Removal of Copper (Cu~(2+)) from Water Using Novel Hybrid Adsorbents: Kinetics and Isotherms

摘要

The mercapto group (—SH group) has a high ability to adsorb heavy-metal ions, this unique characteristic reveals that the group has potential application in the removal of heavy-metal ions from wastewater. For such purpose, novel hybrid adsorbents containing—SH groups were prepared via sol—gel process. The existence of —SH groups in the prepared hybrid adsorbents was confirmed by Fourier transform infrared spectra. The thermal stability of these hybrid adsorbents was detected via thermogravimetric analysis and differential scanning calorimetry studies. The adsorption behaviors of Cu~(2+) ions on these adsorbents were examined, and the obtained adsorption data were modeled using conventional theoretical models. It is showed that the thermal degradation temperature of hybrid adsorbents can arrive at 350 °C. Adsorption experiments revealed that the optimal adsorption temperature was near 40 °C and the Langmuir constant Q_m can arrive at 0.396 mmol g~(-1) at pH 4. Meanwhile, it is found that their adsorptions for Cu~(2+) ions fitted well with the Lagergren first-order kinetic and Langmuir isotherm models. Moreover, testing results indicated that Cu adsorption on samples A to C was solely controlled by intraparticle diffusion. Desorption experiments indicated that these samples can be recovered using aqueous HNO3 solution as a desorbent. These results demonstrate that hybrid adsorbents containing —SH groups are promising in the separation and recovery of heavy-metal ions from wastewater for environmental application.