Coal-derived humic acid for application in acid mine drainage (AMD) water treatment and electrochemical devices

In this research work, isolation of humic acid from coal of Northeastern region of India is reported. The study is also targeted for application of the coal-derived humic acid in acid mine drainage (AMD) water treatment and electrochemical devices. All the obtained results are compared with the standard humic acid and examined the formation of humic acid from the coal. The isolated coal-derived humic acid is found to be high degree of humifications and relatively stable up to about 200 degrees C. The FTIR study indicates the formation of metal-humic acid complexes. On treatment with acidic water (AMD), the coal-derived humic acid was found to have the ability to remove toxic metal such as (in order) Pb > Cu > Zn > Cd. In addition, the preliminary electrochemical properties of the isolated humic acid are also discussed in the paper. The specific capacitance of the isolated coal-derived humic acid via cyclic voltammetry and charge-discharge analysis is found to be 7 mF/g at scan rate 10 mV/s and 22 mF/g within the potential window 0.4 V, respectively. The charge-discharge cycles are stable for more than 1000 cycles within the potential window 0.4 V. This study will create a new pathway for the further research in this field.

Automated summary

This research work focuses on isolating humic acid from coal in the Northeastern region of India, and exploring its application in acid mine drainage water treatment and electrochemical devices. The isolated coal-derived humic acid exhibited high humification and stability, as well as the ability to remove toxic metals from acidic water. The preliminary electrochemical properties of the isolated humic acid were also discussed, showing promising specific capacitance and stability in charge-discharge cycles.