Response surface methodology for the optimization of acid dye adsorption onto activated carbon prepared from wild date stones

Abstract

In the present study, wild date stones (WDS) were used as a novel and sustainable precursor for high-quality activated carbon preparation to be applied for the removal of Acid Blue 25 dye (AB25) from synthetic water. The carbonization temperature of the raw material was selected at 850 °C on the basis of thermo-gravimetric analysis. The adsorbents were characterized by the BET method, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results indicated that the activated carbon presents a high specific surface area (610.84 m 2 g −1 ) and a pore volume (0.224 cm 3 g −1 ) compared with the natural material. Based on the central composite design, the effect of different parameters such as the biomass dose, initial dye concentration, contact time and temperature was optimized and the optimal removal of AB25 (99.61%) was achieved for AB25 concentration of 100 mg L −1 and an adsorbent dose of 0.8 g L −1 , at 45 °C after 120 min. The kinetic studies indicated that the pseudo-second-order model was appropriately applied for the adsorption kinetic of AB25 onto wild date stones activated carbon. The intraparticle diffusion model is not the only controlling step, and other mechanisms may be involved in the adsorption process. The Langmuir isotherm provided the best fit with a high correlation coefficient (R 2 ) of 0.993 and a maximum monolayer adsorption capacity of 181.59 mg g −1 .

Bentonite blended with bagasse ash as an adsorbent for reactive red 198 dyes

“…The maximum calculated adsorption efficiency was 93.2%, at 197 minutes contact time and just under 19 mg/L initial dye concentration. The interaction model results indicate that adsorption efficiency was higher with longer contact time because enough time is available for interaction between dye molecules and the adsorbent surface (Brahmi et al 2019). As can be seen, raising the adsorbent dose from 0.5 to 3 g/L increased dye removal efficiency, while the increase in initial dye concentration reduced efficiency.…”

“…The adsorbent dose increase enhanced the availability of free active sites on the adsorbent surface (Saha et al 2012;Davarnejad et al 2020). This may occur because of the reduced ratio of active sites to dye molecules, so that there was insufficient vacant space on the adsorbent surface (Brahmi et al 2019).…”

Low-cost activated carbon from the husk of Pará nuts for dye removal from aqueous solution: kinetic and thermodynamic mechanism study

“…Intraparticle diffusion is the only controlling step of the process if the graph of qt versus t 1/2 passes through the origin, that is, C equals 0. If this does not occur, the mechanism is accompanied by other steps [18,39,51]. From Figure 6(D) it can be observed that the RO-16 adsorption process occurs in two consecutive steps: the first corresponds to the rapid adsorption on the external surface, that is, the dye molecules are transferred to the easily accessible active sites of the adsorbent and the second denotes the intraparticle diffusion where the adsorption stage is gradual and slow [18,37,52,53].…”

Optimization of p-Nitroaniline Adsorption from Aqueous Medium by TiO2-Flamboyant Seeds Activated Carbon Composite

“…This technique wastes time, requires a lot of experiments and uses large amounts of chemicals. These disadvantages can be overcome by optimizing the variables simultaneously using a statistical experimental design, such as the Box-Behnken design (BBD) in response surface methodology (RSM) [15,16] .…”