Effective Adsorption and Photocatalytic Degradation of 2,4-D Using Silver Plasmonic Nanoparticles Modified Titania/Activated Carbon Based on Date Palm Fiber

In the current paper, the degradation of 2,4-D as a pollutant herbicide is compared to its batch adsorption. Four different solid samples were prepared as KOH-activated carbon based on date palm fiber (AC), titania nanoparticles (T), titania/activated carbon composite (TAC), and silver plasmonic nanoparticles modified titania/activated carbon composite (Ag@TAC). The fabricated solid materials were full characterized by using different physicochemical tools as TGA, nitrogen adsorption/desorption, SEM, TEM, DRS, ATR-FTIR, and pH_PZC. Ag@TAC showed lower energy band gap (2.73 eV), relatively higher surface area (422 m²/g), pH_PZC = 6.09, and the occurrence of many surfaces’ chemical functional groups. Adsorption and photocatalytic degradation were applied at different applications conditions comprising solid dosage, pH, time, initial 2,4-D concentration, and application temperature. Adsorption studies prove that Ag@TAC showed the maximum adsorption capacity (329.38 mg/g) after 180 min of shaking time at 25 °C. The adsorption process by all the solid adsorbents fits well Langmuir, Temkin, PSO, and Elovich nonlinear models. Photocatalytic degradation endorsed that destruction of 2,4-D fits well Arrhenius and Eyring–Polanyi models. It is observed that the presence of plasmonic element (Ag) onto the surface of Ag@TAC enhances its catalytic activity by the production of hot electrons enhancing light absorption and the excessive making of active free radicals. In the presence of Ag@TAC, 100% of 2,4-D (150 mL of 15 mg/L) was completely degraded at 40 °C. Catalyst reusability verifies that after 7 cycles of applications it is accompanied by only 8% decrease in its efficiency.