Aiming to treat pharmaceutical wastewater containing pollutants that are difficult to be biodegraded

and deal with the inhomogeneous temperature and big attrition rate during the microwave regeneration of activated carbon

this study adopted a method

using a mixture of activated carbon and expanded graphite as AC-EG adsorption materials

to adsorb and treat the wastewater of a pharmaceutical factory after biochemical treatment. Based on the component analysis of wastewater from a pharmaceutical company

the adsorption thermodynamics and dynamics mechanism of pollutants in pharmaceutical wastewater adsorbed by adsorption material was studied

and the effect of microwave regeneration was investigated. The results showed that the wastewater contained a variety of unbiodegradable pollutants like pyridine

amide

azole

pyrazine and so on. The removal rate of COD in wastewater reached 58.25% when adsorbent was a mixture of activated carbon and 15% expanded graphite. The adsorption process

which AC-EG with 15wt% expanded graphite adsorbed pollutants in pharmaceutical wastewater

is an exothermic physical adsorption which follows Freundlich model (ΔH=-16.918 kJ/mol)

and its entropy reduced(ΔS=-54 J/(mol·K)). Its kinetics model was relatively consistent with the second-order equation. A mixture of activated carbon and expanded graphite was heated and adsorbed microwave radiation more uniformly. With the increase of expanded graphite's doping amount

the adsorbent regeneration rate increased and the attrition rate declined.