPA and Cu(2+) initial concentrations have been the highest and the least impact on the process, respectively. F-value of model was 54.74 that indicate significance of the model. The optimum values of the operation parameters were determined. The maximum removal of BPA was achieved 99.99 % in optimal conditions and in that condition TOC removal was about 70 %. Finally, validation and accuracy of the model were also evaluated by graphical residual analysis and the influential diagnostics plots. The higher relevance between actual and predicted values demonstrated the validation and applicability of the obtained equation as the model. CONCLUSIONS: According to the results, UV/SPS/HP/Cu system is an effective process in degradation and mineralisation of BPA and CCD methodology is a convenient and reliable statistical tool for optimizing BPA removal from aqueous solutions.