Enhancing Methylene Blue Removal: Impact of Chemical and Physical Activation on Cocoa Pod Husk-Derived Biochar

Synthetic dyes in industrial wastewater pose serious environmental and health risks; therefore, advanced and sustainable treatment technologies are essential for effective wastewater management. The ability and performance of biochar derived from cocoa pod husk waste for removing methylene blue dye from aqueous solutions were studied. Microwave-assisted activation was employed to enhance the surface characteristics of biochar after activation with a low-concentration nitric acid solution. The optimization studies were evaluated using a batch method with various parameters, including pH, concentration, and contact time. The physicochemical properties of the adsorbent were characterized using point of zero charge (pHpzc), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy–Energy Dispersive X-ray (SEM-EDX), and Brunauer–Emmett–Teller (BET) techniques. A maximum adsorption capacity of ۱۷۸.۳۹ mg g-۱ was achieved at pH ۹, a concentration of ۱,۴۰۰ mg L-۱, and a contact time of ۴۵ minutes. The optimum pH value was consistent with the pHpzc value (above pH ۷.۵), which is rich in OH- ions, making it favorable for the adsorption of methylene blue dye cations. FTIR, SEM-EDX, and BET analyses revealed that the adsorption mechanism involved electrostatic interactions, cation exchange, and pore filling. The results indicate that cocoa pod husk-based biochar has good potential as an effective and low-cost adsorbent for removing methylene blue dye from wastewater, as it is abundantly available.

کلیدواژه ها:

Adsorption ، Biochar ، Cocoa pod husk ، Methylene blue ، Wastewater