Adsorption of diesel oil onto natural mud shale: from experimental investigation to thermodynamic and kinetic modelling

Abstract

ABSTRACT A natural mud shale (MS) from Yichang Area, China was for the first time experimentally examined for its potential application to oily effluents treatment. The mineralogical compositions, surface structures and pore size distribution of the prepared MS particles were characterised using various advanced analytical technologies, respectively. The performance of the MS particles during the model diesel oil wastewater treatment was examined based on the designed adsorption experiments. Isothermal and kinetic features were investigated according to a variety of adsorption models. The results showed that some pores, cavities and fractures were distributed on the surface of MS particles. The efficiency of MS particles for removing diesel oil from the model oily effluent was associated closely with experimental conditions including the mass of MS particles, initial diesel levels, residence time and pH values. Equilibrium adsorption isotherms conformed to Langmuir model, indicating that the adsorption of diesel oil onto MS particles tended to monolayer adsorption. Kinetics of adsorption of diesel oil on MS complied with the pseudo-second-order model. This suggested that the whole oil removal rate was mainly controlled by chemisorption. Results of our study indicates potential utilisation of unmodified MS particles as an abundant and inexpensive adsorbent for low-concentration diesel oil wastewater.