Removal of hazardous dyes-BR 12 and methyl orange using graphene oxide as an adsorbent from aqueous phase

Graphene oxide was used as efficient adsorbent for the rapid removal of two dyes basic red 12 (BR 12) and methyl orange (MO) from the aqueous phase, the whole adsorption process was well investigated and elucidated. The impact of several influential parameters such as contact time, initial dye concentrations, initial solution pH and temperature was well studied and optimized. The optimized time for adsorption process was 100 min. The maximum removal efficiency was occurred at optimized pH 3 of aqueous solutions. The adsorption capacity of BR 12 dye was increased; this may be due to increase in effective interactions between dye particles and adsorbent surface. On the other hand on increasing the initial concentration of methyl orange dye adsorption capacity was decreased, this may be due to repulsion between methyl orange negative charge and the graphene oxide surface negative charge. The effect of temperature reveals that adsorption process of dyes on the developed adsorbent was endothermic. The adsorption equilibrium data was of basic red 12 and methyl orange dyes on to the GO adsorbent surface were found to be well fitted and in good agreement with the type (I) Langmuir isotherm; because it possess high value of linear regression (R-2 = 0.999) and least value for chi-square statistic (X-2 = 2.28). (C) 2015 Elsevier B.V. All rights reserved.