Abstract
The low cost, eco-friendly and potential biomass, i.e. walnut (Juglans regia) shell powder was deployed for the removal of toxic methylene blue dye from contaminated water solution. The important characterization of the waste material was conducted by using several techniques, i.e. Scanning electron microscope, Fourier-transform infrared spectroscopy, Energy-dispersive X-ray spectroscopy, X-ray powder diffraction, Brunauer-Emmett-Teller surface area analysis, and Thermogravimetric analysis. The marked impact of various operating conditions, i.e. dose, concentration, time, pH and temperature on the adsorption process was investigated. Increasing pH resulted in an increase of percent dye adsorption, and the adsorption mechanism was occurred by electrostatic attraction between negative adsorbent surface and positive dye molecules. The equilibrium data suited with Langmuir isotherm model while the adsorption practice followed the pseudo-second-order kinetic model. Higher temperature reduced the adsorption of dye molecules. The adsorption process was spontaneous, exothermic and chemical. The critical statistical analysis of the experimental results was directed by forming the design of the experiment, which was further, optimized by ANOVA, 3D and perturbation plots. The error and predicted values of both the studied responses as derived from the statistical model showed the agreeable results. 0.1 N HCl was found to be effective in complete desorption. The results are very practical and prove the effectiveness of walnut shell powder in the usage of decolorization for methylene blue.
Highlights
The low cost, eco-friendly and potential biomass, i.e. walnut (Juglans regia) shell powder was deployed for the removal of toxic methylene blue dye from contaminated water solution
The notable peaks associated with raw walnut shell (WNS) as observed at 1446, 1330, 1236, and 1033 cm−1 may be assigned to the possible presence of many aliphatic, aromatic, and nitro compounds
These peaks are respectively shifted to new positions of 1434, 1335, 1243, and 1024 cm−1, which indicates the involvement of the stated groups
Summary
The low cost, eco-friendly and potential biomass, i.e. walnut (Juglans regia) shell powder was deployed for the removal of toxic methylene blue dye from contaminated water solution. Adsorption proves to be a significant method in term of its effectiveness It is the most famous and highly used process by the scientists worldwide for the removal of different water pollutants[13–15]. The present research aims to use the Box-Behnken design for examining the experimental results obtained by testing the effect of various factors on the proven adsorption performance of raw walnut shell and, for this,a regression equation, ANOVA analysis along with 3D response surface plots and perturbation plots were established. The adsorption experiments were conducted by choosing methylene blue, one of the most trusted and preferred dye used for experimental studies, as a model adsorbate. The present research shows promising applications in waste and biomass valorization
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