Preparation Of Cadmium Sulfide Sensitized Adsorbent And Its Adsorbent-Photocatalytic Degradation Toward Tetracycline

As one kind of most commonly used antibiotics,amounts of tetracycline series(TCs)are used by humans and veterinarians for the prevention and treatment of diseases.TCs residuals have been found in soil,water,and even food.It has been determined that TC has caused a certain degree of ecological crisis.Therefore,it is increasingly important to study green and sustainable technologies for treating TC wastewater.Among them,adsorption is an effective technology widely used,which has the advantages of simple operation,low cost,high efficiency,and no risk of high toxicity by-products.In addition,cadmium sulfide(CdS)can effectively utilize visible light because of its relatively narrow band gap(usually 2.40 eV).Therefore,in this thesis,the combination of adsorption and photocatalysis technology is used to remove the pollution of TCs.Firstly TCs were enrich on the sample surface by utilizing superior adsorption performance,and then the photocatalytic advantages of CdS was used to photocatalyticly degrade the TCs adsorbed on the sample surface.Therefore,The research contents are summurized as follows:(1)A series of covalent triazine-based framework(CTF)samples were prepared using a simple calcination method.Among them,the alkali-activated sample(ACTF)showed good adsorption properties toward TC.It can be attributed to the large specific surface area of the sample and the interaction of the specific groups on the surface with TC.The chemical state and surface groups of the samples were analyzed by means of XRD,FTIR,XPS.The samples' morphology and specific surface area were characterized by TEM,SEM and BET.At the same time,we also explored the factors affecting the adsorption performance(the initial concentration,pH of TC,the amount of adsorbent,and the ambient temperature).Finally,it has been found that ACTF showed great adsorption performance for TC regardless of environmental changes.In addition,in this thesis,the ACTF sample is compounded with CdS.Consequently,the adsorbent is successfully regenerated by the solar light decompositing TC over CdS.It is proposed that ACTF material is promising as a TC adsorbent.(2)CdS samples with different morphologies were synthesized by hydrothermal and solvothermal methods.The effects of their morphologies on the adsorption-photocatalytic properties were investigated by assessing the removal of TC contaminants from aqueous solutions.The different morphologies of CdS were loaded to ACTF and presented ultra-high specific surface area.The formation and chemical states of CdS and CdS-ACTF composite samples with different morphologies were analyzed by XRD and XPS.The morphology and microstructure of the synthesized samples were characterized by SEM and TEM.The adsorption performance of the CdS-ACTF adsorbent was evaluated using TC as the adsorbate.In summary,CdS-ACTF can be used as a promising photo-regenerated adsorbent for TC.(3)We have successfully prepared a series of BiOCl-CdS composites which were used to well remedy the TCs pollutions.BiOCl presented the 3D hierarchical microspheres and CdS nanoparticles were uniformly dispersed on its leave surface,confirming by the characteristic of XRD,XPS,TEM,SEM and EDS techniques.The BiOCl-CdS-3 exhibits highly adsorption-photocatalytic degradation toward the removal of TCs under solar light illuminating.Based on the UV diffuse spectrum,photoelectrochemical measurements,band potential calculation,LC-MS testing,the active species trapping,a novel adsorption-photocatalytic mechanism is proposed.In summary,the designed material could be used to remove antibiotic residue in environment,especially for TCs,driven by solar lighting.