Utilizing Pyrolytic Char from Waste Drill Cuttings in Shale Gas Industry as a Potential Adsorbent for Heavy Metal Removal

The management of hazardous waste drilling cuttings waste (OBDC) from the shale gas industry is challenging. In this study, OBDC from a shale gas block was pyrolyzed at different temperatures such as 300, 400, 500, and 600 °C to generate activated carbon, which was used to adsorb Cu(II), Zn(II), Pb(II) and Cr (III) in aqueous solution. It was found that the adsorption capacity of OBDC char reached the highest at pyrolysis temperature of 500 °C for 30 min. The pseudo-second-order-kinetics and Langmuir model describe the heavy metal adsorption process well. According to Langmuir isotherm calculation, the maximum adsorption capacities of OBDC-500 for Cu(II), Zn(II), Pb(II) and Cr (III) at 500 ℃ are 83.2 mg/g, 38.29 mg/g, 143.95 mg/g and 104.1 mg/g, respectively. OBDC-500 has a simple and environmentally friendly preparation process and excellent adsorption performance. It has great potential for heavy metal removal in the aspect of water treatment.