Quantachrome nova 1200

The textural properties (specific surface area, pore diameter and volume) were calculated through low-temperature nitrogen adsorption-desorption isotherms using a Quantachrome Nova 1200 adsorption analyser (Quantachrome Instruments, Boynton Beach, FL, USA). The Mt samples were degassed in vacuum for 24 h at 120 °C prior to nitrogen adsorption. The specific surface area was calculated according to the standard Brunauer–Emmett–Teller (BET). The pore diameter and volume were determined from desorption isotherms using the following calculation model: N₂ at 77 K on silica, cylindrical pore, non-linear density function theory (NLDFT) equilibrium model.

Activated carbon was prepared from olive stones by heat treatment of ground olive stones/KOH mixture at 275 °C for 45 min followed by heat treatment of the same mixture at 600 °C for 90 min under nitrogen atmosphere [27 ]. An olive stones/KOH weight ratio of 1:1 was used. The obtained activated carbon was washed well with distilled water to remove excess alkali, filtered and dried in an oven at 105 °C for 4 h. Nitrogen adsorption experiments were conducted to determine the specific surface area using Quantachrome Nova-1200 instrument (Quantachrome Instruments, Boynton Beach, FL, USA). The sample was out gassed overnight at 180 °C prior to adsorption measurements. The BET model was applied to fit the nitrogen adsorption isotherms and evaluate the specific surface area of the sample. Microscopic features were investigated using high-resolution scanning electron microscope (Zeiss Merlin FEG-SEM, Zeiss, Oberkochen, Germany). Zeta potential was measured using Zetasizer Nano-ZS90 (Malvern Instruments, Malvern Worcestershire, UK).