A novel application of coal gangue as inexpensive adsorbents is considered in this study. The structural and surface properties of natural and modified gangue were studied via nitrdgen adsorption. Four types of samples were studied: natural, modified with H2NO3 and H2O2 and calcined at 250 degrees C and 600 degrees C. The specific surface area and porosity of the samples were determined using various methods. The raw material is mainly mesoporous with relatively small specific surface area. The chemical modification enlarged the total pore volume and the specific surface area. The calcination at 250 degrees C enlarged slightly the pore volume and lowered the specific surface area, but did not cause significant changes in the structural properties. The calcination at 600 degrees C resulted in a significant increase in pore volume and a decrease in specific surface area. These results suggest that the coal gangue studied here could be used as inexpensive adsorbent in industrial wastewater pretreatment. (C) 2016 Elsevier Ltd. All rights reserved.