Study On The Preparation Of Alginate Composite Material And Its Adsorption Performance For Tetracycline

In recent years,the problem of environmental protection has been paid more and more attention.In the process of production and development of biomedicine industry and animal husbandry,antibiotics wastewater will be produced.Untreated wastewater and excessive discharge will directly lead to soil and water pollution.Tetracycline(TC)will destroy the ecological balance in water environment and even cause the emergence of drug-resistant viruses and bacteria.At present,the methods for removing antibiotics in water mainly include advanced oxidation method,electrochemical method,membrane separation method,biodegradation method and adsorption method.The adsorption method has the advantages of simple operation,high adsorption efficiency and relatively low cost,and is widely used in water pollution treatment.Therefore,the preparation of high-adsorption rate,low-cost and environmentally friendly adsorbents has become a research hotspot.As a natural polysaccharide,sodium alginate(SA)has stable moldability,good biocompatibility,and non-toxic and harmless properties.It can be used as a stable matrix for the preparation of adsorbents for crosslinking reactions.Activated carbon(AC)has stable physical and chemical properties,well-developed pore structure and huge specific surface area.As an adsorbent for sewage treatment,it can quickly and effectively remove a variety of organic and inorganic pollutants.Humic acid(HA)is a type of organic acid with abundant reserves.It is currently mainly used in agriculture,forestry,animal husbandry and medicine and health.However,it contains a variety of functional groups such as carboxyl groups and hydroxyl groups that can undergo a certain complex reaction with pollutants in sewage,Electrostatic attraction or ion exchange,so it has certain environmental protection application value.In this paper,wet spinning technology was used to prepare CA/AC/HA porous fiber aerogel by adding AC and HA powder into SA matrix and fixing them in the matrix by SA cross-linking reaction.Calcium alginate porous aerogel was prepared by using the principle of iron powder and acid reaction to release gas.Scanning electron microscopy(SEM)was used to characterize the morphology of CAH porous fibers and calcium alginate porous fibers,and the specific surface area analysis(BET)was used to analyze the pore structure of CAH porous fibers.Using two adsorbents,systematic experiments were carried out to remove TC in aqueous solution,and the effects of initial pH,temperature,contact time and other factors on the adsorption capacity were analyzed.Langmuir and Freundlich models were used to fit the isothermal adsorption data after TC adsorption equilibrium.The results show that the adsorption of TC by CAH porous fibers can be better described by Langmuir model,the maximum theoretical adsorption capacity was 333.33 mg/g,and the adsorption of TC by sodium alginate porous fibers is more in line with the Freundlich model.The kinetic data were evaluated by Pseudo-first-order model,Pseudo-second-order model and Intra-particle diffusion model.Thermodynamic studies have confirmed that the adsorption of TC on CAH porous fiber and calcium alginate porous fiber is a spontaneous exothermic process and a spontaneous endothermic process,respectively.