Studies On Activated Carbon Adsorption/Microwave Regeneration Of Chloramphenicol During Drinking Water Treatment

With the rapid development of economy and the improvement of people's life quality in China, the safety of drinking water has aroused more and more public attentions. At present, water pollution by antibiotics is especially prominent, which becomes one of the important factors affecting the safety of drinking water. Antibiotics used by human beings and animals are usually emitted directly without metabolism, causing exceeding of antibiotics level in water, which brings hazardous effects on environment and human health. In the present study, chloramphenicol (CAP) was chosen as the target pollutant, and activated carbon was selected to adsorb CAP in drinking water. Microwave (MW) technology was used to regeneration of activated carbon (AC). Regenerated AC were reused to adsorb CAP, and the changes in their properties were studied. Besides, effects of humic acid (HA) in water on the adsorption and regeneration of AC was observed.The main conclusions are as follows:(1) Granular activated carbon was chosen to be the suitable sorbent. The adsorption balance time of activated carbon was 1-2 h. Its adsorption capacity was 24 mg/g when the initial concentration of CAP was 1000 mg/L. The regenerated activated carbon has a stable performance and the mass-loss was minute.(2) The results of regeneration and recycling performance of activated carbon revealed that the optimal process conditions were: MW power 450 W; MW treatment time 4 min; humidity of activated carbon 30%; temperature under 600℃.(3) After 4 min MW regeneration treatment, the regeneration ratio of saturated activated carbon was above 85% (until a regeneration of 5 circles). The highest regeneration ratio was presented after 5 circles of MW regeneration. The ratio began to decrease obviously after 6 circles of MW regeneration. The effect of CAP removal was still above 75% after regeneration for 6 times. Generally, more circles of MW regeneration lead to higher loss ratio of activated carbon, but the loss was much lower than which caused by heat regeneration treatment. MW radiation can change the structure of activated carbon, and increase its BET surface area, pore volume and pore area.(4) It is revealed that humic acid would affect the CAP adsorption of activated carbon to some extent. The CAP adsorption in HA aqueous solution is somewhat less than that in water without HA. If the water contains HA, adsorption capability of activated carbon will rise along with the increase of regeneration times, though lower than the value calculated in no HA case.