高炉水渣负载硫化纳米零价铁对水中土霉素的去除

Removal of Oxytetracycline from Water Using Blast Furnace Slag Loaded Sulfide Nanoscale Zero-valent Iron

利用液相还原法制备了一种高炉水渣负载硫化纳米零价铁(S-nZVI@BFS)材料,并将其用于废水中土霉素(OTC)的去除.本研究通过SEM、XRD和BET等手段分析了S-nZVI@BFS的表面结构特征,探讨了反应时间、OTC初始浓度、溶液初始pH和共存六价铬[Cr(Ⅵ)]等对其去除OTC的影响.结果表明,S-nZVI@BFS表面均匀负载了硫化纳米零价铁(S-nZVI),S-nZVI@BFS的比表面积和孔容分别为141.986 m^(2)·g^(-1)和0.388 cm^(3)·g^(-1).S-nZVI@BFS表面活性点位的利用率随OTC初始浓度的增加而显著提高,当OTC初始浓度从10 mg·L^(-1)增加到100 mg·L^(-1)时,S-nZVI@BFS对OTC的去除量从20.12 mg·g^(-1)增加到202.74 mg·g^(-1).S-nZVI的等电点为7.2,较低pH有利于S-nZVI@BFS对OTC的去除,当pH从3增加至11时,S-nZVI@BFS对OTC的去除量从99.78 mg·g^(-1)降低至41.12 mg·g^(-1),降解机制由Fendon氧化和络合沉淀作用向静电吸附转移.Cr(Ⅵ)与OTC在S-nZVI@BFS去除体系中存在明显竞争关系,Cr(Ⅵ)对OTC的去除存在抑制作用,且浓度越高,抑制作用越显著.

Blast furnace slag loaded with sulfide nano zero valent iron(S-nZVI@BFS)was applied to remove oxytetracycline(OTC)from water.S-nZVI@BFS was synthesized via liquid reduction and characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and Brunauer,Emmett and Teller(BET)theory.The effect of reaction time,initial concentration of OTC,initial pH,and coexisting hexavalent chromium[Cr(Ⅵ)]were investigated.The results show that Fe and S were successfully immobilized on the surface of S-nZVI@BFS,the specific surface area and pore volume of which increased to 141.986 m^(2)·g^(-1)and 0.388 cm^(3)·g^(-1),respectively,following the loading of nZVI and sulfurization.The utilization rate of the surface active sites of S-nZVI@BFS was improved with an increase of the initial concentration of OTC;the removal rate increased from 20.12 mg·g^(-1)to 202.74 mg·g^(-1)when the initial concentration of OTC was increased from 10 mg·L^(-1)to 100 mg·L^(-1).The removal rate decreased with pH,declining from99.78 mg·g^(-1)to 41.12 mg·g^(-1)when pH was increased from 3 to 11 due to the switch from Fendon oxidation to electrostatic adsorption.There was notable competition between OTC and Cr(Ⅵ)meaning that Cr(Ⅵ)can inhibit the removal of OTC,which is dose dependent.