Resource utilization of secondary pyrolysis oil-based drilling cuttings ash for removing Cr (VI) contaminants: Adsorption properties, kinetics and mechanism

Secondary pyrolysis oil-based drilling cuttings ash (OBCDA-sp) was employed as a new absorbing material to remove Cr (VI) in wastewater. Varying factors, including pH value, dosage of OBCDA-sp, reaction time and original Cr (VI) contents were studied to investigate the Cr (VI) removal efficiency. Elovich and Pseudo-secondorder models were fitted well with the adsorption kinetics process. In addition, the Langmuir model was well employed to fit Cr (VI) adsorption isotherm on OBCDA-sp. The calculated Cr (VI) theoretic adsorption quantity of OBCDA-sp was 48 mg/g. XPS, SEM-EDS, FTIR and XRD were used to characterize the physicochemical properties of OBDCA-sp. The result shows that the complex process of the Cr (VI) removal involves physical and chemical adsorption, and co-precipitation and reduction. Ba, Fe, S and P element onto OBCDA-sp surface have exerted significant role in Cr (VI) removal.