In addition, the absorption peak
at 270nm can be observed, which might contain aromatic rings in
organic matter structure [34], indicating that coking wastewater
might contain phenolic compounds. Absorbing light in the visible
region (400–800 nm)means that compounds in coking wastewater
look colored. Fig. 5 reveals that there were aromatic chemicals in
raw coking wastewater, and the color of the coking wastewater
was visible. After adsorption, the absorption peak at 270nm was
not detected. In addition, the removal efficiency of color was 90%,
indicating that most of aromatic compounds might be removed
after adsorption.