Research On The Modified Materials Of Biochars And The Adsorption Mechanism Of Doxycycline Hydrochloride In Watewater

Antibiotics are widely used in medical treatment,aquaculture,and animal husbandry due to their low price and broad-spectrum antimicrobial properties.However,most of antibiotics are weakly absorbed by the body and released into the environment via the urine and feces in the form of an original or metabolite,which cause the residue of antibiotics in environmental media such as water and soil,and therefore threat to environment,ecosystem and human health.Biochar is a commonly used adsorbent,but it is still faced with further improvement of the remove the antibiotic substances in water.In this paper,doxycycline hydrochloride is used as the target pollutant,peanut shell biomass is used as raw material of biochar（BC）,Cu（NO₃）₂.3H₂O is made into organic composite adsorbent to remove the doxycycline hydrochloride of the water.Then,a series of adsorption experiments such as pH,adsorption kinetics,isothermal,thermodynamics,and ionic strength are analyzed,which provide relevant theoretical references and data support for solving the problem of antibiotic environment.The Cu-BC has exhibited excellent sorption efficiency about 93.22%of doxycycline hydrochloride from aqueous solution,which is double higher than that of the unmodified biochar.The physical and chemical characteristics of the composite are analyzed by Scanning electron microscopy（SEM）,Fourier infrared spectrum（FTIR）,X-Ray Diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）and surface Zeta potential,The results shows that the main removal mechanism of doxycycline hydrochloride in Cu-BC composites is electrostatic attraction and complexation.In order to investigate the adsorption characteristic of Cu-BC,a series of adsorption experiments on doxycycline hydrochloride were performed by using Cu-BC composites in this paper,the kinetic model of doxycycline hydrochloride in Cu-BC composite material coincided with the pseudo-second-order kinetic model,and the isotherm was consistent with the Langmuir isothermal model.The optimum adsorption of the Cu-BC was observed at pH 8.0,experimental data conforned pseudo-second order equation and Langmuir isotherm model.The particle internal diffusion model analysis shows that the rate-limiting step of adsorbent and adsorbent surface is controlled by diffusion of membrane and diffusion of particles.Thermodynamic analysis indicated that the sorption process was spontaneous and endothermic.Furthermore,we investigated the effect of the existence of background ionic strength to DOX adsorption,which found the adsorption of DOX slightly facilitated by Na⁺,K⁺and inhibited by Ca²⁺,Mg²⁺,Mn²⁺.In conclusion,Cu-BC would provide a,realistic efficient and potential sorbent for removing DOX and other persistent organic pollutants from water in the further study In summary,the fabricated Cu-BC as cost-effective,high-performance and environmentally-friendly sorbent has excellent physical and chemical properties,which possessed promising potentials for removing DOX.