Activated carbon derived from hawthorn kernel waste for rapid adsorption of fungicides

Abstract

The Hawthorn kernel activated carbon (HKAC), acquired from food waste (hawthorn kernel) by a two-step method including carbonization operation and thermally activating potassium hydroxide process, was prepared. Morphological integrity and crystalline state of the HKAC were characterized by scanning electron microscopye and X-ray diffraction. Structural feature of the HKAC was investigated by the Brunauer–Emmett–Teller method, Fourier transform infrared spectroscopy, Raman spectroscopy together with zeta potential. The HKAC contained a specific surface area of 1269.92 m2/g and pore volume of 0.67 cm3/g. The optimized adsorption conditions were to use HKAC with a carbonization temperature of 550 °C were at a concentration of 0.6 g/L for adsorption in a solution with a temperature of 60 °C and a pH of 6.0. The kinetic studies proved that the pseudo-second-order model fitted experimental data best with the high correlation coefficient values of 0.9968–0.9993. Besides, experimental results revealed that Langmuir isotherm model gave the best fit among the studied isotherm models with a maximum adsorption capacity of 100.00 mg/g, the experimental results revealed that the Langmuir isotherm model was more consistent than the Freundlich isotherm model with a maximum adsorption capacity of 100.00 mg/g, and the adsorption of fungicides onto HKAC was endothermic spontaneous process. Moreover, it was confirmed in tap water and Dendrobium that the removal rate of the six fungicides remained at 86.3% to 96.2% after five cycles of HKAC even in a complex matrix. The aforesaid satisfying experimental results proved that HKAC was a cost-effective and green adsorbent for removing water and plant contaminated by fungicides.