Optimization of Methylene Blue Removal from Aqueous Media by Photocatalysis and Adsorption Processes Using Coconut Biomass-Based Composite Photocatalysts

Biocomposite Based on Polyhydroxybutyrate and Cellulose Acetate for the Adsorption of Methylene Blue

“…The initial pH of the solutions is a crucial factor in the adsorption capacity because it affects the ionization of the adsorbate, the dissociation of the functional groups on the active sites of the adsorbent, and its surface charge. When the pH of the solution is higher than pHpzc, the electrostatic forces increase, especially when the dye molecules are negatively charged and the adsorbent surface [51,52].…”

“…The above is due to the deprotonation of the active sites of the adsorbent, which favors the electrostatic attraction between the dye positively charged and the adsorbent negatively charged. However, in cases where efficiency decreases with increasing pH, it is attributed to hydrolysis of the adsorbent, which generates positively charged active sites [52,58].…”

“…Figure 10a shows that at an initial concentration of 5 ppm and adsorbent doses of 10, 20, and 30 mg, the adsorption efficiency of the CCM remains constant at a maximum of 100%. The above is due to the low concentration of the contaminant, which facilitates mass transfer and increases the adsorption efficiency, regardless of the adsorbent dose [52,59]. However, at a concentration of 40 ppm, the adsorbent dosage follows a gradually increasing pattern, reaching a maximum and then decreasing due to possible aggregation of adsorbent particles, reducing the effective surface area [61].…”