The effect of individual factors, their binary and ternary interactions on photodegradation rate of organic contaminants using photocatalysts based on multi-walled carbon nanotubes (MWCNTs): statistical analysis based on ANOVA and RSM

The influence of three main parameters including irradiation time, weight fraction of photocatalysts including multi-walled carbon nanotubes and different amount of TiO 2 (MCT#1 and MCT#2) and pH is investigated for the degradation rate of methyl orange (MO). Analysis of variance (ANOVA) and response surface methodology (RSM) have been applied to study the binary and ternary interactions of the main parameters on the degradation rate. The ANOVA results confirm that all of three studied factors have a considerable efficacy on degradation rate of MO at 5% level of probability. Meanwhile, the results show that the degradation rate is enhanced with increasing the weight fraction in range of 0.1 to 0.3%wt and irradiation time in a period of 5 to 35min.The lowest and highest degradation are observed at pH=7 and pH=3, respectively. The normality of residue distribution can be confirmed using graphical analysis. The RSM results reveal that the degradation rate dependency on irradiation time is higher than the weight fraction of photocatalysts.