![Table 6 Langmuir constants for removal of Congo red at different temperatures and pH 7.50 [adsorbent dose = 0.05 g/25 mL (bottom ash) and 0.05 g/25 mL (deoiled soya)].](/figures/table-6-langmuir-constants-for-removal-of-congo-red-at-26dbugyd.webp)
![Table 8 Thermodynamic parameters for the uptake of Congo red at pH 7.50 [adsorbent dose = 0.05 g/25 mL (bottom ash) and 0.05 g/25 mL (deoiled soya)].](/figures/table-8-thermodynamic-parameters-for-the-uptake-of-congo-red-2jovfr2m.webp)
Q2. What is the effect of pH on the adsorption of dye?
beyond pH 7.5 with increase in alkaline conditions protonation of the dye is reduced, and electrostatic repulsion between OH– adsorbed on the adsorbent and ionized dye molecule retards the extent of diffusion and adsorption thereby.
Q3. What is the reason for the increase in the extent of adsorption with increase in pH?
The increase in the extent of adsorption with increase in pH value is due to the neutralization of the charges at the surface of the adsorbents.
Q4. What is the main reason why the soya industry is banned?
The abundantly available soya industries waste, i.e., deoiled soya, was employed as an animal feed but its use is banned nowadays due to formation of antimetabolites in living systems [40].
Q5. How much of the dye recovered from the deoiled soya?
5. Desorption of the dye can be successfully carried out by using NaOH solution with about 80% and 90% recovery of Congo red from bottom ash and deoiled soya, respectively.
Q6. What is the effect of the increasing temperature on the mobility of the ions?
It is clear from the decreasing values of effective diffusion coefficient (Di) that as temperature is elevated from 30 to 50 C, the mobility of the ions decreases due to increased retarding force acting on diffusing ions of the dye.
Q7. How many mL of Congo red solution was percolated through each column?
The amount of 10 10 5 M Congo red solution was then percolated through each column under the influence of gravity at a fixed flow rate of 0.5 mL/min.
Q8. What is the relationship between the two adsorbents?
For both adsorbents an increase in value of KF is observed with increasing temperature, thereby indicating an increased dye–adsorbent interaction at higher temperature.
Q9. What was the process of determining the uptake of the dye?
In order to determine the uptake of the dye, an entire set of experiments was performed at different adsorbent dosages, concentrations of the adsorbate, time of contact, temperatures (30, 40, and 50 C), etc. for both adsorbent materials.
Q10. What are the problems related with the pollution of water?
Problems related with the water pollution include damage of the aesthetic nature of water, interference with the process of photosynthesis, destruction of the food web existing in water ecosystem [5], etc.
Q11. What is the kinetics of the adsorption of dye?
The pictorial presentation of the Bt as function of time (Fig. 10) displays linearity with straight lines not passing through the origin in the case of adsorption of the dye over bottom ash and deoiled soya at different temperatures.
Q12. What is the main outcome of the developed methodology for the removal of Congo red from wastewaters?
The important outcomes of the developed methodology adapted for the removal of the anionic dye Congo red using bottom ash and deoiled soya as adsorbents are as follows:1. Studies clearly reveal that both waste materials, bottom ash and deoiled soya, are highly efficient adsorbents for the removal of Congo red from wastewaters.