Photocatalytic treatment of Crystal Violet in aqueous solution:Box–Behnkenoptimization and degradation mechanism

Abstract

A photocatalytic degradation of Crystal Violet (CV) in aqueous solution was investigated in batch reactor. Box–Behnken experimental design was using to establish a quadratic model showing the functional relationship between degradation rate and four operational parameters: pollutant concentration, irradiation time, zinc oxide (ZnO) dose, and stirring speed, at free pH (~ 7), lamp irradiance (45 W m−2) and ambient temperature (~25°C). The results show that the most influential factor on the process was the CV concentration, with an effect of 48.27%, followed by the ZnO dose with an effect of 15.16%, at the third position comes the irradiation time with an effect of 11.81%, and the forth influencing parameter was the stirring speed with an effect of 1.04%. A total CV degradation (100%) was reached for ultraviolet (UV) irradiation time equal to 90 min, ZnO dose of 0.7 g L−1, and stirring speed of 558 rpm for CV initial concentration of 55 mgL−1. For CV concentration equal to 100 mg L−1solar irradiation seems to be better up to 96% of degradation against 62% for UV lamp after 120 min of irradiation time. The O•−2 radicals were the main active species responsible for the degradation of CV. The degradation kinetic was well described by the pseudο first‐οrder mοdel.

Experimental optimization of Waste Cooking Oil ethanolysis for biodiesel production using Response Surface Methodology (RSM)

“…4 and 5) was used to assess the statistical significance of independent factors and their interactive effects on biodiesel yield. p-value lower then 0.05 was considered significant in surface response analysis [31]. Based on the results of ANOVA the model was statistically significant at confidence level of 95% where a small probability value (p-value) and high Fisher value (F-value) were observed.…”

“…RSM has many advantages in terms of time and cost, it reduces the number of experiments needed to interpret several parameters and their interactions. Face-Centered-Composite Design (FCCD) is one of RSM used to prevent the experiments realized under extreme conditions, it used to study the relationship between variables and optimize their individual and interactional effects [31].…”

An overview of prominent factors influencing the photocatalytic degradation of cationic crystal violet dye employing diverse nanostructured materials

“…Additionally, these activities produce a wide range of pollutants that are released into aquatic habitats, jeopardizing the delicate natural equilibrium that facilitates life to evolve on Earth. 1 The textile, paper, leather, printing, culinary, plastic, cosmetics and electroplating industries all employ synthetic dyes extensively as coloring agents. Synthetic dye pollution of the environment is an alarming problem because of its detrimental ecotoxicological consequences and across-the-globe bioaccumulation.…”

“…The world's freshwater sources are under tremendous stress of being contaminated as a result of the continuing expansion of industrial activity throughout the globe. Additionally, these activities produce a wide range of pollutants that are released into aquatic habitats, jeopardizing the delicate natural equilibrium that facilitates life to evolve on Earth 1 . The textile, paper, leather, printing, culinary, plastic, cosmetics and electroplating industries all employ synthetic dyes extensively as coloring agents.…”