Physicochemical and adsorptive characteristics of activated carbons from waste polyester textiles utilizing MgO...

Activated carbons with high specific surface areas were produced, utilizing waste polyester textiles as carbon precursor by magnesium oxide (MgO) template method. Magnesium chloride (MgCl₂), magnesium citrate (MgCi), and MgO were employed as MgO precursors to prepare activated carbons (AC-MgCl₂, AC-MgCi, and AC-MgO). Thermogravimetry-differential scanning calorimetry was conducted to investigate the pore-forming mechanism, and N₂ adsorption/desorption isotherms, XRD, SEM-EDS, TEM, FTIR and pH_pzc were achieved to analyze physicochemical characteristics of the samples. The specific surface areas of AC-MgCl₂ (1173 m²/g) and AC-MgCi (1336 m²/g) were much higher than that of AC-MgO (450 m²/g), and the pores sizes of which were micro-mesoporous, mesoporous, and macropores, respectively, due to the formation of MgO crystal with different sizes. All activated carbons had abundant acidic oxygen groups. In addition, batch adsorption experiments were carried out to investigate the adsorptive characteristics of the prepared activated carbons toward Cr(VI). The adsorption kinetics fitted well with the pseudo-second order, and the adsorptive capacity of AC-MgCl₂ (42.55 mg/g) was higher than those of AC-MgCi (40.93 mg/g) and AC-MgO (35.87 mg/g).