Preparation Of EDTA/chitosan Modified Biochar Composites And Study On Removal Of CIP From Wate

The usage of antibiotics continues to increase as medical technology advances.Antibiotic concentrations in the environment,such as in water bodies,have increased due to the difficulty of properly metabolizing antibiotics in people and organic plant and animal life.Antibiotic quinolone ciprofloxacin(CIP)is frequently found in river basins and coastal locations.One of the most important research questions at the moment is how to swiftly and effectively remove antibiotics from water.In this study,chitosan-modified biochar(CS-FBC)was synthesized from iron by biochar for adsorption of CIP in water,and CS-FBC composite adsorbent materials were analyzed by various characterization methods such as XRD,XPS,BET,FT-IR,SEM and Zeta potential.The effects of pH,contact time,dosage,initial concentration of CIP and temperature on the adsorption process of CS-FBC were analyzed,and the reproducibility of the material was also studied.The maximum adsorption capacity for CIP was 76.72 mg/g at room temperature settings.The adsorption rate of CS-FBC material to CIP was the fastest within the first 30 min.The adsorption equilibrium state was obtained after 150 min.The adsorption process is a natural process of heat activation and entropy rise,according to adsorption thermodynamic research,which is consistent with the pseudo-secondary kinetic model and the Langmuir adsorption isotherm model.The adsorption capacity of the first 6 recycling experiments can be maintained above 70%,and the adsorption capacity of the 7th cycle can still be maintained at more than 65%.In order to further improve adsorption performance,ethylenediaminetetraacetic acid(EDTA)was introduced based on CS-FBC to prepare EDTA-CS-FBC composite adsorbent material.The successful introduction of EDTA increased the specific surface area,the pH working range widened,the functional groups increased,and the adsorption site increased.The maximum adsorption capacity for CIP was 103.7 mg/g,and EDTA-CS-FBC exhibited the fastest adsorption rate of CIP within 30 min at room temperature.It also reached the adsorption equilibrium condition in 180 min.According to both the Langmuir adsorption isotherm model and the pseudo-secondary kinetic model,the adsorption process is a normal process of heat activation and entropy rise.The adsorption capacity of EDTA-CS-FBC is still relatively high after 7 cycles of adsorption-desorption;the adsorption capacities of the first 6 cycles may be maintained at or above 85%,and the adsorption capacities of the seventh cycle can still be maintained at or above 80%.