Preparation Of Ti-Zr Binary Oxide For Efficient Arsenic Removal:Performance And Adsorption Mechanism

Arsenic（As）pollution is one of the problems that need to be solved urgently in the safety of drinking water quality in China.As a heavy metal,arsenic has the characteristics of high toxicity and carcinogenicity.Arsenic is usually present in the form of As（Ⅲ）and As（Ⅴ）in water bodies,and As（Ⅲ）is more toxic than As（Ⅴ）,and the former is more difficult to remove than the latter.Adsorption method has become one of the most promising water treatment technologies with the advantages of simple operation,cost-effective,no sludge generation and multiple recycling of adsorbed materials.Adsorbent is the core of the adsorption method,one-component adsorbent is a widely used adsorption arsenic removal material,but there is a problem of low efficiency of synchronous removal of As（Ⅲ）and As（Ⅴ）,and the problem of solid-liquid separation of powdered adsorption materials is difficult,which limits the application of this technology in the field of arsenic removal in water treatment.In this study,this study broke through the bottleneck problem faced by the one-component adsorbent arsenic removal,and used the synergy of titanium and zirconium oxide components to synthesize a new Ti-Zr binary oxide powder material,and selected chitosan as the carrier to prepare granular Ti-Zr/chitosan adsorption materials;the adsorption efficiency and adsorption mechanism of the two adsorbent materials on As（Ⅲ）and As（Ⅴ）were systematically studied,and the application potential of the adsorbent materials in actual arsenic-containing water bodies was evaluated.The following experimental results have been obtained through research:（1）A Ti-Zr metal binary oxide material was prepared by chemical precipitation method,which was formed by the aggregation of uneven nanoscale particles,which was an amorphous mesoporous material and contained abundant surface metal hydroxyl groups.（2）The Ti-Zr binary oxide adsorbent can quickly and efficiently remove As（Ⅲ）and As（Ⅴ）in water,the adsorption capacity of As（Ⅲ）and As（Ⅴ）is very high,the highest adsorption capacity is 118 mg/g and 120 mg/g,the Ti-Zr binary oxide can be applied in a wide p H range,and the material is almost no component metal ion dissolution shows the stability of the material,common anions on the Ti-Zr binary oxide removal of inorganic arsenic has no obvious impact,effective regeneration and reuse.（3）The removal mechanism of As（Ⅲ）and As（Ⅴ）is mainly based on the synergistic effect of each matrix component of the material to effectively improve the adsorption performance of the Ti-Zr binary oxide.In addition,As（Ⅲ）and As（Ⅴ）interact with the hydroxyl groups on the surface of the adsorbent for ligand exchange,forming a stable internal coordination surface complex at the solid/liquid interface.（4）A granular Ti-Zr/chitosan adsorption material with efficient arsenic removal was constructed by continuous two-step technique.The adsorption material can effectively remove the maximum adsorption of As（Ⅲ）and As（Ⅴ）in the solution of 66 mg/g and 44mg/g,respectively,the applicable p H range of the granular material is wider,the coexistence of anions has no particularly large effect on adsorption,in the dynamic continuous flow experiment,when the initial concentration of As is about 100 μg/L,the granular TiZr/chitosan material can safely handle 1200 column volumes of As（Ⅲ）and 1130 column volumes of As（Ⅴ）,and the Ti-Zr/chitosan adsorption material can be effectively recycled,indicating that the granular Ti-Zr/chitosan material is a feasible and potential arsenic removal adsorption material.