Assessing the mercury removal efficiency of natural adsorbents from wastewater

Organic waste materials viz., coir pith, rice husk, and water hyacinth were studied in the batch experiments to evaluate their potential for mercury removal from wastewater. Five pH (4,5,6,7,8) and five different contact times (1,2,4,6,8 hours) were studied with a constant mercury concentration of 0.1 ppm. SEM (Scanning electron microscopy-energy dispersive spectroscopy) and FTIR (Fourier transform infrared spectroscopy) were used for characterizing the biochars i.e., rice husk biochar (RHBC), coir pith biochar (CPBC) and water hyacinth biochar (WHBC), used for the experiment before and after adsorption studies. Adsorption capacities of each different biochar used for the experiment varied due to their wide range of surface area as well as different shift patterns in the FTIR. Based on the experimental results, among the three adsorbents used for mercury removal from wastewater, coirpith biochar (CPBC) has a maximum removal efficiency of 46.2% followed by rice husk biochar (RHBC–44.8%) and water hyacinth biochar (45.6%) with 6 hours of contact time