| Our country is a big country in the use of antibiotics,and there is a phenomenon of abuse of antibiotics in some aspects.It is produced and used in large quantities in production and domestic water,exists in wastewater,and can infect bacteria through biofilms,disrupt biological networks and threaten human health.To eliminate antibiotics in water,researchers have developed a variety of remediation methods,including modern oxide oxidation,microbial methods,membrane therapy,and adsorption methods.Compared with other treatment methods,the adsorption method has the characteristics of low input performance,easy operation of some technologies in the actual process and no toxic substances.However,the production of many adsorbents requires a large amount of cost,and finding adsorbents that are cost-effective and can be widely used has become an important goal of contemporary researchers.Therefore,in this study,the agricultural waste cow dung in the farm was used as the raw material,and activated biochar was prepared by a series of means to further study the adsorption function of antibiotics..（1）In this paper,ciprofloxacin lactate is used as the representative pollutant,cow dung is used as raw material to obtain original biochar（BC）,and medium-strong acid and strong acid-activated biochar（30P-BC,30N-BC）are prepared by H3PO4and HNO3treatment.The effects of the three biochars on the adsorption time,adsorption kinetics and isotherms of ciprofloxacin lactate were compared,and the adsorption effect of phosphoric acid activated biochar was better,so as to further explore the effect of activation concentration on the adsorption effect of biochar.（2）The original biochar was activated with different concentrations of H3PO4,dried and then calcined at 900°C.Finally,three concentrations of phosphoric acid-activated biochar（10P-BC,30P-BC,and 50P-BC）were prepared.Taking BC as a control,combined with the study of XP-BC scanning electron microscope,X-ray diffraction analysis,Fourier transform infrared spectroscopy,organic element composition and isoelectric point,the results show that the higher the temperature,the better the carbonization degree of biochar.The higher it is,the more pores after activation,the enhanced hydrophobicity,and can be more favorable for adsorption.（3）The important factors influencing the selection of adsorption experiments include:adsorption time,amount of adsorbent added,initial concentration,solution p H,and solution salt ion concentration.The effects of these factors on the adsorption of ciprofloxacin lactate and enrofloxacin by BC and XP-BC were investigated.The results showed that the optimum addition amount of ciprofloxacin lactate for biochar adsorption was 0.4 g/L;the optimum addition amount for enrofloxacin adsorption was 0.32 g/L;the adsorption equilibrium time was 6 h;the optimal initial concentration was 20 mg/L;the original carbon was most suitable for adsorption under the condition of p H=7,and the phosphoric acid-activated biochar was most suitable for the adsorption under acidic conditions;the solution salt ions showed a slight inhibitory effect with the increase of the concentration.（4）The pseudo-first-order kinetics and pseudo-second-order kinetic models were used for fitting,and it was found that all biochars studied in this experiment were more in line with pseudo-second-order kinetics.The combined effect is better.The original biochar BC,phosphoric acid activated biochar 10P-BC,30P-BC and 50P-BC adsorption maximum adsorption capacity of ciprofloxacin lactate were calculated to be 15.20 mg/g,40.00 mg/g,55.25 mg/g and 22.32 mg/g,the maximum adsorption capacity of enrofloxacin by biochar was 12.64 mg/g,51.81 mg/g,63.69mg/g and 26.88 mg/g,respectively.（5）The activation biochar 30P-BC with the best adsorption effect was selected for the adsorption experiment of simulated wastewater,and the removal of ciprofloxacin lactate and enrofloxacin in the simulated wastewater was studied,and the results showed that the removal effect of activated biochar on antibiotics was better within 6 h,more than 90%,which provided basic data and basis for the application of 30P-BC in actual water bodies.（6）The main mechanisms of antibiotic loading on biochar are hydrogen bonding,π-πelectron donor-acceptor interactions,pore filling and electrostatic interactions.To sum up,the raw material used in this study is cow dung,which is agricultural waste and has a wide range of sources.The activation method is simple and easy to operate,and has the characteristics of high speed and high efficiency.It also has important research significance for the utilization of resources to turn waste into treasure.There is an application prospect of being put into use in batches. |
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