Modification Of Fly Ash And Application In Tetracycline Treatment Throw Adsorption-photocatalysis Method

Tetracycline（TC）was discovered in 1940s and it is a broad-spectrum antibiotic that widely used in treating diseases.Due to the abuse of antibiotics in human medicine and animal husbandry,a large amount of antibiotic residues have been detected in the environment.Therefore,it is imperative to effectively remove tetracycline antibiotics in water environment.Up till now,studies showed that modified coal fly ash is an potential and cost-effective adsorbent for removing pollutants in wastewater.In addition,the Bismuth molybdate（Bi₂Mo O₆）has a relatively narrow band gap,non-toxicity and alternative synthesis methods.Consequently,this article combines adsorption and photocatalysis technology to efficiently remove residual tetracycline in the water environment.The research contents are summurized as follows:1.In this study,waste coal fly ash（CFA）was used as raw material to prepare the adsorbent（MFA）by a simple one-step ultrasonic alkaline hydrothermal method.MFA showed good performance in TC adsorption test,which were attributed to the large specific surface area of MFA.The chemical states and groups on the surface of modified samples were analyzed by XRD,FT-IR and XPS,the morphology was characterized by SEM,and the influence of different conditions on its adsorption was also tested.The experimental results show that it is of great significance to use MFA in the field of antibiotic wastewater treatment.2.Etching of coal fly ash with ammonium hydrofluoride by one-step method was used to prepare NFA.Compared with CFA,the SEM results show that the structure of NFA changes from microspheres to the aggregate with rough morphology.It has a certain response to light which was convinced by UV visible diffuse reflectance analysis.After the adsorption-photocatalytic degradation test of TC,it is found that the modified samples have good adsorption-photocatalytic degradation performance.The modified samples were analyzed by XRD,FT-IR and XPS.BET analysis showed that the specific surface area of the samples was well improved.The influence of different conditions on the adsorption and degradation of TC was also studied,and has tested its stability.The modified samples can remove tetracycline residues in water environment by adsorption-photocatalytic degradation,which indicates that coal fly ash has a broad application prospect in photocatalytic degradation of pollutants.3.In order to further explore the possibility of using CFA to develop the photocatalyst,Bi₂Mo O₆-CFA was developed by loading Bi₂Mo O₆.Loading the flake Bi₂Mo O₆ onto CFA microspheres by hydrothermal method,the catalyst has high removal efficiency for TC.The removal of the tetracycline from water was achieved by using the adsorption performance of CFA and the photocatalytic performance of Bi₂Mo O₆.At the same time,the effects of different conditions on TC degradation were also studied.Furthermore,the mechanism of photocatalytic reaction was proposed by using capture experiments and UV visible diffuse reflectance analysis.